Plant bug management begins at first pinhead square
Growing a cotton crop that’s going hard up against plant bugs can seem like a never-ending saga. One minute you see the light at the end of the herbicide-spray tunnel, and the next, it’s time to start managing plant bugs … and managing plant bugs again… and managing plant bugs some more. But that’s how you get the most out of a cotton crop—good management against known insect pressures.
By starting your regular scouting at first pinhead square, and keeping an eye on plant bugs until you see that last boll form, you can ensure efficiency out of every dollar spent on managing plant bugs for your cotton crop.
Here are some tips as you’re out scouting cotton this year:
- Prior to bloom, use a sweep net and monitor squares to make your treatment decisions. Use a threshold of 8 plant bugs in 100 sweeps and 80 percent square retention to treat.
- Plant bugs move up and down in the canopy, so don’t just check the terminal. Make sure you’re keeping an eye on squares from top to bottom.
- Once cotton begins to bloom, use a drop cloth to sample for plant bugs, treating when you find an average of at least 3 plant bugs per cloth. Recent research has shown that insecticide applications during the first three weeks of bloom are critical in preventing yield loss when plant bugs are present at threshold levels. This may also a good time to include Diamond® or Transform® into your pest control program. Each offers a different mode of action for plant bug control.
- Check possible hosts near your cotton crop to get a better understanding of what might be coming your way. Plant bugs can develop on hundreds of plants, including corn and various weeds. Pay attention to crops that may be senescing; such as hay or wheat. As they lose their green, plant bugs will migrate to your still growing cotton crop.
- Make sure you’re checking throughout the field. Plant bugs like to move around, and can move to various places in the field throughout the course of a day.
When you do spray, always read and follow label use instructions, particularly as your cotton crop is growing quickly from one stage to the next, because some active ingredients or modes of action may not be labeled for that growth stage.
Also, keep these five things in mind:
- Use insecticides at effective rates as the label outlines. This is one of the big ways to prevent insecticide resistance. Consider performing a jar test to ensure the product will perform in the way you want for the crop you’re applying.
- Keep an open mind with your program, as tarnished plant bugs are beginning to show some resistance to acephate insecticides in some areas.
- When using organophosphates, such as Bidrin®, utilize a pH buffer to lower spray water pH and improve efficacy.
- Neonicotinoids, such as Centric®, work well early, but lose their effectiveness later in the season. By using neonicotinoids initially, you can rotate to pyrethroids later in the season, preserving beneficials and keeping a cleaner crop later in the season.
- As the season continues, tank mixes will most likely become necessary to control a pest complex that includes plant bugs, stink bugs, bollworms and fall armyworms.