About a month ago, we published an article asking readers for input on what pests they were seeing and what levels of economic damage may be out there in corn and soybean fields. The results are presented below:
Do you scout for mid-season insect pests?
26=Yes 4=No
Q1: Which pests are commonly found causing crop damage during mid-season scouting of soybeans (check all that apply)?
Q2: What percentage of soybean fields that you scout exhibit mid-season insect damage over threshold?
Q3: Which pests are commonly found causing crop damage during mid-season scouting of corn (check all that apply)?
Q4: What percentage of corn fields that you scout exhibit mid-season insect damage over threshold?
Looking over these results, a couple of key points occurred to me:
- First, Japanese beetles are clearly the big player in both crops (#1 in both). Although these generalist feeders are common in virtually any environment (including homes, parks, gardens, etc.) during July and into August, they are usually restricted to cropping field borders because they frequently pop back and forth between multiple potential hosts – they are not restricted to corn or bean fields.
- The second key point are the very low overall damage levels in both corn and soybeans. Roughly 40% of both are estimated to have no treatable (above threshold) levels of damage. When we include the “below 5%” category as well, we have roughly 70-80% of corn and soybean fields included with a low likelihood of damage at this time of year. This is encouraging from a crop health point of view, and matches up with anecdotal reports and what we see in our research trials – even when we are trying to encourage and promote pest infestations, it’s difficult to get those numbers up over economic thresholds. A very different story than 15-20 years ago! Pest numbers are down, and although all of the reasons behind the trend are not clear, these trends offer an opportunity to save time and money when it comes to insect pest management.
