Insect pressure remains intense, corn leafhopper reach expanding

Insect pressure has been “extraordinarily heavy” for Texas crops, according to Texas A&M AgriLife Extension Service pest management expert David Kerns, Ph.D., professor and associate department head for the Department of Entomology.

He said part of the increased pressure comes from unusual pests such as corn leafhoppers that Texas doesn’t typically have in great numbers.

Kerns, who oversees the Texas Integrated Pest Management Program, IPM, has heard from IPM agents, AgriLife Extension specialists and agriculture and natural resources agents with similar pest pressure concerns. Collectively, they say this has been a bad year for pest pressure in grains across the state.

Kerns said with the warmer weather patterns we’ve been having, the increase in pests doesn’t come as a surprise.

Corn leafhopper concerns

Corn leafhoppers, a pest originating in South America, aren’t normally a concern in Texas. Warmer temperatures, however, have helped expand the corn leafhoppers habitat range and this season they have moved much deeper into the state than before.

“It was 2016 that we last saw these pests in large numbers in the lower Rio Grande Valley, but now they are back again and spreading,” Kerns said. He said disease symptoms have been documented all the way up to San Angelo and into the Comanche area, where some good-sized populations have been seen.

Most of the state’s corn was already at a point where the corn leafhoppers, which suck the nutrients from the plants and excrete honeydew, weren’t as much of a concern as the vectors they carry – diseases that can stunt growth, reduce yield and even kill the plant.

“As far as disease goes, most of the corn that was affected was far enough along that you wouldn’t think it would have a huge impact,” he said. “But there’s a lot of anecdotal evidence out there that it very well could be having an impact. Not a devastating impact, but a definite impact.”

Plant pathologists are currently working to get a positive identification on samples taken from the state’s affected areas.

“It could be a number of different diseases that this thing vectors and even the actual impact on the corn itself is debatable,” Kerns said. “If you look at some of these pathogens we know the insect can transmit, you know that the earlier the plant gets infected, the worse it is. In the long run, if it becomes a pest that sticks around or that we see earlier in the season, then the greater impact possibility.”

While the U.S. hasn’t seen large losses to the pest, that can’t be said for other places. In Argentina, once corn leafhoppers spread to what were previously cooler regions of the country, corn losses totaled over $1 billion. Brazil has also been in a fight against the pest as numbers grow across that country as well.

Kerns doesn’t think Texans need to worry since conditions are very different between North America and South America, but the pest is one that needs to be closely watched and will continue to be monitored.

Grazing grasshoppers

Grasshoppers in greater numbers across a larger swath of the state than typical are causing issues for producers as well.

“This year the western parts of the state seem to be getting it much worse than usual,” Kerns said. “Even up in the Texas Panhandle they’ve been having issues with them.”

He said weather plays the biggest role in grasshopper outbreaks since temperatures and moisture influence how many eggs are laid, when they hatch and how many survive.

A free, downloadable guide available on AgriLife Learn identifies the main grasshoppers responsible for crop damage as well as suggested treatments.

False chinch bugs and corn leaf aphids

There have been a lot of issues with false chinch bugs this year, Kerns said. And while this has mainly been seen in grains, it has also impacted some cotton.

False chinch bugs are typically more of an issue for the eastern half of the state, and it isn’t unusual to have problems with the pest even in the South Plains, but this year is different.

“It started down in South Texas, but then followed all the way up,” he said. “I have heard of people having issues as far north as Oklahoma. So, it just seems to be a pretty widespread problem.”

And, he said, producers are still having a lot of issues with corn leaf aphids, which in and of itself isn’t uncommon, but the numbers earlier in the season were really high, which is kind of unusual.

Fall armyworms, fleahoppers and cotton bollworms

Some reports of fall armyworms have already come in and there’s been incidences of pasture-to-pasture spread, Kerns said.

“With the weather we’ve been having, you would expect that to continue and probably to amplify,” he said. “I wouldn’t be surprised at all if we see a pretty good fall armyworm outbreak across the eastern half of Texas.”

Cotton is also seeing more than its fair share of pest pressure.

“We see cotton fleahoppers every year just about, but populations have been extraordinarily high this year,” Kerns said.

“Cotton had to be treated multiple times for pests already, and last week we saw a really big egg lay from the cotton bollworm.”

AgriLife Extension district reporters compiled the following summaries:

Central

The district began the week hot and dry but transitioned to milder weather with scattered light showers reported. Pastures were drying up and needed moisture to boost forage and crops. Producers harvested corn, sorghum and hay. Cotton was in excellent condition and was flowering heavily, but spider mites and stink bug populations were high. Other insect issues that were reported by producers included fall armyworms, Bermuda grass stem maggots and grasshoppers.

Rolling Plains

The district continued to see hot and dry conditions with minimal rainfall reported. A long, soaking rain was needed to reach the subsoil. Grasshoppers continued to be a problem in the northern parts, and hot and dry conditions took their toll on several crops including corn, hay, sorghum and cotton.

