Diseases and Pests of Danshen: Control Methods and Technical Key Points
Danshen Sclerotinia Rot
This is a fungal disease. The pathogen first attacks the base of the stem, the buds, and the rhizome, causing these parts to gradually rot and turn brown. On the surface of the diseased parts, the nearby soil surface, and the interior of the stem base, grey-black sclerotia resembling mouse droppings and white mycelium often develop. At the same time, the stems and leaves of the upper part of the diseased plant gradually turn yellow, and eventually the plant dies.
Control methods:Do not collect seedlings from plots where Sclerotinia rot has occurred; practise crop rotation, and plots that have had the disease should not be replanted with the same crop, but can be rotated with rice; for chemical control, when scattered cases first appear, use 50% dichloran wettable powder 0.5 kg plus lime 7.5-10 kg, and broadcast it on the stem base of the diseased plants and the surrounding soil surface. However, after application, wait at least 10 days before digging up the rhizome, to ensure medicinal safety.
Danshen Leaf Spot
This is a bacterial disease that damages the leaves. The leaves of affected plants bear nearly round or irregular dark brown lesions, and in severe cases the lesions enlarge and merge, causing the leaves to wither and die. It generally begins in May and continues until late autumn.
Control methods:Clean up the field and bury diseased and dead plants deeply; pay attention to drainage; improve ventilation and light conditions.
Danshen Root Rot
This disease can occur throughout the entire growth period. The roots of affected plants are damaged and rot, and the above-ground parts gradually wither and die.
Control methods:Choose high, dry plots for planting, pay attention to drainage and flood prevention, and do not let water accumulate in the field; do not practise continuous cropping; select disease-free planting material; in the early stage of the disease, drench the roots with a 500-800 times dilution of 50% thiophanate-methyl.