| FOR IMMEDIATE RELEASE | CONTACT: Patricia Denke |
| July 8, 2004 | (406) 444-3730
TTY (406) 444-4687 |
Hoppers Threaten Crops as Weather Warms
HELENA, Mont. — Grasshopper problems are beginning to heat up in Montana after cool, wet weather in some areas kept hoppers from developing as quickly as in previous years.
Hay and crops producers should scout fields immediately for grasshoppers and take appropriate action if populations are high enough to warrant treatment, says Ralph Peck director of the Montana Department of Agriculture.
The USDA Animal and Plant Health Inspection Service has coordinated spraying of Dimilin to protect more than 110,000 acres of the Flathead Indian Reservation in Sanders and Lake Counties, says Gary Adams, USDA-APHIS director for Montana. Dimilin is a pesticide that disrupts the grasshopper molting process. It is less harmful to wildlife and beneficial insects, but must be applied when grasshoppers are immature.
Most grasshoppers have now grown too large for Dimilin to be effective, according to Adams and Sue Blodgett, extension entomologist with Montana State University. Future treatment efforts will need to rely on more traditional pesticides such as malathion and carbaryl, also known by the brand name of Sevin.
APHIS personnel have observed high grasshopper populations and offered technical advice to farmers and ranchers in other parts of Montana, from Beaverhead County in the southwest corner to Dawson County in northeastern Montana. High populations also have been found in Park and Sweetgrass counties north of Yellowstone National Park, and particularly in drought areas."Cool, wet weather has slowed the progression in some areas, but we have not had the kind of hot, wet weather that causes diseases that kill large numbers of grasshoppers," says Adams.
Treatment thresholds and treatment advice vary by the crop, grasshopper maturity, the value of what is being protected, pesticide label requirements and pre-harvest restrictions, says Patricia Denke, entomologist with the Montana Department of Agriculture. When hay is close to maturity, the best advice is often to harvest the crop.
Protection of home gardens can be improved by leaving unmowed green vegetation next to vegetable crops, Blodgett says. Strips can be treated with insecticides to improve the protection.
Private pastures and rangelands can be protected with a technique called Reduced Agent and Area Treatment, a program was developed at the University of Wyoming that reduces the amount of pesticide required while preserving natural enemies of grasshopper populations. Blodgett says the technique has been widely used in Montana and is recommended as part of an integrated pest management approach.
Grasshoppers and Mormon crickets often migrate to green areas after grasslands become less palatable, Denke says. It is particularly important to scout field borders as nearby crops become less palatable to the insects.
County Extension Service agents and chemical applicators and retailers can advise growers on the best treatment for their particular situation.
Director Peck reminds applicators that they must follow all pesticide label restrictions. Registrations for several insecticides prohibit application when bees are present in a field. Labels for Sevin XLR, for example, state, "Do not apply this product or allow it to drift to blooming crops or weeds if bees are foraging in the treatment area."
Pesticide labels must be in the possession of all applicators. For more information about grasshoppers, contact Patricia Denke at 406-444-3730 or by e-mail at agr@mt.gov.
