Crop & Pest Report - All
Bacterial Blights Showing up on Dry Beans
Halo Blight and Common Bacterial Blight both are both being frequently reported throughout the growing region this year. In most years, Common Blight is common, but Halo Blight is relatively rare. Halo Blight caused its greatest damage to edible beans when temperatures are in the high 60’s to low 70’s. Common Bacterial Blight causes more damage when temperatures are in the 80’s.
The first leaf symptoms of both diseases begin as water soaked spots on leaves. As the diseases progress, Halo Blight lesions will become small necrotic spots (Figure 1), sometimes with large yellow halos, while Common Blight lesions will have large necrotic areas with narrow yellow halos (Figure 2). Pod symptoms begin as water soaked-lesions that appear as greasy spots (Figure 3). Pathogens will produce a bacterial ‘ooze’ in humid conditions (Figure 4).
The ooze of the Halo Blight pathogen is often silver or cream colored, while the Common Blight pathogen produces yellowish ooze. Lesions may eventually enlarge, become sunken spots, and/or turn reddish. Damage to seed can occur when disease is severe.
There is very little that can be done to manage bacterial diseases once they are established in the field. Fungicides will not work on bacterial diseases. Cupric hydroxides are used in other growing regions (High Plains), but are strictly preventative applications; we are beyond that. Staying out of fields when they are wet may reduce spread.
The most important thing about bacterial blights in this year’s crop is to not save seed for next year. Both bacterial pathogens can survive on seed, and if infected seed is planted, your chances of having a bacterial epidemic increase dramatically. The pathogens can also survive on the residue, so rotating away from dry beans for two to three years and incorporating residue may help limit future infections.
Extension Plant Pathologist
Dry Bean and Pulse Pathologist
Dry Bean Breeder
Be on the Lookout for Late Blight
The cause of the Irish potato famine, late blight (Phytophthora infestans) is rearing its ugly self again this year. Late blight is a serious disease, because it can devastate potato and tomato fields in a matter of days. Many potato growing states and provinces have identified late blight this year, however it has not been found in North Dakota.
One potato field in central Minnesota has been identified to have late blight. Because weather conditions have been favorable for late blight, I will give a reminder of how to identify this disease.
Symptoms: All above-ground plant parts of tomatoes and potatoes are susceptible to late blight. On leaflets, late blight symptoms begin as small, water-soaked lesions that quickly expand to form large gray, pale green or dark brown blotches on leaves, petioles and stems. Under moist conditions, a thin layer of delicate whitish-gray or translucent moldlike growth will form on the undersides of leaves (Figure 1A). Sometimes, a narrow yellow margin forms around the lesion perimeter (Figure 1B). Stem lesions (Figure 1C) and leaf blotches will expand to encompass entire leaves, leaving them brown, shriveled and dead.
At this point, foliar symptoms can resemble those associated with frost damage. On tomato fruit, initial blemishes and blotches appear somewhat greasy and are diffusely brownish or greenish gray (Figure 2). Affected fruits usually retain their normal firmness initially.
The pathogen also can infect potato tubers. Affected tubers may have dry, reddish, granular lesions beneath the tuber skin (Figure 3). Early tuber symptoms often do not extend deeply into the tuber flesh, and they usually are more visible when a thin layer of the peel is removed. Affected portions can provide an entry point for secondary soft rot organisms that rot the tuber. Potato tubers infected with late blight often decay in storage due to secondary invaders.
If you suspect late blight on potatoes or tomatoes, send a sample to the Plant Diagnostic Lab to get a positive identification. Scout fields and gardens, with a focus on low areas and along tree lines that stay wetter longer. It takes only 12 hours of wetness for late blight spores to infect.
NDSU / U of M Extension Potato Agronomist
Update on Sugarbeet Diseases
Some of the common diseases that affect sugarbeet include Cercospora leaf spot, Fusarium, Rhizomania, and Rhizoctonia crown and root rot.
Cercospora leaf spot our most damaging leaf disease of sugarbeet in our area but has not been a problem so far because of cool and dry conditions the past four weeks. Fields should still be scouted for the next two to three weeks and fungicides applied only if leaf spot symptoms are present and conditions become favorable for disease development. Growers should be able to reduce production cost by reducing the number of fungicide applications this year without sacrificing yield and quality.
