Q How do I recognise dollar spot?
A The disease kills affected leaves, producing groups of small, roughly circular dead patches up to 10cm across. In the early stages the leaves develop pale-brown spots then the whole leaf turns straw-coloured.
Caption: Dollar spot usually occurs in the autumn
Q Could I mistake dollar spot for anything else?
A Dead patches in lawns can have many causes. Dollar spot is most likely to be found in close-mown lawns containing red fescue, which is highly susceptible to the disease. The dead areas are smaller than those produced by most other problems.
Q What damage does dollar spot do?
A Dollar spot usually only kills the leaf blades, so the plants generally recover when conditions are less favourable for the disease.
Q What is the life cycle of dollar spot?
A The dollar spot fungus rarely produces spores and survives as a resting mycelium of invisible, thread-like tissues in the thatch. In humid weather grass leaves exude droplets of sap overnight, and this provides nutrients for the fungus and stimulates it to grow.
Q When do dollar-spot attacks occur?
A It's most likely to appear in autumn when the weather is mild and damp.
Q How do I control an attack of dollar spot?
A The disease spreads more quickly in damp conditions, so brushing dew off affected areas to help them dry out more quickly should reduce its advance. There is no chemical treatment available.
Q How do I prevent dollar spot in future?
A Dollar spot tends to appear when grass is weakened by dry soil conditions or lack of nutrients, so good maintenance will help to prevent it. Pruning back overhanging trees and shrubs to reduce shade, so the grass dries out more quickly on autumn mornings, is also worthwhile.