(Bipolaris spp. and Drechslera spp.)
Leaf Spot – or “melting out” in severe cases – is a common turfgrass disease in the United States, affecting a wide range of different grass plants. In northern climates, Leaf Spot damage occurs first in the spring and again in late summer to early fall. In southern climates, the damage occurs from late spring through early winter.
Identifying Leaf Spot -
Leaf Spot can be identified by purplish-brown to black colored spots with tan centers on the leaf blades and sheaths of your turfgrass. As these dark spots or lesions expand, the center becomes lighter in color with a dark brown to black border. The lesions may also be surrounded by a yellow halo and the lower leaves can eventually become shriveled and wilted.
Severe Leaf Spot infections can cause thinning of a turf stand, or “melting out.” On cool season grasses, melting out typically follows the appearance of leaf spot.
Conditions for Leaf Spot Infection -
Leaf Spot can only lead to an infection in your lawn if all of the following conditions are present:
1.Pathogen – Leaf Spot (either Bipolaris spp. or Drechslera spp.)
3. Environment – Moist to wet climates with temperatures ranging from 40-80 degrees Fahrenheit and soils with high nitrogen levels
Cultural disease control practices create favorable conditions for a healthy lawn, and often create unfavorable conditions for the growth of Leaf Spot. Environmental conditions cannot be changed, but cultural practices performed by the homeowner can be modified to lessen the chance of extensive damage from Leaf Spot. Scotts LawnService can help determine a plan for preventing and controlling Leaf Spot in your lawn.
For Leaf Spot control and treatment, Scotts recommends the following cultural control tips: