Crop & Pest Report - All
Weather/Crop Phenology Maps
Assistant Professor of Climatology
This past growing season we had very few reports of wheat streak mosaic virus (WSMV) in winter or spring wheat. The question then is since WSMV incidence was so low this past growing season can we abandon good management practices that reduce the risk of the crop contracting this disease? The short answer is no and especially no this year. The silver lining from the dry conditions experienced late last summer and on into the fall is that Mother Nature enforced a break in the green bridge for the 17 to 21 days that we need before winter wheat emerges in southwest North Dakota. Several producers seeded in early- to mid-September last year into dry soils hoping to pick up enough rain to germinate the crop. We did not receive significant rainfall over most of southwestern North Dakota until October 7. WSMV and wheat curl mite host plants such as volunteer wheat, corn, grassy annual weeds, and some of the perennial grasses were absent or dried down several weeks prior to winter wheat emergence. Since most winter wheat seed was placed into dry soil at planting in southwest North Dakota, germination did not occur until after the October 7 rain. Even with early planting last year it was as if producers had not planted until October 7. Even with late germination and emergence most producers realized adequate stands in the spring and good growing conditions to produce a respectable winter wheat crop.
This fall we have a number of factors favoring WSMV transmission and increased risk of infection and severity of the disease. These factors include: 1) Many recently harvested wheat fields are green or will be green shortly with volunteer wheat and grassy weeds. 2) There are still a few late seeded spring wheat fields that are green. 3) Increased acreage of corn planted this year, some of it planted later than normal and these fields are still green. 4) Host plants in pastures, range, and ditches are still green and growing. 5) Winter wheat plantings are likely to increase since producers want to seed something on prevented plant acres going into the winter as well as moisture conditions are generally better than they were last year. The temptation for producers is to plant winter wheat early on prevented plant acres before the next rain makes it impossible to cross with equipment. This past week’s 4 to 9 inch (yes 9 inches south of Bowman) downpours in parts of southwest ND may have already closed the door for planting during the NDSU recommended planting window.
What strategies should winter wheat growers use to reduce the risk of the winter wheat crop becoming infected with WSMV? Since insecticides as well as miticides are ineffective in controlling wheat curl mites that transmit the disease and fungicides don’t work in controlling viral diseases such as WSMV, growers will need to use management practices such as sanitation and time planting to avoid disease transmission of WSMV from live, green host plants to the winter wheat crop. Breaking the green bridge is extremely important in controlling this disease. The recommendation is to kill all volunteer wheat and grassy weeds at least two weeks prior to planting. Some agronomist advise that all volunteer wheat and grassy weeds be controlled ten days prior to winter wheat emergence but conditions must be ideal for this shorten break in the green bridge to be effective. Wheat curl mites will survive away from a live host plant for up to about 19 days. Delaying planting until after a 14 day period when all volunteer wheat and grassy weeds are killed will provide sufficient time prior to winter wheat emergence to starve out wheat curl mites that are not desiccated by weather conditions. Growers should also kill volunteer wheat and grassy weeds in adjacent fields even if these fields are not to be planted to winter wheat. If the field to be seeded to winter wheat is next to a corn field or a green, late planted spring wheat field, delay planting winter wheat until 14 days after the husks around the ears have dried or the late planted spring wheat has matured. Corn is a host for both WSMV as well as for the wheat curl mite. Wheat curl mites on corn plants are generally found on the husk that surrounds the ear. Wheat curl mites migrate off of corn looking for a suitable host when corn husks begin to dry down. Delaying seeding to the end of the normal planting window will reduce the chances of WSMV being transmitted to emerging winter wheat plants. In southwest North Dakota the suggested planting window is September 15 – 30. Winter wheat planted on September 30 into moist soil at Dickinson will provide sufficient growing degree days to germinate and develop to the three leaf stage, the stage of development in winter wheat where winter hardiness is maximized.
Growers have planted later under no-till systems with good residue coverage and as we saw last year when Mother Nature delayed germination and emergence until after October 7 of winter wheat seeded prior to that date respectable grain yields were produced with little risk of WSMV.
