If you are around the course today and smell a strange odor, that is a product called Bensumec. Bensumec is a pre-emergent chemical used to control Poa annua, or prevent the Poa seed from germination.
Poa annua flowers in the spring and turns to seedhead shortly thereafter. It is that seedhead that gives Poa a bad name. The seedhead in addition to the varying growth rates of Poa/bentgrass growing on the same green can create a bumpy putting surface. By early summer, that seed falls off the plants and lays dormant all summer until temperatures allow for germination. By September 1-15th, 90% of Poa annua will germinate. This is the reason it is so important to have this protective barrier in place.
It has always been my opinion that if you are serious about preventing Poa annua in your greens, this is the most important thing a superintendent can do. Again, this product does have a strong, distinct odor that will not last for long.
