Development of a cashewnut powdery mildew disease resistant variety for enhanced cashew nut production in coastal Kenya
Cashew is the most important cash crop in coastal Kenya. It is grown in Kwale, Kilifi, Tana River, Mombasa and Lamu Counties. The cashew nuts industry directly and indirectly employs 4000 and 50,000 people, respectively. In 2016, the area under cashew was estimated at 21,284 ha with a production of 11,404Mt valued at Kshs. 398,799,443. Kenya has an installed processing capacity of 45,000 tons/year raw cashew, which is way above production level. In 2015 the country exported 600 Mt of cashew kernels. The global demand for processed cashew nuts and its accompanying value added products is increasing steadily. The demand for fair trade and organic cashew is also on the increase. These nuts are in high demand in Germany and Nordic countries. Cashew is therefore a good crop for investment and development support.
The most serious biological constraint in cashew nut production is cashew powdery mildew disease, (Oidium anacardii Noack). This is a fungal disease, which attacks young panicles and flowers, with consequent effect on the apple and the nut and may cause crop loss of 70 – 100%. This explains why mature cashew trees with potential to produce over 30 kg per tree annually are now producing less than 5 kg annually. One of the management practices that have been used to minimize the effect of the disease is use of resistant/tolerant varieties. In Kenya there are many cashew accessions from local collections and introductions from other countries. The collections have not been evaluated for resistance/tolerance to powdery mildew to identify suitable ones for dissemination to farmers. The proposed project will focus on addressing powdery mildew problem in cashew through development of resistant/tolerant varieties. Proposed sub-activities:
- Screen for resistance/tolerance to cashew powdery mildew disease in cashew varieties in coastal Kenya
- Recommend promising varieties for registration by KEPHIS
- Develop an integrated pest management protocol for the management of powdery mildew
- Develop a protocol for rapid multiplication of disease-free planting materials