Crop & Pest Report
The NDSU Plant Diagnostic Lab is a lab that is open to the public. To support the two technicians and to be able to purchase supplies and maintain equipment, a small fee applies. Services and fees are available online at www.ag.ndsu.edu/pdl.
This is the final scheduled issue of the Crop and Pest Report for 2011. An ad-hoc issue may be published on September 15th if important crop and pest issues arise to warrant another issue. Best wishes for a good harvest!
Most of the fields have decreasing populations of soybean aphids now. Shorter day lengths and the maturity of the soybeans have triggered aphids to develop wings and fly back to its overwintering host, buckthorn, or late-planted soybean fields. Bruce Potter of UMN Extension already found soybean aphids on buckthorn on August 15 in SW Minnesota.
This time of year, adult grasshoppers are very mobile and start to fly around after cereal crops and other early season crops are harvested to find green crops. So, it is important to continue to scout for grasshoppers in late-season row crops, such as sunflower, corn, flax, etc.
I’ve received many calls and emails about all of the white butterflies flying around ditches, canola, and other areas and whether they are an insect pest. These butterflies belong to the insect family Pieridae and to the group called Sulphurs and Whites, which are usually white or yellow in color.
Some of the common diseases that currently affect sugarbeet include Rhizoctonia root rot, Aphanomyces root, Fusarium yellows, and Cercospora leaf spot.
During a survey of dry beans last week anthracnose was identified in the Wells Co. area. The disease was found in the same general area last year, and its presence is alarming. Anthracnose is a disease that growers can do little to manage once they have it in their fields.
Dry bean rust was identified in the growing region in the last two weeks. It has been suspected or confirmed in Traill, Grand Forks, and Walsh counties. It is being found on new varieties that have the Ur-3 gene, so it is the new race (or a variant of it) that was first identified in 2008.
SCN is a parasitic worm that can cause 15-30% yield loss without above ground symptoms. The disease can be a ‘silent killer’. It is the #1 soybean disease in the U.S., and is spreading though North Dakota. It was first confirmed in Richland County (2003), followed by Cass (2007), Dickey (2009), LaMoure (2010), Ransom (2010), and Barnes (2010). SCN may take a few years (seasons of soybeans) to build up, but when it does, it is difficult to manage. As such, early detection of SCN is very important.
In an effort to determine how widespread SCN is in North Dakota, NDSU plant pathology is collaborating with the National Agriculture Statistics Service (NASS) and the North Dakota Soybean Council (NDSC) to conduct a survey beginning next week. This is the second year of this survey.
As stated earlier this summer, late plantings, heavy rains, continuously wet crop canopies and soils, high temperatures, and high winds are not a formula for excellent small grain crops. These conditions in many areas of ND took a toll on yield and quality, and also contributed to diseases problems. This was a year to remember and a year to put behind us. What did we see in small grains this year as the season progressed?
As far as temperature is concerned, the 2011 growing season is shaping up to be similar to the long term average, at least for the eastern third of the state. In fact, growing degree day (GDD) accumulations for this region of the state are within 30 GDDs of the long term average. GDDs for the western two-thirds of the state, however, are running 100 to 200 GDDs behind the long term average.
Producers traditionally have swathed rather than straight combined canola; however, straight combining is an option for canola. Straight combining can save time and money, and result in improved seed quality. Heavier canola stands are better suited for straight combining than thinner stands because of the decreased likelihood of shattering from wind. Straight combining has resulted in yield losses of 8 to 54%, as reported by the Canola Production Center in Canada.
The Extension Entomology office has started getting calls on annoying hornets swarming, or hornet nests in homes or in trees nearby houses. Hornets (or yellowjackets) belong to the family Vespidae.
Scouting. Scouting fields for weeds throughout the growing season is extremely important to maintaining herbicide effectiveness and planning for future weed control decisions. Scout fields now and at harvest to determine the effectiveness of this season’s weed control practices. If weeds are present now, determine why they are present.
I anticipate the title made many of you curious what the answer is – FALL WEED CONTROL! Beginning in May 90% of my phone calls were about dandelion. Spring pre-plant applications can reduce dandelion infestations and effective in-crop herbicides can be used in corn and cereal crops.
Maps detailing precipitation, temperature, and departure from normal corn and wheat accumulated growing degree days.
Information from Southwest ND.
Information from North Central ND, including updates on Wheat Streak Mosaic Virus, Soybean Aphids, and Banded Sunflower Moths.
Before using cover crops in the cropping system, it is important to decide what the purpose is of the cover or forage crop. Using a mixture of cover crop species may allow producers to meet several goals simultaneously. Mixtures add more diversity, may be able to better compete with weeds, optimize nutrient cycling, and use the available moisture in a more efficient manner.