Conservation biological control research is strongly uneven across trophic levels and economic measures

Abstract

Conservation biological control suppresses pests by promoting established rather than inoculative or mass released natural enemies. Research in this approach has expanded rapidly this century but uptake remains limited. Why? Most of the 150 peer reviewed papers reporting field experiments include results on natural enemies and/or pests. Only a minority report effects on crop damage levels or yield, and very few consider economic consequences. This is despite evidence for potential benefits across this full spectrum of response variables. We argue that the limited scope of work to date constrains the development of a compelling evidence base to demonstrate the field effectiveness of conservation biological control, hampering its uptake so encourage researchers to include the assessment of economic impact in future studies of conservation biological control. © 2020 Society of Chemical Industry

Prospects for habitat management to suppress vegetable pests in Australia

“…Especially valuable is the identification of plant species which can provide benefits to the beneficial insects in a selective manner, denying benefit to key pest species (Baggen & Gurr 1998;Gurr et al 1998). Whilst the present review draws from successful overseas studies, a limitation of the available literature is that studies of improved efficacy of natural enemies and reduced pest numbers often do not measure effects on plant yield or, especially, the economics of production (Gurr et al 2016;Johnson et al 2020). This deficiency weakens the value proposition to growers (who care most about yield and profit and less about natural enemy densities) and has likely been a factor in the limited levels of uptake despite large numbers of research studies.…”

“…Therefore, we recommend that additional pilot studies should be conducted by researchers and farmers before these plant species are widely promoted. An additional caveat is that economic factors have been little investigated in habitat management research (Shields et al 2019;Johnson et al 2020) so the benefit : cost ratios of each technique need evaluation. Practical considerations, such as capacity to accommodate flower strips in irrigation rows rather than occupying productive, crop growing space, will influence the ratio of benefit to cost as well as general ease with which habitat management plants can be established and maintained.…”

“…2019; Johnson et al . 2020) so the benefit : cost ratios of each technique need evaluation. Practical considerations, such as capacity to accommodate flower strips in irrigation rows rather than occupying productive, crop growing space, will influence the ratio of benefit to cost as well as general ease with which habitat management plants can be established and maintained.…”

“…2016; Johnson et al . 2020). This deficiency weakens the value proposition to growers (who care most about yield and profit and less about natural enemy densities) and has likely been a factor in the limited levels of uptake despite large numbers of research studies.…”

Success, despite another plague year

“…Issues regarding the relatively slow regulatory approval of microbial biocontrol agents (mostly for insect management) are covered 20 . Our lack of adequate knowledge of the impacts (efficacy and economic) of biocontrol measures are considered in a perspective by Johnson et al 21 . The use of zoophytophagous mirid bugs, the parasitoid Trechnites insidiosius , and entomopathogenic fungi for insect biocontrol are reviewed 22–24 .…”