Quantifying corn rootworm damage
The model may, however, be useful to help economists to estimate the effect of corn rootworm. “That’s when a model like this can become really handy,” he continued.
Tinsley said that further directions for this research include developing collaborations with other states. “If we extend to the western Corn Belt where it may be drier, we might start to see differences between two different regions in the relationship,” he said.
Another direction is to explicitly model heat stress and moisture stress into the model, perhaps as a covariate. Such an analysis would look at the effects of combinations of factors.
“For example, if I have one node of roots destroyed but I have 10 inches of moisture stress, what’s going to happen as compared to what happens if I have one node of root injury but no moisture stress,” he explained.
He noted that many studies have demonstrated that often, when there is neither moisture stress nor excessive heat stress, the injury from corn rootworm does not result in significant yield loss.
Another factor to consider is lodging, when plants with root injury fall over. Lodged plants are very difficult to harvest.
“Under certain circumstances, you can have not very much root injury but a lot of lodging and big yield losses,” Tinsley said. “Under other circumstances, you can have what seems to be a lot of root injury but if there are no big storms and you don’t have any lodging, there may be no yield loss.” Future collaborations in the development of this damage function may include lodging in the model.
The article, “The validation of a nested error component model to estimate damage cause by corn rootworm larvae,” was published in Journal of Applied Entomology, which is available online at http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0418.2012.01736.x/abstract. Ronald Estes and Michael Gray, also in the Department of Crop Sciences, are co-authors.