Most lowbush blueberry clones are resistant to hexazinone at the suggested label rates. However, some are not. Sourtop blueberry is more susceptible to injury from hexazinone than is low sweet blueberry. Excessive rates of hexazinone will cause leaf drop beginning with the bottom leaves and moving to the top of the stems. Improper sprayer calibration or spray overlap will cause leaf drop when high rates of hexazinone are used.
Injury increases with higher rates of hexazinone.
Be-cause Velpar L is absorbed by the leaves as well as the roots, treating blueberries after they have emerged or leafed out will cause leaf drop and severe injury. As weeds are controlled, fewer plants are there to take up hexazinone, so injury to blueberries plants may occur. With less weed competition, blueberries will have more light, water and nutrients. The plants will increase stem density and the number of flower buds per stem. This can result in an increase in yield.