SP2: Development of Integrated Pest Management Strategies for the Production of Important Vegetable Crops in Kenya

I. Root-knot Nematode pests, viruses and phytoplasmas on African nightshades (HUB und KU)

African nightshades are of high impact to food security and income generation among the subsistence and semi-commercial farmers in Kenya. Several pests hamper production of the Solanum species are summarized under the label African Nightshade. They include root-knot nematodes (RKN), virus and phytoplasma caused damages. RKN disease incidence of up to 60% on African nightshades in parts of Kenya is reported. Several virus infections are also frequently reported including PepMV, 3 TyLCD, TYLCV, Potato mop top and PLRV. Unfortunately, the knowledge of the situation in African nightshades on these pests is limited. Misinterpretation of symptoms often results in wrong plant treatment. To avert further losses, there is an urgent need to develop a sustainable and environmentally sound management strategy while at the same time maintaining high production standards and food safety in conformity with the market requirements. Such an approach will start with the determination of the Solanum (S.) species summarized under the umbrella of African nightshade including S. nigrum, S. americanum, S. scabrum, S. eldoretii and S. villosum. Therefore, damages caused by these pathogens have to be assigned to species and corresponding phenotypes. Screening, determination and on-site diagnostic tools are a central part of this objective. Furthermore, soil treatment with nutrients and the influence of periodical cultivar changes will be evaluated for the management of nematode infections. All results will be made available through informational material for the local plant protection service and farmers, as well as published in scientific journals.

II. Management of important cowpea pests (HUB, JKI und ICIPE)

The Food and Agriculture Organization (FAO) reported that Kenya produced about 72,274 tons of dry cowpeas in 2010 (FAOSTAT, 2010). This economic contribution of the crop can be improved if constraints faced by farmers are addressed. These constraints include: arthropod pests and diseases, contamination from toxic chemicals from industries, lack of high yielding cultivars and poor crop management practices. Among the major arthropod pests the legume pod borer (LPB) (Maruca vitrata) and the cowpea aphid (Aphis craccivora) play the most important role. They cause 60-80% damage to foliage, flowers, buds and pods and transfer different virus diseases. To counter these pest problems, farmers use expensive and toxic synthetic chemicals without effectively achieving the desired goals. Therefore, raising cowpea production requires scientific intervention focusing on a better knowledge and understanding of pest bioecology. Among the technologies being developed for the management of the LPB include: a refined sex pheromone system for population monitoring, and the use of biopesticides and botanicals for control of different stages of the pod borer. Additionally the subprojects develops entomopathogenic fungi formulations which can be used as biopesticides against cowpea aphids.

III. Production of healthy leafy indigenous vegetables (JKUAT, LUH, ICIPE)

All activities in this subproject will be conducted on small-scale farms in different regions of Kenya. The focus of this subproject is on specific diseases (C1: JKUAT, LUH), spider mites and insect pest species (C2: icipe, JKUAT, LUH). In activity C1 the impact of fungal infections i.e. powdery mildew, will be studied in plant nurseries. Resistance of vegetable seeds/seedlings to diseases will be characterised and strategies to enhance resistance will be evaluated. Additionally, the impact of fertiliser on the potential resistance to diseases will be studied to develop management strategies to reduce fungal diseases on seedlings in plant nurseries. The focus of activity C2 is on the management of sucking pests in the agroecosystem of indigenous leafy vegetables. Based on the analysis of the agroecosystem in terms of population dynamics of sucking pest species and virus-vector interactions, infection pathways will be identified. Additionally, the impact of cultural practice i.e. use of fertiliser, on plant secondary metabolites and population dynamics of spider mites will be studied to minimise crop damage. Finally, the different strategies will be linked to the use of intervention measures (e.g. neem, pyrethrum, natural enemies) to develop integrated pest management strategies for sustainable production of leafy indigenous vegetables in East Africa.

Project partners

Cooperation with other subprojects or third parties