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GENERAL
CROP INFORMATION
This summary was prepared from publications by
Bittenbender, H. C. and H. H. Hirae and
Yokoyama, K. M., et. al.
FAMILY: Proteaceae SCIENTIFIC NAME: Macadamia
integrifolia Maiden and Betche ORIGIN: Subtropical
Eastern Australia
DESCRIPTION
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Neal (1965) describes the macadamia nut tree as a fast
growing, regular-shaped, medium-sized tree with heavy,
dark green foliage. Leaves develop in whorls of three,
paired, or in fours. The leaves are rarely solitary. The
leaves are blunt tipped, oblong, 1 foot in length or
more, edged with fine teeth, and the petioles are about
half an inch in length. The flowers are small, whitish,
tasseled, and grow on long spikes. The nuts ripen in the
fall, both the spring and fall, or through the year. The
nut is encased in a leathery two valved case that is 1
inch in diameter. The case encloses one spherical nut or
two hemispherical nuts. The nuts have a smooth hard shell
that encases a white kernel.
The highest quality macadamia kernels are free of defects
and insect and fungal damage, and they contain at least
72% oil. Kernels with less than 72% oil are usually
immature and harder, and they become over brown when
roasted.
VARIETIES Back To: Menu Bar
Considerable research has gone into selection and
breeding of the best cultivars for Hawaii. The College of
Tropical Agriculture and Human Resources (CTAHR)
recommends the following cultivars: Purvis (294), Kau
(344), Kakea (508), Keaau (660), Mauka (741), Pahala
(788), and Makai (800). Donnison (790) performs well at
elevations below 500 feet.
USES Back
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The kernel is the main product from the macadamia nut
tree. After harvesting, the husks covering the nuts are
removed. The nuts are fried, the shells are cracked, and
the kernels are removed to be oil-roasted or dry-roasted.
Kernels are commonly sold as snack nuts and
chocolate-covered candy. Ice cream manufacturers and the
baking industry also use macadamia kernels as an
ingredient.
The shell and husk also have uses. Shells can be used as
a mulch, fuel for processing macadamia nuts, planting
medium for anthurium culture, plastic manufacture and as
a substitute for sand in the sand-blasting process. Husks
are used as mulch or composted for fertilizer.
Oil can be extracted from culled nuts. The cosmetic
industry, especially in Japan, uses the oil in soaps,
sunscreens and shampoos. The remaining press cake might
be used for animal feed.
A one ounce oil-roasted macadamia nut (approximately
10-12 whole kernels) has 204,000 calories, 21.73 grams of
fat, 2.06 grams of protein, 3.66 grams of carbohydrates,
13 milligrams of calcium, 33 milligrams of magnesium, 57
milligrams of phosphorus, 94 milligrams of potassium, and
2 milligrams of sodium.
PROPAGATION Back To: Menu Bar
In Hawaii, commercial orchards are planted with grafted
seedlings. Macadamia nut trees can start bearing a small
crop in the fifth year after planting, and full
production is reached in 12 to 15 years.
SOIL TYPES and
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Macadamia nut trees can be grown on deep, well-drained
soils with a pH of 5.0-6.5 or on well-drained a'a lava
land that is sufficiently weathered to support natural
vegetation. The trees require 60-120 inches of rainfall a
year and can be grown from sea level to an elevation of
2500 feet.
A major concern is strong wind, which can cause severe
tree loss. Narrow-profile cultivars, such as Kau and
Pahala, are more wind resistant than others.
CULTURAL PRACTICES
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Interplanting with two cultivars, such as 344 and 660,
improves yield through cross-pollination. Beehives near
the orchard can generate additional revenue through honey
production. Another possibility is the integration of
animals. MacFarms of Hawaii and CTAHR are experimenting
with sheep as natural lawn mowers to reduce herbicide use
and weeding costs. Sheep products also provide an income.
Intercropping macadamia nuts with quicker bearing crops
is one way to generate early returns. In Kona on the Big
Island, coffee is sometimes grown between macadamia nut
trees. An alternative is to increase the initial planting
density to get higher total production in the early
years. In Australia, for example, some yields peaked at
8000 lb/ac in high-density plantings before competition
for light caused a decline. Tree removal or radical
pruning to improve light penetration is necessary.
FERTILIZATION
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Semiannual leaf tissue analysis is recommended to
determine the best fertilizer practice for your orchard
and to prevent nutritional problems. If you have never
taken a leaf or soil sample, consult with an extension
agent or fertilizer representative before beginning. If
your orchard appears normal, a sample from one tree per
acre is adequate. Collect a leaf sample before trees
produce new leaves, generally during February and March
or before fertilizing in September or October. Pick three
to four branches where the bud at the tip of the branch
is just opening and beginning to grow. Do not choose
branches with buds with long, hard red scales called
false flushes. These will not open for months. At the
proper stage, buds will have three small pale green
leaves and look like a claw. Pick one healthy leaf from
the second node (whorl) of leaves below the bud. Fifteen
leaves from four to five trees are needed for each sample
submitted for analysis. The samples should be placed in
plastic bags and labeled with your name, date of
sampling, and sample number.
