@article{sosnoskie_culpepper_york_beam_macrae_2009, title={Sequential Applications for Mesosulfuron and Nitrogen Needed in Wheat}, volume={23}, ISSN={["1550-2740"]}, DOI={10.1614/WT-09-019.1}, abstractNote={Mesosulfuron is often applied to wheat at a time of year when top-dress nitrogen is also applied. Current labeling for mesosulfuron cautions against applying nitrogen within 14 d of herbicide application. Soft red winter wheat response to mesosulfuron and urea ammonium nitrate (UAN) applied sequentially and in mixtures was determined at three locations in North Carolina and Georgia during 2005 and 2006. Mesosulfuron at 0, 15, and 30 g ai/ha was applied in water to wheat at Feekes growth stage (GS) 3 followed by UAN at 280 L/ha 2 h, 7 d, 14 d, and 21 d after mesosulfuron. Mesosulfuron applied in UAN was also evaluated in 2006. Mesosulfuron injured wheat 6 to 9% in 2005 and 12 to 23% in 2006 when UAN was applied 2 h or 7 d after the herbicide. Wheat injury did not exceed 8% when UAN was applied 14 or 21 d after the herbicide. Greatest injury, 35 to 40%, was noted when mesosulfuron and UAN were combined. Wheat yield was unaffected by mesosulfuron or time of UAN application in 2005. In 2006, yield was affected by the timing of UAN application relative to mesosulfuron; wheat yield increased as the interval, in days, between UAN and herbicide applications increased. To avoid crop injury and possible yield reduction, mesosulfuron and UAN applications should be separated by at least 7 to 14 d. These findings are consistent with precautions on the mesosulfuron label.}, number={3}, journal={WEED TECHNOLOGY}, author={Sosnoskie, Lynn M. and Culpepper, A. Stanley and York, Alan C. and Beam, Josh B. and MacRae, Andrew W.}, year={2009}, pages={404–407} } @article{macrae_culpepper_batts_lewis_2008, title={Seeded watermelon and weed response to halosulfuron applied preemergence and postemergence}, volume={22}, ISSN={["1550-2740"]}, DOI={10.1614/wt-06-180.1}, abstractNote={Managing weeds in watermelon is challenging because of the limited availability of herbicides approved for use in this crop. Field experiments on efficacy and crop tolerance were conducted to determine the potential for halosulfuron use in watermelon in Georgia and North Carolina. Halosulfuron was applied PRE, early POST (EPOST; one-leaf watermelon), and late POST (LPOST; watermelon with 30-cm runners) at 26, 39, and 52 g ai/ha. Under weed-free conditions, PRE treatments did not injure watermelon. EPOST and LPOST treatments caused 45 and 34% injury 2 wk after treatment, respectively, averaged over halosulfuron rate. EPOST treatments reduced watermelon fruit number and total weight by 15 and 22%, respectively, and LPOST treatments reduced total fruit weight 12%. Halosulfuron PRE at 39 or 52 g/ha provided 94% or greater control of carpetweed, Palmer amaranth, and smooth pigweed. EPOST treatments controlled 84 and 88% of yellow nutsedge and smooth pigweed, respectively, but LPOST treatments controlled less than 83% of all weed species. Sequential applications of halosulfuron at 26 g/ha PRE and 26 g/ha LPOST controlled 89 to 99% of carpetweed, coffee senna, Palmer amaranth, smooth pigweed, and yellow nutsedge. Our data suggest growers can effectively use halosulfuron PRE in seeded watermelon. However, POST applications should be made only after watermelon has 30-cm runners and as a salvage spot treatment where previous weed control strategies have failed to provide adequate control. Nomenclature: Halosulfuron, carpetweed, Mollugo verticillata L. MOLVE, coffee senna, Cassia occidentalis (L.) Link CASOC, Palmer amaranth, Amaranthus palmeri S. Wats. AMAPA, smooth pigweed, Amaranthus hybridus L. AMACH, yellow nutsedge, Cyperus esculentus L. CYPES, watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai ‘Legacy’, ‘Sangria’, ‘Stargazer’}, number={1}, journal={WEED TECHNOLOGY}, author={Macrae, Andrew W. and Culpepper, A. Stanley and Batts, Roger B. and Lewis, Kenneth L.