Dr. Gary Bergstorm, Cornell University College of Agriculture and Life Sciences School of Integrative Plant Science Plant Pathology and Plant-Microbe Biology, spoke to attendees at the 2015 CNY Small Grain Workshop about identifying and controlling some common diseases in small grains.
Bergstrom pointed out that most small grain crops are attacked by the same organisms. Yellow Dwarf Virus, which causes yield reduction and stunting of plants, was one disease discussed. “All the small grains are affected by Yellow Dwarf. This virus is transmitted by insects, specifically aphids.” Bergstrom advises planting after the “Hessian Fly free date” in the fall or early in the spring before the aphid population comes back, to help avoid contracting Yellow Dwarf Virus.
Wheat Spindle Streak Mosaic Virus, a soil borne disease which is prevalent in wheat, occurs state wide in New York soil and survives from year to year. “Resistant varieties are the whole answer here.” Bergstrom reported that there is a related virus that attacks barley and although it has not been noted yet in New York, he said to be on guard for it in Winter Barley crops.
Bunt, smut and loose smut are seed borne diseases. “The key thing here is certified seed and systemic seed fungicide. You really want to have clean seed when you start your crop out.”
Rusts survive in southern states and are spread north by air currents. Ergot is a disease that has resurfaced and can cause ergotism in animals that eat it.
“Net Blotch in barley is shaping up to be one of our challenges in growing malting barley here in New York State,” Bergstrom reported. “I’m seeing a lot of of Net Blotch in the field.”
Observations made in Bergstrom’s lab from the limited number of test plots for malting barley confirmed a variety of 12 diseases. Some of this disease was found to come through the root system. Powdery Mildew and Fusarium Head Blight were also contributing diseases.
Bergstrom spoke about possible resistance to fungicides and confirmed that a Cornell laboratory study found 1 of 50 field isolates to be highly resistant to the fungicide tebuconazole in a New York wheat field.
He advises the use of integrated disease management.
“I think what we’re doing now is the right thing. We’re using integrated management, not just relying on one fungicide treatment. We’re using cultural control, planting varieties and using fungicides where necessary. I think over time we need to alternate or combine the fungicides that we use for this control to keep from a build up and avoid unnecessary fungicide spray particularly putting it on the very early growth stages of the crop.”
Weed Scientist, Dr. Russ Hahn, School of Integrative Plant Science, Soil and Crop Sciences at Cornell University, addressed the use of small grain herbicides and the increase of resistance in weeds to these herbicides.
Hahn noted that the weeds common to winter grains are different than weeds common to spring grains, however, both have limited control options in New York State. “We don’t have a lot of the small grain herbicides that are available in other parts of the country.”
Osprey the most recent registered herbicide in New York State, is only approved for use in Winter Wheat.
Winter annual weeds, like corn chamomile, germinate late summer, live through the winter and flower and set seed early the next season. “One of the key messages here is that most of the winter annual weeds need to be controlled when they are in the rosette stage,” Hahn stated. “Once they start to send up the flower stalk they become more difficult to control and you ultimately don’t get good control. They can be sprayed in the fall or in the early spring.”
When applying herbicide to wheat, there are different stages of growth that cannot be sprayed without damaging the grain and once the wheat has developed the elongation of the stem, many of the herbicides can no longer be used. “If you spray 2, 4-D or or Banvel too late, you’ll get misshaped seed heads. With Harmony Extra you can go a little later in the season.”
Hahn said he does not recommend using Banvel on oats, although it may be registered. “We back away from that one a little bit.” When oats, wheat or barley are seeded, recommendations for herbicides change. Harmony Extra is recommended to control wild garlic and annual broadleaf weeds and should be applied at less than 12 inches with 2 to 4 inches of new growth. Hahn noted that this product does not work on wild onion. Cheat, a winter annual Brome grass weed, Roughstalk and Bluegrass can be by effectively controlled Osprey.
One attendee described a problem with what Hahn deducted to be perennial Sow Thistle. “In that case, it’s one of those where if you have a window in late summer or early fall, put on a good shot of Banvel or Roundup between crops. We’ve had some Sow Thistle in our Aurora research farm in our plot area and we had a hard time killing it. I hate to admit defeat, but we haven’t done that good of a job on it. It’s hard to kill.”
Hahn spoke about the growing resistance to herbicides. “The potential for getting resistance with these herbicides is great. The bottom line is the number of herbicide resistant weeds gets bigger and bigger all of the time.” More information can be found at www.weedscience.org .
DEC pesticide credits were earned at this workshop and CCE Oneida County Ag Program Leader and Field Crops Educator Jeff Miller commented on updates in regulations.
“Anything you can use to track information is very important,” Miller stressed. “It’s really important to keep crop records.” Recording pesticides and herbicides should be done before leaving the field.
“Before you’re leaving the field you should be jotting that information down. It doesn’t have to be pretty, it just has to be written down. If a DEC person pulls you over as your pulling the sprayer out of the field, you’ll have proof that you wrote the information down.”
To meet requirements, chemical information must now be attached somewhere on the tank sprayer.
Emergency response people need to have that information if there is a spill on the road or a leak from your tank. “We need to do this, or it’s a big fine!” warned Miller.
For more information contact CNY Regional Field Crop Specialist Kevin Ganoe at 315-866-7920