What is in this article?:
- Soybeans: need for insect scouting great
- Let natural enemies work
- Soybean insects pests were continual and multiple applications were necessary in 2010.
- This insect activity in soybeans points out the importance of a good scouting program.
- Integrated pest management works in soybeans.
- Unneeded applications lend themselves to developing insecticide resistance issues.
- Tolerance to pyrethroids is being documented for bollworms in the Southeast and, possibly, in Louisiana.
- With the high costs of production and a decent price for soybeans, the need for good scouting has never been greater.
Almost from the time soybeans emerged this year — and all the way until harvest — it seemed there were problems with soybean insect pests.
Early in the season we had outbreaks of fall and yellow-striped armyworms, garden webworms, bollworms and grey loopers, followed by saltmarsh caterpillars, bean leaf beetles and then, once again, bollworms (and some budworms) as bad as we have seen in many years.
Then, the looper complex, soybean and cabbage looper, hit us — not just in the southern half of Arkansas where they usually cause problems, but across the entire soybean-growing region. This resulted in a very significant portion of the acreage across the state having to be sprayed.
All this and I haven’t mentioned the three-cornered alfalfa hoppers, grasshoppers, lesser cornstalk borers, spider mites, and whiteflies that I had countless calls about.
In many locations, pests were continual and multiple applications were necessary because of the overwhelming numbers, pest complexes, or sometimes because the applications just were not effective.
This lack of effectiveness stemmed from application issues (such as not enough volume or spraying in the middle of a 110-degree day with 2 gallons per acre by air), to tolerance, to downright insecticide resistance.
Then, at the end of the season we had stink bugs. One of the positive things about this season, compared to the last several, was lower than average numbers of stink bugs. However, there were still enough that a significant amount of acreage had to be treated.
And when they hit fields in conjunction with loopers it became very expensive to control both pests.
All this insect activity in soybeans once again points out the importance of a good scouting program. I really don’t understand why we still have growers who do not believe in — or are not willing to pay for — good scouting.
Let’s be clear that “good scouting” refers to scouting all fields, at a minimum, of once per week by someone who is adequately trained to sample, identify, and recommend the proper insecticide to control the pests that are present. Scouting on an “as needed” or “whenever I get around to it or think about it” basis will only get you in trouble.
I can’t tell you how many times I had calls this season from people who sprayed pyrethroids for looper control and couldn’t understand why they did not get control.
One person called to ask me what to spray for Mexican bean beetles. We don’t even have this pest in Arkansas, that I am aware of anyway, and certainly not at treatment levels.
Inevitably, when pests are flaring in some areas, I get the call about what to spray for “worms.” When I ask the caller what worm it is, many times they don’t know and can’t even tell me how many worms they have. They just want to spray.
How many applications were made this year “after the fact?” That is, an application made after the damage was done? This is what we call a “revenge treatment” and rarely has any positive impact on yield. It may make you feel better, but it certainly isn’t helping the bottom line. In my opinion, we have too many of those situations.
The flip side is where we are spraying in advance of pest populations reaching threshold. I hear: “I knew they would get to treatment level, so I went ahead and treated.”