}, year={2008}, pages={86–90} } @article{macrae_monks_batts_thorton_schultheis_2007, title={Sweetpotato tolerance to halosulfuron applied postemergence}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-060178.1}, abstractNote={Studies were conducted in 2003 and 2004 to determine the effect of application timing and halosulfuron rate on sweetpotato yield and quality. Halosulfuron was applied 1, 2, and 4 wks after transplanting (WAP) sweetpotato in 2003, and 2, 3, and 4 WAP in 2004. Treatments within each timing included halosulfuron at 13, 26, 39, 52, and 65 g ai/ha plus a weed-free control. Combined over year, site, cultivar and rate, halosulfuron applied at 1, 2, 3, and 4 WAP stunted sweetpotato 32, 15, 11, and 14%, respectively, rated 2 wks after treatment. The stunting observed with the 1 and 2 WAP timings caused a 17 and 10% reduction in yield of No. 1 roots, respectively, compared with the weed-free control. The 3 and 4 WAP timings of halosulfuron did not reduce yield of No. 1 roots. Total yield was reduced approximately 11% at the 1, 2, and 3 WAP application timings. Halosulfuron at 4 WAP did not reduce total yield. Combined over year, site, and cultivar, halosulfuron applied at 39 g/ha did not reduce the weight of No. 1 roots or total crop yield and thus could be an effective POST option for weed control in sweetpotato.}, number={4}, journal={WEED TECHNOLOGY}, author={MacRae, Andrew W. and Monks, David W. and Batts, Roger B. and Thorton, Allan C. and Schultheis, Jonathan R.}, year={2007}, pages={993–996} } @article{macrae_monks_batts_thornton_2007, title={Sweetpotato tolerance to thifensulfuron applied postemergence}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-06-179.1}, abstractNote={An experiment was conducted at two locations in 2003 and 2004 to determine the timing and rate of thifensulfuron that is safe to use on sweetpotato. Thifensulfuron was applied 1, 2, and 4 wk after transplanting (WAP) in 2003 and 4, 6, and 8 WAP in 2004. Within each timing, thifensulfuron treatments were 1.1, 2.1, 3.2, 4.3, and 8.5 g ai/ha plus a weed-free control. The 1 and 2 WAP timings of thifensulfuron reduced the yield of number 1 roots greater than 25%. The 4, 6, and 8 WAP timings had less than 15% reduction in yield, with the 6 WAP timing reducing number 1 roots and total yield 10% or less. When 4.3 g/ha of thifensulfuron was applied 4 WAP, total yield was reduced 13%. The 6 and 8 WAP timings had little yield reduction, with no rate response observed. Application of 4.3 g/ha of thifensulfuron at 6 WAP would allow for control of problematic weed species while limiting potential yield loss. Yield loss from a 4 WAP application of thifensulfuron may in fact be a delay in crop maturity that could be recovered if the sweetpotato harvest was delayed to allow for the optimal amount of number 1 grade roots to be produced.}, number={4}, journal={WEED TECHNOLOGY}, author={MacRae, Andrew W. and Monks, David W. and Batts, Roger B. and Thornton, Allan C.}, year={2007}, pages={928–931} } @article{macrae_mitchem_monks_parker_galloway_2007, title={Tree growth, fruit size, and yield response of mature peach to weed-free intervals}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-06-002.1}, abstractNote={An experiment was conducted at one location in 1999 and two locations in 2000 to determine the critical weed-free period for peach in North Carolina. The cultivars for the three locations were ‘Contender’, ‘Norman’, and ‘Summerprince’. Weed-free intervals of 0, 3, 6, 9, 12, and 15 wk after peach tree bloom were established. Paraquat at 1.1 kg ai/ha plus nonionic surfactant at 0.25% v/v was applied every 10 d, after treatments were initiated at peach bloom, to maintain weed-free plots. Large crabgrass, hairy vetch, and smooth crabgrass were the primary weeds in Contender. Horseweed, smooth crabgrass, and large crabgrass were the primary weeds in Norman. Bermudagrass, smooth pigweed, and common lambsquarters were the primary weeds in Summerprince. No differences in trunk cross-sectional area were observed between the weed-free periods. Maintaining the orchard floor weed-free for 12 wk after peach tree bloom resulted in the greatest fruit size (individual fruit weight and diameter), total yield, and fruit number.}, number={1}, journal={WEED TECHNOLOGY}, author={MacRae, Andrew W. and Mitchem, Wayne E. and Monks, David W. and Parker, Michael L. and Galloway, Roger K.}, year={2007}, pages={102–105} } @article{starke_monks_mitchem_macrae_2006, title={Response of five summer-squash (Cucurbita pepo) cultivars to halosulfuron}, volume={20}, ISSN={["0890-037X"]}, DOI={10.1614/WT-03-144R3.1}, abstractNote={Response of ‘Dixie’, ‘Lemondrop’, ‘Multipik’, ‘Superpik’, and ‘Seneca Prolific’ summer squash to halosulfuron PRE or POST at 0.036, 0.053, and 0.072 kg ai/ha, or halosulfuron PRE fb halosulfuron POST at 0.018 fb 0.018, 0.027 fb 0.027, and 0.036 fb 0.036 kg/ha was field evaluated in 1997 and 1998. All halosulfuron treatments and rates reduced the height of cultivars 17–19% at 6 WAP (weeks after planting) and summer-squash injury (chlorosis and necrosis of crop foliage) was 6, 14, and 11% from halosulfuron PRE, POST, and PRE fb POST, respectively. Early summer-squash