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 override 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.

Identifying critical research gaps that limit control options for invertebrate pests in Australian grain production systems

“…Methods like habitat manipulation for increasing populations of natural enemies have received some attention but have not been operationalised in Australian grain production (Bianchi et al 2006;Gurr et al 2018). Methods like habitat manipulation for increasing populations of natural enemies have received some attention but have not been operationalised in Australian grain production (Bianchi et al 2006;Gurr et al 2018).…”

“…Cultural control approaches such as tillage, stubble retention, planting density and crop rotations are all understudied in relation to pest and natural enemy species. Methods like habitat manipulation for increasing populations of natural enemies have received some attention but have not been operationalised in Australian grain production (Bianchi et al 2006;Gurr et al 2018). Furthermore, integration of control options is critical for successful IPM, and some of the knowledge gaps identified may limit this.…”

Virulence of the plant-associated endophytic fungus <i>Lecanicillium muscarium </i>to diamondback moth larvae

“…Parasitic wasps can attack larvae or pupae of DBM. The most commonly promoted species are wasps of the genera Diadegma, Diadromus or Cotesia, since some can reduce DBM populations by up to 80% (Gurr et al 2018;Hermansson 2016). Use of the bacterium Bacillus thuringiensis (Bt) has proven to be very effective in controlling DBM in many parts of the world.…”

“…Fungal genera such as Lecanicillium, Isaria or Metarhizium have shown ability to control DBM populations. However, the most widely used fungus in field conditions is Beauveria bassiana (Gurr et al 2018).…”

Genetic control of Plutella xylostella in omics era

“…Integrated pest management (IPM), including biological control, habitat management and integration of pest, and natural enemy population dynamics, has been indicated proven to be environmentally friendly and to provide sustainable control of P. xylostella (Shakeel et al, ). However, these strategies are highly dependent on the understanding of natural ecosystems and vary with climatic and environmental conditions (Gurr et al, ; Sarfraz, Keddie, & Dosdall, ). With the advent of genomics and associated “omics” tools, genetic control of P. xylostella becomes possible.…”