Selectivity of pesticides used on cotton (Gossypium hirsutum) to Trichogramma pretiosum reared on two laboratory‐reared hosts

Abstract

The side-effects of pesticides (insecticides, fungicides, herbicides and plant growth regulators) used on cotton were tested on adults and pupae of Trichogramma pretiosum Riley reared in the laboratory on two different hosts, the Angoumois grain moth (Sitotroga cerealella Olivier) and the Mediterranean flour moth (Ephestia kuehniella (Zeller)). The eggs of the host enclosing the parasitoid pupae received direct pesticide sprays, while the adults of the parasitoid were exposed to the pesticides through contact with residues on sprayed eggs offered to parasitism. Alpha-cypermethrin, carbosulfan, deltamethrin, endosulfan, profenofos and zeta-cypermethrin were highly noxious to the parasitoid, significantly reducing the percentage of emergence and parasitism of T. pretiosum developing in E. kuehniella or S. cerealella eggs. However, the pupal stage of the parasitoid developing in S. cerealella eggs was less susceptible to alpha-cypermethrin and deltamethrin. Lufenuron and metamidophos greatly reduced the percentage of adult emergence from eggs of both hosts, while novaluron only interfered on this variable when the wasps were developing in E. kuehniella eggs. However, lufenuron and monocrotophos had no effect on the parasitoid pupae of T. pretiosum developing in E. kuehniella eggs. Chlorfluazuron, diafenthiuron, diflubenzuron, fentin hydroxide, mepiquat chloride, novaluron, thiacloprid and triflumuron did not affect T. pretiosum emergence when eggs of S. cerealella enclosing pupae of the wasps were surface treated. The pesticides azoxystrobin, carbendazin + thiram, mepiquat chloride and novaluron had no effect on the ability of the wasps to parasitise E. kuehniella eggs. However, only mepiquat chloride did not affect the percentage of F1 wasps emerging from E. kuehniella eggs. The remaining pesticides moderately reduced the percentage of emergence and parasitism of the wasps when they had contact with the chemicals during their pupal or adult stage. Thus there were differences in pesticide toxicity according to the host used for parasitoid development. These differences were hypothesised to occur because of differences in egg morphology and parasitoid performance.

Seletividade de herbicidas registrados para a cultura do milho a adultos de Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)

“…O herbicida Gramocil (0,20% paraquat + 0,10% diuron) foi testado por Bastos et al (2005), que ofertaram ovos de A. kuehniella e Sitotroga cerealella (Lepidoptera: Gelechiidae) contaminados ao parasitóide T. pretiosum, resultando em parasitismos de 53,89 e 36,02%, respectivamente, ambos diferindo do tratamento testemunha. Trabalhos envolvendo somente o ingrediente ativo paraquat não foram encontrados na literatura, entretanto se verificou alta mortalidade de adultos de T. pretiosum no presente estudo (Tabela 2, bioensaio III), bem como em pesquisas que envolveram outros ingredientes ativos junto ao paraquat (Bastos et al, 2005).…”

“…Trabalhos envolvendo somente o ingrediente ativo paraquat não foram encontrados na literatura, entretanto se verificou alta mortalidade de adultos de T. pretiosum no presente estudo (Tabela 2, bioensaio III), bem como em pesquisas que envolveram outros ingredientes ativos junto ao paraquat (Bastos et al, 2005). Na literatura não foram encontrados trabalhos relacionados à seletividade de herbicidas a Trichogramma para a cultura do milho, pois somente alguns inseticidas foram testados até o momento (Cruz, 1995;Pratissoli et al, 2004).…”

Selectivity of pesticides used in rice crop on Telenomus podisi and Trichogramma pretiosum

“…Pests and their natural enemies are generally from different orders. Moreover, insect growth regulators affect immature stages of insects during the whole molting process (Reynolds 1987), and, thus, adults of non-target species, such as parasitoids and predators, are rarely affected (Bastos et al 2006). Lufenuron, triflumuron and novaluron, belonging to the Benzoylurea chemical group, as well as diflubenzuron, were also described as harmless to T. pretiosum (Carvalho et al 2010) be recommended for integrated pest management programs.…”

Effect of Some Insecticides on the Egg Parasitoid, Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae)

“…The neonicotinoids Thiacloprid and acetamiprid demonstrated strong larvicidal and ovicidal activity but were somewhat weaker adulticides than the conventional broad-spectrum compounds while, Azinphosmethyl, phosmet, indoxacarb, Thiacloprid, and acetamiprid were all toxic to the egg parasitoid T. minutum Riley. Also, [14] found that Thiacloprid did not affect T. pretiosum emergence when eggs of S. cerealella enclosing pupae of the wasps were surface treated.…”

“…In a standard IOBC glass plate assay, residues of Thiacloprid (SC 480) severely affected adult stages of the cereal aphid parasitoid Aphidius rhopalosiphi whereas pre-imaginal stages (which develop within the host) revealed a high tolerance against spray treatment with the same insecticide [13]. Also [14] studied the selectivity of pesticides including Thiacloprid on cotton Gossypium hirsutum to T. pretiosum relared on two laboratory-reared hosts.…”