SOYBEANS - WHITE MOLD SUPPRESSION
DIRECTIONS FOR USE IN SOYBEANS
Cobra is a selective, broad spectrum herbicide for preemergence and postemergence control of susceptible broadleaf weeds. Cobra is formulated as an emulsifiable concentrate containing 2 lbs. of active ingredient per gallon. In the upper North Central region of the midwest, postemergence applications of Cobra Herbicide to soybeans (at or just before 1st bloom) has resulted in suppression of the soybean disease white mold caused by Sclerotinia sclerotiorum.
Cobra works primarily through contact action. Good coverage of young, actively growing weeds is essential for maximum weed control. The use of a spray adjuvant is usually required. Refer to the label section on ADJUVANTS AND ADDITIVES for specific recommendations.
When Cobra is applied post emergent, a portion of the spray solution may contact the soil surface. If soil moisture conditions are favorable for preemergence activity following the application, suppressed germination of small-seeded broadleaf weeds, such as nightshade species, pigweed species, and prickly sida may be expected for a 2 to 3 week period. The presence of excessive crop or weed foliage at the time of application will reduce the amount of herbicide spray contacting the soil surface and will reduce the level of soil activity.
A temporary crop response should be expected following a post-emergence application of Cobra.
Soybean leaves which are open at the time of application will show some burn, bronzing and speckling.
Trifoliate soybean leaves which have emerged but are unopened at the time of application may appear cupped at the tip and/or crinkled along the edges of the leaf. Soybeans quickly outgrow all initial herbicide effects. When Cobra is used as directed, under commercial conditions soybean yields will not be adversely affected. Under conditions of normal weed growth Cobra is rainfast 30 minutes after application.
Apply Cobra preplant, preemergence, and/or postemergence, but do not apply later than 45 days before harvest or after growth stage R6 (full seed). Do not exceed a total of 25 fl. oz. (0.4 lb. a.i.) per acre per season.
NOTE: New York State Only – Apply Cobra Herbicide only as a postemergence herbicide once per growing season, at a maximum seasonal application rate not to exceed 1 2.5 fl. oz. (0.2 lb. a.i.) per acre, and not later than 90 days before harvest.
Do not graze animals on green forage or stubble. Do not feed treated soybean silage (ensiled soybeans) to cattle. Do not utilize hay or straw for animal feed or bedding.
CONVENTIONAL ROW APPLICATION TIMING
For best results, Cobra and Cobra tank mixes should be applied to small actively growing weeds that are not larger than indicated in Table 2S or tank mix Tables of the label. Normally this occurs 1 4 to 21 days after planting or after last field preparation, when soybeans are at the first to second trifoliate leaf stage.
Soybeans at or larger than the third trifoliate stage may interfere with the spray pattern and reduce coverage of the weed leaves. Do not apply Cobra when the soybeans or the weeds are under stress.
Applying Cobra under conditions that do not promote active weed growth will reduce herbicide effectiveness. These conditions include drought, excessive water, extremes in temperature, and low humidity. Weeds under stress tend to \"harden off\" and become less susceptible to herbicidal action.
Do not cultivate prior to or during application. Do not generate excessive dust while spraying. Excessively dusty conditions may interfere with the coverage of the weed leaf surface by the spray solution. A timely cultivation approximately one week after application will assist in weed control.
DRILLED/SOLID SEEDED APPLICATION TIMING
Under drilled/solid-seeded soybean cropping systems, a dense crop canopy develops more rapidly than conventional row spacings. The crop canopy may restrict penetration of the herbicide spray pattern and reduce coverage of the weed foliage. Applications should be made when soybeans are at the first trifoliate leaf stage usually 7 to 1 0 days after planting. Delaying application beyond the first trifoliate leaf stage may result in unsatisfactory weed control. For improved weed coverage and canopy penetration in drilled or solid seeded soybeans, the higher range of spray volume and pressure is required. See the BROADCAST GROUND APPLICATIONS section of the label for application information.
EARLY APPLICATION TIMING
For early control of Pigweeds, Eastern Black Nightshade, Common Ragweed, Giant Ragweed, Common Lambsquarters, Copperleaf, Common Purslane, Hairy Galinsoga, Cutleaf Groundcherry, and Jimsonweed, apply Cobra Herbicide when soybeans have emerged and are in the cotyledon to unifoliate stage, normally 5 to 7 days after planting. Weed growth may not be visible or may be in the cotyledon stage of growth at early application.
