By tank mixing additional modes of action with dicamba, growers will be able to effectively manage glyphosate and ALS-resistant Palmer amaranth and other troublesome broadleaf weeds while helping to minimize the selection of dicamba resistant weed biotypes. The ability to use either dicamba, glyphosate, or a tank-mix of both herbicides before planting or at selected periods during soybean development will allow growers greater flexibility in managing troublesome weeds in their crop management practices . A proactive approach to weed control is critical; this will slow down or prevent the selection of resistant weed biotypes. Therefore, the objective of this research was to evaluate the efficacy of selected dicamba herbicide programs for the control of Palmer amaranth and pitted morningglory in dicamba tolerant soybean. Pitted morningglory control varied significantly within treatments in 2012 and 2013 when evaluated at 2 WAP1 and 2 WAP2 compared to Palmer amaranth in study 1. This led to a treatment by year interaction being observed for 2 WAP1 and 2 WAP2 rating periods. Some experimental or environmental factors could have contributed to the treatment by year interaction observed, mainly the difference in rainfall observed between the two trial years .
Unlike in Palmer amaranth, a dicamba PRE only, controlled pitted morningglory better than a flumioxazin PRE only when rated 3 WAP . In 2012, 2 WAP1, dicamba PRE only provided marginal pitted morning glory control and in 2013, at the same rating period, control increased to 36%.Niekamp also observed that flumioxazin, while being a good broad spectrum PRE herbicide for broadleaf weed control, provided inconsistent morning glory spp. control. Treatments containing two or three herbicide applications offered good to excellent pitted morning glory control; however, the PRE followed by POST1 were slightly less effective in 2012 than 2013. In 2013,cannabis drying racks all dicamba based treatments provided excellent pitted morning glory control at 2 WAP2.Dicamba PRE alone was not as effective on broad leaf weed control in soybean compared to flumioxazin PRE only. This can be attributed to the high water solubility of dicamba and its rapid loss in the soil profile, especially in coarse textured soils . Overall, a PRE followed by a dicamba + glyphosate POST tank mix provided excellent control of Palmer amaranth and pitted morningglory in these studies. In the treatments evaluated, those containing 2 applications were similar in effectiveness as those containing 3 applications .
In terms of cost, fewer herbicide applications are more efficient and will be able to benefit growers who use these programs by reducing overall input costs. Dicamba PRE alone with no additional POST treatments provided the lowest level of weed control in these studies. Non-dicamba containing POST treatments did provide good to excellent control of Palmer amaranth and pitted morning glory. Although the treatments in these research studies showed good to excellent control of broadleaf weeds in diamba tolerant soybean, more research is needed on additional broadleaf weeds across different environments not present in the selected study locations to validate their effectiveness across a larger geographic area. Wheat is an important cereal grain crop all over the world. It is the staple food crop of Pakistan. It contributes 13.1 percent to the value added in agriculture and 2.8 percent to GDP. During 2008-2009, it was grown on an area of 9.062 million ha–1 with an annual production of 19.5 million tons of grains giving average yield of 23.421 tons ha–1 which is far below the yield level obtained in other wheat growing countries of the world. Every effort is being made to meet the wheat requirements of the country. There are many reasons for low yield of wheat crop but weed infestation is the basic and major component of low yield in crop production system. With the advent of new short stature varieties, weeds competition has become even more severe. The estimated annual losses caused by weeds may be more than 10 billions rupees in Pakistan . Because of high competitive ability and high reproductive potential of weeds, it is imperative to check their infestation. Only due to high weed infestation, average yield losses in wheat crop are about 25% – 30% in Pakistan . Weeds compete with crops mainly for light, nutrients, water and CO2 for canopy development and other growth requirements . Weeds utilize three to four times more nitrogen, potassium and magnesium than a weed free crop . reported that yield losses due to weed are in proximity of 17 – 25 percent which in terms of wheat grain comes to about 2.43 to 3.57 million tons annually.