Transition Zone

Cool-Season Lawn Calendar

Preemergence Weed Control

Preemergence herbicides (products including containing prodiamine, dithiopyr, and pendimethalin) must be in place prior to germination to be effective on targeted weed species. Sequential split-applications improve control over single applications and water-in applications to maximize control and limit off-site movement.
Crabgrass, prostrate knotweed, or spurge germinate in spring, so preemergence herbicide applications should be timed prior to 4” soil temperatures of approximately 55°F for five days.
Winter annuals like annual bluegrass, chickweed, and henbit germinate in the fall and preemergence herbicides should be applied late summer/early fall when soil temperatures at 4” decrease to 70°F.

Summer and winter grassy and broadleaf (BDLV) weeds can be controlled by postemergence herbicides and are most effective when plants are small but actively growing.
Applications of Terradex™ Crabgrass and Broadleaf, Terradex Power Premix or Acclaim^® Accelerate starting in the spring will provide control of summer BDLV weeds.
Control of summer grassy weeds can be achieved with applications of Acclaim Accelerate, Acclaim^® Extra, Terradex Crabgrass and Broadleaf or Solitaire^® starting mid-spring and through the summer.
Perennial or winter BDLV weeds are best controlled in late fall and early spring with applications of Terradex Power Premix.
Sedges, nutsedges, and kyllingas emerge primarily in spring. Applications of Dismiss^® or Dismiss^® NXT are most effective applied shortly after emergence and usually require multiple applications for optimal control.

White grubs are usually controlled with preventative applications made at the first sign of adult flight in the spring. New formulations like Durentis™ allow flexible timing of applications well before white grub adults appear and provides lasting control. Merit^® has been the industry standard for white grub preventative control. Though curative applications are usually inefficient, Dylox^® is the industry standard and provides quick knockdown of white grubs.
Applications of Durentis should be made in the spring (at first sign of adults) for season-long control of caterpillars including fall armyworms, cutworms, and sod webworms. Certain products can provide quick knockdown of caterpillars like Talstar^® (no residual) or Triple Crown^® (some residual control).
Monitor for adult billbug activity in early spring and time preventative applications of Tetrino^® or Merit for mid-spring (April/May) prior to egg laying.
Fire ant mounds can be unsightly, and their stinging makes them a human nuisance. TopChoice^® is the industry standard for season-long control of existing fire ant populations. TopChoice is a restricted use product; refer to label for more information.

Preventative fungicide applications are most effective when combined with proper cultural practices. Limiting leaf wetness durations by avoiding evening watering is crucial to minimizing incidence and severity of most diseases. Apply fungicides prior to disease development for optimal control.
Fairy ring develops in the spring and preventative applications of Armada^® or Fame^® should be made when soil temperatures at a 2” depth reach 55-65°F. Include a wetting agent and water in fungicides to maximize control.
Brown patch can to develop when night temperatures exceed 60°F during hot/humid weather and. Preventative fungicide applications of Armada or Fame should be initiated when night temperatures consistently exceed 60°F in late spring/early summer.
Gray leaf spot is most active when temperatures are between 82-90°F. High relative humidity is also required for infection. Areas in the lawn that hold dew longer (such as shade) will likely be impacted first. Preventative fungicide applications of Armada should be initiated when night temperatures consistently exceed 75°F in mid-summer.

Mosquito control can be accomplished in early spring with larvicides (methoprene, pyriproxyfen) applied to standing water or adulticides, like Scion^® or Talstar, applied as barrier treatments late spring through the fall.