A3B-Lancaster Farming, Saturday, July 21,1990 Worm Devastates Corn Roots (Continued from Page Al) the Landisville farm,” said Roth. “Even so, we took the conserva tive approach and planted all our experiments here. We put down a pre-plant insecticide at planting time in late April.” Last week, Joanne Stellingwerf, Penn State ag technician, noticed what may have been windstorm damage to the crops. “I thought it was a pretty severe windstorm,” said Roth. “(So I) came down here today, looked it over, and found a lot of the characteristic symptoms of com root worm feeding.” Roth said many fanners may be familiar with the infestation. He showed the visitors.the roots of several stalks that were infested. Older roots chewed off “A classic example is on one plant, where the older roots have John Yokum, head of the Landlsville Research Sta tion, speaks to the 80 parti cipants of the Weeds Field Day before heading out to the test plots. /eg rthfPenn , corn specialist, describes the effects of western corn root worm on com stalks to the members of the Weeds Field Day tour group. just been completely chewed off,” he said. ‘ ‘This plant was laying flat on the ground. This is not going to come back. This is going to contri bute to a serious yield loss.” Farmers may be facing extreme losses, according to several exper ts, if dry weather continues. “If you just see a little bit of goosenecking, then we have fairly moist conditions following this time of the year, the plants can compensate. You can sec some of these plants are putting out new roots, and sometimes they’ll come back and you’ll be hard to even pick up a yield response,” Roth said. “If it turns dry, however, yield can be cut severely.” Roth cited a lack of control by several insecticides that may have broken down because of the large amount of rain in May. Though it is hard to determine exactly what type of pesticide is most effective against the bug pre- or post emergence some form of pesti cide must be used, especially if the fanner is not going to rotate out of com. Mid-July is when the control is necessary, according to Roth, when the larvae are actively feeding. Pennsylvania hit hard South central and southeastern Pennsylvania are being hit hard by the root worm, as well as western Pennsylvania, according to several agents. “It’s worse than I have ever seen it,” said Ed Lazowski, field sales agronomy manager for Pioneer. ‘We want to warn these people particularly the extension agents, con sultants, and others that there*s a problem out there with western corn root worm/ Frank Richards, a salesman with P.L. Rohrer in Smoke* town, examines a potato plot to see the spray effects of a pesticide to combat potato beetles on Monday at the Weeds Field Day. Lazowski attributed the prob lem to many fanners who have shied away from using insecticides at planting time. “It’s starting to catch up to us now,” he said ‘ ‘Last year there was a lot of com planted over a long period of time, so it’s very wet in the planting sea son. What happens is, in August, the plant is silking out and the silks dry up, and the bugs migrate to new fields.” The bugs lay their eggs at the adult stage, when their Ufe cycle ends. Farmers should be out scout ing for the bugs to determine the pesticide plan they will use at planting time next season. “Be on the lookout for this problem,” saidßoth. “Ifyouseea lot of this occuring, give us a call so we can get a handle on how widespread this problem is.” “That’s one of the reasons we brought this up,” said Yflkum, ‘ ‘to alert you guys that, all of a sudden, it looks like we’re going to have a problem out here, so that next year we need to be talking to the farmers.” western corn root worm Is shown at the end of the pen. The whitish or yellowish worm Is devouring the roots in many corn fields, and could create a serious yield loss after wet, then extremely dry weather. The Infestation could occur again next season if farmers do not apply pesticide or rotate out of corn. An adult beetle of the western corn root worm. The black-bodied insect with long antennae feeds on the cornstalk silks In the summer and lays eggs. Next season, the resulting white larvae, about a quarter to a half Inch long with a black head, then feed on the
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