ARS | Publication request: The ability of insect-killing fungi to kill pecan aphids under laboratory conditions

Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: December 18, 2008
Publication Date: February 10, 2009
Citation: Shapiro Ilan, D.I., Cottrell, T.E., Jackson, M.A., Wood, B.W. 2009. The ability of insect-killing fungi to kill pecan aphids under laboratory conditions. Pecan Grower. 20(3):18-21.

Interpretive Summary: There is need for efficacious biocontrol agents for pecan aphids in commercial orchards. As a preliminary step to this end we determined the virulence (killing power) of several beneficial fungi to pecan aphids. Overall, during the course of several experiments, we tested three species (kinds) of fungi: 1) Isaria fumosorosea (two strains of this species were tested: ARSEF 3581 and ATCC 20874), 2) Metarhizium anisopliae (strain F52), and 3) Beauveria bassiana (strain GHA). Two different spore forms (blastospores and conidia) can be produced by the fungi and can have differing levels of virulence; hence both spore forms were tested against aphids. In the first experiment we tested the virulence of 3581 blastospores to three pecan aphids: the black pecan aphid, the blackmargined aphid, and the yellow pecan aphid. We found all three aphids to be susceptible to infection by the fungus though the yellow pecan aphid was somewhat less susceptible than the black pecan aphid or blackmargined aphid. In subsequent experiments results indicated the highest virulence against the black pecan aphid using 3581 blastospores and F52 conidia followed by 20874 conidia. The detection of virulence to pecan aphids establishes the potential for commercial usage.

Technical Abstract: There is need for efficacious biocontrol agents for pecan aphids in commercial orchards. We determined the virulence (killing power) of several beneficial fungi to pecan aphids. We tested three species (kinds) of fungi: 1) Isaria fumosorosea (two strains of this species were tested: ARSEF 3581 and ATCC 20874), 2) Metarhizium anisopliae (strain F52), and 3) Beauveria bassiana (strain GHA). The fungi can be produced in two different forms of spores, blastospores and conidia, each of which may have differing levels of virulence. Therefore, we tested both spore types for the appropriate fungi. In the first experiment we tested the virulence of 3581 blastospores to three pecan aphids: the black pecan aphid, the blackmargined aphid, and the yellow pecan aphid. We found all three aphids to be susceptible to infection though the yellow pecan aphid was somewhat less susceptible than the black pecan aphid or blackmargined aphid. In subsequent experiments, results indicated the highest virulence against the black pecan aphid using 3581 blastospores and F52 conidia followed by 20874 conidia. The detection of virulence to pecan aphids establishes the potential for commercial usage. Results reported here will narrow treatments to test in future greenhouse and field trials.