Every threat to a cashew tree is also a market for whoever can control it. Ghana's cashew loses yield and quality to a short list of well-understood diseases, pests, storage failures and weather shocks. Each one is profiled below, with the control that works and the service or product business it opens up.
Cashew is a hardy tree, but it is not risk-free. The losses cluster in four places: fungal diseases at flowering, sap-sucking and boring insects, poor drying and storage after harvest, and dry-season fire and erratic weather. Most have a known control, although Fusarium wilt and gummosis still lack a reliable one.12 Control itself is under-supplied in Ghana, so each threat below is written with the opportunity it creates.
Scored from Muntala et al. (2020, 2021) and the other studies cited in this pillar.
The threats that are both common in Ghana and damaging if left uncontrolled sit in the top right: anthracnose, the sap-sucking bugs led by the tea mosquito bug, and bushfire. Poor drying and storage and the harmattan are common but less severe. Fusarium wilt, the stem borer and powdery mildew are severe where they strike but rare or unrecorded in Ghana, so they sit on the watch-list.
Begin by seeing where the money leaks. Anthracnose alone can take 70 to 100 percent of the crop where it is not controlled,3 and each of the other threats takes a share of the yield, the grade or the whole season.
What is scarce is the control itself. Pest and disease management, drying and storage, and fire and weather protection are all under-supplied in Ghana, so each threat, read from the other side, is an under-served market for a product or a service.
What this means. Every threat that costs a cashew farmer money is, for someone else, a product to sell or a service to provide. The size of each loss is also a map of where a new business can add value, and the biggest losses cluster where control is weakest. That is why each risk below is read as a market.
The flagship disease is anthracnose, caused by the fungus Colletotrichum gloeosporioides. Studies report losses of 70 to 100 percent where it is not controlled, because it attacks flowers and young nuts directly.3 In a 2019-2020 survey of 25 orchards in Dormaa Central Municipality, Bono Region, about 23 percent of trees showed anthracnose,4 a moderate level that can rise in a wet flowering season. A 2025 Ghana screening trial found that a copper-oxide and metalaxyl-M mix completely inhibited the fungus on agar plates in the laboratory, a result not yet tested in the field, and that a soybean extract cut fungal growth by up to about 82 percent, making it a candidate bio-fungicide once formulated for field use.3
Powdery mildew (Oidium anacardii) can cause 70 to 100 percent loss in Tanzania, where it is controlled with sulphur and tolerant clones, but West African surveys record it at very low incidence, although the TCDA and CRIG listed it among the growing disease threats to cashew in August 2026.5 Gummosis and dieback are caused by Lasiodiplodia theobromae with the anthracnose fungus. Gummosis was found on about 7 to 14 percent of trees in surveyed Bono orchards;4 the two diseases kill twigs and young trees and are managed by pruning, wound sealing and copper, although no fully effective control exists.12 Fusarium wilt (Fusarium oxysporum) can cause total loss and has become the top disease in Tanzania, but the Ghana orchard survey did not record it,6 so it belongs on the watch-list.
⚠️ BIOSECURITY WATCH: Witches’ broom is a biosecurity watch-list item. Witches’ broom is sometimes named as an emerging cashew threat, but the Ghana and West African cashew disease surveys record no witches’-broom or phytoplasma disease of cashew.462 It should be treated as a biosecurity and import-screening risk, with surveillance by the Plant Protection and Regulatory Services Directorate (PPRSD) and the Cocoa Research Institute of Ghana.
Anato et al. (2015).
Against untreated trees, weaver ants alone gave 78 percent more nuts, ants with sugar feeding 122 percent more, and ants with a spinosad bait spray 151 percent more. The gain from ants alone is the sales pitch; the larger gains need a paid bait spray.
The tea mosquito bug (Helopeltis species) is among the most damaging insects, the most prevalent insect recorded in surveyed Bono orchards,6 and attacks by the sap-sucking bug complex can cut yield by up to 80 percent.7 Cashew thrips scar the nut surface and lower the nut grade, and the branch girdler beetle (Analeptes trifasciata) snaps fruiting branches; the girdler is recorded as the most common destructive beetle in Ghana orchards and is managed mainly by cutting and burning the affected wood.86 In India the stem and root borer (Plocaederus ferrugineus) kills trees within one to three years, and in a Chhattisgarh trial 7 percent of trees treated with Metarhizium fungus and neem cake were infested against 20 percent of untreated trees;9 the Bono orchard survey did not record it,6 so it is a watch-list pest for Ghana.
