What to Watch Before Tassel

As we approach tassel, there are two things every corn grower should be doing in their fields: scouting diseases and scouting insects.

First, know the difference between Bacterial Leaf Streak (BLS) and Gray Leaf Spot (GLS). These two diseases can look very similar from the pickup window, but they have very different management implications. A fungicide application can provide an excellent return when Gray Leaf Spot is present and conditions favor disease development. However, fungicides will not control Bacterial Leaf Streak. Before investing in a fungicide, spend some time in the field, identify what you're seeing, and make an informed decision.

Second, scout for Corn Rootworm (CRW) beetles and Western Bean Cutworm (WBCW). In continuous corn environments, finding two or more CRW beetles per plant deserves attention, especially if you're considering utilizing TS201 with untraited corn next season to maximize yield potential. Rootworm management doesn't begin next year—it begins this year.

We've also seen Western Bean Cutworm egg masses appearing earlier than normal. After several years of relatively light pressure, we're watching closely to see if that signals a resurgence in populations. Time will tell, but now is the time to be looking. The treatment threshold remains approximately 5–8% of plants with egg masses or young larvae.

The good news is that both pests can often be managed with the same active ingredient: indoxacarb. Timing is critical. The optimal window for Corn Rootworm beetle control is typically 5–10 days after tassel emergence when pollen shed is occurring. That's when beetles are most active and feeding before egg laying begins. Western Bean Cutworm larvae follow a similar timeline—hatching near tassel, feeding on pollen, and then moving down the plant to enter the ear and feed on developing kernels.

This year's message is simple: Don't make assumptions. Scout your fields. Know what you're dealing with. A few hours spent walking corn before and during tassel can pay dividends at harvest.

— Dwayne