AN ATOXIGENIC L-STRAIN OF ASPERGILLUS FLAVUS (EUROTIALES: TRICHOCOMACEAE) IS PATHOGENIC TO THE COFFEE TWIG BORER, XYLOSANDRUS COMPACTUS (COLEOPTERA: CURCULIONIDEA: SCOLYTINAE).

This study isolated and evaluated virulence of fungal entomopathogens of Xylosandrus compactus-an important pest of Robusta coffee in Sub-Saharan Africa. A survey was conducted in five farming systems in Uganda to isolate entomopathogens associated with X. compactus. Four fungal isolates were screened for virulence against X. compactus in the laboratory at 1 x 107 conidia/ml where an atoxigenic L-strain of A. flavus killed 70-100% of all stages of X. compactus compared to other unidentified isolates which caused 20-70% mortalities. The time taken by A. flavus to kill 50% of X. compactus eggs, larvae, pupae and adults in the laboratory was 2-3 days; whereas the other unidentified fungal isolates took 4-7 days. The concentrations of A. flavus that killed 50% of different stages of X. compactus were 5 × 105 , 12 × 105 , 17 × 105 and 30 × 105 conidia/ml for larvae, eggs, pupae and adults, respectively. A formulation of A. flavus in oil caused higher mortalities of X. compactus larvae, pupae, and adults in the field (71-79%) than its formulation in water (33-47%). The atoxigenic strain of A. flavus could therefore be developed into a safe biopesticide against X. compactus. This article is protected by copyright. All rights reserved.