The best-tested control is biological and cheap. Weaver ants (Oecophylla longinoda), which nest naturally in cashew, control the main sap-sucking bugs. In a two-year Benin trial, trees with ants, ants plus sugar feeding, and ants plus a spinosad fruit-fly bait spray produced 78, 122 and 151 percent more nuts than untreated trees, although the authors note the bait is expensive for resource-poor farmers; a Ghana study reported more than four-fold higher yields on ant trees than on trees without ants.7 The ants also raise the absolute number of top-grade nuts, although ant trees suffered more thrips damage, so they need a compatible thrips control. They also suit organic certification because they replace chemical sprays.
OPPORTUNITY: PEST AND DISEASE CONTROL IS AN UNDER-SUPPLIED SERVICE MARKET. Openings include a weaver-ant integrated-management advisory and colony-establishment service (the 78 percent gain from ants alone in a Benin trial is the sales pitch, with larger gains needing a paid bait spray); local production of bio-pesticides (Metarhizium, Beauveria and neem-cake) and bio-fungicides (soybean and cashew-shell extracts, made from the crop's own by-product); and a certified spray-and-scout service timed to the flowering window. Because most of these controls are biological, they double as the enabler for the organic premium in Pillar 2.
A good nut can still be ruined between the tree and the buyer, and the kernel is only about a fifth to a quarter of the raw-nut weight, so quality is everything. A 2009-2010 survey of 247 Ghana farmers found that about 76 percent of farmers had no storage facility and more than half dried their nuts for only three to four days, both of which lower quality and kernel outturn.10 Nuts should be dried to no more than about 10 percent moisture, the level in the 2025/26 price specification, stored in clean jute sacks on pallets in a ventilated store, and never mixed old with new.
Damp storage invites Aspergillus mould and aflatoxin, a serious health hazard.11 Ghana kernels tested in 2009-2010 carried aflatoxin far below the 20 parts-per-billion Ghana standard, with infection starting in the field.10 EU law caps aflatoxin B1 in cashew kernels at 2 micrograms a kilogram for nuts sold for direct consumption and 5 micrograms a kilogram for nuts still to be sorted,12 and the Netherlands rejected a Togolese consignment of organic kernels for aflatoxin in December 2021, so a single lapse can mean market rejection.13
Gyedu-Akoto et al. (2014).
Pick daily, dry on raised mats, cut-test for outturn, bag in clean jute on pallets and store in a ventilated room without mixing old and new nuts. As a package these steps can more than halve post-harvest losses, and every step is a service a farmer will pay for. The target moisture is 10 percent or below, the TCDA price specification.
ComCashew (2020); Balogoun et al. (2016).
Flowering runs from about November to February and the harvest from February to June. Anthracnose, the tea mosquito bug, thrips, the harmattan and bushfire all bite in the flowering and early fruiting months, while pruning and orchard sanitation belong to July to September. Every control has a right moment, and timing is where the money is made.
The single biggest swing factor is weather at flowering. Dry harmattan wind and heat can abort flowers, while unseasonal rain at flowering spreads disease and drops the crop.14 Unfavourable weather was blamed for Ghana’s roughly 30 percent production fall, from about 230,000 tonnes in 2023 to about 161,000 tonnes in 2024,15 before output recovered to about 255,000 tonnes in 2025.16 In the 2026 season heavy rain in key growing areas disrupted collection and drying.17 Dry-season bushfire is the other headline risk: fires in January 2022 destroyed more than 5,000 acres of cashew in 24 communities of Banda District, Bono Region,18 and fires still burn cashew farms each dry season, as at Asueyi in Techiman North in January 2026.19
Over the longer term there is an upside: in a Ghana savannah survey, 71 percent of farmers said cashew is less affected by climate variability than food staples, which positions it as an adaptation crop for the savannah zone.20
What this means. The climate signal cuts two ways. In the short run, weather volatility makes supply and price unpredictable, so growers and plantation investors should invest in irrigation at establishment, windbreaks, fire belts and weather-indexed insurance. In the long run, cashew’s drought tolerance may make it one of the crops Ghana can expand as the climate warms; 71 percent of savannah cashew farmers surveyed said it copes with climate variability better than staple crops.20 Pillar 8 covers what this means for investors.
