Thoroughly examine the crevices and cracks of any buds for fungus. Look at the core to see if there are any signs of rot. If the core has a soggy brown appearance, remove the plant, place it into a bag, and separate it from your other plants to prevent contamination.
Examine other plants to see if there are similar symptoms. Be on the lookout for the development of a dusty gray webbing with white spores. Spores travel easily outdoors due to pollinators, water and wind. Even in indoor grow rooms, spores are extremely difficult to control.