Effect of Pesticides on <I>Colpoclypeus florus</I> (Hymenoptera: Eulophidae) and <I>Trichogramma platneri</I> (Hymenoptera: Trichogrammatidae), Parasitoids of Leafrollers in Washington

Abstract

Pesticides were evaluated for their effect on two parasitoid species, Colpoclypeus flouts and Trichogramma platneri, that are potential biological control agents of leafrollers in apple orchards. Organophosphate and carbamate insecticides were highly toxic to both parasitoids in topical applications, but foliar residues of some products were nontoxic after 7 d. At reduced rates, topically applied pyrethroids were low in toxicity to C. florus were highly toxic to T. platneri, and foliar residues were nontoxic after about 7 d. Imidacloprid and abamectin were highly toxic when applied topically to both parasitoids but were not toxic as 1-d-old residues. Insect growth regulators did not cause mortality either as topical applications or residues; however, diflubenzuron caused severe sublethal effects, completely blocking the production of C. florus offspring. Biorational pesticides, such as soap, oil, and B. thuringiensis products, caused no toxicity to C. florus but had a direct impact on T. platneri as topical applications through physical immobilization. The potential to integrate different pesticides with biological control of leafrollers and the need for a step-wise approach to evaluate the impact of pesticides against natural enemies is discussed.

The Effect of Some Botanical Pesticides Against Citrus Leafminer (CLM) and Two Spotted Mite (TSM)

“…Plant allelochemicals may be quite useful in increasing the efficacy of biological control agents because plants produce a large variety of compounds which increase their resistance to insect attack (Senthil Nathan et al, 2005a). In addition, the translocation and translaminar properties of the above insecticides make them available in the host plant tissues to control leaf feeders, however, surface residues disappear quickly, thus making them safe for parasitoids and most natural enemies (Brunner et al, 2001). Reldan has a lower mammalian toxicity, LD 50 (oral, rat) is 3000 mg/kg, than Dursban with an LD 50 (oral, rat) of 135 mg/kg (Kalyanasundaram et al, 2003).…”

Toxicidade de pesticidas recomendados na produção integrada de maçã (PIM) a populações de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)

“…A tolerância diferenciada das populações de C. externa observada no presente estudo pode estar associada às suas origens geográficas diferentes (Bleicher & Parra 1990, Brunner et al 2001, bem como às variações de exposição das mesmas a determinados compostos, ocorrendo em seu hábitat de origem (histórico de uso de pesticidas), o que, segundo Croft (1990), pode provocar a seleção de indivíduos mais tolerantes, diferenciando as respostas das populações aos pesticidas. De fato, os insetos oriundos dos pomares localizados no município de Vacaria apresentavam histórico de exposição a aplicações dos pesticidas avaliados neste estudo.…”

“…Essa divergência, possivelmente, se relaciona às origens geográfi cas diferenciadas (Bleicher & Parra 1990, Brunner et al 2001 das populações do predador estudadas, o que foi relatado anteriormente, e que pode causar a seleção de indivíduos ou populações mais tolerantes (Croft 1990).…”

The Release of the Parasitoid Trichogramma evancens to Control the Pink Bollworm Pectinophora gossypiella (Saunders) and the Side-Effect of Certain Insecticides on It

“…Chemicals can be immediately toxic and cause death (contact toxicity) and this effect can persist due to toxicity of dried residue Thomson et al, 2000). Contact with pesticides at the less susceptible life stages (parasitoids within eggs of their hosts) can cause prolonged development at time of the immature stages and reduced rates of emergence, fecundity, parasitism capacity, adult longevity and mating likelihood (Franz et al, 1980;Consoli et al, 1998, Hassan et al, 1994Brunner et al, 2001;Takada et al, 2001).…”