Investigation of the occurrence of entomopathogenic fungi in soils and on insects from Corentyne Berbice, Guyana

Abstract

Entomopathogenic fungi is a component of pest management systems in some countries, and have great potential as a biological control agent against insects. The purpose of this study was to investigate the occurrence of entomopathogenic fungi in soils and on insects from Corentyne Berbice, Guyana South America. A total of 190 insects were collected; which belonged to 14 insect families. They are Aleyrodidae, Coreidae, Acrididae, Blattidae, Drepanidae, Libellulidae, Lycaenidae, Pieridae, Vespidae, Apidae, Formicidae, Culicidae, Scarabaeidae and Muscidae. Acrididae was found to be the most dominant insect family. However, insect-associated fungi were defined to include known entomopathogenic fungi, secondary colonizers and non-pathogenic colonizers. Entomopathogenic fungi found from the insects were Beauveria bassiana, Lecanicillium, Fusarium, and Paecilomyces, comprising of 5.62, 1.41, 3.28 and 0.94 isolation percentage respectively. Among the secondary colonizers, Alternaria, Curvularia, Penicillium, and Cladosporium were found, comprising 4.22, 14.75, 5.62, and 5.15 isolation percentage respectively. Non-pathogenic colonizers had high occurrences; among them was Aspergillus niger, Aspergillus flavus, Aspergillus versicolor, Aspergillus clavatus, Phytophthora, Pyricularia, Mucor, Bipolaris, Trichophyton, Trichoderma, and Rhizopus, comprising 22.72, 14.75, 1.64, 1.41, 1.41, 3.51, 7.26, 0.47, 0.23, 4.22 and 1.41 isolation percentage respectively. Moreover, B. bassiana was the only entomopathogenic isolate from the soil samples, comprising of 11.25 isolation percentage. Other soil colonizers present were A. niger, A. flavus, Penicillium, A. clavatus, Mucor, and Rhizopus, comprising of 11.25, 16.25, 6.25, 6.25, 21.25, and 27.50 isolation percentage respectively. These findings highlight that entomopathogenic fungi are present in the bio-systems chosen and further investigations are necessary to establish an effective biocontrol strategy.