Avocado
a. Avocado (Persea americana Mill.), a traditional crop of
Central American and the Caribbean, was introduced to Hawaii by Don Marin,
Kamehameha I's horticulturist, in the early 19th century. The first major
introduction of seedling materials was in Lahaina in 1853. As the possibility
of annexation of Hawaii to the US increased so did speculation about new
crops to diversify Hawaii. By 1901, the Hawaii Agricultural Experiments
Station, forerunner of today's College of Tropical Agriculture and Human
Resources (CTAHR), began research on new propagation, cultivar development,
and postharvest handling to permit shipment to the West Coast.
b. Three races are recognized :
Mexican
(M) - Anise-scented leaves, small fruits with thin, smooth skin.
Guatemalan
(G) - Fruiting occurs from fall to spring. Skin is thick, hard, and often
pebbled. Seeds usually fit tightly in cavity.
West
Indian (WI) - Skin tends to be variable in thickness and color. Seeds
often are loose in the cavity.
c. Cultivars can be placed into two groups according to the time
and sequence of opening and closing of the flower:
Type
A - flowers open in the morning and the pistils are receptive. They reopen
in afternoon of the second day to discharge the pollen.
Type
B - flowers open in the afternoon and the pistils are receptive. They
reopen in the morning of the second day to discharge the pollen.
Research
in Florida and Australia has demonstrated that under conditions of moderate
day temperatures (77F) and cool nights (68F) there is significant overlap
in flower opening to insure adequate self-pollination. Furthermore, the
presence of seedlings and wide range of cultivars in most avocado areas
in the State makes poor pollination resulting from lack of A and B type
cultivars planted in the orchard unlikely.
d. The perfect cultivar, at least in terms of fruit characteristics,
depends on the market.
 Honolulu consumers
prefer:
-
medium sized (usually based on quantity needed for meal),
-
pear-shaped (but preference is not strong),
-
green skin color,
-
"thin"
skinned (actually, medium as truly thin skinned cultivars are not
available) to facilitate peeling.
Source: F.S. Scott and
J.S. Sisson, 1986, Characteristics of consumer demand for avocados in Honolulu,
HITAHR Research Series 044. This information is supplemented by surveys
conducted by the Hawaii Avocado Association in February and March 1988 supported
in part by DOA's 'Island Fresh' program.
Average
mainland consumers prefer (75% of the crop is consumed in western and
southwestern states):
- Hass
- small sized (5 to 12 oz),
- black skin color
- medium skinned
Source: Anon. 1987,
Only Hass gets California Avocado Society recommendation, Cal. Grower, 12
(January):19-20. R. Peterson, 1988, A plea for an adequate introduction
program for California's avocados, Cal. Grower 12 (February):51-59. This
is supported by noting that other standard California cultivars collectively
known as 'green-skins', Bacon, Fuerte, Reed, and Zutano, return less than
half the grower's price of Hass ($0.31/lb) when averaged over the past six
years. However, the strong demand from Hawaii products may override the
preference for Hass in favor of the green-skin 'Sharwil'.
Hawaii institutions
(restaurants and hotels) prefer anything which eases preparation to reduce
labor costs (perhaps, medium to large size, medium skinned).
Source: discussions
in the Hawaii Food Processing Industry Analysis No.1, March 11, 1988.
e. The "ideal" avocado fruit proposed in the last industry analysis
(May 1985) has the following characteristics:
-
size between 12-16 oz.
-
pear shaped.
-
green skinned of medium thickness.
-
small seeded (70% or more edible portion).
-
free of fiber.
-
good postharvest life (e.g., 2 weeks).
-
good flavor (e.g., nutty).
'Sharwil' comes close
to meeting those criteria in terms fruit characteristics.
f. Traditionally, most avocados produced in Hawaii have been seedlings
or cultivars of local origin. The development and introduction of high quality
cultivars (vegetatively propagated to insure each plant is true to type)
is a relatively recent phenomenon.
Today, 'Sharwil'
is the most widely planted cultivar in the State. It originated as a volunteer
seedling on a farm in Redlands, Queensland, Australia in 1951. Scions were
sent from Australia to Hawaii in 1966 by Dr. W. B. Storey, formerly at CTAHR,
to Dr. R.A. Hamilton. It was grafted at the Poamoho Station on Oahu and
tested later at the Kona Station. Station employees informally released
it to other growers after noting its qualities at the Station. Although
'Sharwil' has been widely accepted in Hawaii, it is marginal in parts of
Australia and California.
g. Selected Local Cultivars and Their Characteristics
| Cultivar |
Maturity (months
vary location and elevation) |
Size (oz) |
Oil (%) |
Flower type |
| Sharwil |
Dec-May |
8-20 |
20-24 |
B |
|
Best cultivar currently for local and export use. Mexican X Guatemalan,
green skin color. Yield and maturity are variable by location
and year.
|
| Greengold |
Feb-June |
8-20 |
med |
A |
| CTAHR seedling selection of 'Sharwil', but has longer season and
appears to have higher yield potential. Good flavor. Thick gritty,
green skin is sometimes difficult to peel resulting in stone cells
in flesh near seed and skin. |
| Murashige |
Jun-Aug |
24-32 |
20 |
B |
| Large fruit, green skin. Stem pulls from fruit easily, needs to
be cut at harvest. Good yield. |
| Ohata |
May-Jul |
24-32 |
13.5 |
A |
| Large, purple to black skin, thin skinned Guatemalan, easy to
peel, low yield. |
| Semil-34 |
Oct-Feb |
20-24 |
12 |
A |
MxWI).
Mexican X West Indian, CTAHR introduction from Puerto Rico. Green
skin, mild flavor, yields well at low elevations outside Kona. |
| Rll Tl4 |
Jul-Sep |
12-16 |
med |
B |
| Unnamed CTAHR seedling selection from Murashige, green skin. Under
test in Kona. |
| Malama ki 2-1 |
Sep-Nov |
20-24 |
high |
- |
| Purple skin, sometimes called purple Kahaluu, average yield. Under
test Kona. |
| Hayes |
Mar-May |
8-12 |
15-30 |
A |
| Seedling of McDonald x Hass, purple to black skin. |
| Fibrous with strong nutty flavor. Tough, gritty skin, with curved
neck. Susceptible to post-harvest diseases. |
| Ota |
Aug-Dec |
20 |
21.0 |
- |
| West Indian, very high oil, poor quality, tendency to be pasty
and dry when ripe. Seeds frequently loose in cavity which could
cause internal bruising. |
h. For commercial plantings CTAHR scientists recommend the following
based estimated productivity, ease of peeling, appearance, flesh texture
and color, seed size, and flavor:
Cultivar
Season
__________________________________
Greengold
winter and spring
Sharwil
winter and spring
Murashige
spring and summer
__________________________________
i. For commercial growers in Kona HAA recommends a mixed planting
of 50-75% 'Sharwil' and the remainder in cultivars under test on farms in
Kona. HAA can assist in obtaining scions for grafting.
j. CTAHR feels growers' results from on-farm tests of three
CTAHR selections Malama Ki 2-1 (purple Kahaluu seedling), R11T14 (late maturing
seedling of Murashige), and Greengold (prolific seedling of 'Sharwil') are
encouraging. HAA feels that R11T14 is too similar to Murashige, that San
Miguel and Semil 34 are not acceptable in Kona.
k. The major effort to develop summer (June-September) cultivars
has not advanced rapidly due to lack of lines identified as sufficiently
high yielding to warrant on-farm testing. Of the 600 seedlings planted at
CTAHR stations, one Guatemalan has been selected for advanced testing. Basalua,
#5 Criolla, Azul, Veracruz #48, Josefina are promising introductions with
fruit size 10-16 oz. They ripen from July to September at the Poamoho Station
(on Oahu where Sharwil was first tested).
As promising materials
are identified from its sites at Malama Ki, Poamoho, and Kona, CTAHR will
seek grower cooperators. Bud wood of CTAHR selections and introductions--R11T14,
Malama ki 2-1, and Greengold-- were distributed to HAA members in June 1988.
A total of 47 scion pieces were grafted by 6 growers with the understanding
that 5 scions pieces could be requested by HAA from each tree for future
distributions. Small quantities of the Australian cultivar Shepherd and
new Mexican selections will be available from CTAHR for testing by interested
industry cooperators through HAA in the future.
l. Outstanding cultivars from other avocado areas such as
the world famous Hass when grown in Hawaii do not produce very high quality
fruits. New outstanding cultivars from California, Florida, or Australia
are unlikely to produce comparable commercial yields and quality in Hawaii
based on previous experience, though these cultivars should be tested.
Cultural Practices
a. Information on avocado growing for new growers is available
in "Avocado" (HC-004, 1997). Text of Avocado Industry Analysis No. 3 (1989)
was released as the comprehensive production bulletin (IA-Avocado-003).
