Living ground covers for management of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) and tomato yellow mottle virus (ToYMoV) in Costa Rica

The impact of whitefly-transmitted begomoviruses (Geminiviridae) on tomato yields depends on plant age at time of infection, and is greatest during the first 5 weeks after germination (critical period). A preventative strategy designed to minimize contact between the vector and the tomato plant by masking the crop with living ground covers during the critical period was promoted among small-scale Costa Rican farmers. A large-scale field experiment replicated over time and location was conducted to evaluate this strategy by assessing the effect of different living ground covers in comparison to the conventional control methods (insecticide or reflective mulch). Living covers including perennial peanuts (Arachis pintoi, Fabaceae), “cinquillo” (Drymaria cordata, Caryophyllaceae) and coriander (Coriandrum sativum, Umbelliferae) reduced the number of incoming whitefly adults, delayed the onset of tomato yellow mottle virus (ToYMoV), and decreased disease severity, resulting in higher yields and profits, compared to the bare soil control. Coriander provided additional economic returns when sold and was easier to establish and remove than the other living covers. Whitefly and begomovirus management with ground covers or reflective polyethylene mulch compared favorably with the conventional insecticide treatment using imidacloprid Therefore, living ground covers appeared to offer a viable and economic management alternative for resource-poor farmers.