Area Extension Specialist/Cropping Systems
The region’s rainfall during September 1 to 9, based on NDAWN stations, ranges from 0.6 inches at Fingal to 3.2 inches at Tappen. The recent rain will help existing soybean and corn seed to fill and hopefully have near normal test weight. Accumulated corn growing degree day units (GDDU) on September 9 for corn planted on May 15 ranged from 1830 at Carrington to 2170 at Oakes. For this period, the region’s GDDU are 80 to 190 ahead of the 5-year average. We still need a delay in the first killing frost date to be at or beyond October 1 for the majority of grain corn to reach full maturity.
Small grain harvest is nearly complete. Winter and spring wheat yields are favorable and quality generally good. For example, some winter wheat variety trials have yields that reached 100 bu/acre. The CREC dryland HRS wheat variety trial averaged 54.6 bu/acre and 63.2 lb/bu. Most corn fields are denting (R5 stage). The adverse growing conditions (deficient soil moisture and high air temperatures) during the second half of August may have reduced corn grain yield by 50%. Soybeans generally are in the R6 to R7 stages (nearing full seed size to initial maturity). Pinto beans planted through mid-June are nearing or are at full maturity (R8 to R9 stages).
Area Extension Specialist/Cropping Systems
NDSU Carrington Research Extension Center
Preparing Trees for Winter Checklist
With the coming of fall it is important to remember to prepare your trees for the tough North Dakota winter. The following checklist serves as a reminder of the most important considerations for fall tree care and proper tree winterization.
- Water trees weekly in late fall until freeze-up. Two gallons per inch of stem diameter is recommended, if the soil is dry at a depth of six inches. This will help prevent winter dieback.
- Rake up and remove/destroy fallen leaves. This is the best thing you can do to reduce the amount of fungal leaf disease next year (many fungal leaf diseases overwinter on leaf litter).
- Prune dead wood to decrease overwintering sites for tree diseases and insect pests.
- Wait until the tree is dormant (at least November) to prune living branches, always using proper technique.
- Wrap the lower main stem of trees that have not developed thick bark to protect them from sun scald and rodent feeding damage.
- Wrap burlap around smaller, high-value (landscape) conifers or set up a burlap sun/wind shield to help minimize the chances of winter burn.
- Throughout winter, use caution when applying ice melt products near trees and shrubs. Salts and other chemicals contained in some products may cause harm.
By completing this checklist you will be doing your part to maximize the chances that your trees will make it through the winter in good health and will be ready for a productive growing season.
For more information, please contact: Aaron Bergdahl, Forest Health Specialist, NDSU/North Dakota Forest Service. firstname.lastname@example.org (701) 231-5138
North Dakota Forest Service is on Facebook! Like the North Dakota Forest Service on Facebook for updates on tree insects and diseases, tree species selection and other useful information about the tree resources of North Dakota.
Forest Health Specialist, ND Forest Service
Dealing with Non-Conventional Soil and Fertilizer Amendments
Not that many years ago, the standard method for introducing a product was research and development. Now, most of the products introduced as soil or fertilizer amendments are development and maybe research. And if the research does not support the product use, just ignore it.
The recent high crop prices have spawned a large number of products, from micronutrients, products with elements not even required for plants, growth regulators of all kinds and formulations, biological activators, N enhancement products, phosphate additives, phosphate supply stimulants, soil conditioners, legume nodule enhancers and seed inoculants. To prove efficacy of any of these products would require careful field research by unbiased University researchers at multiple sites within the region of sale, with the site choices based on major soils of the region. Unfortunately, most of these products have no field research associated with them of this type. Some of those that have conducted this research (mostly after the products went to market), have ignored research that did not support their use. So what should a person or company do with these products?
I would suggest two lines of action; not necessarily either/or:
First, put the North Central Region Committee on Non-Conventional Amendments and Additives on your computer ‘favorite’ bar. This committee webpage is a great asset for finding product performance from unbiased sources, or at least finding research results from the category of products where the ‘new’ product would fit.
