Prevalence of Cashew Powdery Mildew Disease in Western Province of Zambia

Cashew powdery mildew disease (PMD) is the most devastating disease of cashew nuts lowering nut yields and quality in Zambia and the rest of the world. Information on prevalence patterns and timing of disease onset is vital to manage the disease in any country effectively. Cashew powdery mildew disease incidence and severity were assessed from 160 farmers randomly chosen from all agricultural camps in eight of the ten cashew-growing districts of the Western province of Zambia in April, May, June and July 2020. A two-way ANOVA was used to compare disease severity by month and district. Results showed significant differences (P < 0.001) in both PMD incidence and severity among different districts, with the highest incidence in Limulunga (55.88 %) and the least in Sikongo District (36.49 %). Disease severity was highest in Nalolo (57.49 %) and lowest in Sioma district (27.87 %). July registered the highest (61.89 %), and April had the lowest (20.08%) incidence of the disease. PMD severity was highest in July (51.69 %). The current study indicates that one of the best strategies to control PMD in this cashew-growing province of Zambia is to include control measures such as the removal of water shoots beginning February through March for all districts, chemical control beginning in April in Limulunga district and delayed to May for the rest of the districts. The study has also identified the hotspots of PMD that should be priority targets for disease management to maximize the use of limited resources.