The wide-spread adoption of glyphosate resistant crops coupled with over-reliance on glyphosate and inadequate diversity in weed management tactics in GRCs have resulted in weed species shifts. Weed species shifts refers to a relative change in weed population or species along with late season weed emergence in an agricultural system in response to weed management tactics . Weed species shifts in GRCs are a result of weeds that have escaped control because of a natural high level of tolerance to glyphosate or glyphosate avoidance from late-emerging cohorts. Glyphosate avoidance through late-season emergence is a mechanism by which some species are increasing in prominence. Emergence of weeds late in the cropping season has become a problem in GRCs . This is due to elimination of competition from early-season weeds controlled by glyphosate, the absence of residual control with glyphosate alone, and the decision by producers not to use a residual herbicide that will extend weed control later into the cropping season.
In the southern US, soybean is usually harvested during August. The long time period between harvest and killing frost provides a favorable environment for certain weeds to emerge and complete a life cycle . Emergence of grasses such as brown top millet , Digitaria spp. , and jungle rice late in the season has become a problem in glyphosate-resistant soybean production in the southern US, where soybean is harvested beginning in August. The time between harvest in August and frost provides a favorable environment for these grasses to emerge, establish, and replenish the soil seed bank. To reduce the risk of late-season weeds and to sustain crop yields, it is imperative to develop and improve strategies to manage these weed shifts using pre-emergence, post emergence,and post-harvest applications of herbicides.Pyroxasulfone is relatively a new herbicide used for control of many grass and some broadleaf weeds in corn , wheat , and soybean . It can be applied from fall through early preplant, PRE to early POST. Pyroxasulfone has been investigated for broad-spectrum weed control in several agronomic crops. It is comparable to other common PRE residual herbicides such as acetochlor, dimethenamid, and S-metolachlor in controlling broadleaf signal grass.However, its efficacy on late-season grass weed control in twin-row glyphosate-resistant soybean is lacking. Therefore, the objectives of this study were: 1) to determine the efficacy of pyroxasulfone as pre-emergence herbicide for control of late-season grass weeds and 2) to determine the efficacy of pyroxasulfone-based in-crop and post-harvest herbicides on late-season grass weeds and yield in twin-row glyphosate-resistant soybean.
Cannabinoid hyperemesis syndrome is associated with cannabinoid overuse. According to the United Nations, in 2017, an estimated 238 million people used cannabis in 2017, 22% percent of that total are users in North America, making it the most widely used drug globally . Cannabis-induced adverse drug effects increased with its increased access and in 2004, CHS was recognized as a new medical diagnosis . CHS is characterized by chronic cannabis use, cyclic episodes of nausea and vomiting, and the learned behavior of hot bathing to relieve symptoms . The clinical characteristics and appearance can be divided into three phases: the prodromal phase, the hyper-emetic phase, and the recovery phase . The prodromal phase can last months to years with recurrent symptoms of early morning nausea, fear of vomiting, and abdominal discomfort . This phase also includes a normal eating pattern with increased use of cannabis to alleviate nausea. The hyper-emetic phase consists of persistent vomiting that could be debilitating with weight loss of up to 14 kilograms and compulsive warm bathing to relieve symptoms of nausea and cannabis vomiting. The recovery phase follows a complete halt to use, with a total resolution of symptoms within 12 hours to 3 weeks, a return of normal eating pattern, weight gain, and recurrent hot bathing habits.Pharmacological treatment of CHS can be divided into two phases: therapy for the hyper-emetic phase and relapse prevention. Patients may require hospitalization during the hyper-emetic phase secondary to abdominal pain, dehydration, as well as severe nausea and vomiting.