Population dynamics of Fall Army Worm [(Spodoptera frugiperda) J.E. Smith] (Lepidoptera: Nuctuidae) in maize-cassava intercrop using pheromone traps in Niger Delta Region

Abstract

Abstract Background This study was conducted to generate baseline information on population dynamics of Fall Army Worm (FAW) in cassava-maize intercrop for management technique. Maize (Zea mays) is Africa’s most staple food crop with pest complex as major constraints to its production. The study was carried out at the Abuja Campus of the University of Port Harcourt, Faculty of Agriculture Teaching and Research Farm. A plot size of 3298 m2 was cleared and ploughed; afterward, thirty six (36) ridges were made for the planting. Three varieties of maize grains (a hybrid Oba Super 98, white and yellow locals) were used for the study. Two cropping patterns (Sole maize and Cassava-Maize.-Intercrop) as main factor with a total of 18 sole and 18 intercrop plots and pheromone trap heights (at 1 m and 1.5 m) as sub-factor were used. The traps were mounted 18 days after planting and insect collection commenced at dawn the following day. FAW data in each trap were collected daily between 06.00 and 07.00 h. Maize cobs, fresh and dry weights, numbers of FAW exit holes, tunnels and tunnel lengths were recorded for both cropping patterns in each maize variety. Data were subjected to two-way analysis of variance. Results The results show higher mean value of FAW count in pheromone trap height placed at 1.5 m, and Oba super 98 maize variety intercropped with cassava had higher FAW count. There were significantly higher (P < 0.05) FAW exit holes in maize with pheromone trap height placed at 1.5 m, and maize-cassava intercrops had higher mean values of FAW exit holes. Number of tunnels and tunnel lengths (cm) due to FAW infestation were higher in maize varieties where pheromone traps were placed at 1.5 m. Conclusion Intercropping maize with cassava may suggest increase in FAW bionomics and the presence of abundant host which might increase a spike in its peak period of infestation. The presence of cassava in maize-cassava cropping pattern encourages feeding and/or oviposition of FAW on maize plant; therefore, an alternative cropping pattern should be encouraged in the region.

Keywords

• Pheromone
• Spodoptera frugiperda
• Cropping pattern
• Trap
• Population dynamics