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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #129202
Title: CARPOPHILUS FREEMANI (COLEOPTERA: NITIDULIDAE) AS A VECTOR OF BEAUVERIA BASSIANA, A LABORATORY STUDY

Author
item BRUCK, DENNY
item LEWIS, LESLIE

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary: Sap beetles are fungus feeding insects commonly found in the tunnels of larvae of the European corn borer (ECB). It is not uncommon to find beetles and larvae in these tunnels infected with the fungus Beauveria bassiana. This study was conducted to determine if the sap beetle C. freemani can vector B. bassiana in the laboratory. Sap beetle adults were fed B. bassiana to determine if viable fungi were present in their fecal material. Beetles were also surface contaminated with the fungus and placed in artificial O. nubilalis tunnels (constructed from excised corn stalks) both with and without ECB larvae to determine if conidia were mechanically transferred. Beetles fed B. bassiana had viable fungus in 14% of their fecal droppings, while none of the fecal droppings collected from control beetles contained viable fungus. Beetles treated with B. bassiana left significantly more fungus in the artificial tunnels than control beetles. European corn borer larvae exposed to artificial tunnels simultaneously with treated beetles or to tunnels from which treated beetles had frequented became infected. European corn borer larvae from tunnels with control beetles or in tunnels from which control beetles had frequented did not become infected. These studies indicate that the sap beetle C. freemani, under laboratory conditions, can transfer B. bassiana mechanically and in their fecal matter. This study is important to scientists and extension personnel in understanding how B. bassiana is moved within the corn field and comes in contact with ECB larvae.

Technical Abstract: Carpophilus freemani, a fungivore commonly found in corn (Zea mays L.), frequents Ostrinia nubilalis tunnels. This study was conducted to determine if C. freemani can vector Beauveria bassiana in the laboratory. Carpophilus freemani adults were fed B. bassiana to determine if viable fungi were present in their fecal material. Beetles were also surface contaminated with 1 x 10**8 conidia/ml and placed in artificial O. nubilalis tunnels (constructed from excised corn stalks) both with and without O. nubilalis larvae to determine if conidia were mechanically transferred. Beetles fed B. bassiana conidia had viable fungus in 14% of their fecal droppings, while none of the fecal droppings collected from control beetles contained viable fungus. Beetles treated with B. bassiana left significantly more colony forming units in the artificial tunnels than control beetles. Ostrinia nubilalis larvae exposed to artificial tunnels simultaneously with treated beetles or to tunnels from which treated beetles had frequented became infected. Ostrinia nubilalis larvae from tunnels with control beetles or in tunnels from which control beetles had frequented did not become infected. These studies indicate that C. freemani, under laboratory conditions, vectors B. bassiana.