Surto de Nystalea nyseus (Cramer, 1775) (Lepidoptera: notodontidae), aspectos da biologia e inimigos naturais

• Autor(a) principal: Magistrali, Iris Cristiane
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Manancial - Repositório Digital da UFSM
• Texto Completo: http://repositorio.ufsm.br/handle/1/8704
• topic: Entomologia florestal; Eucalipto; Lagartas desfolhadoras; Predador; Forest entomology; Eucalipto; Defoliating caterpillars; Predator; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL

The growing demand for forest products has enabled the increase in areas planted to trees in Brazil. Eucalyptus is a fast growing tree species being cultivated on a large scale, however, with increasing of Eucalyptus sp. plantation, entomological problems tend to increase. The defoliating caterpillars represent an important group of insects that are harmful to forest plantations. Thus, this study aims at characterize an outbreak of the Nystalea nyseus (Cramer, 1775) species, as well as its biology aspects and natural enemies. This study was conducted in a seminal plantation of Eucalyptus saligna Smith in the city of São Sepé, Rio Grande do Sul, Brazil. To evaluate the outbreak, a sampling was carried out by using the transect method. Defoliating caterpillars were collected from different instars and pupae of this species and they were sent to the laboratory under conditions at 25°C ± 1°C, 80% relative humidity and 12- hour photophase. The biological aspects evaluated were: color and morphology of eggs, duration of pre-pupal and pupae stage, sex ratio and lifespan adults. A visual inspection of eucalyptus plantation was conducted to catch potential natural enemies. The results showed the presence of attack on all the stands. The eggs are greenish, and after 24 hours, became light red. They have an average length of 1.17 (± 0.387) mm and a width of 1.20 (± 0.229) mm, and as an average incubation period of six days. Pre-pupal stage lasted 3.53± 0.53 days and pupal stage lasted 14.02 (±1.23) and 15.12 (±1.08) days for females and males, respectively. The length (mm), width (mm) and weight (g) of pupae were higher for females, however, with no significant difference. The adult sex ratio was 0.62 females per male and lifespan was 7.63 days for females and 5.47 for males. The following predatory species were registered: Podisus nigrispinus (Dallas, 1851), Brontocoris tabidus (Signoret, 1863) and Alcaeorrhynchus grandis (Dallas, 1851) all belonging to the Heteroptera order, Pentatomidae family. The present paper for this first time reports an outbreak of this species of eucalyptus to Rio Grande do Sul, State, Brazil and extends the range of information about the biology of Nystalea nyseus. For the first time, predatory species are registered as natural enemies.