"This not a model that a farmer can use to say, 'What is my yield loss going to be like this year?'" said Tinsley. "You just don't know what some of these things that are affecting the error are going to do."
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 t
|Contact: Susan Jongeneel|
University of Illinois College of Agricultural, Consumer and Environmental Sciences