General Situation
Very hot and dry. The heat had us at about 98oF all week and with the heat index it made it feel like 106oF. Also, the wind was a lot calmer this week at 10-18 mph so many growers were applying different spray applications throughout Hidalgo, Cameron, and Willacy counties to their row crops. Many growers were either applying plant growth regulators on cotton or applying spray applications for insect pests and weeds management.
Cotton
Cotton throughout the Valley is showing good square set and boll load as we seem to be at peak bloom in majority of cotton growing right now and some cotton has started to cut out with a lot of mature bolls filling on the bottom half of the plants.
There were reports of a few fields being treated for fleahoppers this week, but cotton overall looked very clean throughout the valley as we scouted behind insecticide spray applications and were seeing excellent control and little to none fleahoppers. We checked behind some cotton sprayed last week for chili thrips along the river and were seeing good control as well.
We did pick up on a couple of Verde plant bugs and tarnished plantbugs while scouting in cotton around the Lyford and Raymondville areas so we will be monitoring for plantbugs diligently next few weeks thru July as we have a lot of dime size bolls maturing.
I was checking some mature sorghum heads for plantbugs this week and not really finding any (which was good) as we will be monitoring if we have plantbug populations in sorghum migrate to cotton during sorghum harvest. We did also come across a few bollworm eggs this week in some cotton just to make note.
Grain
Lots of grain sorghum in hard dough stage showing beautiful red and orange seed everywhere in LRGV. Many mature sorghum fields’ leaves starting to senesce as harvest is around the corner. In flowering sorghum, it was very easy to find midge across the Valley this week. Every field we checked that was flowering we found anywhere from 2-6 midge feeding per head.
When checking for midge inspect the heads for a small orange/reddish flying insect around the yellow flowering spikelets as this is where the female will lay her eggs, usually about 50 yellow-white eggs, the adults only live for one day. The eggs hatch in 2 to 3 days so you must check daily for sorghum midge as new populations emerge/hatch each morning. Economic threshold for midge is 1-2 midge per head.
This week scouting some of the sorghum that is barely in soft dough stage we were finding lots of headworms (fall armyworms & cornearworms) about 2-5 per head in fields across the Valley. So if you have soft dough sorghum please go check it.
The economic injury level for headworms in commercial sorghum is about 1 to 2 larvae per grain head. When scouting for headworms first inspect the sorghum plants for frass on leaves and for frass on the ground between rows. Take a white bucket and beat the heads to dislodge the larvae. To get a good idea of what’s going on in your field make sure to beat at least 30 heads.
You can find insecticide treatment options for headworms on Page 37 in the Sorghum pest management guide, to access click on link below and go to page 37. We are seeing a few rice stinkbug adults and nymphs but just a few pockets and nothing near threshold.
Sesame
We have been scouting different stages of sesame this week. There is a lot of sesame in full bloom and some already going into cutout with blooms at the very tops and excellent pod development/load. There is also some sesame that is in early vegetative stages and just started to produce some blooms at growing point.
Sesame looked very clean and free of pests in all stages this week. However, this week sesame leafroller has been spotted in low numbers feeding in some uncontrolled pig weed that is growing alongside sesame. We will just have to monitor the sesame that is the early growth stages thru bloom to make sure sesame leafroller does not become a problem.
Sesame leafroller (SLR) is most destructive in its larvae stage where it is neon green/yellowish in color with black dotted pattern and hairs. The way you scout for leafrollers is you look for black frass (worm poo) on leaves and that’s usually a good give away to look there.
Growers back in 2020 the way we would scout for leafroller caterpillars was to just look where the blooms were at and the tops of plants and if blooms looked mangled and some webbing and if there were leaves twined/clumped together, that’s usually were we would find them. It took a while in 2020 for populations to build and we had problems in late July of 2020.
This is just a heads up for this pest. We have Not seen sesame leafroller in sesame only in pigweed. I just want to make growers are aware of what to look for ahead of time and be prepared. We will be actively scouting and I will report if we do see any development.
If you want more information on SLR visit my webpage, I have the youtube video that former extension entomologist Holly Davis had made where she shows how to scout and look for SLR also if you scroll further down you can click on the SLR efficacy report from 2020 as well.
