Interaction of maize, drought stress, and western corn rootworm on plant and insect growth in B73 x Mo17

Drought can have a major effect on plant production and the western corn rootworm can exacerbate those effects. In order to quantify the interaction of western corn rootworm and drought, the growth rate of western corn rootworm and maize (B73xMo17) under three levels of both stressors was evaluated in greenhouse experiments. Significantly more western corn rootworm larvae were recovered from high and moderate moisture levels than under very dry conditions. All larvae recovered under high moisture conditions were third instar larvae, while under very dry conditions, all larvae were second instars. Under moderate moisture, both were present. Dry shoot and root weight showed similar trends. Under very dry conditions, dry weight of roots and shoots were significantly lower than under moderate and high moisture conditions. Overall, when drought, plant growth, and rootworm growth were all carefully quantified, the interaction of drought and rootworm had expected results under very dry conditions. However, moderate moisture and low rootworm conditions, there was a trend for higher shoot and root weight when compared to the high moisture treatment at similar rootworm infestation levels. As drought traits become commercially available, understanding this interaction becomes more important.