DEVELOPMENT OF Helicoverpa armigera HUBNER, 1805 AND Spodoptera frugiperda SMITH, 1797 IN WINTER FORAGES

• Autor(a) principal: Fernandes, Fabricio Oliveira [UNESP]
• Data de Publicação: 2020
• Outros Autores: Abreu, Jessica Avila de, Christ, Lucas Martins, Schneid Afonso da Rosa, Ana Paula, Mendes, Simone Martins
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.14393/BJ-v36n3a2020-47782; http://hdl.handle.net/11449/196837
• topic: Covering plants; Insect resistance management; Cultural management; Constitutive resistance; Resistance of plants

Helicoverpa armigera Hubner, 1805 and Spodoptera frugiperda Smith, 1797 are polyphagous pests of great agricultural importance in subtropical and temperate climate regions. The usual management of production areas in the southern region of Brazil occurs after the harvesting of summer crops, and the areas are sown with pasture. Thus, forages recommended for grazing are azevem (Lolium multiflorum Lam.) and cornichdo (Lotus corniculatus L.) due to their nutritional benefits, good palatability, regrowth, and hardiness. Considering the high degree of polyphagia of H. armigera and S. frugiperda, and the impact of maintaining continuous feeding areas (green bridges) in the management of these species, this work aimed to evaluate the development of H. armigera and S. frugiperda fed leaves of azevem and cornichdo under laboratory conditions. The insects were collected in the city of Capao do Leao/RS in corn and soybean plantations. For each forage species, 130 newly hatched caterpillars were each placed in autoclaved glass tubes, with one-third of the tube length containing forage. The tubes were capped with waterproof cotton and placed in a climate-controlled room at 25 +/- 1 degrees C, 70 +/- 10% relative humidity, and a 12-h photophase. The food was replenished daily until the caterpillars entered the pupae stage. The pupae were sexed and weighed, and the newly emerged adults were placed in pairs in PVC cages, lined with white A4 sulfite paper. The papers used as a laying substrate were removed and changed daily, and eggs were counted. The number of instars was determined by the linearized Dyar rule model. The complete randomization design was employed for the variables biological cycle length and viability of egg, caterpillar, pre-pupa, pupa, adult, and pre-oviposition phases and weight of caterpillars on the 14th day and pupae after 24 h. Based on the results obtained, a fertility life table was prepared. H. armigera did not complete the cycle, with only three instars and a duration of 22.1 and 24.6 days in azevem and cornichdo, respectively. When evaluated in S. frugiperda caterpillars, development in forage species was observed, with five and six instars and duration of 51.7 and 45.1 days in azevem and cornichdo, respectively. The azevem was distinguished by interference in the development cycle of the species, reducing the effect of the green bridge. In addition, surviving insects were susceptible to the effects of the agroecosystem due to the low-quality food source.