Italian ryegrass (Lolium perenne spp. multiflorum) is a common weed management problem in turfgrasses, cereals and non-crop areas in the United States. In Oregon, the number of populations with multiple-resistance continues to increase. To manage these resistant populations, the resistance patterns must be determined. In this study, five Italian ryegrass...
Understanding the mechanism of resistance, relative fitness and competitiveness of herbicide resistant biotypes is important to predict population dynamics and to establish resistance management strategies. This study was conducted to determine the level of resistance to acetolactate synthase (ALS) inhibitors and the mechanism of resistance of ALS-inhibitor resistant downy brome...
A suspected glyphosate-resistant Italian ryegrass (Lolium multiflorum) (OR) population was collected from a filbert (Corylus avellana L.) orchard near Portland, OR. Based on the dose-response experiments conducted in the greenhouse, it was found that the suspected glyphosate-resistant population was approximately fivefold more resistant to glyphosate than the susceptible (S) population....
Three DCMU resistant mutants of the green alga Scenedesmus
obliquus D₃ are characterized. The mutants exhibit a ten fold
greater resistance to DCMU than the wild type strain; this is
comparable to the level of DCMU resistance detected in other
DCMU resistant algae. In whole cell reactions, as well as...
Weed resistance is usually diagnosed after a weed control practice has lost
efficacy and weed populations begin to increase rapidly. Prediction and validation in
the field at a very early stage of resistance development is a promising method for
preventing an uncontrollable problem. Pattern-thinking helped individuals connect their
experience of...
Growth of individual goosegrass (Eleusine indica (L) Gaertn.) plants of
three dinitroaniline-herbicide resistant (R) and three susceptible (S) biotypes from
North Carolina, South Carolina, and Mississippi was analyzed in greenhouse
experiments. Leaf area and biomass measurements, including root, shoot,
above-ground, and total dry weights were similar among the biotypes studied....
Resistance to acetohydroxyacid synthase (AHAS)-inhibiting herbicides has been reported in over 90 weedy species, including wild sunflower biotypes, since the herbicides were developed in 1982. The AHAS gene family in sunflower, consisting of three paralogs AHAS1 , AHAS2, and AHAS3, has been targeted for inducing herbicide resistance. A polymorphism identified...
Mayweed chamomile (Anthemis cotula L.) is an annual weed in the Asteraceae family that is commonly found in fields of the Pacific Northwest. Acetolactate synthase (ALS)-inhibiting herbicides are frequently used to control a broad spectrum of weed species including mayweed chamomile. Seeds of four biotypes of mayweed chamomile (KJ, KL1,...
Annual ryegrass, or Italian ryegrass (Lolium perenne spp. multiflorum), has been the most stable, in terms of acres, grass produced for the past 25 years in Oregon. Increased interest in Italian ryegrass as a cover crop has increased demand for quality seed. Ideal Italian ryegrass cover crop cultivars are named...