Flowering agricultural landscapes enhance parasitoid biological control to Bemisia tabaci on tomato in south China.

Abstract

Agricultural landscape pattern may enhance biocontrol services by supporting parasitoid populations, including parasitoids of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). In this study, we selected four landscape types in Yunnan province, in south China, which were characterized by flower fields, mountain, river, and urban areas as their main elements. We then carried out systematic surveys in tomato fields found within each landscape type, to determine the diversity, occurrence, and parasitism rate of parasitoids. We found that parasitoids from the genus Encarsia and Eretmocerus were the main natural enemies present, and the most abundant species were recorded in the flower and the mountain landscapes. Also, Encarsia formosa (Hymenoptera: Chalcidoidea) formed the highest relative abundance regardless of the landscape type. We also found that the population density of B. tabaci in flower landscapes was the lowest than that in other landscape types. During the main activity period of B. tabaci, the parasitism rate in the flower landscape was higher than that in other landscape types. Our findings showed that the occurrence of B. tabaci was relatively mild in the flower landscapes. The landscape type was also beneficial to parasitoids as it enhanced their parasitism rate. Therefore, agriculture environmental schemes should consider increasing the size of flower fields in the surrounding landscape to enhance the sustainable control of B. tabaci by the natural agricultural ecosystem.