Did cold weather affect herbicide performance?
Chickweed is the dominant weed in this picture. Some farmers across the country are reporting poor herbicide performance this season in spring crops. Difficult to control weeds such as chickweed and speedwell are of particular concern. In some fields, weeds appeared stunted after herbicide application, but a full kill was not achieved in some cases. Cold weather and label rates should be watched carefully. Frost at the time of herbicide application may have contributed to poor uptake and effectiveness. Plants need to be actively growing when herbicide is applied. The issue not only highlights the importance of timing, but also the need for careful attention to be paid to rates. Some products containing fluroxypyr saw rates decreased on labels in recent years  Fluroxypyr can be used to control chickweed, some of which is resistant to sulphonyl urea products. It is an important product to safeguard. Full rates of the product are recommended to avoid resistance buildup and ensure good control. Some products containing fluroxypyr saw rates decreased on labels in recent years. Farmers should check fields for herbicide success and note which products worked and did not work and then consider the rates and the timing of the application used. It is also important to note weeds which appear at harvest time. If chickweed, for example, has returned at harvest and herbicide was applied at the correct timing, a change in product or higher rate may be needed. We have seen how resistance to plant protection products has affected grass weed control and indeed fungicides. Protection of chemistry is important.