Dollar spot of lawn

Disease Information

Dollar spot

 Sclerotinia homeocarpa

 

Dollar spot can infect most turfgrasses, including Kentucky bluegrass and creeping bentgrass putting greens. Although the disease can develop under any growing conditions, it primarily attacks nitrogen-deficient

turf when daytime air temperatures reach 59 to 86 F, followed by cool evenings and heavy dew.

Symptoms

Infected turf produces bleached white spots about the size of a dime, which can increase to the size of a silver dollar and eventually coalesce to produce large patches. Cottony myceliu m often are visible on infected turf in the morning, especially if dew is present. Leaf constriction approximately half way up the blade and a bleached hourglass-like spot with a black or red margin are noticeable with the naked eye. The fungus lies dormant in thatch and soil until environmental conditions are right, then it infects the turfgrass if adequate leaf moisture is present.

COMMENTS on disease

Primarily a foliar disease, the fungus produces a toxin that can kill the crown of the plant and even the roots during a severe infection.

Management

 Many fungicides are available that are effective in preventing or curing

dollar spot. However, infections on residential lawns are rarely severe enough to warrant chemical control.

 

Chemical control

 Banner Maxx (propiconazole),

Daconil Ultrex (chlorothalonil), Eagle (myclobutanil)

and Bayleton 25WP (triadimefon).

                                                      

Cultural methods

 Provideadequate nitrogen fertility, water deeply and infrequently,

avoid prolonged leaf wetness by watering in the morning, prevent thatch buildup and use resistant turfgrass cultivars.



Share this article