The former comprehensive bulletin "Producing Avocado in Hawaii" (UH-CES,
CIR. 382) (Rev. 1978.) is out-of-print.
b. Grafted trees can be purchased from nurseries throughout
Kona and on most islands. These are produced by grafting a short piece of
wood with buds of a known cultivar onto a young seedling grown in a pot.
Various grafting techniques such as side, whip, and bark grafting can be
employed, depending on the grafter's preference. Seedlings trees can be
top-worked by grafting known cultivars stumped scaffold limbs or on new
shoots from the stumps. Contracting an experienced nurserymen or grower
is recommended.
c. Depending on the cultivar, trees are spaced between 25
and 35 feet apart in the orchard; intercropping with coffee and macadamia
is common in Kona. Neighbor growers should be consulted on best spacing
in their location, particularly, if long-term intercropping is desired.
Kona
and the State in general has a multitude of microenvironments which may
effect the suitability of 'Sharwil' and other recommended cultivars. Only
on-farm research in which growers keep records on fruit set, fruit drop,
yield, nutrition, cultural practices, and environmental factors (maximum
and minimum temperatures and rainfall) can explain cultivar and locational
differences. This research is heavily supported by industry in cooperation
with CTAHR.
d. Fertilization
e. Growers have observed that harvest seasons differ according
to elevation. However, there has been no organized effort to correlate the
effects of nutritional status, fertilizer program, elevation, rainfall,
irrigation, temperature, or cultivar on yield or harvest season.
f. Recent concerns about 'Sharwil' fruit drop and poor yields
may be related to several of the above factors, particularly, drought during
the flowering period. In 1986, rainfall in the Kealakekua was 75% of normal,
and the total through March during the flowering period was 72% of normal.
In 1987, rainfall was 83% of normal and through March during the flowering
period was 49% of normal. In 1988, rainfall through mid March was 50% above
normal. Heavy rainstorms can also knock off flowers and newly set fruit,
thus reducing final fruit set and yield.
Current Status And Potential Of The Industry
The 1988 season saw
the highest farm gate prices for avocados since records were kept, 36/lb.
In spring 1988, retail prices for 'Sharwil' ranged as high as $1.69 per
pound and sometimes per piece in the major Honolulu supermarkets. Other
Hawaii-grown cultivars brought up to $1.19 per pound. Farm sales of avocados
were the highest on record--$438,000.
The increase in
total value of the crop was the result of the highest price on record and
to a return a more normal-size harvest. Compared to other commodities in
1987 avocado farm gate sales ranked 53rd after sugar, pineapple, 22 vegetable
crops, 18 ornamental crops, 5 fruit crops, and 5 livestock commodities.
The increasing yield per acre, total acreage, and portion of the total that
is still nonbearing will continue to push avocado up the ranks.
Although farms
reporting avocado sales has not increased (145 in 1987 and 1988), the increase
in acreage indicates expanding farm size. Total acreage, 580 acres, is the
largest on record. Percentage of crop planted to the high quality 'Sharwil'
continued to increase passing the 50% mark.
Yields per acre
increased for the first time since 1982. As the acreage in young orchards
planted to 'Sharwil' began to bear, the industry-wide yield per acre decreased;
now as the early planted acreage matures the yield per acre should increase
again.
Other contributing
factors may have been the strong price prompting growers to bring in all
their fruit and improved rainfall. The higher prices for 'Sharwil' also
increased sales per acre in 1988.
As mentioned above,
various factors contributed to the long-term decline in yield. Poor weather
conditions, droughts, perhaps acid rain, and volcanic haze (vog) contributed
to the yield decline after 1984. The wet months of December 1987, January
and February 1988 and anticipated wetter conditions in winter 1989 from
a La Nina (cooler than normal tropical ocean currents) no doubt contributed
better yields in 1988 and hopefully in 1989. Still yields are down. High
percentage of new bearing acreage definitely contributes; how much the yield
potential of 'Sharwil' and less than optimal cultural practices for this
cultivar contributed is unknown.
Several significant
events have taken place since the 2nd Avocado Industry Analysis (1985).
The industry resumed shipment to Alaska under new APHIS (Animal and Plant
Health Inspection Service) regulations which permit the shipment of Sharwil,
the industry's premium cultivar, via a fruit fly-proof packing house system.
In March 1989, APHIS proposed to lift the quarantine to mainland markets;
if approved, this may completely change the market situation. Acceptance
of this system for mainland shipment is uncertain at this time, but may
be resolved as early as summer 1989.
Hawaii's avocado
industry, predominantly based in Kona, continues its shift from mediocre
quality cultivars and seedlings to one based on a high quality standard,
the Sharwil. Industry leaders are already expanding shipments to Canada
again, selling more fruit to Hawaii's hotel and restaurant market, while
making contacts with gourmet mainland markets in preparation for shipments
following APHIS approval.
One key to market
development has been the successful program to put ripe fruit into Honolulu
supermarkets. Coupled with an extensive and successful consumer research,
this education and demonstration project partially funded by DOA, Hi. County
Department of Research and Development, and HAA in kind services, 'Sharwil'
is now well received in the highly competitive Honolulu market.
Hawaii Agricultural
Statistics Service. An annual report on number of farms, acreage, yield,
production, farm price, and value.
Diseases
a. Phytophthora root rot (Phytophthora cinnamomi) is the only
serious disease of avocado in Hawaii; it also affects pineapples, pomegranates,
macadamia nut, and many other uncultivated species such as Ohia. Disease
symptoms are trees with sparse foliage, some branches completely lacking
leaves, branch leaves only at the tips, and pale green to yellow leaves
frequently with the dead (necrotic) leaf margins, caused by increased sensitivity
and accumulation of chlorides. Wilting is common.
Dispersal
is by infected nursery stock and other plant material, and soil and water
movement. Infection can occur at any age. The fungus attacks the roots
resulting in a lack of new growth, dieback, and even death of the tree
in severe situations.
b. Many avocado orchards appear to have low-level infestation
of Phytophthora root rot; however, the environmental conditions in Kona
-- moderately acid soil pH, high organic matter, and good drainage -- help
to suppress disease development.
c. Excess soil moisture leads to development of the disease.
Serious problems arise in orchards on soils with poor surface and/ or internal
drainage.
d. The disease organism can persist in the soil for very
long periods of time, even in the absence of a living host.
e. Control measures should consist of a combination of practices:
-
Use of clean nursery stock grown in soil that has been steam-heat
sterilized or fumigated with methyl bromide.
-
Modification of soil moisture and pH to 6.2 to 6.5 on a Wahiawa clay
soil resulted in disease suppression as shown by CTAHR research (M.F.
Falcon, R.L. Fox and E.E. Trujillo. 1984. Interaction of soil pH,
nutrient and moisture on phytophthora root rot of avocado. Plant and
Soil 81:165-176.). Gypsum supplied calcium without raising the soil
pH too high under these conditions when growth was reduced at soil
pH above 6.6. However; specific calcium recommendations have not been
developed for Kona conditions.
-
High levels of organic matter, partially by contributing ammonium
nitrogen (NH+) and other organic compounds, suppress growth of the
fungus. Mulching or grass ground covers should be encouraged, but
not disking or mechanical weeding. The shallow surface-feeding roots
of avocado are easily damaged and wounds are quickly infested with
root rot.
-
Avocado does not tolerate high level of chlorides (Cl-) in the soil
or irrigation water. Phytophthora-infected trees are more susceptible
to chloride toxicity than healthy trees. Fertilizers with Cl- such
as muriate of potash (KCl) should be avoided, if infection by root
rot is possible. Soils known to have been previously irrigated with
saline water or exposed to sea water (not likely to be a problem in
mauka Kona) should be avoided. If well water is to be used for irrigation
it should be checked for total salts content. Soluble salt levels
greater than 120 ppm may result in chloride toxicity, particularly
in areas on heavier soils where Phytophthora root rot is likely to
be found or to become a problem.
-
The fungicide metalaxyl (Ridomil 2E) is registered, but may not be
practical or economical in the long-term for Kona farmers especially
as its effectiveness deceases over time. Other more effective materials
have not been approved yet for use on avocado in the U.S. such as
Aliette and more recently the use of phosphoric acid and potassium
hydroxide. Development of the new technology to trunk-inject disease
phosphorous acid and potassium hydroxide has shown dramatic results
in South Africa and Australia.