HARVESTING Back To: Menu Bar
Macadamia nuts are harvested manually after they have
fallen. In Hawaii, the nuts typically drop 8-9 months of
the year from July to March. Large-scale producers also
employ mechanical sweepers and pickup devices on
relatively even land to offset the high cost of
agricultural labor in Hawaii. CTAHR developed a
tractor-mounted pickup device for smaller orchards. Nuts
should be harvested at least every four weeks when the
weather is rainy and less often in dry weather. This is
to prevent losses from mold, germination, and pig or rat
damage.
POSTHARVEST Back To: Menu Bar
Never store unhusked nuts more than one day in a bag or
box. It is best to husk the nuts immediately and air dry
them or take them to the processor the next day. If the
nuts were picked and cannot be husked nor delivered to
the processor, then the in-husk nuts should be dried. The
in-husk nuts should be spread on a wire or slotted rack
out of the rain and direct sun.
DISEASES Back To: Menu Bar
Macadamia root rot - Kretzschmaria clavis
Trunk canker - Phytophthora cinnamomi
Dieback or slow decline - disease infection in trunk or
root, prolonged drought, anaerobic conditions caused by
compaction or poor drainage, poor root structure caused
by planting root bound trees, toxic chemicals from
herbicides or overapplication or uneven application of
fertilizers, or nutritional problems
Macadamia quick decline (MQD) - unknown stress factors
(Waterlogged soil, low pH, nutritional problems, and
fungal and stem rots are suspected stress factors with
ambrosia beetle attacks hastening the tree decline. The
fungi Xylaria and Nectria are frequently associated with
MQD.)
Flower blights - Phytophtora capsici or Botrytis cinerea
with Cladosporium usually secondary or affecting raceme
tips
Premature nut drop - most premature drop is normal,
environmental stress may cause more premature drop than
normal
INSECTS Back To: Menu Bar
Ambrosia beetle (Xyleborus affinis)
Broad mite (Polyphagotarsonemus latus)
Longhorned grasshopper (Conocephalus saltator)
Narrow-winged katydid (Elimaea punctifera)
Southern green stink bug (Nezara viridula)
Koa seed worm (Crytophlebia illepida)
Macadamia shot borer (Hypothenemus obscurus)
Hawaiian flower thrips (Taenothrips hawaiiensis)
Redbanded thrips (Selenothrips rubrocinctus)
PRODUCTION Back To: Menu Bar
The macadamia nut originated and is grown in Australia,
but commercial production in concentrated in Hawaii. Some
countries in Latin America, Africa and Asia also grow
macadamia nuts. In the continental United States, trees
are found in California and Florida.
The yield of in-shell nuts on poorer land in Hawaii is
about 5200 lb/ac, with at least 7000 lb/ac attainable on
better land. In Australia, the yield in good orchards is
about 4000-5000 lb/ac.
The shell accounts for most of the macadamia nut's
weight. Hawaii's average kernel recovery rate from
in-shell nuts was 23.5% during 1989-1990. With an
improved cracking system, better shell-kernel separators,
and cultivars with a high percentage of kernel, the
recovery rate could increase to 35%.
Of the 49 million lb of gross, wet in-shell nuts
delivered to processors in 1988-89, 3.5 million lb, or
7.1%, were culled. The primary causes of loss were mold
and rot (2.2% of the total crop delivered), followed by
immature nuts (2.1%); stink bugs Nezara viridula (1.1%);
germinating nuts (0.7%); koa seed worm, Cryptophlebia
illepida (0.5%); and the macadamia shot hole borer,
Hypothenemus obscurus (0.5%). The figures exclude nuts
culled before delivery and losses at the farm caused by
rat damage, macadamia quick decline (MQD) and other
factors.
Data on worldwide production are scarce and conflicting.
An estimate for 1989 indicates that macadamia nut
plantings covered 54,600 ac and total production of
in-shell nuts was 62 million lb. Hawaii is the major
producer, accounting for over 73% of total production,
followed by Australia (22%). Other producers include
South Africa, Guatemala, Kenya, Costa Rica, Malawi,
Brazil, Mexico, New Zealand and China.
About 2000 acres are planted in the San Diego area.
Although not all plants have begun bearing, Southern
California growers produced about 150,000 lb (in-shell)
of rough-shell macadamia nuts in 1988 at a farmgate price
of approximately $1.50 lb Rough-shell nuts do not roast
well; the price reflects a novelty demand for in-shell or
raw nuts.
Hawaii is the world's leader in growing and processing
macadamia nuts. In 1989-90, Hawaii harvested a record
50.5 million lb of buts (net, wet in-shell basis) for a
record farm value of $44.9 million, up from 18.2 million
lb and $5.8 million in 1975-76. The crop covered about
22,300 acres in the state, of which 18,200 acres, or 82%,
were bearing acreage.
The price of in-shell nuts has climbed along with
production in Hawaii. The net farmgate price has gone
from 31.6 cents in 1975-76 to 89 cents in 1989-90.
