Economic injury levels and sequential sampling plans for control decision‐making systems of Bemisia tabaci biotype B adults in watermelon crops

BACKGROUND Decision‐making systems are essential parts of integrated pest management programs. The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is a major pest of many crops, including watermelon ( Citrullus lanatus ), the second most consumed fruit worldwide. However, there are still no studies on decision‐making systems for B. tabaci on this crop. Thus, we aim to determine a decision‐making system to control B. tabaci biotype B on watermelon crops. RESULTS The highest densities of B. tabaci biotype B reduced the yield of watermelon crops by up to 56%. Watermelon plants were more susceptible to the pest at the vegetative stage than at the reproductive stage. The economic injury levels of B. tabaci biotype B when watermelon prices were low, average, and high were respectively, 0.52, 0.21 and 0.13 adults leaf −1 at the vegetative stage, and 1.69, 0.69 and 0.44 adults leaf −1 at the reproductive stage. The sequential plans reached the same decisions as the conventional plan, and reduced the time and cost of sampling by up to 92.68%. CONCLUSION The decision‐making systems determined in this study enable an expedited and proper decision to be made for controlling B. tabaci , biotype B and can be used in different price situations for watermelon and in crops at different phenological stages. © 2018 Society of Chemical Industry