These spears (images below), which were among the first to emerge in 2011, have injury (purple spotting and scoring) and consequent bending that is at least partially due to soil particles treated with the herbicide Chateau blowing onto the spears. The manufacturer’s representatives caution that it is very important to observe the label requirement of at least a two-week period between application and first spear emergence.
However, if there has not been significant rain (or irrigation) between the time of application and spear emergence, then it is possible for treated soil particles to blow onto the spears and cause injury. The manufacturer also cautions that harrowing, disking, or other practice that disturbs soil prior to Chateau application can make the problem worse. This is because there are more loose particles on freshly cultivated soil that would be susceptible to wind erosion. This problem can be temporary, decreasing or disappearing in spears emerging after the Chateau is incorporated with water. Untreated soil particles blown onto spears under dry, windy conditions can have a ‘sand-blasting effect’ and cause injury as well.
The field where these spears grew was roto-tilled before herbicide application and rain did not occur afterwards as it had in 2010. Weed control was very good in the affected field, reflecting the excellent activity of this product. (This description prepared with Weed Specialist Andy Senesac and Vegetable Specialist Sandy Menasha.)