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In This Issue:
A) Late Season Grazing Alternatives
B) Bean Leaf Beetle on a Rampage
C) Dig Up Those Beans: Now is the Time to Look for Cysts!
With dry weather throughout Ohio during most of the summer, many livestock producers are searching for alternative forages to graze. Small grain crops, such as cereal rye, seeded in September can provide high quality forage during late fall and early spring. Cereal rye is an alternative which has been tested since 1993 in Jackson County and in 1998 at the Eastern Ohio Research and Development Center (EORDC) in Belle Valley.
Rye can produce grazable forage when seeded in September and may yield in excess of 2000 pounds of dry matter per acre in the fall. Rye breaks winter dormancy early and can also be grazed in the spring. Rye should not be overgrazed in the fall, be sure to leave 3-4 inches of leaf height going into the winter.
Rye seeding is generally accomplished through minimum tillage following corn or tobacco in southern Ohio. However, with adequate moisture, no-till has been used successfully at EORDC. When no-tilling into sod it is recommended to burn down existing vegetation with recommended rates of Gramoxone Extra or Roundup Ultra.
Seeding rates of 110 lb per acre for no-till, 90-110 lb per acre for conventional till, and 2 bu/A broadcast are recommended for cereal rye. If fields have no carryover nitrogen, it is recommended to apply 50 units of nitrogen per acre when the plants are actively growing. Studies in Jackson and Belle Valley have produced up to a ton of dry matter per acre 80 days after planting. Crude protein content of cereal rye ranges from 22-24 %.
According to Dave Samples, Extension Agent in Jackson County, the date of seeding makes a difference in how and when rye can be grazed. In his trial, rye seeded on September 20th yielded from 1300-2700 lb dry matter when harvested 80 days later. Delaying seeding until mid-October will not allow for adequate growth for grazing until spring. Dave has also noted some variety differences in spring and fall growth. In his studies the varieties with the greatest fall growth were Wheeler, Oklon, Winter King and Aroostook. The greatest early spring growth was made from Elbon, Aroostook, Maton, and an untested seed.
Four varieties have demonstrated good yields in three years of trials, according to Dave Samples. These include: Aroostook marketed through Speedway; Winter King marketed by Green Seed; Elbon developed at the Noble Foundation in Oklahoma; Pastar marketed through Southern States Coop. Seed costs for 1999 range from $6.50 to approximately $12.00 per bag.
If you would like more information on the rye cultivars tested at Jackson, call Dave Samples at 740-286-5044 or Ed Vollborn at 740-286-2177. For EORDC trials, call Clif Little at 740-432-9300.
Soybean fields at the present time are at various stages of development. Some fields are already starting to drop foliage, many fields are starting to discolor, and many fields remain totally green as pods develop. At the same time, insect pest populations in soybeans are present at above normal levels. Bean leaf beetles (BLB) are as abundant as the outbreaks of 1988 and 1991. Pentatomid (stink bugs) and grasshopper activity is above normal. Green cloverworms are common, but many are diseased. Japanese beetles continue to be active in some fields.
The primary pest problem on soybeans is currently bean leaf beetles, which have been active throughout the current growing season. In late July, BLB adults averaged about one adult beetle per sweep in central Ohio (Clark, Madison, Union, Delaware & Marion counties). By mid-August, BLB collections in central Ohio were averaging more than two adult beetles per sweep. During the past week, sweep net samples in central Ohio were averaging almost four beetles per sweep. Jim Jasinski (IPM specialist, Southwest District) has reported similar observations for counties in western Ohio. Curtis Young (IPM specialist, Northwest Ohio) has reported higher levels of BLB activity, which in some cases are running 10 to 20 BLB per sweep.
Where BLB activity is abundant, defoliation levels of 20% or more are common and equivalent levels of pod injury are accumulating. One field inspected in Clark County during the past week averaged six BLB per sweep and already had nearly 40% pod injury, and foliage had not yet to turn color. Given the BLB activity in such a field where pods are still filling, pod injury is likely to increase to a level of 50 to 60%. As pod injury increases, pods will accumulate multiple feeding scars and the potential for significant seed discoloration and mold development will increase accordingly.
Given the current levels of BLB injury throughout the state, soybean fields need to be inspected to determine the need for corrective treatments. BLB activity should be evaluated with the use of a sweep net and pod injury should be evaluated by randomly inspecting ten or more plants. Where five or more BLB beetles are collected per sweep and the crop has not begun to discolor, the potential for additional pod injury should justify a rescue treatment. Specific attention should be given to soybean seed and tofu marketed crops which may have a limited tolerance for discolored or moldy seeds.
Now is an excellent time to look for Soybean Cysts on roots, but you need to dig the plants up, not pull the plants up. The best places to look are areas in the fields which are maturing early, places where the beans appear to be shorter than in other places in a field. The reality, however, is that the beans will have no visible signs of stress and may still have high populations of soybean cyst nematode.
How to manage Soybean Cyst Nematodes: Rotation - Rotation - Rotation
In managing soybean cyst nematode - this is going to be a numbers game. You will have to rotate to corn and/or wheat for one to two years to drop the cyst nematode populations below the economic threshold. If very high populations are present (greater than 5,000 eggs/200 cc or cup of soil) - one year of corn will only drop the population in half to 2,500 - that is still enough to cause yield losses especially in a year as challenging as this one has been. A second year of corn will drop the population in half again, or about 1,250 eggs/200cc which is at a level that a SCN resistant variety can be planted.
Soybean cyst nematode can be managed very effectively with rotation - PROVIDED that you know what the population levels are. We are now in a situation in some fields where one year of corn is not enough to drop that cyst population below the economic threshold.
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Past versions of C.O.R.N. can be found on the World Wide Web at: http:/www.ag.ohio-state.edu/~corn/archive/
C.O.R.N. is a summary of crop observations, related information, and appropriate recommendations for Ohio Crop Producers and Industry. C.O.R.N. is produced by the Ohio State University Extension Agronomy Team, State Specialists at The Ohio State University and Ohio Agricultural Research and Development Center. C.O.R.N. Questions are directed to State Specialists, Extension Associates, and Agents associated with Ohio State University Extension and the Ohio Agricultural Research and Development Center at The Ohio State University.
Contributors to C.O.R.N. this week include: State Specialists: Anne Dorrance (Plant Pathology), Pat Lipps (Plant Pathology), Peter Thomison (Hort and Crop Sciences), Hal Willson (Entomology), and Ron Hammond (Entomology); Extension Agents: Howard Siegrist (Licking), Steve Prochaska (Crawford), Larry Lotz (Fayette), Clark Hutson (Seneca), Glen Arnold (Putnam), Roger Bender (Shelby), Clif Little (Guernsey) and Andy Kleinschmidt (Van Wert).
Editor: Andy Kleinschmidt Web Editor: Nathan Watermeier
Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.
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Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.
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