Response of Quackgrass (Elytrigia repens) Biotypes to Primisulfuron

Abstract

Quackgrass biotypes collected from 15 locations exhibited differential response to primisulfuron at 20 g ha−1in field experiments at Hudson, NY during 1990 and 1991. Quackgrass control ranged from 23 to 100% 77 days after application (DAA) in 1990 and from 38 to 100% 88 DAA in 1991. The biotype from Montpelier, OH was the most tolerant both years. Differential response of quackgrass biotypes from five locations was confirmed in greenhouse experiments. The primisulfuron rate required to reduce shoot regrowth by 50% in the greenhouse was estimated at 15, 15, 17, 17, and 37 g ha−1for biotypes from Amherst, MA; Mahnomen MN; Fargo, ND; State College, PA; and Montpelier, OH, respectively. Quackgrass shoot regrowth was reduced more when primisulfuron was applied with the linear alcohol ethoxylate additive 1412-70 compared with Scoil, Sylgard 309, Agridex, or X-77.

Response to low-dose herbicide selection in self-pollinatedAvena fatua

“…Targeted weedy plants can be exposed to a low, below‐label herbicide dose, for example, if there is deliberate underdosing, tardy treatment time (oversized plants) or treatment under suboptimal environmental conditions. Most weedy plant species have significant genetic variability, including variability in response to herbicide dose . Here, we are concerned with the evolutionary impacts of herbicide use at doses (low) that enable survivors that can reproduce.…”

Susceptibility variation to new and established herbicides: Examples of inter-population sensitivity of grass weeds

“…Previous attempts have shown that weed populations can vary greatly in susceptibility to a herbicide (e.g. Bourdot et al, 1990;Cerdeira and Duke, 2006;DeGennaro and Weller, 1984;Ellis and Kay, 1975a;1975b;Gillespie and Vitolo, 1993;Jacobsohn and Andersen, 1968;Patzoldt et al, 2002;Price et al, 1983;1985;Somody et al, 1984;Tardif andLeroux, 1991a Thai et al, 1985;Tranel and Trucco, 2009). Hence, knowledge about the magnitude of such inter-population differences will be pivotal when assessing creeping resistance.…”

Common Cocklebur (<i>Xanthium strumarium</i>) Response to Nicosulfuron

“…Namely, based on these GR50 values for fresh weight, the population CC1 was about 3.9 and 2.6-fold more susceptible to nicosulfuron than population CC2 in 1 st and 2 nd year, respectively, but differences were not so prominent when based on other parameters (plant height, leaf area and ALS activity), ranging from 1.18 to 1.8-fold. As previous investigations have shown that weed populations can vary greatly in susceptibility to herbicides (DeGennaro and Weller, 1984;Gillespie and Vitolo, 1993;Patzoldt et al, 2002), the differences between population CC1 and CC2 could be attributed to inter-population variability in susceptibility to nicosulfuron, though these differences could be the consequence of repeated application of ALS herbicides to the CC2 population during the six previous years. Future investigations are necessary in order to clarify this dilemma and give recommendation for their control in integrated weed management system.…”