Impact of the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff ) Sorokin on Spodoptera frugiperda (J.E Smith), an invasive maize pest in Chad

The invasion of agricultural plots by Spodoptera frugiperda (J.E Smith) constitutes a serious constraint to the sustainable maize production in Chad. Since then, farmers have unsuccessfully used available chemical insecticides to control this pest at that respect, the present study evaluated the bio-efficacy of two strains (Chinese and Senegalese) of Metarhizium anisopliae on the pest, both under laboratory and field conditions. Laboratory results showed that both strains were virulent against FAW resulting in a mortality of 90 ± 5.77% for the strain from Senegal and 75 ± 5.00% for that from China. In the field, significant differences were observed among the four treatments tested, namely the two M. anisopliae strains (2.5 kg/ha), the control and Emamectin benzoate (20g/ha) for both the infestation of maize plants and FAW densities (P <0.05). Meanwhile, maize grain yields were significantly the highest in plots treated with Emamectin benzoate followed by plots treated with either of the two strains of the fungus whose yields were statistically similar (df = 3; F = 27.13; P <0.0001). This biopesticide was more virulent under laboratory and field conditions and could be a promising biological control agent against S. frugiperda as an alternative to synthetic insecticides. However, additional studies that evaluate the implementation cost of the microbiological control are very necessary for more objective and robust conclusions. Key words: Fall armyworm, microbiological control, Zea mays, Emamectin benzoate, biopesticides.