As was the situation last year, we have seen an increase in the frequency of rainfall in Ohio the past couple of weeks, and many fields still need to be planted. We published an article at this time in 2009, and realized it was relevant again this year. Because of the continued rainfall and what will be late plantings for many fields, a portion of the corn and soybean crop will be relatively short in height and growth going into late May and early June. However, the insect populations are somewhat on schedule. Growers should be aware that the presence of smaller plants can intensify the injury that can occur. Many of our thresholds relate to the size of the plants, and thus, later planted crops will be at a higher risk of economic damage. On corn for example, the black cutworm threshold, 3% or more plants cut or tunneled and larvae still 1 inch or less, is for plants in the second to sixth leaf stage. Some of the corn will not even be reaching the second stage for a few weeks considering some of it is not yet emerged or even planted. On soybean, slugs, as well as bean leaf beetles, are more damaging to plants that are recently emerged with unifoliate leaves just opening. We would suggest that growers check their late planted fields as they begin to emerge to prevent unexpected injury from insect pests that would not be of much concern if crops had been planted earlier.
Ful