INSECT, PLANT DISEASE, & WEED SCIENCE NEWS [No. 87-11] [May 29, 1987]

In This Issue: Liquid Nitrogen- Herbicide Mixes After Corn/Sorghum Emergence Safened Sorghum Seed Delayed Preemergence Herbicides Liquid Nitrogen--Herbicide Mixes After Corn/Sorghum Emergence Corn and sorghum in fields intended for liquid nitrogen - preemergence herbicide mixes sometimes emerge before herbicide application. While certain preemergence herbicides can be applied after crop emergence, they are not labeled for application with fluid fertilizer after emergence, due to risk of injury. Emerged corn is more tolerant than sorghum of fertilizer-herbicide mixtures. Some growers may accept the injury in return for accomplishing two jobs at once. Safened Sorghum Seed Sorghum seed treated with the seed safeners Concep II and Screen, is protected from possible injury from Dual and Lasso. Dual is to be used with Concep II treated seed and Lasso with Screen treated seed. Both safeners provide protection from either herbicide, however they are not cross labeled. Delayed Preemergence Herbicides Timely herbicide application is not always possible in the busy planting season. Some but not all preemergence herbicides can be applied early postemergence with good results. However, most of these treatments are more effective when applied preemergence than postemergence especially against annual grasses. A rain or sprinkler irrigation is required after application for best control. The following table lists herbicides that are commonly used in Nebraska and can be used both preemergence and early postemergence