Effect of intercropping on the incidence and severity of damage of fall armyworm (Spodoptera frugiperda J.E. Smith) on maize (Zea mays l)

Abstract

The fall armyworm (Spodoptera frugiperda J.E. Smith) is an invasive and destructive pest that came into
Nigeria recently, where it has established itself as one of the maize’s most important insect pests. The effect
of intercropping on the incidence and severity of damage to maize was investigated, where maize was
intercropped with five different crops, namely, cowpea, groundnut, soya bean, sorghum and roselle, and
controlled plots with sole maize. Randomized Complete Block Design was used, and the treatments were
replicated four times. Parameters taken were number of damaged leaves per plant, severity of damaged on
leaves, number of damaged ears per plot, severity of damage on ears and yield per plot. The result of the
study had shown that plots where maize was intercropped with soya bean had, significantly (P<0.05), the
lowest incidence (17.5 %) and severity of damage (2.8) compared to plots with sole maize, that had the
highest incidence (43.8 %) and severity of damage (5.5). The percentage of damaged tassels was the highest
in plots where maize was a sole crop (17.5 %), followed by maize and sorghum (15 % each). The lowest
percentage of damaged tassels was recorded on maize that was intercropped with soya bean (5.0%), and
was significantly (P< 0.05) lower than the rest of the five treatments. Similarly, the percentage of damaged
ears was the highest with maize as a sole crop (15 %) and lowest on maize intercropped with soya bean (3.7
%). Highest yield was also recorded in plots where maize was intercropped with soya bean (7.43 tons/ha),
followed by maize-cowpea intercropped plots (6.44 tons/ha) and maize-groundnut intercropped plots
(5.23tons/ha) and plots where maize was a sole crop had, significantly the lowest yield (P< .05) The result
of this study is indicative of the potentials of using intercropping, especially when legumes such as soya
bean, are included, as a management tactic against fall armyworm on maize. This will reduce a total
reliance on synthetic insecticide to manage the insect pest by small holder maize farmers in Nigeria