Juliano Ricardo Farias

Managing the sugarcane borer, Diatraea saccharalis, and corn earworm, Helicoverpa zea, using Bt corn and insecticide treatments.

Abstract The sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) and the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), are important pests of corn in Brazil and have not been successfully managed, because of the difficulty of managing them with pesticides. The objective of this study was to evaluate the effect of Bt corn MON810, transformed with a gene from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) insecticide seed treatment, and foliar insecticide spray using treatments developed for control of the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which is the major pest of corn. The experiments were done under field conditions in early- and late-planted corn in the state of Rio Grande do Sul, Brazil, and in the laboratory. The MON810 corn reduced infestations and damage by D. saccharalis and H. zea. The insecticides used in seed treatments or foliar sprays did not affect D. saccharalis and H. zea infestations or damage levels. The exception was the insecticide seed treatment in non-transformed corn, which reduced early infestations of D. saccharalis. The MON810 corn, therefore, can be used for managing these two pest species, especially D. saccharalis.

Capacidade de coleta de dois métodos de amostragem de insetos-praga da soja em diferentes espaçamentos entre linhas

Sampling is a key component in the Integrated Pest Management. In this studit was compared the colleting capacity of two sampling methods for caterpillar (Anticarsia gemmatalis Hueb., 1818) and stink bug (Piezodorus guildinii Westw., 1837). An experiment was carried out in soybean sown in three spacing (0.30, 0.40 and 0.50m). The experiment design was a completely randomized design with ten repetitions (sampling) in a 2x3 factorial. The population of velvetbean caterpillar and stink bug was evaluated in two sampling methods (beating cloth and vertical beat sheet) and three row spacing, at V8 and R6 stages, for caterpillar and stink bug, respectively. Results showed greater efficiency of the vertical beat sheet compared with beating cloth in colleting caterpillar. In the smaller spacing, the vertical beating cloth did not clarify its greater capacity of colleting bugs, as observed for caterpillars. These results show that more studies are necessary to evaluate sampling methods of insects in soybean using different plant spacing.

Volume de calda e inseticidas no controle de Piezodorus guildinii (Westwood) na cultura da soja

Em pulverizacoes com bicos hidraulicos, o volume de calda e um dos aspectos mais importantes para o sucesso do controle quimico de pragas. O objetivo deste trabalho foi avaliar o efeito do volume de calda e inseticidas no controle de Piezodorus guildinii (Westwood), na cultura da soja. Testaram-se os volumes de calda de 50, 100 e 150l ha-1 e os inseticidas endossulfam (437,5g i.a. ha-1) e tiametoxam + lambda-cialotrina (21,15 + 15,90g i.a. ha-1). Tiametoxam + lambda-cialotrina apresentou maior efeito residual e controle de P. guildinii em relacao a endossulfam. Esses inseticidas respondem da mesma forma, aumentando a eficiencia de controle da praga com o aumento do volume de calda.

Plantas infestantes hospedeiras de Rhopalosiphum rufiabdominalis (Sasaki) (Hemiptera: Aphididae) em áreas de cultivo de arroz irrigado

Rhopalosiphum rufiabdominalis (Sasaki) is an insect of world-wide distribution that damages irrigated rice. From September, 2004 to February, 2005, nymphs and adults of this aphid were collected in several host weeds of rice farms in Alegrete, Quaraí and Uruguaiana, located in Western of State of Rio Grande do Sul, and Restinga Seca, in Central region of this State, Brazil. The insect was found in the root of Andropogon bicornis (West Indian foxtail), Echinochloa colona (jungle rice), Oryza sativa (volunteer rice and red-rice), Paspalum sp. (paspalum) and Soliva pterosperma (lawn burweed).

Efeitos da população de plantas e de tratamento fitossanitário no rendimento de grãos do feijoeiro comum, cultivar "TPS Nobre"

Three experiments were conducted in Santa Maria and Constantina - Rio Grande do Sul State - Brazil, to determine the effect of plant population on disease occurrence in common bean (type II grown) in the first and second growing season and to determine the most appropriate plant population. The experiment was established as a split-plot randomized block design with five replications. The results showed that there was no effect of plant population in disease incidence. The high plant populations provided higher or similar grain yield compared with the grain yield of the low plant populations.