Owlet moths (Lepidoptera: Noctuoidea) associated with Bt and non- Bt soybean in the brazilian savanna

Abstract

The use of GMO expressing Bt toxin in soybean production has increased significantly in the last years in Brazil in order to manage the damage caused by lepidopteran pests. In this study, we compared the richness and abundance of owlet moths (Noctuoidea) associated with Bt and non-Bt soybean. We determined the temporal variations as a function of phenology, and correlated the population variations of the most common species with meteorological variables. The research was conducted at the experimental area of Embrapa Cerrados. The collection method used was differentiated being suppressive and absolute. A total of 13 species were collected, of which eight occurred on Bt soybeans. The most representative taxa were Chrysodeixis includens (72.87%), Anticarsia gemmatalis (18.17%) and Spodoptera spp (5.22%). The number of larvae belonging to species targeted by the Bt technology was 10 times lower on Bt than on non-Bt soybeans. Utetheisa ornatrix and Elaphria deltoides were recorded on soybean for the first time, observing larvae of both species in non-Bt soybean and those of U. ornatrix also in Bt soybean. Only A. gemmatalis larvae correlated (p <0.05) negatively with precipitation. This study provided field information on the abundance and species richness of owlet moths on non-Bt soybeans, associated with the effects of Bt soybean. When considering the different levels of infestation between cultivars as a criterion, larvae monitoring is of substantial importance in order to develop the lost control program.

Survival and development of Spodoptera eridania, Spodoptera cosmioides and Spodoptera albula (Lepidoptera: Noctuidae) on genetically‐modified soybean expressing Cry1Ac and Cry1F proteins

“…9,10 In contrast, S. cosmioides and S. albula occur at relatively lower frequencies. 9 However, S. cosmioides can consume almost twice the soybean leaf area as other species from this genus. 11 Spodoptera species are considered secondary soybean pests in South American countries.…”

“…[3][4][5][6] However, outbreaks of Spodoptera species have been reported in soybean fields, including S. frugiperda (Smith), S. eridania (Stoll), S. cosmioides (Walker) and S. albula (Walker). [7][8][9] Of these species, S. frugiperda is an emerging soybean pest due to increased infestations and damage observed on soybean in recent seasons in Brazil. Spodoptera eridania is the most important Spodoptera pest species on soybean in the Cerrado region, and southern Brazil.…”

“…7,8 However, sporadic infestations of these species can cause significant yield loss to soybean due to their defoliation capacity 11 and damage to reproductive structures (flowers and pods). 9,12 Outbreaks of Spodoptera species in Brazilian soybean fields may be influenced by the widespread deployment of transgenic soybean plants expressing Bacillus thuringiensis Berliner (Bt) proteins. 13 Transgenic Cry1Ac-soybeans provide effective control of key defoliating pests (A. gemmatalis, C. includens, C. virescens and H. armigera), but only minimal activity against Spodoptera species.…”

“…The main soybean Lepidopteran pests are velvetbean caterpillar, Anticarsia gemmatalis (Hübner), soybean looper, Chrysodeixis includens (Walker), Old World bollworm, Helicoverpa armigera (Hübner), and tobacco budworm, Chloridea virescens (F.) 3–6 . However, outbreaks of Spodoptera species have been reported in soybean fields, including S. frugiperda (Smith), S. eridania (Stoll), S. cosmioides (Walker) and S. albula (Walker) 7–9 . Of these species, S. frugiperda is an emerging soybean pest due to increased infestations and damage observed on soybean in recent seasons in Brazil.…”

“…Of these species, S. frugiperda is an emerging soybean pest due to increased infestations and damage observed on soybean in recent seasons in Brazil. Spodoptera eridania is the most important Spodoptera pest species on soybean in the Cerrado region, and southern Brazil 9,10 . In contrast, S. cosmioides and S. albula occur at relatively lower frequencies 9 .…”