Coastal Bend

The district reported scattered showers, which delayed harvest of some sorghum and corn. Most corn crops neared maturity and producers began harvest. Cotton was maturing and harvest was in full swing, but some areas were delayed due to recent rains. Round cotton modules were accumulating on the gin yards, and yields looked better than expected due to the beneficial rain.  Rice looked good and was heading out while hay fields were close to being cut. Grain sorghum harvest was completed. Range and pasture conditions were in good shape with livestock looking well. Cattle remained in excellent condition with strong market prices.

East

The district saw good rain this past week with more forecast for this week. Pasture and rangeland conditions were good to excellent and soil conditions were adequate. Producers have been baling and storing hay, with producers in Anderson County reporting yields between 2.5-3 tons per acre. Grasshoppers and feral hogs were still a problem with damage reported in most areas. Cattle markets remained strong.

Southeast

The district received decent rain this past week with some areas averaging more than 3 inches. The rain allowed moisture to return to the soil in most areas, but conditions after Hurricane Beryl continued to hamper harvest in Waller County, which caused additional damage to corn, sorghum and rice. The wet conditions also halted production in hay in a few areas. In other areas, hay yields continued to be excellent, but quality was suffering due to wet conditions and delayed cuttings. Numerous insect pest problems were reported including Bermuda grass stem maggots and armyworms. Watermelon harvest continued with corn and other crops progressing well. Despite the tree damage and cleanup after Hurricane Beryl, Montgomery County received much-needed rain, and the rice harvest in Jefferson County should start next week as soon as the rain ends. Crops in Burleson County were doing well with pastures and ponds looking excellent. Rangeland and pasture conditions varied from very poor to excellent while soil conditions ranged from adequate to surplus. Cattle conditions were excellent with markets remaining high.

South Plains

The district received rainfall accumulations between .02 inch to 1.5 inches with a few areas reporting 6 inches. Cotton did well with crops in most areas in the flowering and squaring stages. Producers reported average to high square retention. Peanuts were making good progress and pumpkin plants were doing well and setting blooms. The final wheat fields were harvested, and sorghum and corn crops were looking good. Cattle were also in good condition.

Panhandle

The district experienced hot and dry conditions, which dried out needed soil moisture for dryland crops and native rangeland. The farming of fallow ground and future wheat ground continued while corn crops were being irrigated. Most wheat fields were harvested with many replanted to row crops. In most cases, no tillage was done in these fields. Sporadic showers helped conserve the soil profile moisture, with overall soil moisture very short to adequate. Pasture and range conditions were reported to be fair to very poor. Overall crop quality ranged from fair to good.

North

The district was hot and dry for most of the week, but some areas received rainfall between 1-4 inches from scattered showers. Soybeans were baled and grains appeared to be growing well. Soil conditions ranged from very short to adequate to surplus and pasture conditions were reported in fair to good condition. Livestock and cattle were in good condition. There were no major diseases or insect outbreaks to report.

Far West

Hurricane Beryl provided extended cloud cover and cooler temperatures to most of the district. Temperatures dropped from the mid-100s to the upper 90s with lows in the upper 60s. Rainfall accumulations ranged between 0.1 inch to 0.75 inch. Earlier planted cotton was beginning to bloom, and bales were being set while later planted fields were setting squares. Pima and upland cotton in the Rio Grande areas continued to thrive in the over 100-degree temperatures with consistent irrigation water. Producers also were spraying plant growth regulators, which held some cotton plants back. Minimal pressures from most pests were reported, but lygus bugs were becoming an issue. Minimal bollworm activity was reported and alfalfa looked good. Pecans did not see any pest pressure while producers continued to irrigate groves and prepared the ground for winter harvest. Pastures remained very dry and bare, but livestock were reported in fair condition with supplementation. Late kid goats continued to be shipped in most areas.

West Central

The district experienced hot and dry conditions with some areas receiving rainfall averaging between 0.25 inch to 1.5 inches. The ongoing conditions caused row crops to suffer from drought and heat stress. Cotton, grain and forage sorghum crops were in mostly fair condition with below average to average yields. There were higher yields in areas that received rain earlier in the summer. Corn and sorghum were good and ready to be harvested. Hay was in good condition and harvest was ongoing. Mesquite tree leaves were turning yellow to brown in color and individual plant treatment has been halted for now. Range and pasture conditions were in poor to fair condition with little to no grazing in most areas. Grasshoppers continued to be an issue in some areas with the dry weather. Livestock were in good condition, and cattle were reported to be good. Cattle markets were still strong in most areas.

Southwest

The district saw slightly cooler temperatures with rainfall that ranged from none to a half inch. Moisture levels in corn and sorghum were dropping and harvest was expected to be in full swing once it dries out. Hay production was in full swing. Livestock and wildlife were in good shape in most areas, but producers were still heavily supplementing livestock and wildlife in some areas. Deer fawns and a few turkeys were seen in most areas.

South

The district experienced hot and humid weather conditions with little to no rainfall reported. Corn and sorghum harvest began wrapping up with a few fields still wet. Most areas saw average to good yields of corn and grain. Sunflower and sesame fields looked good, and cotton was ready to be harvested in most areas. Citrus trees and fruit were doing well, and producers began treating orchards for rust mites and citrus psyllids. Hay production was also under way and looked good in most areas. Pasture and rangeland conditions varied from good to excellent, and livestock and wildlife were good. Cattle conditions were good, and markets were strong.