Evaluation of Napier grass (Pennisetum purpureum) varieties for use as trap plants for the management of African stemborer (Busseola fusca) in a push–pull strategy

Abstract

We evaluated eight Napier grass [Pennisetum purpureum Schumach (Poaceae)] varieties, used in various parts of eastern Africa as fodder, for their potential role as trap plants in the management of the African stemborer, Busseola fusca Füller (Lepidoptera: Noctuidae) through a push–pull strategy. Oviposition preference, larval orientation, settling, arrest and dispersal, feeding, mortality and survival, and development were determined for each of these varieties under laboratory and screen house conditions. Two‐choice tests showed that only two of the varieties tested (cv. Bana and cv. Uganda Hairless) were preferentially chosen by gravid female moths for oviposition over a susceptible maize variety, cv. Western Hybrid 502. Larval preference was, however, highly variable. Larval feeding by first instars on the maize leaves was more intense and significantly more than on leaves of all the Napier grass varieties evaluated. Food consumed and amounts assimilated by the third instars over a 24‐h period were not different among larvae fed on stems of maize and those fed on stems of the various Napier grass varieties. Larval survival was significantly lower on all the Napier grass varieties (below 3%) than on maize (about 44%). Similarly, larval development was about 2–3 weeks longer on majority of the Napier grass varieties. It was concluded that cv. Bana had potential for use as a trap plant in the management of B. fusca because it was more preferred by the moths for oviposition, equally preferred as maize by the larvae for orientation, settling, and arrest, and allowed minimal survival of the larvae. It can thus be used with such ‘push’ plants as Desmodium spp. (Fabaceae) in a ‘push–pull’ strategy, but the effectiveness of such a strategy would strictly depend on proper establishment and management of these companion plants.

Trap cropping with Napier grass,Pennisetum purpureum(Schumach), decreases damage by maize stem borers

“…Although Van den Berg et al (2006) and Khan et al (2007) showed that B. fusca moths did lay their eggs on Napier grass, the preference for the grass to maize was not strong and oviposition was largely similar on these two plant species. Attractiveness alone is, therefore, unlikely to have resulted in the efficacy of Napier grass as trap crop for B. fusca in this study.…”

“…Preferences for oviposition by B. fusca and C. partellus on Napier grass (Pennisetum purpureum Schumach) instead of maize plants under laboratory conditions have been reported by Van den Berg et al (2001), Khan et al (2006Khan et al ( , 2007, Van den Berg (2006a, 2006b and Mohamed et al (2004). Jindal et al (2012) reported attraction of Napier grass to C. partellus under semi-field conditions.…”

Plant volatile‐mediated signalling and its application in agriculture: successes and challenges

“…It was suggested that this system, developed initially for pest management in sub‐Saharan Africa, did not study short‐range interventions between plants and insects. However, in the papers (Khan et al ., , ), evidence is provided on the value of short‐range attractancy by the trap crop P. purpureum to the stemborer moths B. fusca and C. partellus . Eigenbrode et al .…”

Opportunities for Napier Grass (Pennisetum purpureum) Improvement Using Molecular Genetics

“…In crop land management systems, it is used as a mulch to control weed infestation and soil erosion [2] and as a trap plant in the push-pull strategy, a pest management practice which uses repellent intercrop 'push' plants and attractant trap 'pull' plants [23] for insect pest control in Africa, particularly for the maize stem borer [24,25]. Plants are also used to scavenge pollutants, such as heavy metals, and Napier grass has been used in phytoremediation strategies, for example for the cleanup of cadmium-affected soil, reducing the concentration of cadmium to a depth of 15 cm in soil [17].…”