I’ve had some reports of well-above treatment levels of tarnished plant bugs in cotton that is just beginning to square. Be advised that plant bugs will often concentrate in the first fields that begin squaring. There have also been reports of brown and green stink bug adults being caught in sweep nets. Do not get too excited about stink bugs in pre-flowering cotton. On rare occasions, I’ve observed where immature stink bugs will knock off squares, but this has been a very rare event (and only occurs closer to flower). I am not concerned about the adult stink bugs until flowering begins. Plant bugs are a different matter!
The suggested treatment threshold for tarnished plant bugs during the first two weeks of squaring is an average of 8 or more bugs per 100 sweeps. You should take a minimum of 100 sweeps per field. Treatment may also be needed if plant bugs are present in below threshold numbers IF square retention is below 80%. There are a number of methods of monitoring square retention, but the most important component is to randomly and representatively count the number of missing squares on a minimum of 100 fruiting sites per field. The usual approach is to examine first position fruiting sites on the top five nodes of each plant (of course, during early squaring there will not be five fruiting nodes on a plant).
There are several suggested insecticide options for plant bugs in cotton prior to flowering. The many different formulations and trade names of imidacloprid products causes some confusion. Be sure to use comparable rates of active ingredient. I’ve included a table of suggested and comparable rates of imidacloprid products for control of tarnished plant bug (see below). The second table lists other recommended treatment options in pre-flowering cotton.
Comparable Rates of Imidacloprid Products Applied as Foliar Spray for Tarnished Plant Bug
| Lb Active Ingredient per Gallon (representative trade names)* | Suggested Rates (lb ai/a) | Suggested Rates (oz/a) | Labeled Maximum Rate (oz/a) |
| 1.6 (Nuprid 1.6F) | 0.047 – 0.0625 | 3.75 – 5.0 | 5.0 |
| 2.0 (Couraze 2F) | 0.047 – 0.0625 | 3.0 – 4.0 | 4.0 |
| 4.0 (Alias 4F, Couraze 4F, Nuprid Max) | 0.047 – 0.0625 | 1.5 – 2.0 | 2.0 |
| 4.6 (Admire Pro) | 0.047 – 0.0625 | 1.3 – 1.7 | 1.7 |
* The trade names listed are labeled for foliar use on cotton. However, not all imidacloprid products are labeled for foliar application. Be sure to check the label, and do not exceed the maximum application rate.
Alternative Foliar Treatments for Tarnished Plant Bug Prior to Flowering
| Trade Names (active ingredient) | Suggested Rates (lb ai/a) | Suggested Rates (oz/a) | Labeled Maximum Rate (oz/a) |
| Centric 40WG (thiamethoxam) | 0.0375 – 0.0625 | 1.5 – 2.5* | 2.5 |
| Carbine 50WG (flonicamid) | 0.081 – 0.089 | 2.6 – 2.8 | 2.8 |
| Intruder 70WSP (acetemiprid) | 0.05 | 1.1 | 1.1 |
* Do not use the lowest suggested rate except during early season and only when populations do not greatly exceed threshold levels.
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