Biological characteristics of Heliothis virescens fed with Bt-soybean MON 87701 × MON 89788 and its conventional isoline

Abstract

This study aimed to evaluate the larval biology of Heliothis virescens in soybean MON 87701 x MON 89788 and its isogenic non-Bt. In general, the impact of soybean MON 87701 x MON 89788 on H. virescens was evidenced in all bioassays, 100% larval mortality, independent of the structure (leaf or pod) consumed by the pest. The small larvae (1 st and 3 rd instar) demonstrated that they were unable to damage fresh pods of soybean, regardless of whether Bt or not Bt. The large larvae (5 th instar) fed on soybean MON 87701 x MON 89788 soybeans consumed three times less compared to larvae fed on non-Bt soybeans, and resulted in reduced longevity and larval survival. When soybean plants were infested with 5 th instar larvae, H. virescens caused injuries in the steams of the conventional soybean. It was recorded that the insects moves quickly to this region of the plant. However the soybean MON 87701 x MON 89788 was an effective tool in controlling H. virescens.

Potential of antranilic diamides applied in seeds of soybeans with and without cry1ac protein for Helicoverpa armigera caterpillar control

“…The toxic effect of the Cry1Ac protein on H. armigera larvae of different stages in soybean, showing a high mortality (Bortolotto et al, 2014), is confirmed. This insecticidal protein has also been shown to be efficacious in controlling H. virescens larvae in soybean and cotton (Terán-Vargas, 2005;Bortolotto et al, 2014).…”

“…The rapid and high mortality caused by the Cry1Ac protein was also observed for neonate larvae of H. virescens (Bortolotto et al, 2014).…”

“…This insecticidal protein has also been shown to be efficacious in controlling H. virescens larvae in soybean and cotton (Terán-Vargas, 2005;Bortolotto et al, 2014). In soybean, even in more developed plants (withseed pods), the concentration of the insecticidal protein is sufficient to control H. virescens larvae (Bernardi et al, 2013;Bortolotto et al, 2014) (Table 5).…”

Attractiveness and non-preference of soybean cultivars to Heliothis virescens (Lepidoptera: Noctuidae) feeding

“…Bernardi et al (2014) and Bortolotto et al (2014) assessed the larval biology of H. virescens in genetically modified soybean plants (Bt) and concluded that the pest is highly susceptible, thereby suffering larval mortality. The lower consumption indexes in this cultivar are due to the presence of toxins from Bacillus thuringiensis (Eubacteriales: Bacillaceae), which induce the formation of endotoxins (Waquil et al, 2002) poisonous to insects, especially lepidopterans.…”

“…This insect is a facultative migratory pest that can fly long distances in search of its host plants (Farrow and Daly, 1987). Inappropriate insecticide applications and their undesirable effects as well as the selection of individuals resistant not only to chemical insecticides but also to transgenic plants (Blanco et al, 2009;Sosa-Gomez and Silva, 2010;Bernardi et al, 2014;Bortolotto et al, 2014) lead to the need to investigate alternative pest control methods and strengthen integrated pest management (IPM) (Bueno et al, 2011a). Among the alternative methods, the exploitation of plant resistance to insects is considered ideal because this approach does not affect the environment, may be concomitantly used with other control methods, and does not require producers to deal with sophisticated technology (Smith, 2005;Seifi et al, 2013;Boiça Junior et al, 2015).…”