Biologycycle and Natural Enemies of Spodoptera frugiperda (Lepidoptera: Noctuidae) in Maize Crops in Cote D’ivoire

Assienin Hauverset N’guessan, Hugues Annicet N’da, Brice Sidoine Essis, N’klo Hala and N’guessan Alphonse Kouassi

Background and Objective: In Cote d'Ivoire, maize is the second most important cereal crop after rice. However, fall armyworm, which is now the most important pest of this plant, is found throughout Africa and Cote d’Ivoire. This study aimed to study the biological cycle of S. frugiperda and to identify natural enemies and entomopathogenic fungi to counter the spread of this pest in maize crops in Cote d'Ivoire. Materials and Methods: Regular monitoring of maize plots set up in three agroecological zones was carried out. This allowed to collect dead larvae of the pest, to capture predators of the pest and to collect live larvae of the pest for rearing in the laboratory. Results: The results showed that the complete biological cycle of S. frugiperda reared at a temperature of 24-26°C and relative humidity of 60-63% is approximately 54 days, with an average of about 39.79±4.59 days. The sex ratio is in favour of the males which were more numerous than the females. The identification of natural enemies revealed the presence of four main predators which are Doru sp. (Dermaptera: Forficulidae), Hymenoptera Sphecidae and Heteroptera Reduviidae Rhynocoris rapax and Rhynocoris segmentarus. The culture of dead larvae on PDA medium allowed isolation and identification of entomopathogenic fungi Penicillium sp., Metarhizium sp., and Fausarium sp., causing the death of this pest in the plots. Conclusion: The life cycle of Spodoptera frugiperda is about 40 days and four main predators and three entomopathogenic fungi of fall armyworm have been identified in Cote d'Ivoire.

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