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Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) was reported for the first
time in Africa in 2016 from America. FAW is widely distributed in Tanzania, causing
significant damage to maize. Two factor, cropping systems and biopesticides were tested
in Randomized Completely Block Design arranged in a two - way factorial experiment
with three replications for their efficacy against FAW and associated parasitoids on maize
field at Crop Museum of Sokoine University of Agriculture (SUA). Cropping systems
tested included maize sole crop, maize + cowpea, and maize + desmodium and napier
grass (push pull system). Biopesticides tested included Metarhizium anisopliae and
Beauveria bassiana. The insecticide flubendamide was applied as a positive control,
between August 2018 - December 2018 and December 2018 - March 2019 cropping
seasons. In the laboratory sampled FAW egg masses and larvae were reared, emerged
parasitoids were recorded. Three species of parasitoids (Chelonus bifoveolatus,
Coccygidium luteum and Cotesia sp) were recovered. Results showed that C. bifoveolatus
was mostly dominant parasitoids. However, highest parasitism rates were in Cotesia sp in
push pull plots treated with M. anisapliae in season 1 and 2 (13.7% ± 0.14 and 14.5% ±
0.17 ) respectively. Abundance of parasitoids was significantly affected by cropping
systems (p ˂ 0.01) and sampling weeks (p ˂ 0.001 for season 1 and p ˂ 0.01 for season 2)
and percept damaged maize plants by FAW was significantly affected by cropping
systems (p ˂ 0.001) pesticides (p ˂ 0.001) and cropping systems x pesticides application
(p ˂ 0.01). Furthermore, highest maize grain yields and cost benefit ratio were estimated
in push pull and cowpea + maize cropping systems compared to sole maize. These results
prove that, biological control are effective and involves conservation of natural enemies
for sustainable control of FAW. |
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