Impact of Cowpea-maize Intercropping and Bio-rational Product on Fall Armyworm, Spodoptera frugiperda (JE Smith) in Fodder Maize

Abstract

Background: A recent occurrence of fall armyworm (FAW), Spodoptera frugiperda (JE Smith) a new invasive pest in Africa attained epidemic form in 2016. Consequently, researchers probed various ecofriendly methods to manage the pest. The effect of intercropping cowpea [Vigna unguiculata (L.) Walp.] with fodder maize (Zea mays L.) on the incidence of FAW was investigated. Methods: The maize fodder was protected against FAW by intercropping with cowpea along with a biorational product, Brahamastra and compared with the recommended insecticide used to manage the insect by conducting field experiments during kharif 2020, 2021 and 2022 comprising the eight treatments viz. T1: Maize + Cowpea 1:1 ratio (unsprayed); T2: Maize + Cowpea 1:1 ratio (coragen @ 100 ml ha-1); T3: Maize + Cowpea 1:1 ratio (brahamastra @ 12.5 litre ha-1 sprayed); T4: Maize sole (brahamastra @ 7.5 litre ha-1 sprayed); T5: Maize sole (brahamastra @ 10.0 litre ha-1 sprayed); T6: Maize sole (Brahamastra @ 12.5 litre ha-1 sprayed); T7: Maize sole (coragen 18.5 SC @ 100 ml ha-1 sprayed as standard check) and T8: Maize sole (Unsprayed). The plot size for each treatment was 500 m2, demarcating 5 ´ 4 m2 for sampling with three replications in a completely randomized design (CRBD). Result: The treatments, Maize + Cowpea (1:1 row) (Coragen @ 100 ml ha-1 sprayed) and Maize sole (Coragen @ 100 ml ha-1 sprayed) though had significantly the lowest pooled pest incidence and the highest per cent reduction over control (PROC), the bio-rational applied on maize + Cowpea (1:1 row) (brahamastra @ 12.5 litre ha-1 sprayed) encounted the lowest pest incidence, the highest PROC combined with the highest fodder yield and economic returns without any statistical singnificant difference with Maize + Cowpea (1:1 row) (unsprayed).