-
Preventing the movements of soil and water from infected areas in
the orchard to non-infected areas is very important, but it may not
be a practical or economical control measure in Kona.
f. Moderately resistant rootstocks (e.g., G-6 and Duke-7)
are used with some success in southern California. Preliminary studies show
them to be less effective in Hawaii. Several mainland commercial nurseries
sell grafted and ungrafted trees of clonal rootstocks. CTAHR has selections
tentatively identified as being highly resistant and more vigorous than
those from California. Further tests are being made with 'HAES 7315 Sel.l"
under field conditions.
g. Other fungicides are registered for use on avocado in
Hawaii:
Tri-Basic
Copper Sulfate (WP)
Kocide 606 Flowable Agricultural Fungicide
Kocide 101
Clean Crop Micro Cop 1-2
Ortho Phaltan 50 (WP) (folpet)
Blueshield
Fungicides for which tolerance have been established though lacking a SLN
(local needs) label for Hawaii are:
Chemical
name
|
Tolerance
(parts per million (ppm) in fruit
|
|
benomyl
|
3
|
|
captan
|
25 (post harvest
only)
|
|
terrazole
|
0.15
|
|
thiabendazole
(TBZ)
|
10
|
h. Wholesalers, retailers, and consumers continue to experience
postharvest disease losses. A research project was initiated by CTAHR with
GACC funding after the 1985 Avocado Industry Analysis (no. 2) to investigate
possible solutions. The scientist met with the Hawaii Avocado Assn. to develop
a control strategy. He learned that few farmers would practice a preharvest
spray program to control postharvest diseases because of the terrain, cost
of equipment, labor, and time. The HAA Board recommended a research program
to investigate the efficacy of postharvest applied fungicides that could
be applied in the grower's or packer's facilities.
i. CTAHR determined that postharvest disease losses have
been traditionally attributed to anthracnose (Colletotrichum gloeosporioides).
In high rainfall areas of east Hawaii and probably other areas in the state
75% of the surface body rots commonly called anthracnose, are caused by
C. gloeosporioides.
However,
on 'Sharwil' fruit from west Hawaii (Kona) Dothiorella sp. is more commonly
the cause of surface body rots. Furthermore. other species (Phomopsis
sp., Dothiorella sp, and Stilbella cinnabarina) and not C. gloeosporioides
are associated with postharvest wounds which cause stem-end rot, the next
most frequent postharvest disease. Neither stem-end or surface body rots
are not prevalent until the fruit soften.
j. Copper based fungicides registered for Hawaii applied in
the field and cultural practices should control these diseases.
k. CTAHR is researching the development of disease control
technology utilizing postharvest applied, fungicidal chemicals in fruit
dips, sprays, and/or waxes to control postharvest body and stem-end rots.
These unregistered fungicides--iprodione (Rovral), imazalil (Fungaflor)
and thiabendazole (Mertect), and Chlorox (0.25% a.i.), and simply waxed
fruit alone were tested by applying after harvest. All were as ineffective
as no treatment at all.
l. Prochloraz (Sportak), used in Australia at 250 ppm, is
not registered in the U.S. Preliminary results from CTAHR's initial tests
with Prochloraz were promising. Subsequent results at rates 10 times greater
than recommended in Australia have been erratic and ineffective. Presumably,
these erratic results are related to different organisms in Kona. Prochloraz
cannot be used with wax or non-ionic surfactants which interfere with its
activity. The emulsifiable concentrate is superior to the wettable powder.
m. Research is continuing on Prochloraz, modified temperature
control, organic forms of bromine and basic fruit and pathogen biology behavior
during the critical postharvest period. Since these rots are not seen until
the fruit ripens, refrigeration at 50F before ripening may be an important
tool for delaying postharvest disease development.
Fertilization
a. This is a partial summary of "Fertilization of Avocado
Trees" (HITAHR Commodity Fact Sheet Avo 3 (B) , 1988, available from any
Hawaii Cooperative Extension Service office.
1. Soil should
be tested and amendments made before planting, analytical services are available
from fertilizer companies, soil testing companies and CTAHR's Agricultural
Diagnostic Service Center (ADSC). Extension agents can advise on collecting,
submitting, and paying for samples to ADSC.
2. Optimum soil pH appears
to be around 6.2 to 6.5. If Phytophthora root rot is known to be problem
in the area, soil pH should be checked. Gypsum (CaSO4) may be necessary,
if the pH is higher than 6.5, to suppress this disease as soil calcium levels
appear to aid suppression.
High
levels of organic matter also suppress this disease partially by contributing
ammonium nitrogen (NH+) and other organic compounds. Fertilizing with
manure, composts, and mulches is encouraged and should be placed at least
one foot from the trunk to one foot beyond the drip line. Fertilizer and
lime should be premixed in the soil prior to planting, but subsequent
fertilization should be broadly banded but not incorporated in a zone
one foot from the trunk to 1 to 2 ft. beyond the drip line of the branches.
Incorporating fertilizer could damage surface roots and lead to Phytophthora
root rot.
3. Avocado does not
tolerate high levels of chlorides (Cl-). Phytophthora-infected trees are
even more susceptible to chloride toxicity than healthy trees; therefore,
fertilizers with Cl- such as muriate of potash (KCl) should be avoided when
fertilizing orchards infected with Phytophthora root rot. For these infected
orchards with signs of chloride toxicity such as leaves with extensive tip
burn, K can be supplied as potassium nitrate (KNO3) or potassium sulfate
(K2SO4).
Soils
known to have been previously irrigated with saline water or exposed to
sea water (not likely to be a problem in mauka Kona) should be avoided.
If well water is to be used for irrigation, it should be checked for total
salts content. Soluble salt levels greater than 120 ppm may result in
chloride toxicity, particularly, in areas on heavier soils where Phytophthora
root rot is likely to be found.
4. In general young,
nonbearing trees will require more nitrogen (N) and phosphorus (P) such
as 10-30-10, and bearing trees more potassium (K), such as a 10-5-20 or
the coffee fertilizer sold in Kona. The K in fertilizers formulated for
coffee is supplied by KCl.
5. The fertilization
program below is suggested for a unirrigated orchard on rock in Kona. No
fertilizer program can be perfect for all sites. Even in Kona there are
sites on soil that will have much different requirements, particularly,
for P compared to sites on rock with organic matter between the rocks. More
frequent fertilization intervals is necessary if the site is irrigated.
Again, the soil should be tested and amendments made before planting.
At planting:
thoroughly
mix 1 to 4 oz. of 0-46-0, depending upon soil test and 1 oz. 10-30-10
with soil in the hole.
3 months:
1
oz. 10-30-10 around each tree, at least 1 ft. from the trunk to 1 ft.
beyond drip zone.
6 months:
1
oz. 10-30-10 around each tree, at least 1 ft. from the trunk to 1 ft.
beyond drip zone.
9 months:
1
oz. 10-30-10 around each tree, at least 1 ft. from the trunk to 1 ft.
beyond drip zone.
12 months:
1
oz. 10-30-10 around each tree, at least 1 ft. from the trunk to 1 ft.
beyond drip zone.
Year 2:
1.5
to 2 lb. of 10-30-10 (or 10:10:10 or similar ratio if soil and leaf test
indicate adequate P) around each tree, at least 1 ft. from the trunk to
1 ft. beyond drip zone, but split over 3 applications.
Years 3 and 4:
2
to 3 lb. of 10-30-10 (or 10:10:10 or similar ratio if soil and leaf test
indicate adequate P) around each tree, at least 1 ft. from the trunk to
1 to 2 ft. beyond drip zone, but split over 3 applications per year.
Bearing trees:
1 lb. of 10-5-20 or coffee fertilizer (supplemental
N may be necessary if indicated by leaf test) for each inch of trunk diameter.
Split application over 2 to 3 applications beginning after harvest and after
the initial fruit drop period (spring).
6. Once trees are growing and bearing, leaf and soil testing should be used
to fine tune the fertilization program. The avocado leaf analysis guide
below is a synthesis of the University of California Leaflet 2024 is based
on Fuerte and D. J. Reuter and J. B. Robinson 1986 Plant Analysis, Inkata
Press, Sydney. No values have been established specifically for 'Sharwil'
or other cultivars grown under Hawaiian conditions. Leaf nutrient standards
for mature trees are expressed in dry-matter basis (as would be reported
by the ADSC or other analytical service) are:
|
Nutrient
|
Symbol
|
Unit
|
Deficient
|
Adequate
|
Excess
|
|
Nitrogen:
|
N
|
%
|
<1.6
|
1.6-2.0
|
>2.0
|
|
Phosphorus:
|
P
|
%
|
<0.05-0.10
|
0.08-.025
|
>0.3
|
|
Potassium:
|
K
|
%
|
<0.35
|
0.75-2.0
|
>3.0
|
|
Calcium:
|
Ca
|
%
|
<0.5
|
1.0-3.0
|
>4.0
|
|
Magnesium:
|
Mg
|
%
|
<0.15
|
0.25-0.8
|
>1.0
|
|
Sulfur:
|
S
|
%
|
<0.05
|
0.20-0.60
|
>1.0
|
|
Boron:
|
B
|
ppm
|
<10-20
|
50-100
|
>100-250
|
|
Iron:
|
Fe
|
ppm
|
<20-40
|
50-200
|
?
|
|
Manganese:
|
Mn
|
ppm
|
<10-15
|
30-500
|
>1,000
|
|
Zinc:
|
Zn
|
ppm
|
<10-20
|
30-150
|
>300
|
|
Copper:
|
Cu
|
ppm
|
<2-3
|
5-15
|
>25
|
|
Molybdenum:
|
Mo
|
ppm
|
<0.01
|
0.05-1.0
|
?
|
|
Chloride:
|
Cl
|
%
|
?
|
0.01-0.23
|
>.25-.50
|
|
Sodium:
|
Na
|
%
|
-
|
0.01-0.23
|
>.25-.50
|
|
Lithium:
|
Li
|
ppm
|
-
|
-
|
>50-75
|
b. Only the most recently matured (not still expanding or
leaves whose color indicate they are not mature) healthy leaves from the
tips of non-flushing and non-fruiting branches should be sampled during
mid-August to mid-October. Use of leaf tests should help to confirm suspected
nutritional imbalances. For instance, excessive application of N fertilizer
resulting in leaf N levels > 2 - 2.6 % may cause poor fruit set or suppress
flowering in some cultivars. No data are available on special requirements
for 'Sharwil'.
