Fall armyworms on the march early due to unseasonable rains
Writer: Robert Burns, 903-834-6191, firstname.lastname@example.org
COLLEGE STATION – Fall armyworms are more like “summer” armyworms this year due to unseasonable rains, according to a Texas A&M AgriLife Extension Service entomologist.
“It’s related to the rains we’ve had in July,” said Dr. Allen Knutson, AgriLife Extension entomologist, Dallas. “The rains were favorable for crops, but they also set up conditions for armyworms to survive and increase in numbers.”
The armyworm is named for its habit of moving across pastures in large numbers like the legions of an advancing army, devouring grasses in their wake, Knutson said.
Fall armyworms are called “fall” armyworms because in a typical year that’s when they usually make their appearance in greater numbers.
But this hasn’t been a typical year, he said. July through early August is usually the hotter, drier period in much of Texas, he said. This year, more rain – sometimes in quite heavy amounts – came in late June and early July.
This unseasonable rain is what’s behind the early arrival in large numbers of fall armyworms, Knutson said.
“It’s an interesting situation,” he said. “Armyworms cannot overwinter in the northern parts of Texas. It’s too cold for them. They all die off in the first cold weather in November. But they continue to survive in the upper Gulf Coast.”
Armyworms are the larval form of a migrating moth. In the spring, the moths begin migrating northward from the Gulf Coast, looking for favorable places to lay eggs.
The eggs hatch within about four to five days, “regardless of weather conditions,” but few of the young larvae survive when it’s hot and dry, he said. Each female moth can lay as many as a thousand eggs. This year, the larvae found favorable conditions thanks to a wetter-than-normal mid-summer, Knutson said.
Also there are indications that the migrating moth populations are higher this year, he said.
More information on the current Texas drought and wildfire alerts can be found on the AgriLife Extension Agricultural Drought Task Force website at http://agrilife.tamu.edu/drought/ .
AgriLife Extension district reporters compiled the following summaries:
Central: Nearly all counties reported soil moisture, crops, rangeland and pastures, and livestock in good condition. Grasses were in great condition in some areas, but showed moisture stress in others. Harvesting of corn for silage was going full steam. As temperatures increased, farmers have had to increase irrigation for coastal Bermuda grass fields. Hay producers continue cutting and baling. Horn fly numbers on livestock increased. Sunflowers were being harvested, with good yields reported. Livestock were in good condition where forage growth was good and stock-water tanks full. The harvesting of grain sorghum and corn began. Bee swarming reports declined.
Coastal Bend: Hot and humid conditions prevailed. Higher summertime temperatures were rapidly drying topsoils, though recent rains helped subsoil moisture. Crops were in good to excellent condition. The grain sorghum harvest was winding down. Isolated showers kept a few sorghum fields from being harvested. The corn harvest began, with decent yields reported. Cotton continued to mature; some producers were already defoliating. Soybeans were filling pods. Rice was nearly ready for harvest. Pastures were in fair to good condition, with increased grass growth in areas that recently received rain. Pastures in drier regions were beginning to decline. There was limited supplemental feeding of livestock.
East: Counties across the region reported rain mid-week. Scattered thunderstorms brought high winds that downed trees and caused isolated structural damage and electricity outages in some areas. Topsoil moisture continued to be adequate in most counties. Pastures and rangeland were in excellent condition. Hay harvesting continued with excellent yields and quality. Some Panola County producers have had three or four cuttings so far. The vegetable and fruit harvests continued with very good results. Corn was in good to excellent condition. Armyworm and grasshopper infestations continued to be a problem for some producers. Cattle were in good condition.
North: Topsoil moisture throughout the region was mostly adequate, with a few counties reporting short levels. All counties except Kaufman reported receiving between 1 inch to 4 inches of rain. Summer heat was beginning to brown up pastures. Crops benefited from the rains, and corn, grain and soybeans looked good. Livestock were in good condition. Grasshopper populations continued to increase. Armyworms were spotted in hayfields of Bowie and Camp counties. Feral hogs were still causing damage in Camp County.
Panhandle: The region remained dry with near-average temperatures all week. Soil moisture continued to be rated short to adequate. The summer heat depleted some soil moisture, but corn and cotton benefitted from the heat units. Producers continued to fight weeds. Deaf Smith County producers resumed irrigating corn. Pigweed in cotton was being tested for resistance. There were several fields that had repeated chemical treatments without successful weed control. Rainfall or lack of it has been a factor in weed outbreaks. While some parts of Deaf Smith County have received almost 18 inches of rain since May, others have only gotten 1 inch to 2 inches. Hall County crops and livestock all looked good to excellent.
Ochiltree County reported extreme heat and drier conditions had stressed all crops and pasture grasses, but dryland sorghum took the biggest hit. Dallam and Hartley counties reported cattle were heat stressed, and their water needs were high. Hemphill County reported they have grown a lot of grass in the last 60 days, and cattle were fat.
