Dollar spot
Sclerotinia homoecarpa Lanzia
What is Dollar Spot (Clarireedia jacksonii)?
Dollar spot (Clarireedia jacksonii, formerly Sclerotinia homoeocarpa) is a worldwide fungal disease that affects highly managed turf. It forms small, round, bleached to straw-colored spots, ranging from 1-6 inches in diameter. In addition, it primarily infects cool-season grasses like bentgrass, fescue, and ryegrass. Moreover, symptoms include patches of blighted turf, visible white mycelium in dewy conditions, and hour-glass shaped lesions on leaves.
How does Dollar Spot (Clarireedia jacksonii) occur?
Dollar spot (Clarireedia jacksonii) reproduces through spore production and spread. The fungus survives in infected plants or debris, as well as stromata (masses of mycelium) on leaf surfaces. It becomes active in temperatures between 60-90 °F, favoring warm days, cool nights, and heavy dew. The pathogen is spread by mowers, golf carts, wind, and water. Inadequate nitrogen fertility and dry soils increase disease severity.
Symptoms
1 - Impacts on plants
Dollar spot directly affects plants, causing foliar damage, reduced photosynthesis, weakened growth, reproductive impact, and overall stress and decline.
2 - Soil Health
Dollar spots can cause thinning or dieback of turfgrass, leading to reduced vegetative cover. This can result in increased soil erosion and hinder organic matter accumulation, potentially impacting soil structure and nutrient cycling.
4 - Impact on Biodiversity
Dollar spots can influence plant species composition and diversity in turfgrass areas. Severe cases may lead to the loss of certain grass species, altering ecosystem dynamics and reducing biodiversity.
Solutions
1 - Cultural Practices
• Water deeply and infrequently, avoiding extended leaf wetness. • Remove dew and guttation fluids by mowing, rolling, or brushing early in the morning. • Maintain adequate to high nitrogen fertility with light, frequent applications. • Prune trees and shrubs to improve air circulation around the turf. • Overseed with newer cultivars that are less susceptible to dollar spot. • Consider lightweight rolling on golf greens to suppress the disease. • Explore organic fertilizers, composts, and biological control agents as potential control measures.
4 - Applications of Fungicide
• There are Many fungicides available to cure Dollere spot such as Benzimidazoles (e.g., thiophanate-methyl), demethylation inhibitors (e.g., propiconazole), dicarboximides (e.g., iprodione), carboxamides (e.g., boscalid), chlorothalonil, Emerald, Honor, Curalan, Eagle, and Torque. • Adhere to label instructions for proper application. • Avoid repeated use of fungicides from the same class or FRAC code to minimize resistance. • Consider tank mixing or alternating fungicides with different modes of action.