CTAHR
and several private analysis labs perform tissue analysis for a fee. Some
fertilizer companies provide soil and tissue analysis at reduced rates
or no charge if minimal quantities of fertilizer are purchased.
c. Very few growers have submitted leaves for testing, it
is unknown if nutritional problems are limiting production. Growers are
encouraged to use tissue analysis. Some growers believe the tissue levels
for K, S, and B for 'Sharwil' in Hawaii should be higher.
Harvesting
a. All harvesting is done by hand, generally with poles and
baskets. The industry has numerous modifications of this equipment. Mechanical
harvesting equipment (e.g., hydraulic lifts) cannot be used unless the land
is level.
b. Determining maturity
1.
Immature fruit will shrivel in storage and will not ripen properly. Determining
when fruit are mature and ready for harvest can be difficult. Especially
so in seedling orchards, where there is a high degree of variation between
trees.
2.
Several approximate methods are used to determine fruit maturity, such
as the presence of fallen mature fruit which ripen when stored, lack of
glossy skin, 'normal' picking date, mature fruit size, seed membrane change,
stem turns yellowish brown and snaps more easily, and skin color change.
To use the seed membrane of fruit as an indication of maturity, several
fruits of the desired size must be cut open to reveal the entire seed.
Seed membranes of immature fruits are fleshy and white to light brown
color. Mature fruits have a seed membrane which is thinner, even papery
and darker in color.
One of the advantages
of purple and black skin colored cultivars is that they change from green
to dark color when mature. Distinguishing mature fruit of green skin cultivars
is not as easy, they may show a yellowish tint near the stem end when mature.
Furthermore, just
because a cultivar will ripen, meaning that it has reached a minimum level
of maturity, the optimum level of maturity at which the fruit ripens with
the highest quality occurs later in the season. For export grade fruit harvest
should be made at the stage of maturity for optimum ripening.
3.
Hawaii Department of Agriculture regulations specify a minimum of 12%
oil content for "Hawaii Fancy" and "Hawaii No. l" grades at maturity.
Other grade categories are "Hawaii No. 2" and off-grade. However, several
cult ivars vary significantly in oil content above and below this level.
Halowax, a chemical used commercially to determine oil content, is no
longer commercially available. As fruit mature, the per cent dry matter
increases as does the oil content. There is cultivar to cultivar variation
in this relationship. California and Australia have chosen per cent dry
matter as the method to indirectly determine oil content and hence maturity
for different cultivars.
4.
Research is necessary to develop maturity standards for commercial cultivars.
Specifically, it is necessary to correlate minimum and optimum level of
maturity with oil content, and dry matter per cent for each cultivar.
This method has several advantages--microwave ovens and inexpensive balances
can be used to determine per cent dry matter in less than a half hour
after harvest. Dry matter is also more accurate than harvest date which
can be quite variable in Kona. Furthermore, growers and packers could
use the dry matter method to monitor quality and prevent marketing fruit
that is too immature just to get the higher price for early season fruit.
The procedure
for determining dry matter is simple. Several fruits representative of the
majority of fruits on the tree at the desired size and other maturity characteristics
are collected, cut open, and a portion of the flesh from each is grated,
and the sample mixed and weighed. After drying in the microwave for approximately
15 minutes, the sample is weighed again. The percentage of the original
weight which remains is dry matter and will correlate with oil content.
Maturity standards, the procedures, and dry matter to oil percentage curve
and relationship to quality must be developed for each cultivar.
c. Specifics of the current standards and regulations are available from
DOA marketing inspectors. Any violations of the regulations should be reported
to the inspectors. However, as long as a market exists for seedling and
poor quality fruit, violations will continue.
Summary Of Bottlenecks And Actions
Discussed
In The Avocado Industry Analysis No. 3 (1989)
A
copy of the analysis is available from your local extension agent.
As
you read, if want more information click on the various topics to the
right.
MARKETING
Currently, Hawaii
supplies about half of the fresh avocados sold in Hawaii, California supplies
the remainder. In 1987, industry supplied 900,000 lb. or 45% of the local
market. The percentage supplied is higher when the amount of fruit consumed
from home production is considered. Competition is intense in the local
institutional market which currently uses the cultivar Hass as the standard.
Hawaii's avocados cannot be shipped to the mainland or Japan. However, the
Animal and Plant Health Inspection Service (APHIS) has proposed to permit
the shipment of 'Sharwil' avocado to mainland destinations. Final decision
will be taken after May, 1989.
Export currently
is limited to Alaska and Canada and other foreign markets not concerned
with fruit flies infestation. Alaska is a relatively small market, whereas
the Canadian market is much larger and underdeveloped. Building upon Hawaii's
strong image as a high quality tourist destination for Canadians, the industry
believes that marketing research is essential to better target and promote
'Sharwil' and other Hawaii cultivars in the large Canadian market.
1. Inadequate marketing and promotion of Hawaiian avocados.
1.1
Promote Hawaiian avocados in markets identified as having potential for
development.
INDUSTRY ORGANIZATION
The Hawaii Avocado
Association (HAA) the statewide industry association representing growers,
packers and wholesalers of avocado is active in promoting avocado. A five-year
proposal for Promotion Assistance totaling $230,000 was submitted to the
Marketing Branch of the DOA in August, 1987. The proposal was not funded.
DOA has supported HAA's in-store promotions in Honolulu supermarkets in
1987 and 1988 under the 'Island Fresh' program.
HAA lacks resources
to sponsor research, educational, and promotional programs for its members
and the industry. HAA needs paid staff to accomplish these goals, to provide
long term continuity, to promote and lobby for industry activities. Dues
($20 per member) totalling $900 in 1988 were used for the HAA newsletter
for its members. HAA desires to actively expand membership.
2. Industry lacks a mechanism to raise funds (beyond dues) to maintain a
part-time executive director to support industry activities.
2.1
Actively expand membership in West Hawaii and other parts of the state
where avocado is produced.
2.2
Actively participate in Hawaii Farm Bureau.
2.3
Develop method to raise funds to support and achieve goals.
2.4
Hire a part-time executive director to build HAA membership, clarify short
range goals of the association, develop a budget, look at a marketing
order and other fund raising activities, and handle communications and
correspondence.
INFORMATION DELIVERY SYSTEM
HAA felt inadequate delivery of new production and marketing information
to the industry was severely hindering its expansion. Insufficient on-farm
visits and programs by the extension agent, the slow production of extension
bulletins, no promotion of new technologies or cultivars, and late and/or
complete lack of reporting of CTAHR research results are part of the problem.
3.
Lack of extension and research personnel and production information delivery
system for West Hawaii.
3.1
Provide extension personnel and budget for fruit and nut crops for West
Hawaii.
3.2
Provide assistantship for a graduate student on fruit and nut crops for
West Hawaii.
3.3
Publish the industry analysis narrative as an extension bulletin.
3.4
Develop computer information repository/database directly accessible by
fruit and nut crop industries including suitable computer at the extension
office.
3.5
Improve CTAHR response to industry needs, especially small to medium sized
farms.
3.6
Provide funding for industry newsletter to improve communication between
UH and industry.
Cultural Practices
While
some general information is known from other avocado growing areas in
the world, little research information is available based on Hawaii's
conditions. In terms of the range of production conditions in Kona alone,
the best way to alleviate this situation is to initiate a collaborative
on-farm research program involving growers and CTAHR scientists.
4. Lack of information relevant to west Hawaii's conditions on effects of
elevation, irrigation, and nutrition on yield and harvest season.
4.1
Initiate on-farm collaborative research to demonstrate effects of elevation,
fertilization, and irrigation on yield and to extend harvest season.
4.2
Analyze and publish results.
4.3
Transfer avocado research program to Kainaliu Experiment Station.
Cultivars
There
is a shift away from a seedling based industry to one dominated by 'Sharwil',
a high quality, winter season cultivar. The demand for high quality avocados
is strongest in the summer months, particularly in the Canadian market.
Currently, CTAHR recommends 'Murashige' to commercial growers for the
summer production, but a superior cultivar is needed.
5. Lack of high quality, high yielding, summer-bearing cultivars.
5.1
Institute collaborative on-farm testing of promising selections identified
by CTAHR involving industry with the goal of jointly developing a list
of recommended cultivars based upon yield and quality for high and low
elevations and all seasons, particularly summer.