Rolling Plains: The region had several days of temperatures over 100 degrees. Topsoil moisture and forage conditions declined. Lakes and pond levels dropped. However, the hot weather was perfect for cotton. The downside was the weather was perfect for weed growth too. Producers were having a hard time killing weeds and had to revert back to plowing and hoeing cotton fields. Pastures and rangeland also benefited from the recent weather. Grasses and forages made a strong comeback and were producing more than enough for livestock. Grasshopper infestations were affecting forage growth and production. Livestock were in good condition, and some producers were weaning and selling calves early due to high prices and fear the rains will stop and grazing will be limited again. Fieldwork continued in preparation for the fall wheat crop.
South: Temperatures ranged from the upper 90s well into the triple digits. Isolated showers were reported in the northern, eastern and western counties, which helped crop growth slightly, but did not add enough moisture to benefit rangeland and pastures. In the northern part of the district, peanuts were starting to peg and were under irrigation. Farmers were preparing to harvest corn and were nearly finished harvesting watermelons. Rangeland and pastures continued to decline due to extremely hot temperatures and no rain. Soil moisture was short to very short. In the eastern part of the district, grain harvesting was interrupted in some areas by rain. Grain yield reports were not yet received, but poor yields were predicted. Some grain, corn and sunflower fields were reported to have been damaged due to heavy rains and strong winds followed by extremely hot temperatures. In the western part of the district, soil moisture varied from county to county, from 56 percent adequate to as much as 100 percent short. Both vegetation and livestock were reported under stress due to high temperatures and very minimal rainfall. The high potential of wildfires became a concern. Pecan growers were forced to apply substantial amounts of irrigation water as the crop was at the critical nut-development stage. Cotton under irrigation was doing well. Livestock producers reported good to fair grazing availability, but expected to have to resume supplemental feeding if no rain is received in the next 10 to 12 days. In the southern part of the district, grain sorghum harvest continued with a few acres left in the fields. Soil moisture conditions were 45 to 100 percent short. Cotton was progressing well with the help of very hot temperatures. Corn harvesting was active. In Starr County, growers were preparing land for fall vegetable planting, and row crop harvesting was almost complete. Livestock producers in that area continued to provide supplemental feed.
South Plains: Without rain, producers had to begin irrigating again. Cotton was squaring and fruiting, but needed moisture to continue to develop. Highs were in the upper 90s and 100s, which normally would be good for cotton growth, but topsoil and subsoil moisture levels were dropping rapidly. Many acres of cotton were later than normal in development, and producers were hoping for a late first freeze to allow more time for crop development. Spotty infestations of cotton aphids were reported. Peanuts had light insect leaf damage, but no damage to developing pods was found. Leaf spot was found in a few fields. Grain sorghum and peas were progressing. Pasture and rangeland were in fair condition. Some producers had problems with herbicide resistant pigweed. Corn ranged from whorl to dough stages and looked good, with irrigated fields tasseling and silking. Fall armyworm feeding was widespread.
Southeast: Soil moisture throughout the region was mostly adequate, but some counties reported from 100 percent short to as much as 100 percent adequate. Rangeland and pasture ratings varied too, from excellent to good, with excellent ratings being the most common. Brazoria County row crop producers were spraying sorghum to speed up the drying process so they could begin or continue to harvest. Pastures and livestock there were in good condition. In Chambers County, rice was maturing, but frequent afternoon showers retarded pollination and increased chances for disease. In Orange County, it was dry and hot, with only limited scattered showers.
Southwest: Extremely hot and dry conditions continued, with temperatures reaching into the 100s and very little moisture. The corn harvest was nearly complete, while the grain sorghum harvest was just beginning. Cotton was in fair to good condition across the region. Pastures were beginning to decline again due to shallow soil moisture profiles and no rain. Hay producers were cutting and baling, with good to average yields reported. Livestock and wildlife were in good condition Bucks’ antlers were almost fully developed, and there was a small turkey hatch. Cattle and sheep prices remained high.
West Central: Days were hot and humid. Triple-digit temperatures continued to deplete soil moisture. Cotton was progressing well and nearing squaring. Producers continued cutting and baling hay. All summer forages and crops were showing stress from heat and lack of moisture. Pastures and hayfields needed rain soon to maintain yields. Some limited grazing of hayfields was underway after a good harvest of Bermudagrass hay. Row crops were progressing well with a few insect issues, such as armyworms and head worms. Grasshopper numbers continued to increase, with some producers spraying to control the pest. Livestock remained in good condition. Some producers were restocking at this time. Water levels continue to decline in stock tanks and ponds. Pecan growers were spraying orchards and expecting good yields.