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Caprock Pest Management examines crops in Floyd County
By Dagan Teague
AgriLife Extension, Floyd/Crosby IPM Agent—
On Friday, July 17 our oldest scouted cotton is sitting at 8-9 nodes above white flower. We are still seeing fleahoppers in field and with a population increase. As we move farther into bloom and NAWF stages fleahoppers become less of a pest and can actually become a bollworm predator later in the season. This gives us one more reason to not want to treat for fleahoppers unless we must.
We also have several fields with enough blooms that the fleahoppers can easily find blooms and the easily accessed pollen to feed upon. Not all of our fields are ready to place the fleahoppers into this category yet. Because some of our later cotton has not bloomed yet and many fields are not blooming consistently, fleahoppers are still a threat for a while longer in these situations.
We are starting to pick up more Lygus in the area while we are still concerned with fleahoppers in some fields. Lygus, while their damage is similar to the fleahopper early in the season, are much more of a threat for a much longer period of time.
Lygus will feed on the squares and bolls up to 750 heat units of boll development. This means that Lygus, along with a few stink bugs, which are also in the area, could be a pest well into the fall.
For both fleahoppers and Lygus using a drop cloth paired with whole plant inspections will be the best way to monitor these plant bug populations while accurately calculating fruit drop, or conversely, fruit retention.
The threshold for fleahoppers using the drop cloth or sweep net method is 1 fleahopper per 1.5 to 2 row feet, or by the whole plant inspection method, 25-30% infested terminals with associated square loss. This square loss is a bit of a sliding scale starting around 10% fruit loss during the first week of bloom and ending at about 20 to 25% loss for the first week of bloom.
In corn we are seeing some small colonies of spider mites. The colonies can be seen in the mid to lower leaves of the corn plant. You can see the yellowish discoloration on the midrib of the leaf. Spider mites are very, very small and can cause significant damage if the colony numbers get out of control.
“Finding trace amounts of spider mites, which are difficult to find, in some fields. In mature corn the heavier the pressure seems to be an amount to justify application closer to Lockney. Most other fields predict to be at the same pressure next week. Pre-tassle or just starting to tassle corn seems to not have problems yet,” says Clay Golden, local consultant.
“Finding only 1-2 sugarcane aphids West of Croby near the county line around Lorenzo. Nothing to be worried about in the upcoming weeks as the sorghum is only at 6 leaf,” said Dakota Keyser, local consultant.
Sorghum damage results from a combination of loss of plant nutrients, and reduced photosynthesis because of the buildup of sooty mold on the honeydew the aphids excrete.
An uncontrolled infestation can reduce the number of heads and seed weight, delay plant development and maturity, and could lead to plant death. In forage sorghum, mold can reduce sorghum quality and honeydew buildup can cause cutting and baling problems.