Repeat sequential applications (1 - 4) of imazaquin herbicide were applied to 100% pure stands of purple nutsedge during the summer of 198& Treatments were applied every two weeks. Maximum suppression for plots receiving only one application was reached 1 month after application (25% control). Two 14-day sequential applications achieved 60% control 2 weeks after the second treatment. Both 3 and 4 sequential applications resulted in 88% and 92% control after 2 and 4 weeks from the third and fourth applications, respectively. Resprouting eventually reoccurred on all plots. This data shows the enhanced effect of repeat applications of imazaquin for purple nutsedge suppression.

A field test was implemented at Paradise Valley Country Club to investigate the effect of two rates of imazaquin (Image) herbicide (0.38 and 0.50 lbs ai /a) in both the granular (G) and emulsifiable concentrate formulation on purple nutsedge and common bermudagrass in a mixed stand (85 ± 20% nutsedge).

An experiment was devised to evaluate application technique, and elucidate the plant response (herbicidal activity) of imazaquin herbicide on single plants of purple nutsedge. Herbicide treated plants showed increased filleting and stunting 31 days after treatment. Soil treatments tended to increase herbicidal response. Imazaquin activity was minimized when the herbicide was not irrigated into the soil. Soil applied-imazaquin postponed the emergence of shoots from viable nutlets, but did not prevent emergence altogether.

A one-time application of MON1S1S1 or 0.5 lb. ai /a on September 1, 1988, was evaluated for potential overseeding effects. Treated plots, which were overseeded with perennial ryegrass at 10, 20, or 30 lbs. per thousand square feet, were not significantly different compared to untreated plots for percent ryegrass stand and verdure. Only seed rate effects increased percent ryegrass and verdure weights slightly. These data show no detrimental effects of using MON15151 ("Dimension" trade name) six weeks before overseeding.