I. Cruz

Survey of ear flies (Diptera, Ulidiidae) in maize (Zea mays L.) and a new record of Euxesta mazorca Steyskal in Brazil

Levantamento de mosca-da-espiga (Diptera: Ulidiidae) em milho (Zea mays L.) e primeiro relato de ocorrencia de Euxesta mazorca Steyskal no Brasil. Especies de Euxesta (Diptera, Ulidiidae), conhecidas como moscas do cabelo ou moscas da espiga estao aumentando em importância nas culturas de milho em diferentes paises, embora muito pouco se conheca sobre elas no Brasil. As larvas das especies representativas de Ulidiidae inicialmente danificam a parte reprodutiva feminina da planta e depois os graos em desenvolvimento. Como resultado da alimentacao das larvas ocorre fermentacao e odor forte tornando a espiga inapropriada para o consumo humano ou animal. O principal objetivo deste trabalho foi avaliar a incidencia de especies de Euxesta em areas de producao de milho e identificar as especies predominantes usando dois atraentes alimentares diferentes a base de proteinas hidrolisaveis, BioAnastrepha® (proteina hidrolisavel de milho) e Torula, colocados no interior de armadilha McPhail. As duas especies identificadas foram E. eluta Loew and E. mazorca Steyskal, registrada pela primeira vez no Brasil. Entre as especies, E. eluta foi predominante no milho. Ambos os atraentes foram eficientes na captura das duas especies. No entanto, as armadilhas com BioAnastrepha® capturaram significativamente mais insetos do que aquelas com Torula.

Response to the insecticide chlorpyrifos by arthropods on maize canopy

We assessed the response of maize canopy arthropods to the insecticide chlorpyrifos. Four 0.3 ha (18 2 180 m) plots were divided into two subplots, a control and a treated area. During tasseling of the plants, the treated area was sprayed twice, with an interval of 3 days. Ten plants were sampled: 1 day before spraying, and 7, 14, 21 and 28 days after spraying. The insecticide had no effect on insect herbivores: a high density of Spodoptera frugiperda larvae was present in the treated plots. A few predator arthropod species were negatively affected by the insecticide, but their numbers or activity increased 2 weeks after the treatment of the plots. A canonical variate analysis showed no pronounced effect of the insecticide on arthropod communities; the largest variations on species abundance were related to sampling occasion. These results can be explained by the combination of the short period of chlorpyrifos residual activity on the plant surface and the great potential for recolonization of the areas by most of the monitored arthropods.

Development and Reproduction of Olla v-nigrum (Coleoptera: Coccinellidae) Fed Anagasta kuehniella (Lepidoptera: Pyralidae) Eggs Supplemented with an Artificial Diet

ABSTRACT Olla v-nigrum Mulsant (Coleoptera: Coccinellidae) preys on eggs and larvae of Coleoptera and Lepidoptera and on aphids in arboreal plants. Alternative prey supplemented with artificial diets may be used to mass rearing Coccinellidae predators for biological control programs. This study assessed the development and reproduction of O. v-nigrum fed Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) eggs supplemented with an artificial diet. Adults of O. vnigrum were collected from Caesalpinia peltophoroides Benth. (Fabales: Fabaceae) and taken to the laboratory. Three male + female couples were fed on A. kuehniella eggs and an artificial diet (100 g of yeast, 40 g of honey, 0.5 g of ascorbic acid and 60 mL of water). Eight male + female couples obtained from this initial generation were subjected to the same procedure in order to assess the effects on subsequent generations. The mean number of eggs per egg mass was 11.7 ± 0.7 with a viability of 54.8 ± 2.9% and an incubation period of 3.1 ± 0.02 days. The durations of instars I, II, III and IV and the durations of the larval, pre-pupal, pupa and larva to adult stages were 2.4 ± 0.3, 1.8 ± 0.2, 2.0 ± 0.3, 5.8 ± 0.1, 12.1 ± 0.3, 1.0 ±0.01, 4.0 ±0.2 and 17.1 ± 0.5 days, respectively. The viabilities of the larval, pre-pupal and pupal stages of this predator were 46.3 ± 4.5%, 90.0 ± 5.0% and 100%, respectively. The diet and other methods employed in this study were adequate for laboratory rearing of O. v-nigrum but, because of the low viabilities of the eggs and immature stages observed with these methods, further improvements will be necessary for successful mass rearing of this valuable predator.