In Hawaii, macadamia nuts are grown by both small-scale
farmers and large corporate producers. Most operations
are located on the Big Island. Mauna Loa Macadamia Nut
Corp. (a subsidiary of C. Brewer) and MacFarms of Hawaii
are the two largest local growers and processors.
A 1989 CTAHR study calculated annual net returns per acre
in Hawaii from start-up to maturity (16 years or older)
for farms of 25, 50, 100, and 500 acres. Various price
and yield scenarios were used for mature orchards,
showing substantial economies of scale for the larger
farms. A previous study published in 1982 assessed the
economic feasibility of 5-, 10- and 20-acre farms in
Hawaii. Most growers are multiple-income farm families,
and macadamia nuts supply only a fraction of their
income.
Australia is the second largest producer of macadamia
nuts, with an estimated 15,000 acres planted in 1989.
While most of the Hawaii trees are mature, an estimated
20% of the trees in Australia are bearing. As the trees
mature Australia will become a more formidable
competitor.
US per capita consumption of macadamia nuts increased
from 0.04 lb in 1979 to 0.06 lb in 1988. macadamia nut
consumption in 1988 was somewhat comparable to that of
filberts (0.09 lb) and pistachios (0.19 lb), but
considerably lower than that of almonds (0.66 lb), pecans
(0.52 lb) and walnuts (0.44 lb).
In 1989-90, US (Hawaii) production of macadamia kernels
was about 11.9 million lb (assuming a 23.5% kernel
recovery rate). During 1989, the US also imported 5.1
million lb of macadamia nut products, of which 4.2
million lb were shelled nuts at a CIF value (cost,
insurance and freight) of $20.4 million. In addition,
673,000 lb of prepared or preserved nuts and 189,000 lb
of unshelled nuts were imported at values of $1.2 million
and $175,000, respectively.
In 1991, the farm value of macadamia nuts fell to $34.7
million, the lowest since the 1984-1985 crop season, as
grower prices slid to a seven year low. Production was
estimated at 49.5 million pounds, net wet-in-shell, down
1 percent from the previous season. Weather in the major
growing areas was drier than usual, however the effects
on yield were varied. Continued dry weather in Kona and
South Kona generally had a downward effect on yields,
whereas normally wet East Hawaii orchards benefited from
the drier conditions. Total acreage, at 22,500 acres,
remained at about the same level. An anticipated increase
in bearing acreage was postponed pending rejuvenation of
major plantings.
US imports of macadamia kernels have increase nearly
eight times, from 539,700 lb in 1982 to 4.2 million lb in
1989. Australia was largely responsible for the increase;
its exports to the United States rose from 21,800 lb in
1982 to 2.4 million lb in 1989. Imports from Malawi also
increased substantially, from nothing in 1982 to 945,800
lb in 1989.
In the 1992-1993 (July 1, 1992 to June 30, 1993) crop
year, there were 660 farms with 20,500 acres in crop.
There were 17,500 acres bearing a net production of 2,700
pounds per acre. There were 53,000,000 pounds of
macadamia nuts delivered wet in-shell to processors. The
net production less the total spoilage through cracking
was 48,000,000 pounds. The gross farm price (farm value
divided by gross production) was 61.6 cents per pound and
the net farm price was 68 cents per pound. The farm value
(net production multiplied by net farm price) was
$32,640,000.
In 1989, Australia supplied 94% of unshelled macadamia
nut imports to the US. Australia also was the major
supplier of shelled macadamia nuts, accounting for 58% of
the total US imports, followed by Malawi (22%) and
Guatemala (15%). Other suppliers included Costa Rica,
Kenya, Zimbabwe and Brazil.
The average US import price (CIF) of macadamia kernels
was $4.81/lb in 1989. The major ports of entry were
Honolulu (32.6% of total imports), San Francisco (31.4%)
and Los Angeles (28.8%).
Hawaii is the most developed market for macadamia nuts.
The estimated value of Hawaii's chocolate-covered
macadamia nut wholesaling industry is over $100 million.
The snack nut market is another major outlet for
macadamia nuts.
Japanese visitors purchase a large quantity of macadamia
products in Hawaii to take home. These "suitcase
exports" are not included in the US export
statistics.
The Hawaii Macadamia nut Association publishes an annual
proceedings of research and issues, and a quarterly
newsletter, MacFacts.
REFERENCES Back To: Menu Bar
Bittenbender, H. C. and H. H. Hirae. 1990. Common
Problems of Macadamia Nut in Hawaii Research Extension
Series 112. College of Tropical Agriculture and Human
Resources, HITAHR, University of Hawaii.
Neal, Marie C. In Gardens of Hawaii. Hawaii: Bishop
Museum Press, 1965.
Yokoyama, Kevin M., Kulavit Wanitprapha, Stuart T.
Nakamoto and H.C. Bittenbender. 1990. Macadamia Nut
Economic Fact Sheet #9. Department of Agricultural and
Resource Economics, CTAHR, University of Hawaii.
Statistic of Hawaiian Agriculture 1991. Prepared by:
Hawaii Agricultural Statistics Service, P.O. Box 22159,
Honolulu, Hawaii, 96823-2159. December 1992. 105 pages.
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