Landscape ecology and expanding range of biocontrol agent taxa enhance prospects for diamondback moth management. A review

Abstract

Diamondback moth (Plutella xylostella) is a globally significant pest of Brassicaceae crops that has attracted enormous research investment. It is typical of many agricultural pests, with insecticides remaining the most common method of control, despite frequent cases of resistance in pest populations and the potential for other management options such as natural enemies to provide suppression. Here we review scope to make better use of neglected natural enemy taxa and integrate recent work on landscape ecology to identify opportunities for more effective pest suppression. Our main findings are as follows: (1) relatively neglected taxa of natural enemies, especially predators and entomopathogens, are now attracting growing levels of research interest, although parasitoids remain most frequently used and researched; (2) knowledge of the spatio-temporal dynamics of populations at the landscape scale have advanced rapidly in the last decade; (3) ecological insights open new possibilities for exploiting spatial heterogeneity at scales larger than individual fields and even farms that influence pests and their natural enemies; (4) there is evidence for landscapes that selectively favor particular guilds and this knowledge could be developed to favor targeted natural enemies over pests in focal crops; and (5) landscape-scale effects can even over-ride field-scale management practices. The significance of these advances is that future management of diamondback moth and similar pests will benefit from a move away from reliance on the use of particular species of biological control agents, especially exotic parasitoids, and strategies that depend on use of broad-spectrum insecticides. Together with this move, we call for greater use of area-wide management that exploits the potential of landscapes to promote diverse assemblages of natural enemy species.