|Shapiro Ilan, David|
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2004
Publication Date: 3/1/2005
Citation: Shapiro Ilan, D.I., Dutcher, J.D., Hatab, M. 2005. Recycling potential and fitness in steinernematid nematodes cultured in curculio caryae. Journal of Nematology. 37:12-17. Interpretive Summary: The pecan weevil is a devastating pest of pecans. We are seeking new environmentally sound methods of controlling this pest. Insect-killing nematodes are small round worms that kill insect pests but don't harm people or the environment. Initial studies indicate that these nematodes are promising alternatives for pecan weevil suppression. The effectiveness of using nematodes to control the pecan weevil will depend, in part, on how well the nematodes can reproduce inside the dead insect, and how well emerging (baby) nematodes can go on to kill new weevils. In this study, we found that nematodes can reproduce in pecan weevil larvae. The nematode progeny that emerge from dead pecan weevils are fully capable of killing more pecan weevils, but the ability of the nematode progeny to continue to reproduce in pecan weevil appears to be diminished.
Technical Abstract: The recycling potential of entomopathogenic nematodes in the pecan weevil, Curculio caryae, is an important factor in considering whether nematodes could be incorporated into a C. caryae management strategy. Our objective was to determine the recycling potential and fitness of S. carpocapsae and S. riobrave cultured in pecan weevil larvae, C. caryae. Lipid content was higher in S. carpocapsae cultured in C. caryae than in Galleria mellonella, but S. riobrave lipid content was not affected by host source. Host source did not affect subsequent infectivity or virulence to C. caryae, but did affect reproductive capacity. Both nematode species produced more progeny in C. caryae when they were first cultured in G. mellonella than when they were first passed through C. caryae. In terms of potential to recycle under field conditions, we predict that nematodes resulting from one round of recycling in C. caryae larvae would be equally capable of infecting the killing more weevils, but the potential to continue recycling in C. caryae would diminish over time due to reduced reproduction in that host.