Tolerance as a Putative Mechanism for Hessian Fly Control in Winter Wheat

Monday, June 1, 2015
Big Basin (Manhattan Conference Center)
Kirsten Roe , Entomology, Purdue University, West Lafayette, IN
Brandon Schemerhorn , USDA-ARS and Department of Entomology, Purdue University, West Lafayette, IN
Host plant resistance genes are a key method in reducing Hessian fly populations and infestations, but this resistance can lead to the risk of resistance in Hessian fly populations. Tolerance in wheat may hold the key to reducing damage caused by Hessian flies while preventing the flies from gaining resistance. Tolerance may allow the plant to survive infestation and to continue growing, pushing larvae out of the leaf sheath, making them vulnerable to desiccation and parasitism. Susceptible wheat lines 25R75 and Newton plus the tolerant line 25R78 were evaluated. Several time increments were used for measurements: 8, 9, 16, and 32 days after infestation. At 16 days, significant differences were observed between the treated lines for tiller number, leaf number, total leaf length, and larvae surface area. There were no significant differences for leaf number or tiller number between the control and treated plants for line 25R78, but there were differences between control and treated plants of 25R75, suggesting that tolerance had a positive effect. Infestation had a much smaller impact on the tolerant line compared to the susceptible line. There was a 20.74% reduction in leaf length for line 25R78 compared to a 47.08% reduction in leaf length for line 25R78. The tolerant line also showed significantly more visible larvae (50% of plants) present than the susceptible line (0% of plants). An increased number of tillers for the infested tolerant line versus the infested susceptible line could result in more fertile heads and a higher grain yield.