I'm Baaaaaaack!

By Christopher Hartwiger and Patrick O'Brien, USGA Green Section SE Region
September 16, 2004

	Cool August conditions were prime for Poa annua germination. This photograph was taken on August 23, 2004.

The unseasonably cool conditions experienced in mid-August in the Southeast were most appreciated by creeping bentgrass greens and those who manage them. The night time temperatures in the mid-50's also were prime germination time for our yearly uninvited guest, Poa annua. The picture was taken on a Turfgrass Advisory Visit on August 23. Look at the development!

An informal survey of golf courses taken over the past three weeks has revealed that more than half of all golf courses applied their fall preemergence herbicide application after the onset of cool temperatures. At these courses, it is likely that a substantial amount of Poa annua has germinated and will not be controlled by the preemergence herbicide. At this time of year it can be difficult or impossible to see young Poa annua seedlings beneath the bermudagrass canopy, but be sure that they will be noticeable by early winter. The bottom line for those applying their fall pre-emerge a little late this year - do not blame the preemergence herbicide for high Poa annua populations this winter and begin mapping out a post-emergence strategy now.

Source: Patrick O'Brien 770-229-8125 or patobrien@usga.org and Chris Hartwiger 205-444-5079 or chartwiger@usga.org