Fusarium is becoming more widespread in the Valley. Fusarium yellows is characterized by interveinal yellowing and death of older leaves, sometime distinct death of half the leaf on one side of the midrib, followed by death of the younger leaves and vascular discoloration of otherwise healthy looking roots. The best way to manage Fusarium yellows is to plant tolerant varieties that are high yielding.
Another important disease is Rhizomania where plants are infected by the Necrotic Yellow Vein Virus. Plants infected with Rhizomania have distinctly fluorescent yellow-green leaves with hairy adventitious roots. Here again as for Fusarium yellow, the only way to manage Rhizomania is to plant resistant varieties. Therefore, in fields with a history of this disease, use resistant varieties approved for your factory district. Please note that all Roundup Ready varieties are resistant to Rhizomania. However, for fields with a known history of Rhizomania, check with your agriculturists, consultants, and seed company representatives for varieties that will perform well in heavy Rhizomania conditions.
Rhizoctonia solani causes Rhizoctonia crown and root rot of sugarbeet and root rot is becoming more prevalent, probably because of planting into warmer soils that have remained wet most of the season. Fields with a known history of severe Rhizoctonia should be planted to a tolerant variety. Crop rotation with a non-host, namely wheat, early planting, proper drainage, and avoidance of throwing soil into crowns of plants at cultivation will assist in managing the disease. The use of the effective fungicides at planting and/or when the soil temperature at the four inch depth is about 65ºF will also help to control Rhizoctonia crown and root rot. Hopefully effective seed treatments will be available next year as well so that will help growers expedite planting.
There are also fields infected with Aphanomyces root rot. Warm and wet soils earlier in the season provided favorable conditions for infection by the fungus Aphanomyces cochlioides. In fields with a history of this disease, growers should use tolerant varieties and have the seeds treated with Tachigaren fungicide.
Growers need to plan management strategy early to manage diseases – planning should start with field and variety selection. Fields with diseases at this time should be recorded so that appropriate varieties and production practices will be used the next time these fields go into sugarbeet.
Late planting, cool and dry conditions may all contribute to a relatively small sugarbeet crop this year. As such, prepile may start until September this year. Please follow all safety rules at harvest and when transporting and piling beets. Have a good and safe harvest.
Extension Sugarbeet Specialist
NDSU & University of Minnesota
Tips for Planting Winter Wheat in 2013
Winter wheat can be a viable crop in today’s cropping systems. It is usually planted and harvested during periods that do not compete with other farm activities, has high yield potential and can be an excellent option for land that was not planted this spring if properly managed. The downside of growing winter wheat in North Dakota, however, is that it can be injured during the cold winter months. The following are some suggestion to help ensure a profitable winter wheat crop.
When possible plant winter wheat into standing stubble. Survival of winter wheat during the winter is enhanced when it is covered with snow during the coldest months of the year. Standing crop residues can effectively retain snow that may fall. Tall, erect flax and canola stubble works best, but any erect stubble that will retain snow is recommended. Planting winter wheat into wheat stubble is not ideal for disease reasons, but as long as disease management is planned, wheat stubble can be an acceptable residue.
Plant winter-hardy adapted varieties. Use a winter hardy variety, especially if you are not planting into a standing residue. Accipiter, Peregrine, Radiant, Jerry, and Decade are among the most winter hardy varieties. Varieties developed in Canada and North Dakota usually have good winter-hardiness. Varieties that were developed for Nebraska may not have sufficient winter-hardiness some years, and should be used only if planted into standing stubble. Varieties developed in SD and MT tend to be intermediate in winter hardiness to those developed in ND/Canada and those developed in NE. Additional information to aid in variety selection can be found in the most recent winter wheat variety selection guide. The directories of certified winter wheat seed growers are available on the web for North Dakota and South Dakota.
Apply P at time of seeding. Phosphorus fertilization can play a role in winter hardiness, especially if soil tests are low for P. Applying 10-15 lbs of P with the seed may improve winter survival some years in low test soils. Excessive N prior to winter freeze-up, however, can reduce winter survival.