5.2
Continue research to identify high quality, high yielding, summer-bearing
and disease-resistant lines.
5.3
Topwork seedlings with identified recommended cultivars.
5.4
Improve CTAHR's plant material distribution system.
Harvest and Postharvest
In high rainfall
areas of east Hawaii and probably other areas in the State 75% of the surface
body rots commonly called anthracnose are caused by Colletotrichum gloeosporioides.
However, on 'Sharwil' fruit from west Hawaii (Kona) Dothiorella sp. is more
commonly the cause of surface body rots. Furthermore, other species (Phomopsis
sp., Dothiorella sp., and Stilbella cinnabarina) and not C. gloeosporioides
are associated with postharvest wounds which cause stem-end rot, the next
most frequent postharvest disease. Stem-end and surface body rots are not
noticeable until fruit soften. Thus, the quality of exported 'Sharwil' is
in jeopardy. The extent of this problem is unknown.
Postharvest treatments
with fungicides have not been successful. Research is continuing.
Harvesting fruit
prior to optimum maturity for ripening results in fruits which will not
ripen or have lower oil content and quality. Maturity standards are lacking
for 'Sharwil' and other commercial cultivars. Procedures for controlled
ripening and handling of ripened fruit are needed to meet the local market
demand for to ready-to-eat fruit.
USDA's
Trifly program is working to eradicate fruit fly pests on Kauai. If successful,
this program will have a major impact on fruit and vegetable production
in the State by reducing pesticide application and eliminating the quarantine
on many fresh products.
6. Lack of practical information on crop loss and the control of economically
important pests, diseases, and disorders manifested after harvest.
6.1
Determine optimum maturity indicators and postharvest handling conditions
for major cultivars.
6.2
Continue evaluation and economic feasibility analysis of cultural practices,
preharvest, and postharvest treatments that will reduce losses from postharvest
diseases.
6.3
Register fungicides if feasible.
6.4
Support USDA program to eradicate Trifly in the state.
Pests and Diseases
The
role that pests and diseases including Phytophthora root rot play in reducing
yields is unknown. To accurately determine this requires extensive and
expensive in-orchard surveys in conjunction with the industry. A number
of pesticides are registered to control avocado pests and diseases. However,
application of pesticides in most orchards by mechanized spray equipment
is impossible due to steepness and/or uneven orchard floor and the interplanting
of other fruit and nut crops.
7. Lack of practical information on crop loss and control of important pests
and diseases prior particularly root rot (Phytophthora cinnamomi) to harvest.
7.1
Survey for diseases particularly root rot and pests.
7.2
Develop cost effective field practices to prevent preharvest losses.
REGULATIONS
Current APHIS
regulations do not permit export of avocados from Hawaii to the mainland
due to the danger of fruit fly infestation of Hawaiian fruits. Japan bans
our fruit for the same reason. U.S.D.A. scientists in Hawaii have determined
that 'Sharwil', if harvested properly and handled in a fly-free packinghouse,
will be free of flies.
APHIS has ruled
that Hawaii may export to Alaska. In order for growers to export to Alaska,
their trees must be certified to be 'Sharwil', their harvesting practices
monitored, and the fruit shipped via a certified fly-free packinghouse and
containers. These regulations are quite cumbersome. A simplification of
the procedure and/ or a new, simpler method of demonstrating that fruits
are free of live fruit flies is needed.
8. Most growers and shippers cannot afford to meet current Federal (Trifly)
fruitfly quarantine regulations for export packing facilities.
8.1
Encourage cooperative efforts within industry to utilize current approved
packing house.
8.2
Review and simplify Federal quarantine regulations to permit more growers
to participate in program.
8.3
Determine how to satisfy Japanese quarantine regulations.
8.4
Hasten completion of APHIS review to permit 'Sharwil' to be exported to
the mainland.
WATER
While
agricultural use water rates are available in Kona, many areas simply
do not have access to water.
9.
Lack of water in potential growing areas (South Kona and Kau) and lack
of low cost water elsewhere.
9.1
Develop water sources for areas which need to be irrigated.
9.2
Provide water at agricultural rate.
9.3
Provide low cost loans to farmers for water project development.
TRANSPORTATION
Transportation
within Kona and to Honolulu needs improvement to provide the most convenient,
reliable and inexpensive service to growers.
10. Transportation system is inadequate.
10.1
Provide adequate refrigerated storage at Kona marshalling yard, Kawaihae
harbor, and on barges for avocados.
10.2
Provide regular barge service on public holidays which fall on Mondays.
LAND
Continued
pressure on ag land for development keeps land prices high and leases
short term. This limits long term availability of land for production
in Kona.
11. Lack of low-priced land for avocado production.
11.1
Create zoning regulations to protect prime and potentially productive
agricultural lands from being developed for housing.
11.2
Create agricultural parks in the mauka Kona area with long term leases
and large enough parcels for orchard crops.
Industrial Organization
a.
Hawaii's earliest association of avocado growers was formed in the late
1920s by the two major growers--Baldwin on Maui and the Hawaiian Avocado
Company on Oahu. At that time, acreage was about 750 acres with an estimated
production of 1,200,000 pounds. That association eventually disbanded.
b.
The Hawaii Avocado Association was formed in the early 1980s in response
to the increased planting of 'Sharwil' on coffee lands in Kona resulting
from the long-term decline in the Kona coffee industry. Its members include
growers, packers, shippers, exporters, brokers, wholesalers, and vendors.
HAA represents 65% of the avocado acreage, less than half the growers,
and 70% of the dealers and marketers.
c.
HAA members elect a Broad of Directors composed of the president, vice
president, secretary, and treasurer who meet monthly. Officers are volunteers,
there has been no paid staff, but the GACC approved $15,000 for a part-time
executive in 1989.
d.
HAA is in need of a paid part-time director or secretary to provide assistance
to officers in support of industry activities. HAA funds a newsletter
for its members, but desires to actively expand membership in West Hawaii
and other parts of the state where avocado is produced, to participate
in Hawaii Farm Bureau.
e.
Annual dues are $20. If 100 or half of Hawaii's growers were members that
would raise $2,000 per year. This is insufficient to meet the goals. Another
method is needed to raise funds to support HAA goals.
f.
HAA is active in promoting avocado. In spring 1986, HAA participated in
4th annual 4-H Mini Fair in Kailua-Kona by renting and staffing a booth
offering samples and information. A five-year proposal for Promotion Assistance
totaling $230,000 was submitted to the Marketing Branch of the DOA in
August, 1987. HAA's five-year proposal for promotional assistance was
turned down by DOA. Instead, HAA embarked on a campaign with DOA assistance
to do consumer research and product demonstrations in Honolulu markets
in 1987-89.
Information Delivery
a. Within Hawaii's major avocado producing area, the districts of
North and South Kona, only one extension agent is assigned to fruit, nut,
and some ornamental crops. The agent's area extends from South Point to
Kohala. Therefore, assistance is very limited to avocado growers.
Legislation
was passed in 1989 to fund a tree crops extension position in Kona.
b. Two extension specialists are assigned state-wide to fruit
and nut crops. One is assigned avocado, coffee, cacao, guava, and macadamia,
thus limiting his ability to assist the industry.
c. Recent CTAHR publications on avocado include:
'Weed
control in Avocado' by Chia and Nishimoto (HITAHR Brief No. 059) for commercial
growers, 'Avocado' by Chia and Evans (HC-004) a general bulletin for new
growers and/or hobbyists, and 'Characteristics of consumer demand for
avocados in Honolulu' by Scott (HITAHR Research Series 44), a technical
report based on marketing research in Honolulu,
'Fertilization
of Avocado Trees' by Chia, McCall and Evans (HITAHR Commodity Fact Sheet
AVO-3B).
d. The industry desires more on-farm research, particularly,
on testing cultivars and cultural practices and seeks greater influence
in directing the organization of research and production of extension materials.
To improve this situation an "Avocado Action Committee" will be formed after
the Industry Analysis to oversee the implementation actions to address bottlenecks,
particularly, those actions which result in funded projects. The Avocado
Action Committee's primary role will be to insure that the development of
projects resulting from the analysis have the industry's input and that
the results are communicated to the industry and GACC in a timely manner.
e. HAA produces a bimonthly newsletter with information relevant
to the industry, which is its major expense. The GACC approved $500 to support
this newsletter.
f. The HAA Board feels there is a strong need for a computer-based
information system to facilitate the collection, storage, and the dissemination
of new information to growers.
g. In response to this need, CTAHR Horticulture Dept. scientists
developed a Web-based information system called "The Farmer's Bookshelf."
This version of the Farmer's Bookshelf was developed in 1997, replacing
the previous developed versions for the Macintosh and Windows platforms.
h. The Agronomy and Soil Science Dept has acquired a computer-based
information system somewhat similar to Farmer's Bookshelf developed for
Florida extension personnel and growers called FAIRS (Florida Agricultural
Information Retrieval System). This program requires an IBM or compatible
computers preferably with 20 megabyte hard disk drives. The information
in FAIRS was specially developed for Florida growers and crops; however,
there is an avocado section. The Agronomy and Soil Science Department reports
that FAIRS has been purchased and there is now a program underway to evaluate
the data and adapt it to Hawaii conditions.
i. Coconut Telegraph, CTAHR's computer bulletin board system (tel.
