Introduction:
Cashew (Anacardium occidentale) is a tropical evergreen tree from north-east Brazil. Distribution of the species around the world is mainly attributed to the Portuguese, who brought the cashew to their colonies in East Africa and India during the 14th and 15th centuries. World production of cashew in 2002 was about 2,100,000 t of nut-in-shell (NIS), produced mainly in India, Brazil, Vietnam and Africa.
Local consumption and demand by importing countries continues to increase, providing opportunities for expansion of the crop worldwide. Commercial cashew growing has potential in the Australian tropics. Large areas of land with adequate water supply and suitable climate exist in the Northern Territory and Far North Queensland.
Cultivation in remote locations does not have the risks associated with highly perishable fruits as the nut can be stored for long periods and can tolerate long-distance transport. Australia imported an estimated A$50 million (wholesale value) of cashew kernels in 2002. A local industry would provide import replacement and create export opportunities for sale of NIS, raw kernel and value-added products. There are currently two major plantations in Australia, one in north Queensland and the other in the Northern Territory.
To be profitable, the Australian industry needs suitable varieties and field management practices to achieve and sustain economic yields. Areas of at least 500 ha in single or cooperative plantations can be required to establish a brand name in the local and international market and to minimize the unit costs associated with production and the overseas processing. Sound financial, personnel, agronomic and marketing skills are required to manage and operate plantations of this size successfully.
Markets and marketing:
Of the total world production of cashew kernel (estimated at 522,000 t), 241,000 t was traded on international markets in 2002. India (51%), Vietnam (26%) and Brazil (13%) are the major exporters. The major consumers are the United States (46%), the Netherlands (10%), the United Kingdom (5%), and Australia, China and Canada (4%). Australia imported about 8695 t of kernel in 2002.
As the major importer of cashew, the United States has a strong influence on the world price, which is fixed in US$/pound of kernels. The price of W320 grade (320 kernels/pound) over the last 10 years has been quite volatile, ranging from US$2.30 in March 1994 to US$3.15 in September 1999 and US$1.75 in July 2003.
Overseas, the nuts are collected from the growers by local traders, who in turn sell to large processing companies. After processing, the kernels for export are sold by trading companies to overseas markets through agents or dealers. Several Australian dealers who import from India, Vietnam and Brazil supply the major retailers in Australia with kernel. The main Australian dealers are GB Commtrade Pty Ltd, Michael Waring Trading and Scalzo Food Industries.
The raw nut produced in Australia is shelled overseas and the kernel returned to the grower and sold raw or as value-added products. Australian production of raw nut in 2002 was 130 t. As the Australian industry expands, it is likely that growers will benefit from pooling their production, producing value-added products, and marketing with an Australian brand name.
Production requirements:
Commercial cashew production requires a seasonally wet–dry tropical climate, the dry season coinciding with flowering and nut development. The area selected for cashew production should be frost-free. Mean daily temperatures of less than 25°C will limit growth and production. These conditions can also delay flowering, resulting in nut maturity during the wet season and potential crop loss. With exceptions, areas south of 16°S latitude are generally considered marginal for cashew in Australia (see map).
Soils should be free draining: cashew does not tolerate water logging. Rocky or stony soils disrupt harvesting and increase post-harvest cleaning costs and should be avoided. Slopes should not exceed 12% to minimize erosion risk and facilitate the operation of heavy machinery. Cashew is known for its drought tolerance, but it is unlikely that economic yields (above 3 t/ha NIS advisable) can be achieved without irrigation. Sufficient water should be available to apply irrigation during flowering and nut development ( July to December, depending on location) at weekly intervals at the rate of 500 L/tree/ week.
Varieties:
Australian plantings have been established mainly with locally selected or recently imported varieties, and generally this material has not been proven under commercial culture in local climatic conditions. A number of hybrids were selected under a joint government–grower plant improvement program in 2002.
Royalties apply to the use of this material and inquiries regarding availability should be directed to CSIRO. Limited genetic material of some local selections is available from the Departnment of Primary Industries and Fisheries in Queensland and the Department of Business, Industry and Regional Development in the Northern Territory.
Cashew growth and yield is influenced by environment (climate, soil and culture). Material should therefore be tested on a range of rootstocks in the intended plantation location if the environment of this location is different from the environment from which the material came.
Agronomy:
Before developing the property, a farm plan defining the placement of infrastructure (buildings, roads, dams, underground irrigation mains, and so on) and a schedule of development tasks should be formulated. Careful site preparation (land clearing, windbreaks, erosion and drainage structures, soil tilth and amelioration, irrigation installation, and root and rock removal) will promote healthy tree growth and harvest efficiencies. In areas where giant termite (Mastotermes darwiniensis) exists, root removal is also important to reduce the risk of infestation.
