| NEW HERBICIDE SHOWS PROMISE FOR NATIVE GRASS ESTABLISHMENT AND RELEASE
During the third week of May I had the privilege of working with Dr. Joe Vollmer, Sr. Market Development Specialist for American Cyanamid. Cyanamid has developed a herbicide, PLATEAU, specifically for prairie grass and wildflower establishment and release. Dr. Vollmer and I were putting in demonstration plots under several different scenarios and test plots on Eastern Gamagrass. The demonstration plots included different application rates on native grasses infested with fescue, both burned and unburned; remnant savannah; switchgrass, burned and unburned and several established forbs. PLATEAU does not currently carry a label for Eastern Gamagrass, thus the test plots on Gamagrass.
According to the label for PLATEAU, more than 60 weeds which compete with new prairie seedings as well as nonindigeonous species which invade native prairie areas are controlled. Some of the key weeds controlled are tall fescue, foxtails, crabgrass, panicums, barnyardgrass, shattercane, johnsongrass (seedling and rhizome), ragweeds, lambsquarters, pigweeds, morning glories, thistles, leafy spurge, nutsedge and many others.
Big bluestem, Little bluestem and Indiangrass are all approved at application rates from 4 to 12 ounces per acre. Sideoats grama, Blue grama and Buffalograss are approved at application rates of 4 ounces for seedlings and 4 to 8 ounces for established plantings. Four ounces per acre will provide control or suppression of labeled annual grass and broadleaved weeds. Six to 8 ounces per acre will provide additional control or suppression of perennial weeds and 10 to 12 ounces per acre will control annual and perennial labeled grass and broadleaved weeds. PLATEAU is not labeled for Switchgrass. PLATEAU controls fall panicum and switchgrass is a member of the panicum genus, however, trials have shown that 8 to 12 ounces of PLATEAU suppress established switchgrass, but not kill it. It is believed that seedling switchgrass will be killed by PLATEAU. For some of you, this could be good news. Some older mixed stands which are dominated by switchgrass may possibly be reclaimed by using PLATEAU.
Wildflower/flower species which are tolerant to PLATEAU are black-eyed susan, Illinois bundleflower, chicory, coneflowers, coreopsis, cornflower, cosmos, ox-eye and shasta daisy, leadplant, lupine, lespedeza, partridge pea, purple prairie clover and others. It is important to use lower rates when wildflowers are present in a mixed planting. In addition, some may be susceptible as seedlings but not as established plants.
So far the information I have given you is pretty much off of the PLATEAU label. The advantage of having worked with Dr. Vollmer for a week is that I learned some "inside" information about PLATEAU which will be helpful. First of all PLATEAU is much more efficient when using methylated seed oil as the surfactant rather than nonionic surfactants or silicone based surfactants. This knowledge can be used in different ways. Forbs which are more sensitive to the PLATEAU may be better sprayed with a surfactant other than methylated seed oil or when spraying seedling forbs and only trying to control annual grasses or weeds.
Converse to that, bad weed problems can be better controlled by using methylated seed oil or if trying to suppress switchgrass. In addition, Ammonium sulfate can be added to boost PLATEAU's performance. Caution should be used here though. I would use it only on big bluestem, little bluestem and/or indiangrass. If really trying to put the hammer on switchgrass, 12 ounces of PLATEAU with methylated seed oil and Ammonium sulfate should really knock it, but don't expect total control.
Another tid bit of information was Dr. Vollmer recommends spraying PLATEAU about 14 days after planting. PLATEAU works as both a pre and post emergent. By waiting a couple of weeks you will still control anything that has germinated while the preemergence activity will give you control later in the season which will help with late germinating foxtail or fall panicums. PLATEAU provides the best control of rhizome johnsongrass when johnsongrass has reached 18 to 24 inches high at the whorl. PLATEAU is rainfast in one hour. PLATEAU does not currently carry a grazing label, meaning the EPA has not approved PLATEAU treated fields for haying or grazing but the chemical is extremely safe. (The grazing label in "in the process") PLATEAU is nonmutagenic, nongenotoxic and falls into the Practically Non-Toxic Category for mammal, avian, fish, crustaceans and arthropods. This category is the least toxic category given by the EPA. Ninety-eight percent of the chemical absorbed or ingested is expelled with the urine as the parent material after 24 hours, the other 2% within 48 hours.
Though there is a lot we still don't know about PLATEAU, according to the label and field trials throughout the midwest, it is an excellent tool for establishing big bluestem, little bluestem and indiangrass. In addition, the use of forbs is not excluded by the use of PLATEAU. PLATEAU appears to be just the tool we've been needing. I will report on the results of the PLATEAU plots we established in future issues of The Native Grass Manager.
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