Rolette County Ag Alerts!

 Mark Miller
County Agent
Courthouse, Box 430
Rolla,  ND  58367
Phone: 477-5671
mamiller@ndsuext.nodak.edu

May 22, 2001                                                                                                                                              Issue #3

FLEA BEETLE INSECTICIDE COMPATIBLE WITH ROUNDUP USE IN RR CANOLA

It is that time of year that we should be monitoring seedling canola for flea beetle activity. Jan Knodel, Crop Protection Specialist, Minot, is reporting movement of flea beetles. A common question that comes up at this time is the tank mix compatibility of Capture, a pyrethroid insecticide used to control flea beetles, with glyphosate (e.g., RoundUp).

There should be no problems with this mixture. Plot trials conducted by J. Knodel and Dr. B. Jenks in 1999 evaluated two different pyrethroids in combination with glyphosate (RoundUp Ultra). They observed no phytotoxic effects on plants. Weed control was not reduced. Control of flea beetles was the same between treatments. Monsanto has not reported any problems with these mixtures. Finally, there have not been any reports of problems from a number of people who used this mixture last year.

HARROWING FOR WEED SEEDLINGS

Populations of shallow emerging weed seedlings such as pigeon grass, kochia, Russian thistle, wild mustard, pigweed, nightshade and below ground white weed sprouts can be severely reduced by timely harrowing. Harrowing will not reduce wild oat, cocklebur and volunteer sunflower populations that much due to their deeper emergence, however control will be higher if they have not yet emerged and happen to be near the soil surface.

Light spring tooth harrows should be set shallow (½ inch deep) and angled back to reduce the potential of crop injury.

It's best to harrow wheat and barley at the two leaf stage and not later than the three leaf stage to minimize injury potential. Wheat can be harrowed twice while barley should be harrowed only once. Corn can be harrowed between the one and four leaf stage, and sunflower, 2 to 6 leaf stage. Soybeans and dry beans can be harrowed between the 1 to 2 trifoliolate stage. It's advised not to harrow canola, mustard, crambe or flax seedlings.

UREA TOPDRESSING

Because of the flurry of seeding, sometimes urea application has to be delayed until after seeding so that the seeder does not have to wait until the fertilizer applicator finishes their job. With recent temperatures in the 80's and above, ammonia volatilization following surface application will be very fast. This application needs to be incorporated in some manner or rained in by at least 1/4 inch of rain on bare soil or at least ½ inch of rain or more on no-till residue (more if there is significant residue covering the soil surface), or losses of up to 50% in a week are possible. Impregnating the urea pellets with Agrotain® has been shown effective in many University trials in the US and Canada in delaying the breakdown of urea for about 10 days longer than normal. Cost of the product depends on the rate of urea used. Impregnation rate is based on a 5 qt/ton urea at maximum rates. At the rates of urea normally used in the region for small grains, cost would be somewhere around $6-8/acre.

If you don't have a 100% chance of rain in the next 48 hours, this product could reap many times its cost if N is lost through urea volatilization.

CROP INJURY AND REPLANTING DECISIONS

The decision to replant requires careful assessment of crop injury, alternate crop choices and cultural practices related to crop growth and development. Each case of injury should be considered individually.

Optimum plant population for maximum yield in both barley and wheat is about 30 plants per square foot. Reductions in the plant population will reduce yield albeit in a non not proportional manner. Under favorable growing conditions good yields have been obtained with plant populations below 10 plants per square foot. Replanting small grains should not be considered when populations are at 10 plants per square foot or greater.

The effect of planting date on yield is also important when considering replanting. Delays in planting small grains past May 15 typically result in yield reductions on the order of 0.5 to 1.5 % per day. It is difficult to compare yield of an early planted crop with a less than desirable stand and a much later planted crop with an optimum stand; however, when the original crop is planted well before mid May its yield potential may be better than that of a replant. Under dry conditions the availability of soil moisture must be considered, as it may be depleted by the current crop and will be further reduced during replanting.

The final decision on replanting should be an economic one, based on sound agronomic information. If the cost of replanting is equal or greater than any yield gains, then exercise is the only thing gained. The critical determination is the yield potential of the damaged crop compared to that of a replant, and the cost of replanting.

Mark' Stress Workshop                                        

A blonde pushes her BMW into a gas station. She tells the mechanic,"It died."

After he works on it for a few minutes, it's idling smoothly.

She says: "What's the story?"

He replies: "Just crap in the carburetor."

She says, "How often do I have to do that?"

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Updated May 22, 2001 Shelley Armstrong, Webmaster

NDSU Extension Service, North Dakota State University of Agriculture and Applied Science, and U.S. Department of Agriculture cooperating. Sharon D. Anderson, Director, Fargo, North Dakota. Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. We offer our programs and facilities to all persons regardless of race, color, national origin, religion, sex, disability, age, Vietnam era veterans status, or sexual orientation; and are an equal opportunity employer.
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