Valéria Fonseca Moscardini

Toxicity and sublethal effects of seven insecticides to eggs of the flower bug Orius insidiosus (Say) (Hemiptera: Anthocoridae).

The predatory bug Orius insidiosus is an important biological control agent of several insect pests, and is one of the most commonly used species in biological control programs worldwide. This study assessed the lethal and sublethal effects of insecticides on this species through life table, and classified the insecticides according to the definitions of toxicity given by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). A bioassay was carried out using a completely randomized design with eight treatments and 40 replicates. Eggs of O. insidiosus laid naturally in plant stems were immersed in aqueous solutions of the chemical products. Egg viability, duration of the embryonic period, survival of nymphs, and duration of the nymphal period were assessed daily. Insects that reached adulthood were paired and their reproduction assessed. The number of eggs produced and the survival of adults were assessed daily. The insecticides abamectin, cartap hydrochloride, spirotetramat+imidacloprid, and flubendiamid were classified as harmful. Pyriproxyfen and rynaxypyr were categorized as harmless and pymetrozine was classified as slightly harmful. Pyriproxyfen affected the population parameters rm, GT, DT, and λ, whereas other insecticides did not.

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

The goal of this work was to evaluate the effects of the pesticides abamectin, carbaryl, fenitrothion, methidathion, sulphur and trichlorfon on eggs of two Chrysoperla externa (Hagen) populations, as well as on the subsequent developmental stages and reproduction capacity of this green lacewing. Pesticide exposure and distilled water (control) were accomplished using a Potters tower. None of the evaluated pesticides affected the egg viability of the C. externa populations studied, but abamectin and carbaryl caused significant mortality of other developmental stages of the predator. Sex ratio and reproduction capacity of females originated from treated eggs were unaffected. However, egg viability of C. externa from Bento Goncalves, RS, Brazil, was reduced by sulphur. Considering to the total effect (E) of each pesticide, trichlorfon, fenitrothion, methidathion and abamectin were harmless to both C. externa populations (Bento Goncalves and Vacaria), when applied on eggs, whereas carbaryl was slightly harmful. On the other hand, the fungicide sulphur was slightly harmful to C. externa from Bento Goncalves, but harmless to those from Vacaria.

Efeitos da aplicação de agrotóxicos utilizados na produção integrada de maçã sobre pupas de Chrysoperla externa

Chrysoperla externa (Neuroptera: Chrysopidae) is an important biological control agent of artropod-pests in apple crop. In this research the effects of the pesticides (g a.i. L-1) abamectin (0.02), carbaryl (1.73), fenitrothion (0.75), methidathion (0.40), sulphur (4.80) and trichlorfon (1.50), on C. externa pupae from Bento Goncalves and Vacaria regions, Rio Grande do Sul, Brazil, as well as on the development of the adults obtained and its reproduction were evaluated. The sprayings of those compounds and distilled water (control) on pupae were accomplished using a Potter tower. Carbaryl and trichlorfon caused mortality of treated pupae in both studied populations. Abamectin only caused significant mortality of treated pupae from Vacaria; sulphur, fenitrothion and methidathion presented to be harmless to the predator. None of the compounds reduced the oviposition capacity of C. externa from Bento Goncalves, originated from treated pupae; however, fenitrothion caused reductions in that biological parameter for females from Vacaria. Among the evaluated pesticides, only carbaryl and abamectin did not reduced the viability of eggs laid by C. externa from Bento Goncalves and Vacaria, respectively. According to the total effect (E) of each pesticide, sulphur, fenitrothion and methidathion are harmless, whereas abamectin, carbaryl and trichlorfon are slightly harmful to insects from Bento Goncalves. Abamectin and sulphur are harmless to insects from Vacaria, while carbaryl, fenitrothion, methidathion and trichlorfon are slightly harmful, according to the IOBC classification.

Seletividade de inseticidas utilizados em cultura cafeeira para larvas de Cryptolaemus montrouzieri Mulsant

As well as most of the crops, in coffee crop, the association of selective compounds and natural enemies, composes an important tool for the integrated pest management (IPM). The objective of this study was to evaluate the selectivity of some pesticides used in coffee crops on larvae of Cryptolaemus montrouzieri Mulsant, 1853 (Coleoptera: Coccinellidae) under controlled laboratory conditions (climatic chamber) at 25±2°C, RH of 70±10% with a 12 h-photophase. The randomized experimental design was used, with six treatments and ten repetitions, being each composed for two larvae. For the comparisons of the averages of treatments, a factorial scheme was used with the products x number of instars for the different instars subsequent the application. The pesticides and doses in g of a.i. L-1 were: thiamethoxan (0.5), imidacloprid (0.7), mineral oil (13.3), endosulfan (2.63) and dimethoate (0.48). Distilled water was used as control. The sprayings of the pesticides were accomplished using a Potters tower. The parameters evaluated were: specimens survival after the application of the compounds, and the compounds effects over the reproductive parameters of the predator. Thiamethoxan (0.5), imidacloprid (0.7) and endosulfan (2.63) were the most harmful to the treated individuals and for the first two compounds it was observed 100% of larvae mortality of the first and second instars soon at 1 day after the application and reduction in the survival of the larvae of third and fourth instars. Dimethoate (0.48) was harmful for the larvae of the first instar and slightly harmful for larvae of fourth instar. As a function of the selectivity presented by mineral oil (13.3), it can be recommended aiming its compatibilization with the C. montrouzieri natural enemy in programs of IPM in coffee crop.

Life history parameters and feeding preference of the green lacewing Ceraeochrysa cubana fed with virus-free and potato leafroll virus-infected Myzus persicae

The sap-feeding aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) causes significant damage to potato crops and is a main transmitter of potato leafroll virus (PLRV). The lacewing Ceraeochrysa cubana (Hagen.1861) (Neuroptera: Chrysopidae) is a natural predator of the aphid and an important biological control agent. The aim of this study was to determine whether the biological characteristics and feeding preferences of the predator are modified by PLRV-infected aphids. The larval and pupal stages of lacewings fed on PLRV-free M. persicae were prolonged in comparison with those of predators provided with PLRV-infected aphids or eggs of Ephestia kuehniella, although larval, pupal and adult predator survivals were not affected significantly by dietary regime. Ingestion of PLRV-infected aphids reduced the proportion of fertile female lacewings and increased their pre-oviposition period, but had no effect on fecundity or egg viability. In laboratory bioassays, the predator showed no preference for PLRV-infected or PLRV-free aphids.