956-2626) is being developed by Scott Campbell, (956-6971). This system
is accessible by anyone with a computer connected to a telephone. A user
can copy computer files and open them on their own computers. Currently,
Industry Analysis materials on coffee, guava, and macadamia as well as the
macadamia 'book' from Farmer's Bookshelf are on it. In the future, bulletins
and other timely materials can be placed on it.
Land
a. Most of the commercial avocado orchards are in the Kona district
(mauka areas between 800' and 1800') of the Big Island. There are also orchards
established in the Kau district on Big Island, Kula on Maui, Molokai, and
Kauai.
b. To produce avocado on a year round basis, land must be available
at different elevations (0-3,500 ft.) with microclimates suited to the culture
of different cultivars. Well-drained soil is essential to prevent Phytophthora
root rot. Maintaining high levels of organic matter, soil pH between 5.7
and 6.5, and high levels of calcium have been shown to be beneficial. Australian
research found superior growth at soil pH of 5.5 to 6.0. This can be achieved
by liming with crushed coral (calcium carbonate); however, higher calcium
levels can be attained with gypsum (calcium sulfate) which does not affect
soil pH as much.
c. Land is available in Kona, but may be overpriced at $20,000-
35,000/acre. Land is available in South Kona for about $15,000/acre and
in Kau for $3,000-5,000/acre. With the resort expansion in North Kona, land
prices will likely increase resulting from demand for more residences due
to increased population, income, and outside investors.
d. State agricultural loans are available to qualified farmers
for land purchase. Individuals wishing to enter farming or farmers who do
not meet loan program criteria must seek capital on the open market.
e. The Hawaii Department of Agriculture has completed 3 Agricultural
Parks on Big Island--Pahoa, Keahole, and Panaewa, the last includes lots
for orchards. The Keahole Ag Park in Kona is too warm and therefore not
suitable for avocado, coffee, or macadamia nut. There are no plans to expand
this program into mauka Kona at this time.
The
objectives of this program are to provide lands of appropriate size and
productive potential, with an adequate supply of water to ensure economically
viable farm operations from land at reasonable cost with long term tenure
and security from urbanization. Further information can be obtained in
DOA pamphlet Agricultural Park Program, available from any local DOA office.
To date ag parks operated by private land holders on Oahu have not been
successful.
f. Most avocado growers farm outside the agricultural park system.
They feel the existing zoning regulations do not sufficiently protect prime
agricultural lands from housing development, particularly in Kona. The state
legislature has yet to act on LESA, Land Evaluation and Site Assessment
program.
Marketing
a. Hawaii's 1.2 million pound 1988 crop with farm gate sales value
of $438,000 supplied at least 45% of the avocados purchased in Hawaii. Average
reported farm price was 36.5 per pound. Retail prices for 'Sharwil' has
ranged as high as $1.69 per pound and sometimes per piece in the major supermarkets
in 1988, and other cultivars as high as $0.88 per pound. Avocado farm gate
sales in 1987 ranked 53rd agricultural value after sugar, pineapple, 22
vegetable crops, 18 ornamental crops, 5 fruit crops, and 5 livestock commodities,
this ranking should improve in 1988.
b. Five out-of-state markets with potential are U.S. Mainland,
Alaska, Canada, Japan and Europe.
c. The U.S. Mainland market remains closed to Hawaii-grown
avocados unless fumigated with methyl bromide which damages the fruit. However
APHIS has proposed to admit Hawaii if handled in the same manner as those
exported to Alaska. The size of California's avocado industry ( 86 to 92%
of US production) has an effect on the economic potential of the mainland
market, its main cultivars are:
Average Price to Grower
Cultivars 11/80
Recommended to 6/87 Season Characteristics
Hass
31 Apr-Oct Black
Not recommended but in commercial
production
Fuerte 19
Nov-May Green
Bacon
14 Dec-Mar Dark-green Zutano 14 Oct-Mar Yellow/green Reed 14 Jul-Oct Green
Being tested Pinkerton not Oct-Apr Dark green available Gwen not - Green
available Whitesell not - Dark green available Source: California Grower,
Only Hass gets Cal. Avocado Society Recommendation, December 1987, p.
19.
d. Preliminary forecasts for the California avocado crop in 1988-89
is estimated at 500 million pounds from 77,000 acres. The California industry
is discussing various methods to restrict production and increase promotion
to maintain a more stable and higher price. Changes in the Federal tax law
for 1988 and increasing water costs and urbanization will also reduce the
profitably of the California industry. California plans more aggressive
promotion programs to broaden the consumption base, at present 75% of US
avocados are sold in the West and Southwest.
e. During years with big California crops Florida's growers also
experience low price; growers in fall 1987 received 14/lb for large Hass
and Choquette and as low as 2/lb for the smallest size .
f. HAA expects mainland demand for 'Sharwil' to surpass supply
as soon as permission to ship is granted by APHIS. This is based on HAA's
position that 'Sharwil' is superior Hass and the much inferior green-skin
cultivars and that the market in December to January is a time of restricted
supply for Hass. Furthermore, shipping avocados to the mainland will raise
local price to growers by increasing demand. Hawaii can expect competition
in competing on the open mainland market, especially in years of surplus
and early production in California. On the other hand, a speciality fruit
mail order company has evaluated the 'Sharwil' and expressed an interest
to incorporate 'Sharwil' into its inventory pending clearance by APHIS is
to enter the mainland market.
Public
hearings and comment period were necessary before approval was obtained
to export avocado via the current APHIS approved program to Alaska. The
California industry has political and legal resources available to resist
imports from Hawaii. Researc h on Sharwil's resistance to Trifly is encouraging.
HAA is optimistic that APHIS will lift the quarantine soon.
g. Canada's market has always been open, even though we must
compete with Mexican and Mainland avocados in Canada. Our exports to this
significant market have decreased, Hawaii's exports peaked at 200,000 pounds
in 1983, were 9,000 pounds in the 1987-88 'Sharwil' season. Poor price was
cited as the reason due to competition with Mexican fruit.
h. The Agricultural and Resource Economics Dept (CTAHR) reviewed
Canadian avocado imports over the past decade (B.P. Goungetas and F.S. Scott
1988. An analysis of Canadian avocado imports with respect to Hawaii's sales
potential, draft manuscript). The value of avocados imported by Canada is
estimated to have increased to $8 million in 1987 (up 360% from 1977). While
the export trend predicts continued increase, actual volume decreased in
1985 and 86, no data is available on the actual 1987 volume.
Mexico's
share of the Canadian market has increased to $ 3/4 million (10 % of the
total up from about 1% in 1976) the major increases are since 1981. Thousands
of newly planted acres in the states of Nayarit and Jalisco have not yet
come into production (N. Bezona, 1988, Trip report on Mexico).
i. Export to Alaska is cleared by APHIS for 'Sharwil' through joint
efforts of USDA/ARS and UH scientists, utilizing Ataraxia Farm's Trifly-proof
packing facility approved by APHIS. Hawaii shipped 48,000 pounds during
the 1987-88 'Sharwil' season.
j. The large Japanese market is closed pending a fruit fly
infestation procedure. California exports millions of pounds to Japan annually.
If a APHIS approves shipment to the mainland, negotiations can begin with
the Japanese Ministry of Agriculture, Fisheries and Forestry. Perhaps, the
easiest way to export the Japan market would be to sell "six packs" of Hawaiian
avocados at the airport to returning Japanese tourists.
k. There is some avocado production in the southern portions
of Japan. Japanese horticulturists are active in programs to expand domestic
avocado production. This will be a deterrent to exporting to Japan.
l. The potential European market particularly France and Germany
has not been adequately explored. Although Israel supplies much of Europe,
there is a winter season window near Christmas that might be exploited.
m. Many in Hawaii consider 'Sharwil' superior to California
cultivars and feel it should be promoted as a gourmet product. Industry
has a display at the Hawaii Tropical Plantation on Maui to promote Hawaiian
avocados to local, Canadian, Alaska, and U.S. Mainland visitors. Spring
1986, HAA participated in 4th annual 4-H Mini Fair in Kailua-Kona by renting
and staffing a booth offering samples and information.
n. HAA submitted to DOA in August 1987 a 5-year proposal for Promotional
Assistance for the Hawaii Avocado Industry. The proposal fashioned after
the model used by other industries, requests several years of DOA assistance
followed by increased cost sharing. Proposed items included:
-
Maui Plantation Booth Renovation
-
Video Development of promotional material for consumers
-
Product demonstration
-
Fruit Decal Program
-
Institutional Buyer Promotion
-
County Fairs and Trade Show Participation
-
Recipe Contest
-
Data Collection and Analysis, Including Market Research
-
Administration of Promotional Campaign
Proposed
budget over five years- DOA $212,420
HAA $24,380
Total $236,800
o. HAA proposal could not be funded; however, DOA's Marketing Branch
developed an alternative promotional program with HAA for the Honolulu market
via the Island Fresh Campaign. HAA organized three 3-day promotions funded
by DOA for 11 major supermarkets (Foodland, Safeway, Times, and Holiday
Mart)--one in 1987, and two in winter 1988. Consumers tasted 'Sharwil' avocados
and completed surveys. Development of a decal for fruit and point of purchase
(p.o.p) materials has been completed under the Island Fresh program. DOA's
1987-88 avocado season budget was over $3,200.
p. The results of the DOA-sponsored in-store survey conducted
by HAA in Honolulu supermarkets reveal that about 8% of public had eaten
'Sharwil' in 1987, by 1988 35% had tasted it. Response to Sharwil's flavor
and other characteristics was overwhelming; in 1987, 95% thought 'Sharwil'
better to definitely superior to other avocados. In 1988, 98% thought 'Sharwil'
good to excellent. 'Sharwil' has very high consumer acceptance in Hawaii
based on the 530 people who completed questionnaires.