Cashews are commonly planted in rows 8 m apart and 6 m apart within the row. Commercial trees are propagated by grafting because trees raised from seed do not grow true-to-type. With good culture, grafted trees will produce sufficient yield by the third year after planting to warrant mechanical harvesting. Nuts with “apples” attached are harvested from the ground, then cleaned and dried, the apples removed and the nuts stored.
A well-managed plantation will require propagation/nursery facilities, an under-tree sprinkler irrigation system with fertigation capability, tractors, slasher/ weedicide boom, mist-blower, hedger, sweeper/harvester, nut cleaning, drying and apple removal equipment and storage facilities.
Cultural practices are designed to promote healthy trees while at the same time managing canopy growth, nut yield and quality, and the timing of nut drop. In the period from planting to first harvest, a canopy framework is developed that is structurally sound, is shaped to facilitate spray coverage and mechanical harvesting, and maximises nut yield in the shortest time from planting.
The main season of vegetative growth (December ? April) coincides with the wet season and is followed by flowering ( July ? September) and nut drop (October ? December). The critical aspects of managing growth and nut production are insect control during vegetative growth, flowering and early nut development; irrigation during floral and nut development; and adequate nutrition during vegetative growth. Additional operations include pruning immediately after harvest (before vegetative growth season), preharvest field preparation, and weed control.
Cashews require all the major nutrients (N, P, K, Ca, Mg and S). They are particularly sensitive to zinc deficiency, and iron deficiency has been observed in trees growing in high-pH soil (over 8.0). Nitrogen nutrition is very important because it has a major influence on vegetative growth, which determines nut yield and timing of nut drop.
Pest and disease control:
Various insect and animal pests are prevalent in cashew growing areas in Australia. Only two diseases are of significance—cercospora blotch (Pseudocercospora anacardii) in north Queensland and anthracnose (Colletotrichum gloeosporioides) in areas where rainfall occurs throughout the year.
Some insects are confined to the wet season—for example, mango shoot caterpillar (Penicillaria jocosatrix), leaf miner (Acrocercops spp.) and leaf roller (Anigraea ochrobasis). Others can attack trees at any time during the year—for example, giant termite (Mastotermes darwiniensis), tea mosquito bug (Helopeltis spp.), fruit spotting bug (Amblypelta lutescens), red-banded thrips (Selenothrips rubrocinctus) and pink wax scale (Ceroplastes rubens). Insects (Ephestia spp.) can also infest nuts in storage.
Most of the insect pests attack tender growth, causing defoliation, death of flowers and premature nut drop. Control during mid to late vegetative growth, panicle emergence and early nut development is essential as damage during these periods can result in the greatest reduction of nut yield.
An integrated pest management approach involving regular monitoring, biological control, and strategic sprays during critical times should be taken. Green ants (Oecophylla smaragdina) attack a number of insect pests of cashew and the wasp Anicetus beneficus is a parasite of pink wax scale.
Giant termite—only a problem in the Northern Territory and Western Australia—burrows within the tree, gaining entry through the roots from subterranean canals. Infestations can exist unnoticed until death of the tree. Control requires constant surveillance and baiting. Fruit bats and rats can also cause economic loss. Fruit bats feed on the apple and can remove significant quantities of nut from the plantation boundaries.
Windbreaks planted within the plantation have been effective in encouraging bats to feed on the cashew apples and drop the nuts within the plantation. Rats can destroy polyethylene irrigation pipes and fittings. Damage can be minimised by baiting and plantation hygiene (grass control).
Currently there is only one insecticide registered with the Australian Pesticides and Veterinary Medicines Authority for use in cashew. This chemical does not control the full range of insect pests and will burn some cashew varieties. Effective management of insects in cashew will require the registration of additional chemicals.
Harvest and post-harvest:
Cashew fruit (nut with apple attached) falls to the ground when mature. The fruit is swept to the centre of the inter-row and then picked up by a harvester. Tree canopy obstruction and ground surface condition influence the speed of harvest, the quantity of nuts harvested, and the amount of extraneous material mixed with harvested nuts.
A pre-harvest clean-up is necessary to remove low branches, level the ground surface and remove trash and old nuts. While the harvester aspirates light extraneous material, further cleaning can be required before the nuts are dried and the apples removed. Nuts must be stored at less than 9% moisture content to prevent rancidity.
There are no shelling facilities in Australia. The process of kernel extraction is complicated and laborious and involves removal of the shell’s caustic oil, shell cracking and testa removal.