A weaver-ant integrated-management advisory. In a Benin trial weaver ants alone lifted nut numbers by 78 percent, and by 151 percent with a bait spray, so a service that establishes, feeds and manages colonies sells a tested yield gain that also suits organic buyers.
Local bio-pesticide and bio-fungicide production. Metarhizium, Beauveria and neem cake for the borers, and soybean and cashew-shell extracts for the fungi, are made from cheap inputs and the crop's own by-product; the extracts are still at laboratory stage, and all are barely supplied in Ghana today.
A certified spray-and-scout service timed to flowering. Anthracnose and the tea mosquito bug do their damage in the flowering window, so a scouting and timed-spray service priced against the loss avoided beats blanket spraying on both cost and result.
Solar drying, aggregation stores and aflatoxin testing. With about 76 percent of farmers surveyed in 2009-10 holding no store, solar dryers, raised platforms, ventilated warehouses and a testing lab at the aggregation point turn a good nut into a premium, export-safe product priced on outturn.
Firebelt and windbreak services. Fire belts, community fire-volunteer squads and windbreak agroforestry protect the crop from the two weather shocks that move the whole year, and each is a service or an agroforestry business in its own right.
A digital scout-and-alert service. SMS and voice alerts timed to the flowering window, of the kind Esoko and Farmerline already run, and smartphone-photo diagnosis of the PlantVillage Nuru kind, pair a trained agent with a phone app and the spray calendar in this pillar (Pillar 7).
MARKET SIGNAL: AI AND DIGITAL OPENING. Plant protection is where cheap digital tools pay first. Feasible now for a smallholder or a service agent: SMS and voice pest-and-disease alerts timed to the flowering window, the model Ghanaian platforms such as Esoko and Farmerline already run for other crops in local languages, and smartphone-photo disease diagnosis of the kind PlantVillage Nuru pioneered for cassava elsewhere in Africa. Commercial-scale only for now: drone spraying and automated pheromone-trap monitoring. The realistic low-capital business is a scout-and-alert service that pairs a trained agent with a phone app and the spray calendar in this pillar (Pillar 7).
The table below is the cashew risk register. Each card names the threat, its impact, the control that works, and the business opportunity it creates.
| Threat | Impact | Key control | Opportunity |
|---|---|---|---|
| Anthracnose (C. gloeosporioides) | 70-100% loss; quality + yield | copper or mancozeb sprays timed to flowering; pruning | bio-fungicide + spray service |
| Powdery mildew (O. anacardii) | 70-100% in Tanzania; rare in West Africa | sulphur; resistant clones | tolerant-clone nurseries |
| Gummosis / dieback (Lasiodiplodia) | twig death; young-tree death | prune, seal wounds, copper | pruning + sanitation crews |
| Fusarium wilt (F. oxysporum) [WATCH] | up to 100% (not yet in Ghana) | quarantine, clean material | clean-planting-material certification |
| Tea mosquito bug (Helopeltis) | up to 80% loss (bug complex) | weaver-ant IPM; targeted spray | weaver-ant IPM service |
| Cashew thrips | nut scarring; lower kernel grade | bait spray; monitoring | scouting + quality linkage |
| Stem & root borer (Plocaederus) [WATCH] | kills tree in 1-3 yrs | Metarhizium + neem cake; early detection | bio-pesticide production |
| Girdler beetle (Analeptes) | branch snap, fruit loss | cut and burn girdled wood | sanitation service |
| Poor drying & storage | 76% no storage (2009-10); low outturn | dry to 10% or below; jute + pallets | solar dryers; aggregation stores |
| Aflatoxin (Aspergillus) | health risk; export rejection | low moisture; reject mouldy nuts | aflatoxin testing labs; certification |
| Bushfire | over 5,000 acres lost (Banda District, 2022) | fire belts; community volunteers | firebelt service; living firebreaks |
| Harmattan / erratic rain | flower drop; weather cut 2024 crop ~30% | windbreaks; timed disease control | windbreak agroforestry; index insurance |
| Climate-belt shift [WATCH/ADAPT] | hotter, more erratic seasons; no Ghana cashew projection yet | drought-tolerant clones; siting | resilient planting material |
| Witches' broom [BIOSECURITY WATCH] | none recorded in Ghana | import screening; surveillance | phytosanitary / diagnostics service |
Sources: Bukari et al. (2025); Muntala et al. (2020, 2021); Mbasa et al. (2025); Wonni et al. (2017); Anyetei (2026); Anato et al. (2015); Azeez (2025); Sahu and Sharma (2008); Gyedu-Akoto et al. (2014); Musangi et al. (2024); European Commission (2023); Adjomah (2022); Food Business Middle East & Africa (2025); Botir et al. (2025).