You can search the trade name of the product. Since some products change their name over time from their original state (i.e. the active P agent in TagTeam™ used to be called Provide by another company), searching by product category would include all research on those groups of products (in this case, search phosphate enhancer, or Pennicilium bilajii). If the research has been highly supportive, then use of the product would be a good choice. If research did not support the use of the product, then not using the product, or at most trying it on a simple series of small test strips (not testing it on 10,000 acres of fields) would be a good choice.
The second course of action is a logical, but currently radical idea- don’t use a product unless the company first conducts the proper R&D. Why should a retail supplier or more importantly a farmer have to be the guinea pig? Why can’t the company that manufactures or distributes the product do the hard research work to support its sale? Why can’t we use products that actually conduct R&D? No one uses a herbicide, or other IPM product without knowing that it was thoroughly tested for efficacy before-hand. The retailer can sell the product with confidence and the farmer can use it with the confidence. If a herbicide has pigweed on the label, at least some effect on pigweed would be expected. Many non-conventional amendments cost the same or more than a herbicide application, but they want the farmer to be the guinea pig. Is this good business? I guess it is for the manufacturer.
So my recommendation to distributors, retailers, consultants and farmers is “Show me the Soil Facts!” If there are nothing more than testimonials and in-house research in the brochures, then don’t stock it, sell it or buy it. If there is sound University research that supports the product use at multiple locations and, better, multiple years within the region, then the product can be used with more confidence.
As the North Dakota State University representative to the North Central Non-conventional Additives and Amendments committee, I welcome any information regarding new and unusual products that are being sold in the region. Just send me a copy of any literature they have and I will respond with my take on the product or its product category and I will share the information with my colleagues at our November meeting.
NDSU Extension Soil Specialist
Ear Rot Disease Concerns At Harvest For A Corn Grower In ND
Keeping in view of the weather and insurance concerns, growers should keep an eye out for corn ear rots at harvest.
Corn is known to be susceptible to a number of ear- and kernel-rotting fungi that affect the yield, quality, and feeding value of the grain. In North Dakota, ear rot occurrence has been mild to date and losses can vary greatly between years and regions.
Types of ear rot and their identification:
Aspergillus: This ear rot is generally of minor importance before harvest. However, Aspergillus infections often follow drought stress, damage done by corn earworms, European corn borers and other insects. Aspergillus might also cause serious losses in stored corn, on the ear or shelled. Typical symptom of Aspergillus rot is an olive green tan, sooty-black or greenish yellow mold growing on and between the kernels (Figure 1). Damage is most common at or near the tip of the ear. Silk infection is favored by high day and night temperatures.
Gibberella: Pinkish mycelia can be seen growing from the tip of the cob, which is a typical identification symptom of this rot. Cool wet weather during silking favors infection (Figure 2).
Fusarium: A salmon colored individual kernel is characteristic for this ear rot. Infection is favored by heat and insect stress. The occurrence of this fungi increases when harvest is delayed beyond physiological maturity (Figure 3)
Penicillium: Blue-green mold (Figure 4) on and in between kernels is found particularly on ears injured mechanically or by corn earworms and European corn borers. Additionally, colonized kernels are frequently bleached and streaked. Damage usually occurs at the tip of the ear, but may be found on other parts.
Diplodia: Infection usually starts at the base of the ear or from the stalk into the shank. Characteristics of this ear rot are white fungal growth between kernels, and black specks seen on the cob occasionally. Infection is favored by early dry weather and wet weather late in the growing season (Figure 5).
Cladosporium: Symptoms often appear after an early frost and include the development of dark, greenish black, blotched or streaked kernels scattered over the ear (Figure 6). The black discoloration of the kernels proceeds toward the crown in more or less irregular streaks. The fungus may also invade crowns damaged by growth cracks. Further rotting may occur during storage.
Ear rots can be classified into two groups:
- Toxin producing ear rots:
Gibberella, Fusarium (vomitoxin, zearalenone, trichothecene and fumonisin), Aspergillus (aflatoxin), and Penicillium (ochratoxin)
- Non-Toxin producing ear rots:
Diplodia and Cladosporium
Past History of Ear rot occurrence in ND:
A preliminary survey on common corn ear rots in 2009 was conducted by Dr. Marcia McMullen and reported that Cladosporium was the predominant ear rot followed by Fusarium. The toxin levels in Fusarium infected ears were generally lower than the FDA acceptance levels (Personal communication: Dr. Marcia McMullen, Professor emeritus).
