Surrounding Vegetation, Climatic Elements, and Predators Affect the Spatial Dynamics of Bemisia tabaci (Hemiptera: Aleyrodidae) in Commercial Melon Fields.

Abstract

Studying the spatial dynamics of pests allows the determination of abiotic and biotic factors affecting time and locations of pest attack to the crops. Such abiotic and biotic factors mainly include 1) climatic elements, 2) natural enemies, 3) phenological stage of plants, and 4) surrounding vegetation. Melon (Cucumis melo L. [Cucurbitales: Cucurbitaceae]) is among the most consumed fruit in the world, and the whitefly Bemisia tabaci (Gennadius) is among the main pests of this crop. This work aimed to determine the effects of surrounding vegetation, natural enemies, climatic elements, and stages of plants on the spatial dynamics of B. tabaci in commercial melon fields. Adult whitefly densities were monitored on four melon fields in a tropical climate region. Sampling location in crops was georeferenced. Experimental data were submitted to geostatistical analysis. The highest densities of B. tabaci occurred during hot periods experiencing lower rainfall, and when the surrounding area presented crops hosting B. tabaci, especially other melon farms. The density ratio of the predators (i.e., spiders and Geocoris sp.) were dependent on pest density. The pattern of field colonization by B. tabaci varies according to its density. Therefore, the surrounding vegetation, air temperature, and predators influence the spatial distribution of B. tabaci in melon fields. These results provide important information to melon farmers, assisting them to improve the management of B. tabaci in the field.