Eco-pathological validation of weed preferences as reservoirs for tomato yellow leaf curl virus and whitefly

Weeds provide essential habitat for various agricultural pests and plant pathogens, making them a persistent threat to crop production. In the absence of their primary hosts, weeds serve as alternative reservoirs for pathogens, enabling pests to complete their life cycle and survive under adverse conditions. The sweet potato whitefly (Bemisia tabaci), a major global agricultural pest, sustains its population by utilizing diverse host plants, including weeds, which facilitate its migration to crops. Tomato yellow leaf curl virus (TYLCV) is a highly destructive plant virus with significant economic implications. It has a broad host range, including non-cultivated plants and weeds. This study analyzed naturally growing weeds for TYLCV, tomato chlorosis virus (ToCV), and whitefly infestation. Among 37 weed species comprising 93 individual plants from 16 families tested, 21 supported whitefly proliferation, 16 tested positive for ToCV, and 24 were infected with TYLCV-with 11 species harboring both viruses and whiteflies. To validate these findings, a greenhouse experiment was conducted using 59 weed species from 22 families infested with TYLCV-positive whiteflies. The results revealed that 38 species supported whitefly proliferation, 14 were TYLCV-positive, and 11 served as hosts for both viruses and whiteflies. This study confirms the role of weeds as reservoirs for TYLCV and its vector, the whitefly, under both natural and experimental conditions. By examining a diverse range of weeds across seasons, the study identified perennial, summer annual, and winter annual species as hosts. Further research is recommended to assess how seasonal fluctuations in infected weed populations influence virus transmission to healthy crops.