Plant in September: The optimum planting date for the northern half of the state is September 1-15 and for the southern half September 15-30. In recent years, plantings during the first ten days of October have largely been successful. The last practical date that winter wheat can be planted will depend on the weather since there must be enough moisture and growing degree days so that the seed can germinate and the seedling vernalize by spring. Larger seedlings will over winter better than a small seedling. Target the earlier portion of the recommended planting date range if planting into bare, fallow ground.
Plant 1 to 1.5 inches deep: Adequate moisture for establishing winter wheat is often a concern as the soil profile is usually depleted of moisture in the fall. If there is little or no moisture in the soil’s surface, planting shallow (1 to 1.5 inches deep) and waiting for rain is recommended. Furthermore, these relatively shallow planting depths allow for faster emergence when temperatures are rapidly declining.
Seed about a million seeds per acre: Generally a seeding rate of 900,000 to 1.2 million viable seed per acre is adequate. The higher seeding rate may be appropriate if planting late or when planting into poor seedbeds. Since winter wheat tends to tiller more profusely than spring wheat, 1.2 million seeds per acre is the upper end of the recommended seeding rate. Excessively high seed rates can result in more lodging by harvest time, particularly if you are using a taller variety (like Jerry).
Break the green bridge. Breaking the green bridge is critical to reducing the risk of infection of the Wheat Streak Mosaic Virus. This disease is vectored by a tiny mite that moves from green tissue to green tissue largely by wind. Breaking the green bridge is particularly important when winter wheat is planted early The green bridge is broken by controlling volunteer cereal crops and grassy weeds in a field two weeks prior to planting winter wheat. A two-week window of not having a host present assures that the mite has gone through its lifecycle and not found a subsequent host to feed on and transmit the virus.
Extension Agronomist for Cereal Crops
National Sunflower Survey Training Session
The annual sunflower survey training will take place on Thursday September 5, 2013, starting at 12:30 and ending at 3:45 p.m. The event will be at the NDSU Carrington Research Extension Center, 663 Hwy 281 N, Carrington, ND.
12:30-1:00 p.m. Nuts and Bolts about the National Sunflower Survey
Discussion on logistics of conducting and recording the 2013 National Sunflower Survey.
Dr. Hans Kandel, NDSU Extension Agronomist.
1:00-1:25 p.m. Identifying Sunflower Diseases
Discussion about the main sunflower diseases including Rust, Sclerotinia (head, base, and mid-stalk rot), Phomopsis, Phoma, Verticilium, and other diseases.
Dr. Sam Markell, NDSU Extension Pathologist.
1:25-1:50 p.m. Identifying Insect Damage in Sunflower
Identifying sunflower insects including Dectes and recognizing insect damage.
Dr. Jarrad R Prasifka ARS Entomologist or Theresa Gross ARS.
1:50-2:00 p.m. Weed Identification
An overview about weeds in sunflower and how to identify them.
Greg Endres, NDSU Extension Agronomist.
2:00-2:15 p.m. Go to the field
2:15-3:30 p.m. Hands on Training in the Field
There will be three stations in the field each 25 minutes: a) Identification of sunflower diseases, b) insects, and c) weeds and estimating sunflower yield.
3:30-3:45 p.m. Return to the Main Building
Two Integrated Pest Management and one Crop Management continuing education credits (CEU’s) are available for those participating in the sunflower training session.
If you plan to attend please e-mail RSVP to firstname.lastname@example.org
The sunflower training will be followed by the annual Carrington Row Plot tour at 4 p.m.
Extension Agronomist Broadleaf Crops
New Pesticide Labels Will Better Protect Bees and Other Pollinators
WASHINGTON – In an ongoing effort to protect bees and other pollinators, the U.S. Environmental Protection Agency (EPA) has developed new pesticide labels that prohibit use of some neonicotinoid pesticide products where bees are present.
“Multiple factors play a role in bee colony declines, including pesticides. The Environmental Protection Agency is taking action to protect bees from pesticide exposure and these label changes will further our efforts,” said Jim Jones, assistant administrator for the Office of Chemical Safety and Pollution Prevention.
The new labels will have a bee advisory box and icon with information on routes of exposure and spray drift precautions. Today’s announcement affects products containing the neonicotinoids imidacloprid, dinotefuran, clothianidin and thiamethoxam. The EPA will work with pesticide manufacturers to change labels so that they will meet the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) safety standard.
