Management of the Fall Armyworm (Spodoptera frugiperda J. E. Smith) on Maize in Seke District, Mashonaland East Province of Zimbabwe

Abstract

The Fall Armyworm, Spodoptera frugiperda (J. E. Smith) (FAW) is serious pest of maize and other cereals. A field trial was conducted at Mangwiro farm in the Beatrice Area of Seke district to evaluate the response of three maize varieties and chemical treatments in the control of FAW. The three maize varieties used were; SC513, SC529 and PAN53. There were three chemical treatments namely; Ecoterex, lambda cyhalothrin and Cabaryl. The fourth treatment was an untreated control. Each treatment was replicated three times. The trial was set up as a 3X4 factorial experiment with three varieties and three chemical treatments. Each treatment plot had four lines which were three meters long and replicated three times. The total number of plots was thirty-six. Inter-row spacing was 0.90cm and in row spacing was 0.20cm within the plots. Inter-row between blocks was 1.5m and inter-row within the block was 1m. Data on effect of chemical treatments on mean number of larvae per plot at 7, 8, 9, 10 and 11 weeks after planting (WAP) was collected. Data was also collected on the mean number of days to maturity for three varieties, mean leaf size, mean plant height, mean total number of leaves, plant vigor at maturity, mean plant biomass, mean cob quality scores, mean cob size (cm) and mean grain weight (tons/Ha).There were no significant differences (p>0.05) for the mean insect larvae numbers among the four treatments and between the three varieties at 7 WAP. There was a significant difference (p<0.05) in the mean insect larvae numbers among the four treatments at 8 WAP. The Ecoterex and lambda chemical treatments had significantly lower mean insect larvae numbers but were not significantly different from each other. There was a significant difference (p<0.05) in the mean insect numbers among the four treatments at 10 and 11 WAP. The Ecoterex and lambda treatments had significantly lower mean insect numbers but were not significantly different from each other at 10 WAP. There were significant differences (P<0.05) in the number of days to maturity across the three varieties. Variety SC513 had the lowest mean number of days to maturity and this was significantly different from variety SC529 which had a mean number of 135 days to maturity. There was no significant difference in grain yield across the three varieties and this was predominantly because the varieties are in the same medium maturity category. Overall, farmers are advised to use Ecoterex and lambda cyhalothrin in the control of FAW and this should preferably be done in a rotation to avoid the development of resistance in FAW to the insecticides.