We asked experts from two pesticide manufacturers: 2015 was the hottest year on record, continuing a recent trend of warmer weather. Assuming the warm weather continues, what impact will it have on weed control on sports turf? Could more Northern fields begin to see more Southern weeds?

Kyle Miller
Senior Technical Specialist
Professional and Specialty Solutions Ornamental Products (Northern U.S.) / BASF

“With the trending warmer weather, I believe we see a few things happening with regard to weed populations.

Milder winters allow perennial tropical/Southern weeds like bermudagrass to persist when in the past the cold would keep plants from surviving in Northern climates. This means weeds that have not been a problem in the past may now be a new target for field managers. With the warmer summer temperatures, it means Southern weeds will have a longer growing season in Northern climates, helping them to persist by increasing weed density and ultimately providing greater weed seed dispersion.

A good example of this would be goosegrass, which normally has a very short growing season as we move northward, limiting its spread.”

Lane Treadway
Field Technical Manager
Syngenta

“With warm-season turf, heat will help produce dense turf that will choke out weeds. With coolseason turf, it is important to make sure that a solid herbicide program is in place as prolonged heat is likely to thin the turf, giving weeds a chance to emerge.

Regardless, weeds do not significantly evolve after just one year of warmer weather. Changes in herbicide-use patterns, cultural practices or resistance issues are much greater contributors. Warm and wet conditions will promote Poa annua to become well established and it will also break down preemergent herbicides quicker so field managers should be mindful not to stretch applications.”