Hot water treatment of banana and yam planting material - IITA

IITAI N I T I A T I V E SHot water treatment of banana and yamplanting materialThe challengeHighland banana, plantain, and yams are important food crops in Africa.Banana and plantain are staple foods for more than 70 millionpeople. Yams are a preferred carbohydrate for many people, and play amajor role in West African culture.Among other pests and diseases, worm-like nematodes can cause seriousdamage to these crops.Nematodes attack the roots andcorms of banana and plantain,drastically reducing the bunchweight, and in extreme casesYam tuber dry rot caused by ScutellonemaHighland banana roots destroyed by Radopholus similisbradys.causing the plant to topple sothat the bunch is lost. Averageproduction losses due to nematodes are estimated at 30% of the harvest for highland banana in East Africa, and can exceed60% for plantain in West Africa.Nematode damage to yams can occur either during crop growth or during storage. Infestation during the growing seasonresults in poor plant development and reduced tuber weight, and hence lower market value. Even more damage is causedwhen nematode-infested yam tubers are put into storage. Nematodes cause dry rotting or severe galling of the yam tuber,which can be exacerbated by secondary infection by fungi and bacteria. More than 80% of stored tubers can be lost thisway, seriously depleting the farmer’s source of available food and potential income. Moreover, up to a third of stored yamtubers are used for planting the following season, and a nematode attack can significantly reduce the quantity, quality, andviability of this planting material.Nematodes are usually introduced to farmlands through the use of infectedplanting material. The nematodes are embedded deep in the plant tissue.Meeting the challengeOne control measure promoted by IITA is to immerse the banana, plantain,or yam planting material in warm water, at an optimum temperature of53°C, for approximately 20 minutes. This kills the nematodes in the tissuewithout affecting the germination of the planting material. Plants cleaned inthis way can then be planted in new farmland, or land where break cropshave been grown for one or two years, so that nematode numbers in the soilare low.This simple control method is low cost, environmentally friendly, and relativelyeasy for farmers to practice. A 1 m 3 tank is often used for the treatment,heated by propane gas, and easily transportable on a pick-up truck.Banana planting material treated in water of53ºC for 20 minutes

This treatment is most effective when combined with other pest management strategies,for example regular weeding, crop rotation including nonhost plants, and use ofpest-resistant cultivars.The impactWhen hot water-treated banana or plantain planting material is planted in previously uncultivatedland it can take 3–5 years before the plants are reinfested by nematodes to asignificant level. During this period production can be up to 50% higher compared withuntreated planting material, with the help of good management practices, especiallyweeding. Using this treatment, plantain’s plantationlife of two or three cycles can increase to fiveor more cycles. This means less pressure on theland as it reduces the need to clear new areas forA clean healthy yamfarming.Treatment of yam tubers before storing reducesdamage in storage, and significantly improves the next season’s harvest. Combining hot water treatment with other innovationscan have added benefits.In Ghana, where the availability of plantain planting material is a major production constraint, farmers effectively combinethis technology with rapid multiplication of plantain planting material.The futureIITA research in future will focus on:• facilitating adaption and adoption of the technology by farmer communitiesand NGOs• developing alternative designs of the tank and/or developing multiple uses forthe tank, so that it can be used at village level• the use of clean planting material for the dissemination of beneficialorganisms, such as those that help control the banana weevil or nematodes, orthat improve plant growthHealthy banana planting materialProductive highlandbananaFor further information, or if you would like to help fund this or similar work, please contact:Director GeneralInternational Institute of Tropical AgricultureOyo Road, PMB 5320, Ibadan, NigeriaTelephone: (+234 2) 241 2626Fax: (+234 2) 241 2221E-mail: iita@cgiar.orgor visit IITA’s website: www.cgiar.org/iitaInternational mailing addressIITA, c/o L.W. Lambourn & Co.Carolyn House26 Dingwall RoadCroydon CR9 3EEUnited KingdomInternational Institute of Tropical AgricultureA member of the Consultative Group on International Agricultural Research