What should a concerned grower do?
I would recommend opening up a field and harvesting a strip to make it easy to sample. Walk down the edge of the strip and check for ear rots.
After scouting if you see indications of any ear rots contact your crop insurance agent for instructions. They will probably need to collect an official sample or may indicate to leave a test strip. You need to prove the ear rots/toxin occurred in the field and not in the bin in order to have a legitimate crop insurance claim.
Best management practices to minimize ear rot/toxin issues:
Adjust combine to minimize kernel damage and remove fines and debris. Do not allow wet grain to sit in wagons and trucks overnight.
If storing on-farm, run grain through a cleaner or screen before putting in the bin or dryer, if you have access to cleaner immediately dry to 15%, if you are planning long term storage then dry to 13%. As weather permits, cool the grain as quickly as possible. Aerate as needed to keep temperature and moisture in the grain mass equalized.
North Dakota State University Plant diagnostic lab at Fargo has options for testing these ear rot pathogens. Please refer to the following NDSU website for further information: http://www.ag.ndsu.edu/cornmold
The mycotoxin risk levels for dairy cattle, expressed on a total ration, dry-matter basis.
- DON (vomitoxin): less than 5 to 6 parts per million
- Fumonisin: less than 25 ppm million
- T-2 toxin (trichothecene): less than 100 to 200 parts per billion
- Zearalenone: less than 300 parts per billion
- Aflatoxin: less than 20 parts per billion
If grain exceeds toxin levels but is below the 300 ppb, it might still be used in livestock feed. Some elevators may have arrangements in place with large feeders and may take the grain and keep it segregated. The FDA action limits for animal feed vary depending on the type of livestock, dairy-20ppb, breeding livestock and poultry-100ppb, finishing swine over 100 lbs-200ppb, and finishing beef cattle-300ppb. Additional information on FDA acceptable toxin levels can be found in the websites:
Utilizing affected grain:
If it is below FDA levels, it can be sold to local livestock producers, generally at a discounted price. Toxin will not show up in ethanol from infected grain, but will be in the by-products that producers normally sell for livestock or pet feed. Therefore, acceptance by ethanol producers may be reduced and at a discounted price. As last resort, nutrients in the grain can be recycled by land application of contaminated grain. However, this may cause weed issues in the coming year.
Area Extension Specialist/Crop Protection
NCREC, Minot, ND-58701
Soil Sampling For Soybean Cyst Nematode (SCN)
Soil samples for cysts require a different test than a fertility sample. It is important to treat the SCN soil sample with care and get the sample to the lab as soon as possible. Although cysts are tough, they are still living creatures and do not do well in the sun in a truck for week. Private and public labs can do cyst tests (Agvise, NDSU, UMN, etc.).
For more information about SCN sampling, an excellent youtube video by Dr. Greg Tylka at Iowa State.
Also, the website www.planthealth.info has excellent information about SCN, sample techniques, and other diseases.
Extension Plant Pathologist, Broad-leaf Crops
Impact of End of Season Drought on Corn 2013
The end of the growing season for corn is fast approaching. At this point, it appears likely that we will make it to the end of September without a hard killing frost. Moreover, current climate predictions seem to indicate that October and November will be warmer than normal. This is great news for the drying of the corn crop prior to harvest. Though we started the season with concerns about corn not reaching maturity before the first killing frost, for much of the state our concerns are now focused on the lack of moisture determining the end of the effective cropping season. The impacts of drought on a corn crop are more gradual than that of a hard frost (temperatures below 28 degrees). Drought stress begins by reducing photosynthesis as the stoma close and leaves begin to curl. As this stress continues, the lower leaves begin to die and ultimately the entire plant can be killed. During this process, stored carbohydrates and other nutrients are moved from the lower leaves and the stem into the developing kernels. When stored and newly synthesized carbohydrates are not sufficient to support the development of all the kernels in the cob, the uppermost kernels stop growing (see following photo). Depending on their stage of development, these kernels may be so small that they will be blown out the back of the combine. Those large enough to not be lost during combining will be smaller than normal and have low test weight.