Australian nuts are currently sent overseas (to China, for example) for kernel extraction. Overseas processors are reluctant to accept small quantities (less than 100 t) of raw nut . Growers with less than 100 t can sell to a local large producer or combine their raw nut crop with other small producers to meet processor’s requirements.
Nuts can be sold as NIS, raw kernel or as processed valueadded products (roasted, chocolate coated). The price paid for NIS is influenced by the nut’s size and kernel recovery, which together determine the yield of kernel to the processor. Kernel price is influenced by kernel quality (for example, kernel size, whether whole or broken), and quality specifications are defined by the International Organization for Standardization.
Australian nuts to date have been sold mainly as processed valueadded products. Such sales reap higher returns compared with NIS and raw kernel sales. In addition, broken kernel, which would otherwise be downgraded under ISO standards, and so draw a lower price, can be marketed at the same price as premium-grade kernel.
Financial information:
Since 1987 a number of economic analyses of the profitability of commercial cashew growing in Australia have been undertaken; they have concluded that various yields up to 5 t/ha NIS are needed to attract investment. The most recent analysis, completed in 1998, investigated the profitability of growing cashew in the Mareeba ? Dimbulah Irrigation Area of Far North Queensland.
Growing cashews in that area was profitable based on an analysis of a 200 ha farm. The analysis used a farm-gate price of A$1.63/kg NIS and a most likely yield of 14 kg NIS/tree from year 6 onwards. All nuts were processed in China and the raw kernels were sold in Brisbane. The estimated equivalent annual return (net of all operating, labour and capital outflows) was $144,000 or $0.34/kg NIS. The internal rate of return and discounted payback period were 14% and 11 years respectively.
To establish the farm it was estimated that an investor would outlay $1,607,000. This included cash outlays for land, capital equipment, water allocation and establishing the plantation.
Key references:
Blaikie, S., O’Farrell, P.,Müller, W., Wei, X., Scott, N., Sykes, S. & Chacko, E. (2002) Assessment and Selection of New Cashew Hybrids. Pub. no. 01/177, RIRDC Canberra.
Grundon, N.J. (2000) The Australian Cashew Industry: an information system. Pub. no. 00/15, RIRDC, Canberra.
Grundon, N., O’Farrell, P., Hinton, A., Kulkarni, V., Leonardi, J., Blaikie, S., Richards, N., Armour, J., Shearer, P., Duncan, I. & Hood, S. (1999) CashewInformation Kit. Department of Primary Industries, Brisbane.
Hinton, A. W. (1998) Cashew Production in North Queensland— estimating profitability. Department of Primary Industries, Brisbane.
O’Farrell, P., Armour, J. & Reid, D. (2002)The Effect o f Nitrogen on Cashewin North Queensland 1995–99. Web pub. no. W02/001, RIRDC, Canberra.
Peng, R. K., Christian, K. & Gibb, K. (2000) Implementing Ant Technology inCommercial Cashew Plantations and Continuation of Transplanted Green Ant Colony Monitoring. Web pub. no. 04/088, RIRDC, Canberra.
About the authors:
Pat O’Farrell is a Senior Experimentalist with the Department of Primary Industries and Fisheries based in Mareeba in north Queensland. He has worked in horticulture research for over 30 years, mainly in banana, cashew and macadamia agronomy.
Dr Sam Blaikie was a Senior Research Scientist with CSIRO in Darwin. Since 1995 Dr Blaikie had extensively researched the agronomic management of tropical tree crops, principally mango and cashew.
Key contacts:
Mr Patrick O’Farrell (cashew agronomy) Senior Experimentalist Department of Primary Industries and Fisheries PO Box 1054 Mareeba QLD 4880 Tel: (07) 4048 4653 Fax: (07) 4092 3593
Email: patrick.o’farrell@dpi.qld.gov.au
Mr R. K. Peng (pest management) Principal Researcher Charles Darwin University Darwin Northern Territory 0909 Tel: (08) 8946 6763 Fax: (08) 8946 6847 Email: rpeng@cdu.edu.au
Mr Peter Shearer (cashew grower; marketing) Managing Director Cashews Australia PO Box 122 Dimbulah QLD 4872 Tel: (07) 4093 6161 Fax: (07) 4093 6178 Email: pshearer@ledanet.com.au
Ian Duncan (consultant; processing) Director Australian Cashew Company 36 Old Byron Bay Road Newrybar NSW 2479 Tel: (02) 6687 8443 Fax: (02) 6687 8853 Email: ied@ozemail.com.au