In May, the U.S. Department of Agriculture (USDA) and EPA released a comprehensive scientific report on honey bee health, showing scientific consensus that there are a complex set of stressors associated with honey bee declines, including loss of habitat, parasites and disease, genetics, poor nutrition and pesticide exposure.
The agency continues to work with beekeepers, growers, pesticide applicators, pesticide and seed companies, and federal and state agencies to reduce pesticide drift dust and advance best management practices. The EPA recently released new enforcement guidance to federal, state and tribal enforcement officials to enhance investigations of bee kill incidents.
Source: Reprinted from U.S. EPA Pesticide Program Updates, August 15, 2013.
Flea Beetles Feeding on Pods of Canola
The new generation of adult flea beetles is emerging and feeding on developing pods of canola. This is the overwintering generation that will emerge next spring. Usually the upper or younger pods and later seeded crops are most impacted. This feeding damage results in poor seed fill, premature pod drying, or pod shattering during swathing or direct combining. However, yield loss from pod feeding is uncommon, because canola obtains most of its yield from the lower pods. No insecticides are recommended for control of flea beetles feeding on canola pods, unless populations are extremely high, and there is significant feeding on the lower pods. No economic threshold has been developed
Sap Beetles Feeding On Corn Ears
Sap beetles (or picnic beetles) have been observed feeding and damaging corn ears. One of the most common sap beetles is Glischrochilus quadrisignatus, which is ¼ inch long, black with four orange-red spots on the wing covers and has “knobbed” antennae. Adult sap beetles feed on decaying, ripening plant material. They are commonly observed feeding on overripe fruits (raspberries, strawberries) and vegetables (tomatoes). In corn, they typically invade the ear near injury sites from birds or other insects. Sap beetles are a nuisance and congregate in large numbers near field edges. They are also common around garbage cans or picnic areas, or anywhere fermenting plant juices occur. Some sap beetles carry organisms that cause rots in fruits. Damage from sap beetles is generally non-economic in field corn.
Watch For Late Season Grasshoppers
This time of year, adult grasshoppers start to move around and feed on late-season row crops, such as sunflowers, corn, dry beans, soybeans or flax. It a good idea to continue to scout ‘green’ fields until the crop matures. Grasshoppers can feed on the directly on the pods, or grain head of crops causing significant yield loss. The season final map from the NDSU Extension IPM Survey shows that grasshopper populations are the highest in the western region of the state. When 20 or more adults per square yard are found in field margins or 8 to 14 adults per square yard are occurring in the field, treatment would be justified. In some cases, only field edges need to be sprayed to protect fields from grasshopper infestations. Be sure to check label for any preharvest intervals before spraying any insecticide application.
Soybean Aphids and Spider Mites Update
Continue scouting for soybean aphids and spider mites in soybeans.
Soybean aphids are generally low except for a few hot spots in the northern valley. Continue scouting for soybean aphids through the beginning seed (R5) stages. Shorter day lengths and the maturing soybeans will be triggering aphids to develop wings and fly back to its overwintering host, buckthorn, or late-planted soybean fields. The USDA NASS report for North Dakota indicated that soybean maturity is behind from last year with only 79% of the soybeans are setting pods (R4).
Once soybeans reach the full seed set (R6) stage, no insecticide treatments for soybean aphids are recommended because of inconsistent and nominal yield returns.
Spider mites are showing up mainly on field edges and only in drought areas. For spider mites, treatment is advised when heavy stippling on lower leaves with some stippling progressing into middle canopy. Leaf yellowing is common on lower leaves. If spider mites are the main pest problem, the only pyrethroid that will control mites is bifenthrin active ingredient (Tundra, Sniper, Brigade, Fanfare, Bifenture, etc.) in soybeans. Other pyrethroids, such as lambda-cyhalothrin (Warrior, Silencer, etc.), will cause spider mites to flare up and increase their reproductive rate. Two active ingredients of organophosphate (OP) insecticides for control of spider mites include chlorpyrifos and dimethoate. After R6.5, no treatment is recommended for spider mites.
Check out the YouTube video on pest management of two-spotted spider mites in soybeans.