By Luke Samuel
Corn Insect Traits Manager
When it comes to farming it’s always tough to predict the weather from one year to the next. Turn the clock back one year and we were all talking about how the combination of a mild winter, early spring planting and a hot, lengthy summer drought created significant stress on corn and soybean crops. This, in turn, resulted in small root masses and heavy corn rootworm pressure throughout the Corn Belt.
What a difference a year makes. With much of the country experiencing a far wetter than normal spring, many growers were delayed (sometimes significantly delayed) in getting their fields planted. In some areas, the wet weather may have diminished the rootworm population, drowning the larvae.
However, rainy weather early in the season doesn’t necessarily mean that pests are going to be easy to manage, and we don’t want growers to get a false sense of security with their late planted corn fields.
Since adult corn rootworm beetles prefer to feed on pollen and fresh corn silks, late planted corn can act as a trap crop for adult corn rootworm beetles. The increase in beetles may lead to increased silk clipping, which can interfere with pollination and can lead to a high number of egg-laying females. A key to success for these late fields, as it goes for any corn field, is diligent scouting. We recommend scouting for adult corn rootworm beetles through August when peak beetle activity occurs, and given the cooler than normal temperatures, that peak may be later than normal in 2013.
Scouting is an integral part of insect management and Monsanto’s best management practices. Growers should keep a close eye on their fields by employing regular, appropriate scouting techniques. When scouting a field for corn rootworm beetles, it should be sampled weekly, and we recommend collecting the following information:
– Randomly select 10-25 locations within the field and count the total number of beetles on at least two plants within each location. The minimum number of plants sampled should be 20-50 depending on the field size and activity level of beetles.
– In between beetle counts, collect them and determine the number of males and females in a sample. They can be captured by hand, with a small sweep net, or use of a motorized hand-held vacuum.
Scouting can provide valuable information about insect and disease pressure in this year’s crop and help decision for next year’s seed choice. In-season scouting, using the correct corn trait package such as dual mode-of-action (pyramided) Bt-trait products, and rotating crops to soybeans or another non-host crop and/or using soil- or foliar-applied insecticides as needed, can be extremely effective in controlling this “billion-dollar bug.” Each of these steps are part of the foundation for an effective integrated pest management system on your farm.
While you may not have control over the weather, you can control the steps you take to manage the insect population on your farm. In the end, you’ll be protecting your investment and optimizing your yield.