NDSU Crop and Pest Report

Entomology


ISSUE 2  May 8, 2003

 

INSECTICIDE UPDATES

24(c) Special Local Needs: Mustang Max® on Surgarbeets

The ND Department of Agriculture issued a 24(c) label for the use of Mustang Max® (zeta-cypermethrin) on sugarbeets to control several soil insects (wireworm, white grub, and cutworm) with at planting treatments, and foliar pests including cutworms, flea beetles, and grasshoppers.

The at planting applications call for applying in-furrow treatments to manage wireworm and white grubs using a 3 to 4 inch T-band in a minimum of 3 to 5 gallons of water per acre. If cutworms are the concern, then treatments are made on the soil surface in a 5 to 7 inch band or braodcast.

This SLN registration is active starting March 17, 2003, and it expires on March 17,2008. The user must have a copy of this label in their possession before use. The web version of the NDSU Crop and Pest report has an electronic version of the 24(c) label available for downloading at:

http://www.ag.ndsu.nodak.edu/aginfo/entomology/ndsucpr/Years/2003/May/8/Mustang.pdf

Warrior® Sec 3 label expanded to include Canola

Warrior® (lambda-cyhalothrin) uses have expanded to include application to canola for managing flea beetle, cutworm, armyworm, diamondback moth, Lygus bug, and grasshoppers. This provides an additional insecticide tool for use in this crop. The label rate ranges from 1.92 to 3.84 fl oz per acre. The post harvest interval has been set at 7 days, allowing for application a little bit closer to swathing time than other products currently labeled (Capture® - PHI=35 days; methyl parathion - PHI=25 days).

Spinosad Receives Organic Label

A new formulation of spinosad, known as Entrust®, is being marketed by DowAgrosciences. The interesting aspect of this label is that the formulation meets the certification standards set forth by the Organic Materials Review Institute (OMRI) for allowing the use of this product in organic production systems.

The crops approved for the use of this product are similar to previous registrations of this active ingredient (Spintor®, Tracer®, Success®). Labeled uses for insects and crops applicable to our region include: cereal leaf beetle and armyworm in small grains; armyworm and European corn borer in corn; armyworm and cabbageworm in cucurbits; Colorado potato beetle in potato, tomato, and peppers; diamondback moth, cabbage looper, and imported cabbageworm in cole crops; armyworms and thrips in strawberries; and others.

Organic growers may want to become familiar with this label and its potential uses for various vegetable and tree fruit crops grown in the region. Though the activity of this product is limited to certain caterpillars, leaf feeding beetles, and thrips, it should provide a nice management tool for some key pests when they exceed recommended treatment levels in organic crops. A copy of the label can be obtained through your local dealer or at:

http://www.ag.ndsu.nodak.edu/aginfo/entomology/ndsucpr/Years/2003/May/8/Entrust.pdf

 

WHEAT MIDGE RISK - OUTLOOK POSITIVE

The wheat midge risk map for 2003 was released in February. Estimated populations of overwintering midge continue to be low overall based on the North Dakota Wheat Commission sponsored survey.

None of the 200 fields sampled in the survey had healthy, overwintering populations of wheat midge larvae exceeding 1,200 larvae per square meter. This level of midge has been critical in past seasons. Because of the high risk of infestation associated with that level of overwintering midge, management recommendations suggest that when larval counts exceed 1,200, farmers should consider growing wheat only if they are prepared to monitor their fields for the adult midge and only if they are prepared to budget for and make timely insecticide treatments where warranted.

One word of caution, though. Midge larvae were present in significant numbers at three locations: north_central Mountrail, central Ward, and northeastern Rollette counties. These small areas had cocoon counts that exceeded 800 per square meter, but larvae were parasitized at a rate as high as 75 percent. Parasitized larvae do not produce adult midge and therefore parasitism reduces the midge potential for the coming year in those locations.

As in previous years, areas where population estimates were above 500 midge larvae per square meter still require close vigilance by wheat farmers. These larval populations can lead to major economic infestations if the wheat crop is heading during adult midge emergence and environmental conditions are favorable for midge activity.

As a reminder, the map is presented your reference. You can also find the map and keep track of degree day accumulations at the NDSU Entomology Updates, found at:

http://www.ag.ndsu.nodak.edu/aginfo/entomology/entupdates/index.htm

 

ARMY CUTWORM WAITING FOR WARM WEATHER IN SOUTHWEST ND

Cutworm problems are expected every year . . . the problem is always recognizing their presence before significant stand losses occur. By this time, the first reports of cutworm activity start trickeling in, usually in the southwest where army cutworm are likely to be present. This cutworm overwinters as partially grown larvae and becomes active when soil temperatures reach 40 F. There were reports earlier from Kansas, but known so far from South Dakota where situations provide a better outlook for what we might expect. Perhaps, dry conditions last fall, when the moths would have been laying eggs and larvae were hatching, have contributed to poor winter survival

In the east it is the dingy cutworm which can cause harm. The dingy cutworm also overwinters as a partially grown larva and begins feeding with warming soils. Monitor stand emergence for this and other insect concerns in the next few weeks.

As in previous years, here is some reference information for cutworms, though we hope the need is limited.

Action Thresholds for Cutworms by Crop:
Canola 1 per square foot
Small Grain 4 to 5 cutworms per square foot
Corn 3 to 6% of plants cut and small larvae less than 3/4 inch present
Sugarbeets 4 to 5% of plants cut
Soybean/Drybean 1 or more larvae per three feet row or 20% of plants cut
Sunflower 1 per square foot or 25 to 30% of plants cut
Forage 5 or more per square foot

Insecticides labeled for treating the above crops for cutworm control include:

Canola ........ Capture, Warrior.
Wheat ......... Lorsban 4E-SG, Mustang, and Warrior.
Corn ........... permethrin (Ambush, Pounce), Asana, Lorsban, Mustang, Sevin, and Warrior.
Sugarbeets .. Asana, Lorsban, Mustang, and Sevin.
Soybean ...... Asana, Lorsban, Mustang, Pounce, Scout X-tra, Sevin and Warrior.
Dry Bean .... Asana, Mustang, Sevin, and Orthene.
Sunflower ... Asana, Baythroid, Lorsban, Sevin, and Warrior.
Alfalfa ........ permethrin (Ambush, Pounce), Baythroid, Lannate, Lorsban, Mustang, Sevin, and Warrior

Phillip Glogoza
Extension Entomologist
pglogoza@ndsuext.nodak.edu


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