Cool weather slows but doesn't stop armyworms

Though cooler weather slowed down the advance of armyworms, the pest is still eating up pastures and small grain fields in many parts of the state, report Texas AgriLife Extension Service personnel.

“There are places where they’re still a problem,” said Dr. Noel Troxclair, AgriLife Extension entomologist based at Uvalde. “The cold weather does slow down the growth of armyworms, but when we go through these cycles where they get cold and then warm back up, they’ll start eating again, and they’ll continue their development, although it will be at a slower rate.”

It will take a good, hard freeze to completely stop armyworms in their tracks, Troxclair said. But the slowed development also means less damage to pastures and crops.

“As they slow down their development, they’re subject to more mortality that we normally would see if they’re really cranking through their life cycle,” he said.

More mortality results from parasites, diseases, and predation from insects and birds, which will reduce their numbers, Troxclair said.

“Also, the slower they grow, the more the plants can compensate for the damage they are incurring,” he said. “With the cooler weather, larvae will take longer to hatch. Instead of three days, they probably take five. And instead of taking three weeks to go through the five instars (to fully develop) it may take more like 28 days.”

Weekly reports from AgriLife Extension county agents across the state back Troxclair up.

In Baylor County, Brad Easterling, AgriLife Extension agent, noted in his report that armyworm activity had slowed in the last week.

In Archer County, south of Wichita Falls, Justin Gilliam, AgriLife Extension agent for agriculture, reported that armyworms were trying to eat all of the newly emerged wheat.

In Clay County, east of Wichita Falls, Missy Hodgin, AgriLife Extension agent, said farmers were still spraying for armyworms, especially in the west southwestern portions of the county.

Gary Clayton, AgriLife Extension agent in Wise County , west of Denton, also said the armyworm invasion seemed to have slowed somewhat.

The following summaries were compiled by AgriLife Extension district reporters:

CENTRAL: Much needed rain continued to fall across the region. Many hay producers tried to get another cutting in between rains. Wheat and oats emerged. Livestock were improving and were in good condition. Armyworms were still causing problems in small grains.

COASTAL BEND: Light rain and near normal temperatures further alleviated the aftereffects of the drought. Harvest of sesame and sunflowers was delayed by rain and wet field conditions. Armyworms continued to be a problem in pastures. Farmers were cleaning up fields. Morning glories and other weeds came on after the rains. Most producers were controlling the weeds with herbicides; some were using tillage. Ranchers were trying to harvest hay as winter supplies remained short. Cattlemen were working cattle with minimal supplemental feeding.

EAST: Rain continued to fall across the region, causing flooding and delaying hay harvesting and the planting of winter pastures. Livestock were in fair to good condition. Armyworms were still a problem, but feral hogs were causing more damage to pastures and crops, according to AgriLife Extension agents. Wrecks due to hogs crossing roads were reported.

FAR WEST: The region received from 0.1 to 1.5 inches of rain. Pastures and rangeland were rapidly browning in some areas. Pecans started shuck split. Apples were being harvested, and the crop was reported as being fair. Farmers began to harvest cotton and reported yields of about three-quarters bale per acre, which was better than expected. Rain slowed the cotton harvest. Chilies were being harvested. Producers were planting winter wheat.

NORTH: Fields were waterlogged, and high ground was getting hard to find with flooding everywhere. Mosquitoes were ferocious. Armyworms, along with the flooding, inflicted heavy losses on pastures and newly emerged small grains, and delayed planting for an extended period. Some small grains and winter pastures may have to be replanted. Farmers were having difficulty harvesting soybeans and any corn and grain sorghum still in the fields. Field preparation, harvest, wheat planting, all crop field work and hay production were at a standstill. The heavy rains negatively impacted the peanut producers. Cotton was in fair condition, but rain on open bolls lowering the grade and put some of the crop on the ground. Feral hogs continued to be a major problem. Rangeland and pasture conditions were fair to good. Livestock were in good condition.

