How to prevent and treat tulip leaf blight? A few practical methods to teach you
Symptoms: Infected leaf buds develop poorly, appearing deformed and curled; once young buds are affected, the leaves that grow from them become curled. If the environment is humid, a large number of gray mold-like conidia are produced on the diseased tissue, spreading to nearby healthy plants and causing leaf infection, so bulb growth is greatly affected.
After flowers are affected, white or light yellowish-brown lesions first appear, then rapidly expand and cause the flowers to wither and drop, or turn brown and dry up. Ring-like bands also appear on the flower stalk, sometimes with a layer of conidia on them. At every stage of the disease, flowers are highly susceptible to infection. Sclerotia form on the outer shell of diseased bulbs, or circular to oval sunken spots appear on the outer scales, grayish-yellow in the center with brown edges, containing one to several sclerotia. Pathogen: Botrytis tulipae Lind. [BotrytistulipaeLind.], belonging to the subphylum Deuteromycotina, commonly found in tulip-growing areas, and more severe in the rainy season. Its conidiophores bear colorless or gray conidia; the sclerotia are black, 1-2 mm in diameter, with a flat surface, round or oval.
Transmission route: Mycelium and sclerotia remain in decayed bulbs and soil to overwinter. After diseased bulbs are planted, large numbers of conidia are produced on the killed young shoots, which are the source of infection for aboveground disease.
Disease conditions: The pathogen can produce conidia at 5°C and humidity of 90%-100%. The disease is severe when spring temperatures are low and there is much rain and humidity.
Prevention and control methods:
1. Remove diseased bulbs before planting and practice crop rotation.
2. Once buds or flower buds showing symptoms of this disease are found, remove them immediately to control the development of the disease.
3. Before planting, soak the bulbs in a 2% formalin solution for 30 minutes, then dry them before planting to reduce remaining pathogens.
4. During the growing period, spray 50% iprodione 1000-fold solution or 50% procymidone 2000-fold solution or 50% dimethirimol 1000-fold solution.