About half of the crop is now in the dent stage. Generally when a crop gets to this stage, we are not overly concerned about the impact of drought stress on yield. However, this year, since the drought stress started well before this stage of development, continued stress has the potential to dramatically impact yield. In fact, 40% of the total kernel weight is yet to be added to kernels in the dent stage. Therefore, even the kernels at the lower end of the cob will likely fail to fully fill and will have low test weight at harvest. The recent rain brought relief from severe drought stress in much of the state, but for many farms it came too late to have much of an impact on the corn crop. Crops with few or no green leaves will not benefit from these recent rains.
In addition to its impact on yield, drought stress affects stalk quality. Severely stressed crops will be prone to lodging (see attached photo of lodged corn plants near Fargo). Additionally, ear drop can become more problematic in some hybrids after severe drought. Plan to harvest your most severely stressed fields first, and probably sooner than you would normally plan to, in order to minimize losses associated with downed plants or dropped ears.
Extension Agronomist for Cereal Crops
Keeping Dry Bean Seed Is Risky
There are many seed-borne diseases of dry beans; bacterial blights, Anthracnose, and bacterial wilt to name a few. If you keep seed that is infected with one of the pathogens causing these diseases, you greatly increase your likelihood of having an epidemic in the future. Much of the state has experienced greater-than-normal levels of bacterial blights (halo and common primarily), bacterial wilt was also reported, and even though we don’t have a confirmation of Anthracnose, it has been problematic in the past and it may be kicking around in low levels. Unfortunately, many of the seed-borne pathogens are ones that are not well-controlled by fungicide seed treatments. Although it may be economically tempting to save seed, if that seed is infected it can create an economic problem when conditions are conducive to epidemic development. We encourage you to plant disease-free seed in 2014.
Extension Plant Pathologist, Broad-leaf Crops
Direct Harvesting Dry Beans
Direct harvest reduces equipment investment, harvest time, and operational costs. However, direct harvesting may result in reduced seed yield and quality if certain factors are not taken into account. Direct harvesting has become more popular in recent years, especially for navy and black beans, due to their more upright architecture. Some of the new pinto and great northern cultivars also have an improved upright architecture and still keep competitive seed yields.
Field surveys at harvest time were conducted in 2006 and 2007 across three counties in the Devils Lake region in North Dakota. The average seed loss was higher for direct harvesting than for the conventional method (undercut and windrowed prior to combining). The seed losses were mainly due to larger seed and pod loss measured in the area between combine harvest swaths. This indicates losses occurred at the cutterbar.
The top three conventionally harvested fields averaged 24 pounds per acre (lb/A) of harvest loss, while the three worst fields averaged 219 lb/A of harvest loss. The top three direct-harvested fields averaged 101 lb/A of harvest loss, while the three worst fields averaged 347 lb/A of harvest loss.
These surveys suggest that direct harvest loss can be lowered significantly by improving management conditions, such as equipment setup and operator care, especially at harvest.
Experiments were conducted (Carrington and Prosper, N.D., in 2008 and Carrington and Hatton, N.D., in 2009) to evaluate seed yield of commonly grown cultivars in North Dakota and Minnesota under conditions of conventional and direct harvest.
As expected, the seed loss was significantly higher under direct harvest. Harvested yield, under direct harvest, for the cultivars Lariat (pinto), T-39 and Eclipse (black), and Vista (navy) showed the lowest yield loss when compared with the other cultivars within the same market class.
This research emphasized the important role of cultivar and environmental conditions at harvest time in determining the seed yield under direct harvest. Cultivar selection should not be based only on yield potential but also on architectural attributes leading to a minimal yield loss if the direct-harvest method is used. Growers need to consider the cultivar, environmental conditions, seed moisture at harvest, proper equipment setup, and operator skill when deciding on the harvest method to use.
Extension Agronomist Broadleaf Crops
Dry Bean Breeder