Controlling silverleaf whitefly (Bemisia tabaci biotype B) using limonene-scented kaolin: A non-insecticidal approach

Despite intensive control efforts, silverleaf whitefly, Bemisia tabaci biotype B, remains a difficult pest to manage due to its wide host range and ability to easily switch feeding between vegetable hosts and surrounding weed hosts. To develop more economic management strategies, kaolin clay was tested as a whitefly repellent in association with limonene, a natural plant-based repellent. Whitefly host selection was evaluated between kaolin and limonene-coated plants compared to controls using closed cage bioassays. It was found that combining limonene and kaolin had an additive effect on controlling adult whiteflies compared to controls. In addition, both nymph and adult populations were surveyed in tomato field trials conducted during two fall seasons in Quincy, Florida. The field trials included a limonene only treatment, kaolin only treatment, limonene-scented kaolin treatment, and a control. It was found that, during dry conditions, tomatoes treated with limonene-scented kaolin had a three to four-fold reduction in B. tabaci adult populations compared to controls and a two to three-fold reduction compared to both kaolin and limonene only treatments. In addition, infection with Tomato Yellow Leaf Curl Virus (TYLCV) was at least two times lower on average in limonene-scented kaolin treatments compared to controls. This translated to a two-fold increase in total quality weight at harvest. During wetter conditions, we only observed a decrease in adult populations with limonene-scented kaolin. The results from this study demonstrate a promising novel pest management strategy that lowers the amount of conventional insecticides used and targets B. tabaci adult behavior.