Over
10,000 people tasted 'Sharwil' in each of the demonstration programs.
The results of the consumer research are very helpful to HAA. Consumers
reported:
-
Poor reputation and reliability of Hawaiian fruit due to seedling
variability.
-
Poor recognition of Hawaii fruit as opposed to California fruit.
-
Overwhelming preference for 'Sharwil' over all other fruit.
-
Strong preference for ripe fruit.
q. HAA predicted in 1987 that if normal weather conditions prevailed
in Kona state production will grow as follows:
Year Acres
Bearing 1000 lbs/acre Total
Acres
(x 1000 lbs)
actual 1986 540
330 3.9
1300
estimate 1987 590 390
4.2 1630
actual 1987 500
300 3.0
900
estimate 1988 625 450
4.4 1800
actual 1988 580
290 4.1
1200
estimate 1989 650 500
4.6 2300
estimate 1990 680 525
5.0 2625
estimate 1991 700 570
5.2 2964
r. CTAHR Research Series publication (no. 44, 1986) "Characteristics
of Consumer Demand for Avocados in Honolulu" by F. S. Scott, Jr. and J.
S. Sisson) provides a consumer profile of purchases, preferences and uses
of avocados as a guide to selection of cultivars and market development
in the state. It found:
- 30% of respondents consumed avocados once or more in two weeks.
- 65% bought avocados during the year preceding the survey.
- 49% usually obtained avocado from their own trees or from friends
or relatives.
- 20% purchased them one or more times in a 2-week period.
- 57% had a strong liking for them.
- 52% thought good quality avocados were generally available.
- 50% considered them too expensive.
- 26% listed them on their grocery list before entering the store (most
respondents bought avocados on impulse because they looked good on display
in the marketplace).
- Predominant preference was for medium sized, pear-shaped, green,
thin skinned avocados.
- 67% would buy more avocados if ripeness were indicated. This can
be very important for expanding the market locally.
- 66% indicated a preference for Hawaiian avocados over California
imports (but only 37% were aware of the source.)
- Most thought avocados were high in food value (but 50% were concerned
that avocados were high in calories and, thus, fattening.)
- Avocados were typically served at dinner time in salads.
- Most respondents thought avocados were expensive and that price had
an important effect on purchases.
s. A recent Industry Analysis of Hawaii's Food Processing industry
(March 11, 1988) noted that gaining a greater share of Hawaii restaurant
and hotel food service sector is dependent upon supplying food products
that require the minimum labor input prior to serving owing to the labor
shortage on the neighbor islands. Some processed avocado in form of guacamole
is imported from the mainland now.
t. CTAHR scientists have contacted industry members to initiate a
cost of production study for avocado.
u.
The Department of Agriculture has established standards and regulations
for Hawaii-grown avocados. Any violation of the DOA regulations should
be reported to the marketing inspectors. Industry feels that enforcement
of regulations regarding mixing of cultivars, grades, misleading promotional
materials, and pricing California fruit by piece, but Hawaii fruit by
pound confuses consumers.
Pests
a. Earlier in the century the West Indian types were more common
in Hawaii, but they were attacked by fruit flies. Because Guatemalan and
Guatemalan & Mexican hybrids grown are today, fruit flies are not a
production problem per se; nonetheless, Hawaii-grown avocados and most other
soft fruits cannot be exported to the mainland.
b. Thrips and mites are common problems in avocado orchards. Black
twig borers can be a problem when trees are undergoing stress.
c. The following insecticides are cleared for use on avocado:
Read
Label Before Use
Insecticide
Insect
Cythion 5 E C
caterpillars, loopers, scales and thrips
Cythion 8 Aquamul
Sok-BT
caterpillars
Lannate
Thuricide
Stan-Guard Nudrin Methomyl
Bactospeine Flowable
Laser Microbial
Dusting sulfur
mites
Snail and slug pellet
snail and slugs
metaldehyde methiocarb snails
Nematocides
Nematodes
D-D Soil Fumigant
all
d. Industry may apply for Sec. 24c - Special Local Needs registration
for pesticides, provided adequate and appropriate data are submitted.
Planting
a.
Information on avocado growing for new growers is available in "Avocado"
(HC-004, 1997). The former comprehensive bulletin "Producing Avocado in
Hawaii" (UH-CES, CIR. 382) (Rev. 1978.) is out-of-print.
b.
Depending on the variety, trees are spaced between 25 and 35 feet apart
in the orchard, intercropping with coffee and macadamia is common in Kona.
Neighbor growers should be consulted on best spacing in their location,
particularly, if long-term intercropping is desired.
Postharvest
a. CTAHR scientists have not determined the optimum storage temperature
for 'Sharwil' or other commercial Hawaiian cultivars. In Florida, the optimum
storage temperature for cold tolerant cultivars is 40F, for cold susceptible
cultivars (e.g., West Indian), it is 55F.
b. In general avocados will ripen during storage, and the best ripening
temperature range is between 55 and 75F.
c. Ripening avocados generate much heat. In closed packages
or containers, fruit can be heat-damaged. Vented and screened boxes and
airfreight containers designed for fresh products should be used.
d. Customers often have difficulty in determining when avocados
are ready to be eaten. Many California retailers are now selling ethylene-ripened
and ready-to-eat fruits on the shelf. In Australia, forced ripening of avocados
with ethylene gas can be accomplished by several pulse injections (200 ppm
ethylene) into a 60 to 68F storage room over a two-day period or by continuous
injection of 10 to 15 ppm ethylene for the same period.
Exact
procedures for forced ripening of Hawaiian cultivars have not been determined.
Gassing could be done on farm, in the packing house, in the wholesale
storage, or in retail storage. Alternatively, natural ripening which takes
longer and is more variable between individual fruits can be used to supply
ripened fruit to the market. Wholesalers in Honolulu are beginning to
gas ripen or ripen fruit naturally. The ripening time varies with time
of the season. HAA is anxious to see this program expanded.
e. Postharvest diseases are appear to be the major cause of
losses at the retailer and consumer level. Several symptoms and disease
organisms are involved, no postharvest control procedure ( chemical or otherwise)
is adequate to prevent these diseases if the fruits have been infested prior
to harvest.
f. There is a limited but growing demand for avocado oil and
perhaps processed guacamole, which is imported by some Hawaiian hotels and
resorts. A detailed study (Cavaletto, 1978. Avo. Res. Contract No. 7992)
concluded that the potential for an avocado processing industry in Hawaii
is very limited and can only follow the development of a large fresh fruit
industry. The grower will receive a far lower price for processing fruit
than for fresh market fruit and the market for processed avocado is very
limited.
g. Quarantine related to the fruit fly problem. Because Hawaii has large
populations of three fruit fly species that can infest mainland fruit and
vegetable crops, Federal Quarantine regulations require that avocados destined
for the U.S. Mainland must be fumigated with methyl bromide or some other
effective treatment to kill fruit flies. Methyl bromide and irradiation
damage fruit even at doses too low to control fruit flies.
h. Studies published in 1983 by USDA/Agriculture Research Service
(ARS) entomologists indicated that Hawaii-grown 'Sharwil' avocados are not
host fruit for the Mediterranean fruit fly, melon fly or oriental fruit
fly when attached to the tree or up to 24 hours post-harvest. See J.W. Armstrong
et al., 1983, Resistance of 'Sharwil' avocados at harvest maturity to infestation
by three fruit fly species (Diptera: Tephritidae) in Hawaii. J. Econ. Entomol.
i. Development of the current USDA/Animal and Plant Health Inspection
Service (APHIS) export regulations 'Sharwil Avocados From Hawaii' was based
on the above ARS research. The regulations are paraphrased below, for complete
technical details see Rules and Regulations, Federal Register 52 (54 ):
8863-8865 (March 20,1987) and amended May 20, 1988. These regulations require
that:
(a) Fruit have
an attached stem, no length specified.
