The role of Desmodium intortum, Brachiaria sp. and Phaseolus vulgaris in the management of fall armyworm Spodoptera frugiperda (J. E. Smith) in maize cropping systems in Africa

Abstract

BACKGROUND The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) is a serious pest of maize. Farming systems such as push‐pull or maize‐legume intercropping have been reported to reduce FAW infestations significantly. However, the exact mechanisms involved in FAW management have not been practically elucidated. We therefore assessed larval host preference, feeding and survival rate when exposed to four host plants commonly used in push‐pull and legume intercropping. We also compared adult moths' oviposition preference between maize and other grasses used as trap crops in push‐pull. RESULTS The larval orientation and settlement study showed that maize was the most preferred host plant followed by bean, desmodium and Brachiaria brizantha cv Mulato II. The larval arrest and dispersal experiment showed that mean number of larvae was significantly higher on maize than on Desmodium or B. brizantha cv Mulato II. However, no significant differences were found between maize and bean after 24 h. Maize was the most consumed plant, followed by bean, desmodium and finally brachiaria. The mean percentage of survival to the pupation stage was significantly higher on maize. The study on FAW oviposition preference showed no significant differences in egg deposited between maize and other grasses. However, B. brizantha cv Xaraes, which received more eggs than maize, could be a promising alternative to B. brizantha cv Mulato II for the control of FAW. CONCLUSION The study provides a better understanding of the mechanisms involved in the control of fall armyworm under the push‐pull and maize legume intercropping. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A review of the impact of maize-legume intercrops on the diversity and abundance of entomophagous and phytophagous insects

“…For example, several studies have reported that maize intercropped with legumes had the greatest diversity and abundance of natural enemies, including a number of parasitoids known to attack S. frugiperda (J. E. Smith), a Lepidopteran pest attributed to up to 60% yield damage in some maize-producing regions globally ( Jiménez-Martínez & Gómez-Martinez, 2013 ; Goergen et al, 2016 ). Similar results were also reported by Scheidegger et al (2021) . To address the likelihood that phytophagous insects would spread into new areas and destroy maize crops in intercropping systems, a comprehensive study of the effect of maize-legume intercrops on the diversity and abundance of entomofauna is needed to create techniques that could be used to reduce the potential for pest infestations.…”

Spodoptera frugiperda: Ecology, Evolution, and Management Options of an Invasive Species

“…However, oviposition choice tests conducted in Kenya ( 111) also found that FAW laid similar number of eggs on D. intortum as on maize plants, and larvae could develop on D. intortum plants. In this region, Brachiara grasses were suggested as possible pull plants because FAW females oviposited similarly on these plants as on maize plants (111). Examples of intercropping experiments in Congo's Kashusha district also reported less frequent FAW attack on onion when intercropped with groundnut (17).…”

Application potential of push-pull cropping of maize and beans to fall armyworm (Spodoptera frugiperda) management in China

“…Results indicated that FAW could complete the life cycle on all tested host plants, but the developmental duration, pupal weight, pre-adult survival rate and APOP of FAW reared on maize were signi cantly preferable than those of FAW reared on other host plants. Several studies have also shown the high adaptability of FAW to maize (Pitre et al 1983;Scheidegger et al 2021;Liu et al 2022). Unexpectedly, the adaptability and preference of FAW to red bean and yardlong bean were also strong, not much less than that of maize, but much better than that of the other three beans, especially in terms of pre-adult survival rate.…”

“…. A previous report byScheidegger et al (2021) showed that special volatiles released by some leguminous plants have repellent in uences upon FAW. Liu et al (2022) also found the feeding rate of FAW on faba bean was the lowest in the preference test.…”