Gulf Zone

St. Augustine Lawn Calendar

Preemergence Weed Control

Preemergence herbicides must be applied prior to germination to be effective on targeted weed species. Sequential applications improve control over single applications and applications should be watered-in to maximize control and limit off-site movement.
Crabgrass, sandbur, 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. Spring applications of Specticle^® FLO or Echelon^® can prevent germination of summer grassy and broadleaf (BDLV) weeds.
Winter annuals like annual bluegrass, chickweed, and henbit germinate in the fall. Fall applications of Specticle FLO or Echelon can prevent germination of winter grassy and BDLV weeds with late summer/early fall applications at 4” soil temperatures at 70°F.

The most flexible and effective control for annual bluegrass is with a combination of pre- and postemergence herbicides in the fall.
The Dual Defense program combines Specticle FLO and Celsius^® with applications timed for mid-September to mid-October to prevent germination and control young annual bluegrass plants that have already germinated.

Summer and winter grassy and BDLV weeds are best controlled by postemergence herbicides when plants are small but actively growing.
Summer annual grassy and BDLV weeds are best controlled in late spring/early summer with Celsius, Celsius XTRA or Blindside^®.
Winter annual grassy weeds and BDLV weeds are best controlled in fall or early spring with Celsius, Blindside or Xonerate^®.
Sedges and kyllingas emerge primarily in spring. Dismiss^®, Blindside or Celsius XTRA are all effective, but herbicides for these sedges usually require multiple applications for most effective 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 chinch bugs throughout the summer with soap flushes or watch for insect damage that mimics drought stress. Applications of Triple Crown or Talstar can provide quick knockdown and residual control (Triple Crown) of chinch bugs throughout the summer.
Fire ant mounds can be unsightly, and their stinging makes them a human nuisance while mole crickets can cause significant damage to turf. TopChoice^® is the industry standard for season-long control of existing fire ant populations and mole crickets.

Large patch typically develops with high soil moisture and when 2” soil temperatures decline to below 70°F. Applications of preventative fungicides, like Armada^® or Fame^®, in the fall when conditions are conducive for disease development.
Take-all root rot (TARR) can develop starting earlier in the summer with 2” soil temperatures at 77-86°F, which is when preventative fungicide applications of Armada or Fame should be made for optimum control.
Gray leaf spot (GLS) can cause significant damage to turf and develops at temperatures between 70-95°F under prolonged leaf wetness. Applications of Armada or Fame should begin prior to disease development for optimum control.

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