How to handle spring lawn pests and diseases?

Check your thatch layer annually and dethatch if it exceeds half an inch. Maintain mowing height at the upper end of the recommended range for your grass type. These two cultural practices form the foundation of disease prevention.

Keep spring nitrogen rates moderate (under 0.5 lb N per 1,000 sq ft), avoid watering in the evening, and do not mow below the recommended height for your grass type. These three practices dramatically reduce brown patch risk.

Maintain a consistent nitrogen fertilization schedule and water only in the early morning. Dollar spot is most common on under-fertilized, drought-stressed lawns that stay wet overnight.

When melting snow reveals circular patches of matted, gray-white or pinkish grass, gently rake the affected areas to break up the matted turf. Apply a light dose of nitrogen fertilizer (0.25-0.5 lb N per 1,000 sq ft) to encourage new growth into the damaged areas.

If the float test confirms chinch bugs, apply a bifenthrin-based granular insecticide (such as Talstar) at the label rate to affected areas and a 5-foot buffer zone around them. Water in lightly. If retreatment is needed, switch to a different active ingredient.

Chinch bugs live at the base of grass plants and are easily missed. The float test forces them to the surface where they become visible. They pierce grass blades and suck out plant juices while injecting a toxin that blocks the plant's vascular system. Damage mimics drought stress — irregular…

If grub counts exceed 5 per square foot, apply trichlorfon (sold as Dylox or Bayer 24-Hour Grub Killer) immediately. Water in heavily — at least half an inch — within 24 hours of application to move the product into the root zone.

Not all brown patches are caused by grubs. The peel-back test and grub count provide a definitive diagnosis and help you decide whether treatment is justified. Below 5 per sq ft, healthy lawns can typically tolerate the damage without treatment.

Purchase Heterorhabditis bacteriophora nematodes from a reputable supplier. Apply in late July to early September when grubs are small and soil temperature is above 50°F. Water the lawn thoroughly before and after application. Apply at dusk or on an overcast day.

Apply Scotts GrubEx (chlorantraniliprole 0.08%) or equivalent between April 1 and May 30 at the label rate. Water in lightly after application. This prevents the next generation of grubs from establishing in summer and fall.