PANHANDLE: The region had a weather roller-coaster ride, with temperatures cresting out in the 80s, then suddenly dropping to near freezing. Along with rain, the cool weather slowed harvesting. Some cotton fields showed losses due to freeze and unopened bolls. Wheat progressed well with the rain. Peanuts were reported to be in good condition. Rangeland and pastures were also in good condition, as were livestock.

ROLLING PLAINS: Sunshine and cool weather prevailed, just what winter wheat and cotton needed. Producers were busy defoliating cotton, and some started harvesting. Peanut producers were seeing a good crop this year if it will dry up enough to finish harvesting. Most of the already planted wheat was emerged. Cooler temperatures slowed down the life cycle of armyworms. Pastures were in good condition with rye starting to grow and looking good. Livestock were in good condition. The pecan crop appeared good as well.

SOUTH: Significant rainfall and mild temperatures prevailed throughout the region. AgriLife Extension agents in several counties reported 2 to 3 inches of rain. Continual rain kept soil moisture levels adequate for fall planting. Rangeland and pasture conditions remained stable with soil temperatures dropping. Producers decreased supplemental feeding of livestock thanks to an increase of forage availability, but stock tank water levels were still low at many ranches. Cattle body condition scores were improving, and livestock producers were reported to be purchasing replacement livestock to restock some herds that were culled during the summer drought. Armyworms were still a problem throughout the region. Some farmers were able to spray for the pest, but some could not because of wet conditions. In the northern parts of the region, peanut harvesting was delayed due to rainfall in that area but was back in full swing by the end of the reporting period. Green bean harvesting began. Spinach producers were planting both fresh-market varieties and those used for canning and processing. Limited harvesting of cabbage continued. In the eastern part of the region, fieldwork for the 2010 crop season slowed down, and hay baling continued. In the southern parts of the region, crops progressed well, onions were planted and citrus harvesting was picking up.

SOUTH PLAINS: Temperatures fluctuated from a high of 89 degrees to a low of 35 degrees. Some areas received from 0.2 to 1 inch of rain, slightly delaying harvesting operations. Soil moisture was short to adequate. Most of the corn has been harvested, with only some really late corn that was planted behind wheat remaining. The peanut and sunflower harvest neared completion. The cotton harvest continued, and modules were beginning to accumulate at gin yards. Winter wheat planting also neared completion. Irrigated wheat was making good stands. Pastures and rangelands were in fair to good condition. Cattle were in good condition with continued supplemental feeding.

SOUTHEAST: Brazoria County and other areas received an average of 2 inches of rain, the result of Gulf moisture and a recent cold front. There was no flooding. Topsoil moisture improved, and burn bans were lifted. Subsoil moisture was still a concern for next year's crops. Moisture levels have been ideal for planting ryegrass and oats, but AgriLife Extension agents reported armyworms as being "horrible." Most fields may require spraying to limit damage; some will perhaps require replanting. Hay harvesting was slowed by the rain.

SOUTHWEST: The region received about 10 inches of rain from September through October, ending the second driest 12-month period on record. The rain significantly improved the agricultural situation. The September rains made small-grain planting possible, and the October rain helped the crops make excellent progress. The rains will also make early spring planting possible. The forage situation improved, but more rain will be needed this winter to sustain all crops. The sweet corn, cabbage, pickling cucumber, green beanand pecan harvests were ongoing. The peanut harvest gradually gained momentum.

WEST CENTRAL: Conditions were much cooler and windy. Scattered showers were reported in some areas. Soil moisture was very good. Winter wheat and oat planting was under way as fields dried out. Some hay producers were preparing for their third cutting of the year. Fall armyworms continued to plague warm-season pastures. Rangeland and pasture conditions improved from recent rains. Winter forages were up and growing. Stock ponds and water tanks caught runoff and improved. Livestock remained in fair to good condition. The pecan crop looked very good, and harvest was expected to begin soon.

TAGS: Corn
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