Insect Pressure Increases in Louisiana Cotton Fields

By AgFax Media LLC, AgFax.com

Aphids have been turning up in scattered locations in Louisiana and Mississippi. The aphid fungus appeared to have developed in one case in Louisiana. Scattered fleahoppers continue to turn up in parts of Louisiana. 

Thrips have lingered longer than usual, based on reports this week. But any treatments now would likely be on a limited, isolated basis. 

More rain fell over the weekend and into this week. However, the weather has started clearing through the region and the forecast calls for an extended period of dry, sunny conditions.

Sebe Brown, Northeast Louisiana Region Extension Entomologist:

"We are exceedingly wet (as of 6/6). North Louisiana has had hardly any break from the rain in the last 2 weeks. A little dry spell is in the forecast, which may allow growers to return to some fields by Friday or Saturday. But on heavier ground, it could be a couple of weeks before anything can be done.  

"The majority of our cotton is out of the thrips window and much of our crop is pushing 5 leaves. We're dealing with sporadic aphid and fleahopper populations. Aphids started turning up right before all of this rain. A consultant today did find aphids that were infected by the fungus. I think we've had the right moisture and temperature conditions to take them out. Our cotton is definitely not drought stressed.  

"Fleahoppers are knocking off a few squares. Generally, they're not at treatment levels, although we have historic hot spots where they might have hit that point.  

"With all the mud, everything has been going out by air. I haven't heard of any ground rigs running for at least 2 weeks. Cotton's age is all over the board. Some is beginning to square but guys have been holding off on any treatments because they're afraid that it will rain and the materials will be washed off. Or, if they have to treat by ground they can't get into the field.  

"Treatments for redbanded stink bugs (RBSB) have started in R5 soybeans in south. I'm afraid that some folks are getting a bit trigger happy with RBSB between R3 and R5. If beans are at R5 and you're at threshold levels, you need to treat. But I'm hearing about cases where these are still sub-threshold levels and beans don't have seeds in pods yet.  

"If you don't have beans in pods, there's really nothing for RBSB to feed on, so there's really nothing to protect. Decisions may get a bit more complicated with indeterminates since you may only have pods at the bottom as RBSB populations build. If you've only got 2 pods at the bottom, that's probably not enough to justify treating yet. Applications should be based on both the crop's stage and insect pressure.  

"With this year's mild winter, RBSB did not go into diapause, even in north Louisiana. We found them in January and February north of Interstate 20, and they were reproducing in legumes during the winter. We could have a pretty big fight on our hands with RBSB in the late beans, and with a $9 soybean market we can't waste any applications."