flowering was reduced 32–82% by halosulfuron, resulting in reduced early yields. Dixie was the cultivar most tolerant to halosulfuron. Early flowering of Dixie was reduced 32–36% compared to 32–82% for the other cultivars. Marketable yield of summer squash was reduced 20–30% by all rates of halosulfuron when averaged over all application timings. Marketable yield of Seneca Prolific, Superpik, Dixie, Multipik, and Lemondrop was reduced 0–17% by halosulfuron PRE. Halosulfuron POST or PRE fb POST reduced marketable yield of all summer-squash cultivars by 25–46%. Thus, summer squash was not tolerant of POST halosulfuron; however, Dixie, Multipik, Seneca Prolific, and Superpik exhibited tolerance to halosulfuron PRE.}, number={3}, journal={WEED TECHNOLOGY}, author={Starke, Keith D. and Monks, David W. and Mitchem, Wayne E. and Macrae, Andrew W.}, year={2006}, pages={617–621} } @article{silvey_mitchem_macrae_monks_2006, title={Snap bean (Phaseolus vulgaris) tolerance to halosulfuron PRE, POST, or PRE followed by POST}, volume={20}, ISSN={["0890-037X"]}, DOI={10.1614/WT-05-046.1}, abstractNote={A field experiment was conducted in 1996 and 1997 to determine snap bean tolerance to halosulfuron based on crop injury, height, and yield. Halosulfuron was applied preemergence (PRE), postemergence (POST), and sequentially PRE followed by (fb) POST at 35, 53, and 70 g ai/ha, respectively. For comparison, a hand-weeded check was included. When data were averaged across years and halosulfuron rates, halosulfuron PRE, POST, and PRE fb POST provided similar yellow nutsedge control (74 to 82%) at snap bean harvest. Halosulfuron PRE resulted in 4% snap bean injury at harvest. Similarly, halosulfuron PRE fb POST resulted in 5% injury, while halosulfuron POST caused the most damage at 8%. Snap bean height at harvest was reduced 14% with halosulfuron POST compared to the weed-free check, with only 5 and 6% reduction caused by halosulfuron PRE and PRE fb POST, respectively. Halosulfuron POST reduced yield 39% compared to the weed-free check, while the PRE and PRE fb POST application timings produced yield similar to the check. When averaged across years and halosulfuron application timings, an increase in halosulfuron rate had no effect on yellow nutsedge control or snap bean yield. A linear trend was found for snap bean injury and plant height at harvest with snap bean injury increasing with an increase in halosulfuron rate while snap bean plant height decreased with an increase in halosulfuron rate. Application of halosulfuron PRE is the safest means to control yellow nutsedge in snap bean in North Carolina.}, number={4}, journal={WEED TECHNOLOGY}, author={Silvey, Brandy D. and Mitchem, Wayne E. and Macrae, Andrew W. and Monks, David W.}, year={2006}, pages={873–876} } @article{macrae_mitchem_monks_parker_2005, title={White clover (Trifolium repens) control and flower head suppression in apple orchards}, volume={19}, ISSN={["1550-2740"]}, DOI={10.1614/WT-02-024}, abstractNote={White clover is a weed in apple orchards that competes with the crop; also, flowers of this weed are unwanted attractants of honey bees at times when insecticides, which are harmful to these pollinators, are being applied. In 1997 and 1998, white clover flower head and plant control by clopyralid alone and with 2,4-D and apple tolerance to these herbicides were determined. Treatments consisted of clopyralid at 0.10 and 0.21 kg ae/ha, 2,4-D at 1.1 kg ae/ha, and 2,4-D at 1.1 kg ae/ha plus 0.03 or 0.05 kg ae/ha clopyralid, which were applied 2 wk before full apple bloom and 2 wk after full apple bloom, and a nontreated check. No crop injury occurred with any treatment. All herbicide treatments provided some white clover control and flower head suppression. No differences in white clover bloom reduction were observed through May among treatments containing clopyralid. As summer progressed, the effect of clopyralid rate became more apparent. Clopyralid at 0.21, regardless of application time, provided 99% vegetative control and 100% flower head reduction through July. Clopyralid plus 2,4-D controlled white clover better than 2,4-D alone. However, vegetative control and flower head reduction with clopyralid at reduced rates (0.03 or 0.05 kg ae/ha) plus 2,4-D were not acceptable (76% or less and 78% or less, respectively). Thus, clopyralid at 0.10 and 0.21 kg ae/ha will be necessary for acceptable white clover vegetation control and flower head reduction.}, number={2}, journal={WEED TECHNOLOGY}, author={MacRae, AW and Mitchem, WE and Monks, DW and Parker, ML}, year={2005}, pages={219–223} }