Northern Zone

Cool-Season Lawn Calendar

Preemergence Weed Control

Preemergence herbicides (prodiamine, dithiopyr or 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.

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 Acclaim^® Accelerate, Terradex™ Crabgrass and Broadleaf, or Terradex Power Premix starting in the spring will provide control of summer BDLV weeds.
Control of summer grassy weeds can be achieved with applications of Acclaim Accelerate or Acclaim^® Extra, or Solitaire^® starting mid-spring and through the summer.
Perennial or winter annual BDLV weeds are best controlled in late fall or spring with applications of Terradex™ Quickstrike or Terradex Power Premix.
Nutsedge 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) and also curative control of chinch bugs.
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.

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.
Brown patch occurs during hot/humid weather and can begin to develop when night temperatures exceed 60°F. Symptoms include circular patches that are brown, tan, or yellow and can coalesce to affect large areas. 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 can develop between 70 and 95°F but requires at least 14 hours of continual leaf wetness for infection. Symptoms initially appear as tan color spots on the leaves with a dark brown border. Gray and fuzzy spores may be visible under extreme conditions, which will result in leaf tip dieback. Applications of Armada or Fame should be initiated in mid-June/early-July for most locations.

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