Effects of cowpea cultivars and neem oil on attractiveness, feeding, and development of Spodoptera eridania (Cramer) (Lepidoptera: Noctuidae)
Rodrigues,Nara Elisa Lobato
Silva,Anderson Gonçalves da
Souza,Bruno Henrique Sardinha de
Júnior,Arlindo Leal Boiça
The southern armyworm Spodoptera eridania is a polyphagous species that can feed on cowpea plants. Although there is some knowledge about the resistance of cowpea cultivars, little is known on the effects of neem oil to control pest insects of cowpea in Brazil. This study aimed to evaluate the effects of cowpea cultivars combined with neem oil on attractiveness, feeding, and development of Spodoptera eridania (Cramer). The experiment was carried out under environmentally controlled conditions, and set up in a 6 x 3 factorial arrangement using six cowpea cultivars and two doses of neem oil plus the control (deionized water). Free-choice and no-choice feeding preference assays were performed to assess treatment attractiveness to the larvae and leaf consumption. Duration and survival of larvae, pre-pupae, and pupae, weights of larvae and pupae, longevity of adults, sex ratio, duration of larva-to-adult period, and larval mortality after 3, 6, 12, and 24 days were recorded. Cultivars BRS Urubuquara and BR17 Gurgueia were the least consumed in the free-choice test. Neem oil at 0.35 and 0.7% reduced leaf consumption. Cultivars BRS Novaera and BR17 Gurgueia showed to be the least suitable for S. eridania development. Neem oil at both doses affected S. eridania development. Cultivars BR7 Gurgueia and BRS Novaera were moderately resistant; BR3 Tracuateua, susceptible; and Sempre Verde, Milênio, and BRS Urubuquara were highly susceptible to S. eridania.