Avaliação populacional de lagartas e inimigos naturais em azevém, com rede de varredura

Abstract

Avaliação populacional de lagartas e inimigos naturais em azevém, com rede de varredura (1)Alexandre Specht (2) Termos para indexação: Lolium multiflorum, Noctuidae, população de insetos, manejo integrado de pragas. Evaluation of caterpillar populations and natural enemies in the ryegrass with sweeping netAbstract -Noctuids are the main phytophagous pests of gramineae and decisions about its control are based on percentage of defoliation, not considering the level of larval infestation. The objective of this study was to test the sweeping net in the evaluation Noctuidae population and of the principal groups of natural enemies in ryegrass (Lolium multiflorum Lam.), in the morning and at night. The work was conducted in two crops in Salvador do Sul, RS, Brazil. In the first experiment, insects were sampled weekly, and in the second one, which was complementary, the collections were done in each phase of ryegrass development, maintaining laboratorial rearing. From the first one, a total of 2,044 caterpillars were collected, but only 151 in the morning. Statistical differences occurred at night between sampling dates and caterpillar sizes. Three hundred and eighty seven spiders, 577 microhymenopterans and 983 other insects with interest in biological control were also captured; statistical significance was observed between day periods and dates for Carabidae, Forficulidae, Tachinidae, Nabidae, Vespidae, microhymenopterans and Araneae. From the second experiment eleven species were obtained, and Pseudaletia sequax Franc., 1951, was the predominant. The use of sweeping net allows the evaluation of Noctuidae population, as well as the main groups of natural enemies in ryegrass, in the evening.

Revision of the species of Mythimna Ochsenheimer, 1816 (Pseudaletia) (Lepidoptera: Noctuidae: Noctuinae: Leucaniini) occurring in Brazil

“…Native and cultivated grasses (Poaceae) such as rice, oat, barley, wheat, corn, canary grass, annual ryegrass, rye, sugar cane, sword grass and other grasses (Biezanko et al, 1974;Buainain and Silva, 1990;Matrangolo et al, 1997;Specht and Corseuil, 2002a;Specht et al, 2004;Fritz et al, 2008;Bortolotto et al, 2015).…”

Incidence of Mythimna sequax parasitized in wheat crop

“…Assessments were performed every seven days, starting from the emergence (the first visible leaf) (May, 25 th ) until the grain maturation stage (September, 08 th ). Wheat armyworm larvae are nocturnal pests (SPECHT & CORSEUIL, 2002) that during the day remain probably beneath mulch or soil clods of soil, sheltered from the sunlight. Therefore, collection of M. sequax larvae was carried out daily, at around 14hs, by raising the trap and examining carefully the soil surface for larvae sheltered among the clods of soil.…”

Diversidade e Atividade de Voo de Himenópteros Parasitóides em Pomar de Macieira em Vacaria, RS

“…No entanto, ainda poucos são os estudos que abordam estes aspectos conjuntamente. sPecHt & corseuil (2002) em plantio de azevém verificaram diferença na abundância de alguns grupos de himenópetros parasitóides, quando amostrados pela manhã ou à noite. Em remanescente de Cerrado, MarcHiori et al (2007), observaram diferenças na atividade de voo de Ichneumonidae (diurno) e Encyrtidae (noturno).…”