Tolerance of Potato Varieties to Pests and Diseases under Irrigated and Non-Irrigated Conditions in Semi-Arid Machakos, Kenya

Publication Type

Journal Article

Journal Name

Potato Research

Publication Date

4-1-2026

Abstract

Droughts, pests, and diseases are among the most challenging production constraints facing smallholder potato farmers in Africa. The current study evaluated the response of potato cultivars to tuber pests and diseases under varied soil moisture regimes in a semi-arid region in Kenya. Sixteen potato varieties were subjected to field experimental screening in two seasons at two different sites based on a randomized complete block design with non-irrigated and irrigated plots constituting the main experimental blocks. The treatments showed significant (P ≤ 0.05) variations in the susceptibility of varieties to crop and tuber pests and diseases in respective seasons, sites and time intervals. No single variety exhibited complete tolerance to aphid infestation under either soil moisture regimes. In contrast, Desiree and Royal varieties exhibited significantly higher tolerance to beetles and whiteflies in seasons one and two, respectively (P ≤ 0.05). Mayan Gold was the only variety that recorded significant tolerance to early and late blight. Similarly, no single variety exhibited susceptibility or tolerance to tuber diseases and pests across treatments, sites and seasons. Correlation analysis revealed significant relationships among and between pests, diseases and yield. A significant and strong positive correlation was observed between whitefly presence, diseased tubers, and yield across treatments (P ≤ 0.05). Overall, cultivar susceptibility to insect pests and diseases varied significantly, with no single variety demonstrating consistent resistance. These findings underscore the importance of considering both soil moisture availability and local agroecological conditions when selecting potato varieties for pest and disease management. For farmers and researchers, integrating water management with site-specific varietal selection offers a practical pathway to improve resilience and productivity in potato farming systems under climate stress.

Keywords

Alternaria solani, Arid and semi-arid lands (ASALs), Drought stress, Phytophthora infestans, Potato diseases, Potato pests, Varietal tolerance

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