Smooth crabgrass (Digitaria ischaemum) and goosegrass (Eleusine indica) are problematic weeds in creeping bentgrass (Agrostis stolonifera) because of limited herbicide options for postemergence (POST) control and turfgrass injury potential. Metamifop is a herbicide currently being considered for release to markets in the United States but information is lacking on the most effective rates and application timings for smooth crabgrass and goosegrass control in creeping bentgrass. Field trials were conducted in Auburn, AL in 2009 and 2013 to evaluate metamifop rates (200 to 800 g·ha−1) and single or sequential application timings compared with fenoxaprop (51 to 200 g·ha−1) at two different mowing heights. Metamifop applied twice and three times sequentially at 200 g·ha−1 provided the greatest smooth crabgrass (>97%) and goosegrass (>90%) control at rough (1½ inch) and green (1/8 inch) mowing heights without unacceptable creeping bentgrass injury at 56 days after initial treatment. All treatments caused <20% visible injury on creeping bentgrass at both mowing heights except the highest rate of metamifop. Smooth crabgrass control at the green mowing height was greater than at the rough mowing height, especially at lower metamifop rates with a single application.

When ATZ is used for several years, enhanced degradation will undoubtedly change the way ATZ is used in agronomic crops and also its ultimate environmental fate. © 2017 Society of Chemical Industry.

Aminocyclopyrachlor (AMCP) is a synthetic auxin herbicide used for broadleaf weed control in pasture and rangeland. The tolerance and fate of AMCP within pertinent grass species is not well understood. Research was conducted to establish the tolerance of four grass species to AMCP application and observe their absorption, translocation, and metabolism. Results indicate that tall fescue is the most tolerant of AMCP at rates required for weed control. Bahiagrass and bermudagrass are marginally tolerant, and cogongrass is the most sensitive. Tall fescue and bahiagrass absorbed more AMCP than bermudagrass and cogongrass, but cogongrass absorption is the most rapid and complete within 2 days after treatment (DAT). Cogongrass and bermudagrass translocated the least amount out of the target area, whereas bahiagrass and tall fescue translocated the most. Radioisotope imaging revealed that tall fescue may sequester absorbed AMCP in leaf tips. This sequestering may be the basis of the greater tolerance to AMCP by tall fescue relative to the other species evaluated. No metabolism of AMCP was detected in any grass species out to 42 DAT.

Because pronamide has produced tumors in laboratory animals, this product is for retail sale to and use only by Certified Applicators or persons under their direct supervision, and only for those uses covered by the Certified Applicator's certification.

The triazines are one of the most widely used herbicide classes ever developed and are critical for managing weed populations that have developed herbicide resistance. These herbicides are traditionally valued for their residual weed control in more than 50 crops. Scientific literature suggests that atrazine, and perhaps others-triazines, may no longer remain persistent in soils due to enhanced microbial degradation. Experiments examined the rate of degradation of atrazine and two other triazine herbicides, simazine and metribuzin, in both atrazine-adapted and non-history Corn Belt soils, with similar soils being used from each state as a comparison of potential triazine degradation. In three soils with no history of atrazine use, thet1/2of atrazine was at least four times greater than in three soils with a history of atrazine use. Simazine degradation in the same three sets of soils was 2.4 to 15 times more rapid in history soils than non-history soils. Metribuzin in history soils degraded at 0.6, 0.9, and 1.9 times the rate seen in the same three non-history soils. These results indicate enhanced degradation of the symmetrical triazine simazine, but not of the asymmetrical triazine metribuzin.