ISSUE 8 JUNE 24, 1999
WHEAT MIDGE EMERGENCE UNDERWAY
Emergence of female midge has begun in the southeast corner of North Dakota and the valley. We should see emergence begin in the central part of the state by early next week. The northern counties will have emergence of females by July 4.
1999 Expected Emergence Dates
for Female Wheat Midge
Growers in Pierce, Benson, Eddy, Wells, Foster, Stutsman and LaMoure counties should be vigilant due to the overwintering levels of midge in their county soils. In past surveys, overwintering populations had been relatively low. This year, larval numbers in these counties are high enough that with favorable weather (i.e. warm, humid, and still nights) major infestations could occur similar to the 1995 outbreak in the Devils Lake region.
Monitoring is essential. Here's how to go about it:
If monitoring shows that the action threshold has been reached, producers should consider the following guidelines for taking action:
For further information regarding wheat midge, contact your local office of the NDSU Extension Service, and listen for updates regarding midge activity in your area. Orange Wheat Blossom Midge web page:
SPECIAL LOCAL NEEDS LABEL FOR WARRIOR IN NON-CROP FOR GRASSHOPPERS
The North Dakota Department of Agriculture issued a 24(C), Special Local Needs label for Warrior T to control grasshoppers in non-crop sites adjacent to agricultural fields.
This label is a nice addition to our grasshopper control options. It will make the use of Warrior legal to use in ditchbanks and roadsides adjacent to some of our field crops, such as wheat, where no other pyrethroid was currently available. Restrictions on this product include: Restricted Use Product (RUP), no haying or grazing, and restricted use around bodies of water. Restrictions that apply on the full label will apply on the state label.
The label is for use on non-cropland: Agricultural areas that include right-of-way, barrier strips, and fence rows that are adjacent to crop outlets registered for the use of Warrior T. the labeled rate is: 2.56 to 3.84 fl. oz. The user must have in their possession a copy of the SLN label. Refer to the federal label for further use restrictions or recommendations.
GRASSHOPPER REPORTS INCREASING
More reports of young grasshoppers, particularly from central counties in the state. Continue to monitor hatching sites and field margins to determine if populations are threatening to field crops.
CEREAL APHIDS CONTINUE TO INCREASE
Small grains continue to have ever increasing numbers of aphids in them. Scout fields now to determine the need to treat. The treatment threshold is when 85% of the stems have at least one aphid present, and the field has not headed. Using the percent infested stem procedure, count a main stem as infested if one or more aphids are found. With this procedure, at 85% infested stems, there will be an average of at least 12 to 13 aphids per stem if you were to count them and then calculate an average. The percent method speeds up the scouting and decision process.
The recent rains in the aphid infested areas may help reduce populations. With wet weather, parasitic fungi often infect the aphid colonies, resulting in declines in the size of the population. If fields are below threshold, hold of treating to see where these populations may respond to current conditions.
ALFALFA WEEVIL IN SOUTH CENTRAL ND
Several reports of alfalfa weevil larvae feeding in area fields. Many fields have been or are being cut. If larvae survive the harvest operation, they can concentrate beneath the swath. If this happens, larvae feed on the regrowth in this narrow band. It may be necessary to control surviving larvae in this small area to prevent damage. Monitor this situation closely.
EUROPEAN CORN BORER MOTH FLIGHT
ECB moths are being detected in blacklight traps. Numbers are small and represent the start of the bivoltine, two generation type, population in southeast North Dakota. Corn borer larvae can only survive on young corn plants that are 17 inches or greater in extended leaf height.
To keep track of moth capture records, go to the NDSU web site:
NDSU Extension Entomologist