The stand-alone one-page cards
The flagship disease. It attacks flowers and young nuts, so it hits both quantity and quality.
70 to 100 percent yield loss reported where uncontrolled; about 23 percent of trees infected in a 2019-20 survey of 25 Bono orchards.
Every orchard, worst in a wet flowering season when the fungus spreads fastest.
Copper-based fungicide or mancozeb (copper oxide with metalaxyl-M did best in laboratory tests); sprays timed to flush, flowering and fruiting; open the canopy by pruning; remove infected material. The opening: develop bio-fungicides (soybean and cashew-shell extracts, still at laboratory stage) and a certified spray-and-scout service timed to flowering.
A flowering-season fungus that does most of its damage at flowering.
Losses of 70 to 100 percent recorded in Tanzania. West African surveys find low incidence, but TCDA and CRIG listed it among growing disease threats in August 2026.
Orchards in humid, poorly ventilated sites, and any crop caught unprotected at flowering.
Sulphur dust; systemic triazoles; plant resistant or tolerant clones; prune for airflow. The opening: tolerant-clone nurseries and sulphur or fungicide distribution.
Twig and branch dieback and gum exudation, caused by Lasiodiplodia theobromae with C. gloeosporioides; it can kill young trees.
Gummosis found on about 7 to 14 percent of trees in surveyed Bono orchards.
Young orchards and stressed trees, and any block where dead wood is left standing as inoculum.
Prune and burn dead wood; seal wounds; copper fungicide on cuts; remove inoculum. The opening: pruning and sanitation service crews; wound-sealant products.
A soil-borne wilt, now the top cashew disease in Tanzania, and a watch-list item for Ghana.
Up to 100 percent loss where it takes hold. Not recorded in the Ghana orchard survey.
Nurseries and new plantings raised on unclean material, and any region importing seedlings without quarantine.
Quarantine seedlings; clean, true-to-type planting material; soil health; resistant rootstock (the toolbox is weak). The opening: clean-planting-material certification; Trichoderma or Bacillus biocontrol supply; a surveillance service.
A sap-sucking bug that feeds on flush, flowers and nuts.
The most common insect in surveyed Bono orchards; the sap-sucking bug complex can cut yield by up to 80 percent.
Orchards through the flush and flowering window, worst where sprays are mistimed or absent.
Weaver-ant colonies (a bait spray lifts the gain further); targeted sprays (dimethoate, lambda-cyhalothrin) only when needed. The opening: a weaver-ant integrated-pest-management advisory and bait-spray service.
Sap-feeders that scar the nut surface and lower the nut grade, and can defoliate a tree.
The loss is more in quality than in yield.
Growers selling into graded, quality-linked markets where a scarred nut is downgraded.
Fruit-fly bait spray (which also suppresses thrips); monitoring and scouting; sanitation. The opening: a scouting and monitoring service linked to a quality premium.
In India the grub bores the trunk and can kill a tree in one to three years.
It was not recorded in the Bono orchard survey, so it is a watch-list pest for Ghana. In an Indian trial, 7 percent of trees treated with Metarhizium fungus and neem cake were infested against 20 percent untreated.
Established orchards, should the pest arrive, where early trunk damage goes unnoticed until the tree is lost.
Metarhizium fungus with neem cake; neem-oil trunk swab; early detection. The opening: local production of bio-pesticides (Metarhizium, Beauveria) and a prophylaxis service.
Girdles fruiting branches so they snap in wind, losing all their fruit.
Recorded as the most common destructive beetle in Ghana orchards.
Orchards in windy, exposed sites where snapped fruiting branches cut the harvest.
Cut and burn girdled wood (sanitation is the best control); targeted insecticide at the base in the rains. The opening: sanitation crews and extension training.
A handling failure that ruins a good nut between the tree and the buyer, lowering quality and kernel outturn.
About 76 percent of 247 farmers surveyed in 2009-10 had no store and many dried for only 3 to 4 days.