BROADCAST GROUND APPLICATION
Cobra and Cobra tank mixes can be applied by ground equipment using standard commercial sprayers equipped with flat fan or hollow cone nozzles. Cobra is a contact herbicide. Special attention should be given to preparing and operating the sprayer to assure proper coverage of the weed leaf surface. Use Cobra on a broadcast basis in 20 to 30 gals. of water per acre and a spray pressure of 40 to 60 PSI measured at the boom. Apply Cobra using a flat fan or hollow cone nozzle designed to deliver the desired spray pressure and spray volume. Avoid use of flat fan nozzles larger than 8006 (or equivalent) because they do not break up spray patterns into small enough droplets to provide adequate weed coverage for foliar herbicides. Spray nozzles should be centered at a 20 inch spacing to provide adequate coverage. Ground speed should not exceed 1 0 mph to provide proper spray coverage. Boom height, ground speed, and pressure recommendations should not exceed those recommended by the spray nozzle manufacturer for the type and size of nozzle being used. Improper use of the selected spray nozzle will adversely affect the spray pattern, prevent proper coverage of weed leaf surface, and reduce weed control. Refer to the manufacturer's spray chart for nozzle selection and operating information.
REFER TO THE AERIAL APPLICATION SECTION FOR SPECIFIC INSTRUCTIONS FOR AERIAL APPLICATION.
Row banding equipment should be adjusted to provide maximum coverage of weeds in the row. Base the band use of Cobra and Cobra tank mixes on a broadcast use rate of 20 to 30 gals. of water per acre by reducing the spray gallons in proportion to the area actually treated. The spray pressure should be 40 to 60 PSI measured at the boom. A minimum of two nozzles per row is required to provide optimum coverage of the weed foliage.
DO NOT make band applications while cultivating or create excessive dust while spraying. Excessively dusty conditions will interfere with proper coverage of the weed leaf surface, thereby reducing contact activity.
LOW VOLUME GROUND APPLICATION
Application of Cobra and Cobra tank mixes using a low volume application require a minimum of 1 0 gals. of spray solution per acre.
A minimum of 20 gals. of spray solution per acre is required in North Dakota, South Dakota and Minnesota. Applications at less than 1 0 gals. per acre will provide inconsistent weed control. The spray pressure at the boom should be between 40 to 60 PSI. Flat fan nozzles are recommended at 20 inch spacing for proper spray coverage. To provide adequate coverage flat fan nozzles larger than 8006 (or equivalent) should not be used. Height of the spray boom should be adjusted so as not to exceed the manufacturer's recommendation for proper coverage by the spray nozzle being used. Maximum speed of operation should not exceed 1 0 mph as spray coverage of weed foliage may be adversely affected.
Crop oil concentrate is required at the rate of 2% v/v to achieve optimum control with low volume applications.
To obtain satisfactory weed control with aerial applications of Cobra and Cobra tank mixes, except 2,4-DB, uniform coverage must be obtained. Do not spray when drift is possible or when wind velocity is more than 5 mph. Avoid spraying Cobra within 200 ft. of dwellings, or adjacent sensitive crops such as ornamentals, cotton, tobacco, or sorghum. To obtain satisfactory application and minimize drift, the following directions must be observed:
Volume and Pressure: Use Cobra in 5 to 10 gals. water per acre and a maximum spray pressure of 40 PSI. Applications at less than 5 gals. per acre will provide inadequate control. The higher gallonage applications generally afford more consistent weed control.
SOUTHERN STATES: In low-laying areas of Southern states which typically experience excessive soil moisture in the spring, the state recommendation for adjuvants may call for either a non-ionic surfactant or reduced rate of crop oil concentrate. Where this situation exists, use the adjuvant recommendations of the state extension service.
- Applications of Cobra Herbicide for white mold suppression in soybeans must be made at or just before 1 st bloom. Generally this occurs after the 4th trifoliate is fully expanded.
- The soybean disease white mold is caused by Sclerotinia sclerotiorum.
- Rates higher than 8 oz./A will not increase the level of white mold suppression. In cases where rates higher than 8 oz./A are desired for weed control please refer to Table 8S or Table 2S.
NOTE: It has been shown that the effects of Cobra on white mold is not a fungicidal response but one that may involve Systemic Acquired Resistance (SAR).
Precaution : DO NOT APPLY COBRA AFTER WHITE MOLD INFECTION HAS OCCURRED.