(b) Fruit is only picked
directly from trees previously indicated on a map as inspected and determined
to be the Sharwil cultivar. No fallen fruit picked from the ground may be
used.
(c) Harvested
'Sharwil' fruit are placed in containers with only fruit from 'Sharwil'
trees.
(d) Fruit must
be moved into an approved packing facility meeting the following conditions:
1-
the facility is maintained free of all Trifly host material
2-
the facility is free of Trifly.
3-
All doors and other openings to the packing facility are maintained to
prevent entry of Trifly.
4-
All avocados are inspected by the packer to insure adequate stem length,
those fruit not meeting criteria will be culled.
5-
All culls will be removed daily.
(e) Fruit inspection
and culling occurs within 24 hrs of harvest and packing into cartons of
APHIS-approved Trifly-proof construction, clearly labelled "To be distributed
in the United States only in Alaska.
(f) All harvesting
and handling activities will be done subject to monitoring by APHIS inspectors,
conducted only during approved time periods, and in compliance with the
above procedures.
(g) Avocados must
remain in their marked cartons during transit and maybe inspected at anytime.
(h) Trifly means
Mediterranean fruit fly, melon fly, and Oriental fruit fly.
j. At least three growers
ship their 'Sharwil' avocados to Alaska through the APHIS-approved Ataraxia
packing house. However, meeting all the criteria of certification and inspection
schedules has prevented most growers from selling to the Alaska market.
Simplification
of the current regulations would enable more growers to participate in
the Alaska and potentially the US mainland and Japan markets.
k. Other research
by CTAHR scientists to be published in 1989, research conducted in 1982-83
funded by a special legislative appropriation on 'Sharwil' avocados using
Mediterranean and Oriental fruit flies, indicates that at natural levels
of fly populations, 'Sharwil' grown in Kona, Hilo, and Oahu is free from
infestation. For details see D.H. Oi. and R.F.L. Mau 1989, 'Relationship
of Fruit Ripeness to Infestation in Sharwil Avocados by the Mediterranean
Fruit Fly and the Oriental Fruit Fly, Journal of Econ. Entom.).
Individual
intact fruits exposed to 50 females per fruit for 25 hrs as soon as 1
day after harvest could be infested and produce viable pupae under conditions
of cutting the fruit 5 days after exposure and holding fruit for an additional
9 days after cutting. Both species were successful in ovipositing at the
juncture of the stem and fruit and through the skin, though high levels
of infestation did not occur until exposure 3 days after harvest.
Individually
caged, green mature fruits on the tree exposed for 3 days to 35 female
flies were infested at the rate of 16% and 5% Mediterranean and Oriental
fruit fly, respectively. When the skin was cut prior to fruit fly exposure,
all fruits became infested.
'Sharwil'
fruit on the tree or postharvest can only be host to Mediterranean and
Oriental fruit under conditions of artificially high fly populations,
not those normally found in the orchard or in transit to the packing house.
l. ARS is investigating
an avocado orchard near a guava farm on Kauai in which 'Sharwil' fruits
were stung by the oriental fruit fly. In the first half of the 1988-89 season
more than 3,000 stung or otherwise damaged fruit were examined. No live
larvae were recovered from intact stung fruit. Only four larvae from one
severely mechanically-damaged fruit.
m. In the past,
industry, ARS, and CTAHR faced significant opposition from California's
avocado and other fruit and vegetable industries in the development of acceptable
data and a harvest and packing methodology to satisfy Federal quarantine
regulations to reenter the Alaska market. However, the successful compliance
of the Hawaiian avocado industry in shipping to Alaska resulted in APHIS
reconsidering the situation.
In
March 1989 APHIS docket 87-092 7CFR part 318, Sharwil Avocado from Hawaii
proposed rule: We are proposing to amend subpart -Hawaii Fruit and Vegetable
Quarantine and Regulations to allow interstate movement of untreated 'Sharwil'
avocado from Hawaii to any destination. Movement would be authorized by
certificate of compliance with certain harvesting and handling requirements.
A comment period ended June 17, 1989. Check with your local extension
agent on the current quarantine status.
Propagation
Grafted
trees can be purchased from nurseries throughout Kona and on most islands.
These are produced by grafting a short piece of wood with buds of a known
cultivar onto a young seedling grown in a pot. Various grafting techniques
such as side, whip, and bark grafting can be employed, depending on the
grafter's preference. Seedlings trees can be top-worked by grafting known
cultivars stumped scaffold limbs or on new shoots from the stumps. Contracting
an experienced nurserymen or grower is recommended.
Pruning
Pruning
is not widely practiced nor recommended. However, new research is underway
in Florida to lower and spread out the branches of large trees to facilitate
harvesting. The tree is cut back to the scaffold limbs 5 to 6 feet above
ground, this is sometimes referred to as stag horning.
After
the tree grows out one year, it is cut back again but one foot above the
previous cut. This cycle repeats until the tree is growing laterally instead
of straight up.
Soil
Well-drained
soil is essential to prevent Phytophthora root rot. Maintaining high levels
of organic matter, soil pH between 5.7 and 6.5, and high levels of calcium
have been shown to be beneficial. Recent reports from Australia indicate
superior growt h at soil pH of 5.5 to 6.5, therefore elevated Ca levels
must be achieved with gypsum.
Transportation
a.
Fruits are shipped from Kona to Honolulu either by Young Bros. barge (1-1/2
- 3-1/2 cents/lb) or by air (19 - 20 cents/lb) or (10 cents/lb for 1,000
lb or more). There is no direct air shipment from the Big Island to Canada
or Alaska (present markets). However, the air cargo facilities at Keahole
airport are being improved and direct United Airlines service from Kona
to the mainland has begun.
b.
Young Brothers, Limited has refrigerated containers; however, when set
at 35F, they are too cold for avocados. Barge service is available from
Kawaihae on Mondays and Wednesday; normally, there is no service on state
holidays which fall on Mondays. However, Young Bros. claim to have operated
on Monday holidays if sufficient loads were anticipated. Due to expanding
transportation business related to hotel growth in Kohala in 1988 barges
sailed on 25% of Monday holidays or 83% of all Mondays. HAA feels that
the remaining non-shipping Monday (17%) is a serious problem for farmers.
Young Bros. has no plans at this time to expand holiday service.
c.
Storage facilities at Kawaihae have improved, though proper temperature
storage is lacking for avocados.
d.
Paving for a marshalling yard in Kona is complete. It lacks a management
authority, buildings, and refrigerated storage which is in the master
plan.
Water
a. Hawaii County has
an agricultural water rate for usage above 25,000 gallons monthly. In Kona,
water costs 89 cents/1,000 gallons if consumption is below 25,000 gallons
monthly and 65 cents/1,000 gallons if above 25,000 gallons monthly.
b. Rainfall in
Kona generally ranges 50-80 inches/year. In 1986 rainfall in Kealakekua
was 75% of normal (61 inches), and the total through March during the flowering
period was 72 % of normal. In 1987, rainfall was 83% of normal and through
March during the flowering period was only 49% of normal. In 1988 rainfall
through mid March was 50% above normal. Some growers expressed concern that
'vog' may be contributing to low yields. However no symptoms were reported
during this period on crops grown in Kona such as tomatoes which are known
to be sensitive to build up of volcanic emissions in rainwater.
c. Avocados are
susceptible to drought, but poor drainage resulting in occasional water-logged
conditions promotes the development of Phytophthora root rot. Rainfall of
50 inches of well-distributed rainfall throughout the year is adequate;
higher rainfall is tolerated if drainage is good. During flowering and fruit
development, lack of water can cause premature fruit drop and fruit shriveling.
d. Water availability
( via irrigation and rainfall) can be a problem in South Kona and Kau, where
land is less expensive.
e. Makai plantings
give desirable early production, but normally need more water. Kona well
water is often of poor quality, having a high salt content, private wells
should be checked before establishing an irrigation system. Water with soluble
salts level greater than 120 ppm may result in chloride toxicity, particularly
in areas on heavier soils where Phytophthora root rot is likely to be found
or to become a problem.
f. Enactment of the
State Water Code will address the issue of assessing surface and ground
water use. Each county will receive $150,000 to develop a county water plan
by 1989. Results of the plan should include addressing the agricultural
and residential water needs in Kona.
g. The avocado
industry in Kona is essentially rainfed. Cost benefit analysis comparing
irrigated versus unirrigated orchards in Kona is needed.
h. Low cost loans for
water project development by farmers are needed. Soil Conservation Service
(SCS) will provide technical assistance to growers on irrigation and orchard
development related to soil conservation. The Agricultural Stabilization
and Conservation Service can provide funds improving for irrigation on previously
irrigated sites but not sites with no history of irrigation, because ASCS
mission is conservation of water not expansion of irrigation.
Growers
interested in the services offered by SCS and ASCS should contact these
agencies on their island, they are listed in the telephone directory under
Agriculture Department in the United States Government Section in the
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