Survival of Geocoris punctipes Say (Hemiptera: Lygaeidae) Following Exposure to Selected Reduced-Risk Insecticides

Abstract

Survival of Geocoris punctipes Say adults following exposure to azadirachtin, spinosad, thiamethoxam, diazinon, and imidacloprid was assessed in laboratory assays and greenhouse tests. In the laboratory assays, adults were continuously exposed for 48 h to filter papers treated with the individual insecticides. Survival was greatest following exposure to the untreated control (100 ± 0.0%), azadirachtin (95.0 ± 2.2%), and imidacloprid (81.7 ± 7.9%). Mean (± SEM) survival following exposure to spinosad (55.0 ± 11.2%) and thiamethoxam (46.6 ± 3.3%) was significantly lower, whereas diazinon killed all adults within 12 h of exposure. In the greenhouse tests, adults were continuously exposed to bush beans, Phaseolus vulgaris L., foliage treated with the individual insecticides. Mean (± SEM) survival following 144 h of continuous exposure to treated foliage was 97.5 ± 2.5% for the untreated control, 92.5 ± 5.3% for azadirachtin, 92.5 ± 3.7% for diazinon, 72.5 ± 8.4% for imidacloprid, 70.0 ± 8.4% for spinosad, and 57.5 ± 8.8% for thiamethoxam. Statistically significant differences were observed with thiamethoxam versus diazinon, azadirachtin and the control. The results for the filter paper assay and the greenhouse tests are encouraging in terms of potential natural enemy conservation in IPM programs employing these insecticides.

Efficacy of Reduced-Risk Insecticides to Control Flower Thrips in Early-Season Blueberries and Their Effect on <i>Orius insidiosus</i>, a Natural Enemy of Flower Thrips

“…The number of survivors was significantly lower than the control after 15 h of exposure to treated green beans. This 'lag time' has been observed with other species such as Geocoris punctipes Say [17] and in blueberry maggot, Rhagoletis mendax Curran [28].…”

The negative effect of some selective insecticides on the functional response of a potential biological control agent, the spider Philodromus cespitum

“…Azadirachtin, the active ingredient of NeemAzal, is an ecdysone antagonist that disrupts insect molting (Tomlin 2000). NeemAzal was found to be only slightly harmful to Geocoris bugs (Myers et al 2006), Harmonia beetles, and Mallada lacewings (Qi et al 2001). Podisus bugs had, however, slightly reduced survival and reproduction (Viñuela et al 2000).…”

“…Spinosad, its active ingredient, causes paralysis by activation of the nicotinic acetylcholine receptors (Tomlin 2000). It was found to be toxic to heteropterans (Studebaker and Kring 2003;Myers et al 2006), some hymenopteran parasitoids (Nowak et al 2001), staphylinid beetles, and earwigs (Cisneros et al 2002). It has, however, little negative effect on the survival or reproduction of predatory mites, Harmonia coccinellids (Musser and Shelton 2003), Deraeocoris bugs (Kim et al 2006), Picromerus bugs (Mahdian et al 2007), and braconid wasps (Vargas et al 2001).…”

The non‐target impact of spinosyns on beneficial arthropods

“…The survival of G. punctipes adults was assessed under greenhouse conditions following exposure to dry residues of spinosad (sprayed at 50 g AI ha −1 ). Predator survival was reduced significantly after a 6 day exposure period, while no differences were highlighted for shorter exposure periods, thus indicating that the side effects were related to the time the predator takes to ingest and absorb the compound 63. The same exposure‐time‐dependent effect has also been demonstrated by Lakshmi et al 132 when the two mirid bugs Cyrtorhinus lividipennis Reuter and Tytthus parviceps (Reuter) were exposed to spinosad (56 g AI ha −1 ) under controlled greenhouse conditions the mortality rates increased in relation to the length of exposure time (24, 48 and 72 h after treatment).…”

“…For example, topical treatments and exposure to dried spinosad residues at the field rate had no significant lethal effect on Chrysoperla carnea (Stephen),59, 61 but, when adults ingested treated prey or insecticide mixed with artificial diet (concentrations ≥ 12.5% of the field rate), 100% mortality occurred rapidly 61. Exposure of heteropteran predators to dried residues (see supporting information Table S1) was harmless for Nesidiocoris tenuis (Reuter), Macrolophus pygmaeus (Rambur) and Picromerus bidens L. adults,38, 62 harmful (50% mortality) for Geocoris punctipes Say,63 while it was very harmful (up to 100% mortality) for Orius laevigatus Fieber and O. insidiosus (Say) adults 39, 40, 64, 65. An acute lethal effect on O. laevigatus has also been found 14 days after the initial treatment with the rate recommended for management of Diptera leafminers in multiple crops (360 mg AI L −1 ) 39.…”