Potential for Integrating Eleven Agricultural Insecticides with the Predatory Bug <I>Pristhesancus plagipennis</I> (Hemiptera: Reduviidae)

Abstract

A problem for growers attempting to implement integrated pest management programs is the lack of information regarding the compatibility of insecticides with natural enemies. To provide information about this problem, we evaluated the acute and residual effects of 11 commonly used insecticides on nymphs of Pristhesancus plagipennis (Walker) under both laboratory and field conditions. For each insecticide, the length of time that weathering residues caused > 50% mortality was evaluated and compared against the LC50 (acute-toxicity) divided by the recommended field rate. Plots thus combined the acute and residual toxicity of each insecticide. Results suggested that carbaryl, esfenvalerate, endosulfan, and deltamethrin had low residual and acute toxicity to P. plagipennis, whereas chlorpyrifos, methomyl, and monocrotophos were highly toxic at low concentrations and left persistent harmful residues. Cypermethrin, methidathion, malathion, and dimethoate were moderately toxic. The potential use of these insecticides to supplement the control activity of P. plagipennis is discussed.

Utilizing the assassin bug, Pristhesancus plagipennis (Hemiptera: Reduviidae), as a biological control agent within an integrated pest management programme for Helicoverpa spp. (Lepidoptera: Noctuidae) and Creontiades spp. (Hemiptera: Miridae) in cotton

“…Previous registered options for Creontiades spp. control were predominantly organophosphate products, such as dimethoate and omethoate, which were found to be highly toxic to P. plagipennis during this and earlier experiments (Grundy et al , 2000a). The high toxicity of diafenthiuron to P. plagipennis was unexpected as previous research on related predators such as Nabis , Geocoris and Orius spp.…”

“…Four-day-old first instar P. plagipennis were used in each experiment, as earlier studies indicated that this stage was the most sensitive and, therefore, provided a ‘worst case’ test result (Grundy et al , 2000a). Pesticides that are found to be non-toxic using the assumptions of a ‘worst case’ test generally require no further testing on other stages (Hassan et al , 1994).…”

“…Earlier insecticide compatibility studies suggested that P. plagipennis were tolerant of some organochlorine and carbamate insecticides (Grundy et al , 2000a). However, these insecticides are generally considered toxic to a range of other beneficial insects found in Australian cotton fields for which disruption can give rise to secondary pest problems (Wilson et al , 1998) and are, therefore, unsuitable for use within integrated pest management programmes that seeks to emphasize the conservation of natural enemies for biological control.…”

Broad spectrum pesticide application alters natural enemy communities and may facilitate secondary pest outbreaks

“…Beyond the target pests, broad-spectrum pesticides (that kill insects and mites indiscriminately) may affect non-target invertebrate species ( Readshaw, 1975 ), including causing reductions in natural enemy population abundance and activity (e.g., Wilson, Bauer & Lally, 1998 ; Wilson, Bauer & Lally, 1999 ), and competition between pest species (known as competitive release, Zeilinger, Olson & Andow, 2016 ). Assays of invertebrates against weathered residues have shown the persistence of pesticides might play an important part in their negative impacts on natural enemies in the field ( Grundy et al, 2000 ).…”

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

“…A series of studies (Grundy et al . ; Grundy & Maelzer ; Grundy & Maelzer ; Grundy , ) have assessed the potential of artificially reared P. plagipennis in inundative releases for biocontrol in broad‐acre crops. In cotton and sunflower, where poor nymph dispersal is likely, the mechanical release of nymphs with vermiculite may be possible but requires further testing (Grundy & Maelzer ).…”