Which of the following is a root-infecting turf disease?

• A. Necrotic ring spot
• B. Take-all patch
• C. Summer patch
• D. Fairy ring

Answer: (B)

Root-infecting turf diseases attack the plant at its underground connection points—the roots and crowns—so the grass loses its ability to take up water and nutrients. Take-all patch is the classic example of this type. The fungus colonizes and decays the roots and crowns, leading to thinning patches in the lawn. Often the below-ground damage precedes obvious leaf symptoms, so patches can appear to develop despite relatively normal green blades at first. You may also see dark, decayed roots and sometimes a white or cottony fungal growth around the crown under moist conditions. This below-ground focus is what makes it a root-infecting disease, distinguishing it from disorders that mainly show above-ground foliar symptoms or non-root growth in the thatch, like necrotic ring spot or fairy ring.