So you wake up one July morning to find your grass with spots that look like spider webs covering the yard. They could be Grass Spiders or they could be Dollar Spots.
Grass spider identification is easy because the spiders seldom leave their webs, spider webs will have a hole in the center of the web and the tiny threads will be spun in a circular pattern. The spiders like to hide in a part of the web sheltered by fallen leaves, rocks or debris. They quickly run to another part of the web when disturbed, and they can deliver a painful, but otherwise harmless, bite. Grass spiders are beneficial because they catch and eat insects that feed on lawn grass. It occurs when temperatures are between 50 – 95 degrees with high relative humidity or extended periods of leaf wetness. Early symptoms on individual leaves are chlorotic (yellow) areas that become water-soaked and later turn a bleached straw color. The fungus generally appears as small, circular spots about the size of an old silver dollar, thus the name dollar spot, even though these spots can be as large as 2-8 inches in diameter.
During early morning hours, when dew is present, you may observe on your lawn small circular patches of fungal growth on top of the leaf blades that resemble tiny spider webs. Sclerotinia homeocarpa, better known as dollar spot, is a common fungal disease that attacks most warm season turf species, but most severe on bermudagrass and zoysia. It occurs when temperatures are between 50 – 95 degrees with high relative humidity or extended periods of leaf wetness.The disease is most severe when the turf is growing slowly either from entering or leaving dormancy, or from nutritional stress particularly the lack of nitrogen.
Prevention is the best control of this disease. Good cultural practices including 1) maintaining adequate soil moisture, 2) adequate nutrition particularly nitrogen, 3) mow regularly and maintain correct mowing height, 4) prevent thatch buildup, 5) water early enough in the day to reduce overnight leaf wetness. The more you know!