Smallholders without a store, and any aggregator paying a flat price that ignores outturn.
Dry to 10 percent moisture or below on raised mats; store in clean jute sacks on pallets in a ventilated store; do not mix old and new nuts. The opening: solar dryers, raised platforms and aggregation warehouses; outturn-based pricing.
Carcinogenic aflatoxin B1 concentrates in damp storage and is an instant export-rejection risk.
The EU caps aflatoxin B1 at 2 micrograms a kilogram in kernels for direct consumption, and 5 for nuts still to be sorted.
Any exporter or processor selling into the EU and other tested markets, where one lapse loses the consignment.
Keep moisture low; reject mouldy or insect-damaged nuts; ventilated storage; aflatoxin testing for export. The opening: aflatoxin-testing labs and food-safety certification for market access.
Dry-season fire that can take a whole block of orchard.
Fires in January 2022 destroyed more than 5,000 acres of cashew in 24 communities of Banda District, and fires still burn cashew farms each dry season, as at Asueyi in Techiman North in January 2026.
Orchards bordering grassland, and farms without cleared fire breaks in the dry season.
Fire belts of 20 to 30 metres; community fire-volunteer squads; by-laws; agroforestry buffers; cashew itself as a living firebreak. The opening: firebelt-ploughing services and community fire-prevention programmes.
Flowering-window weather. Dry harmattan wind and heat abort flowers; unseasonal rain at flowering spreads disease and drops the crop.
Unfavourable weather was blamed for the roughly 30 percent fall in 2024, and heavy rain disrupted drying in 2026.
Orchards in exposed corridors, and any grower whose flowering window catches the harmattan or an unseasonal rain.
Windbreaks; site selection out of exposed corridors; time disease control to the wet flowering window. The opening: windbreak agroforestry and weather-indexed advisory or insurance.
Hotter, more erratic seasons are expected, but no Ghana cashew projection has been published.
71 percent of savannah cashew farmers surveyed said cashew copes with climate variability better than staple crops.
Growers on the drying margins of the current belt, and investors siting new orchards for the next twenty years.
Drought-tolerant clones; agroforestry and intercropping; suitability-based siting; irrigation at establishment. The opening: resilient planting material, and positioning cashew as an adaptation crop for the savannah zone.
Witches' broom is sometimes named as an emerging cashew threat, but the Ghana and West African cashew disease surveys record no witches'-broom or phytoplasma disease of cashew. It should be treated as a biosecurity and import-screening risk.
No cashew witches'-broom or phytoplasma disease is recorded in Ghana or West African cashew surveys. It is an import-screening risk to monitor.
Import and quarantine authorities, and nurseries bringing in material from affected regions.
Import biosecurity and phytosanitary screening; surveillance by the Plant Protection and Regulatory Services Directorate and CRIG. The opening: a phytosanitary and early-warning diagnostics service.
Every cashew threat is also a market: the disease sells a spray-and-scout service, the pest sells weaver-ant biocontrol, the mould sells testing and safe storage, and the fire sells fire belts and windbreaks.
Anthracnose and the flowering-season fungi decide the crop, taking 70 to 100 percent where uncontrolled; a copper-oxide and metalaxyl-M mix did best in laboratory tests in Ghana, and a soybean extract is a candidate bio-fungicide.
Weaver-ant biocontrol is a near-free yield multiplier: in a Benin trial ants alone gave 78 percent more nuts and ants with a bait spray 151 percent more, and because the ants replace chemical sprays they are an enabler for the organic premium.
Drying and storage decide the price: about 76 percent of farmers surveyed in 2009-10 had no store, and damp nuts invite aflatoxin, which the EU caps at 2 micrograms a kilogram in kernels for direct consumption.
Fire and weather decide the year: fires in January 2022 burnt more than 5,000 acres of cashew in Banda District, and unfavourable weather drove Ghana's roughly 30 percent production fall in 2024, yet cashew's drought tolerance makes it an adaptation crop for the savannah.
Where this connects. The biological controls that run through this pillar are the enabler for the certified-organic premium in Pillar 2, and the drying, storage and food-safety discipline decides the grade and price that Pillar 5 turns into money. The drought tolerance that lets cashew hold in the savannah is part of the strategic case in Pillar 8, and the digital scout-and-alert service belongs to the technology openings in Pillar 7. Across all of them the pattern is the same: sell the control as well as the crop.
