Identification and Control Methods for Tulip Gray Mold

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Tulip gray mold, also known as tulip blight, is a common disease in greenhouses. The disease harms tulip leaves and flowers, causing leaf blight and flower rot.

Symptoms: When affected at the seedling stage, plants often grow curved and eventually die. Infected leaves and flower stalks produce light gray lesions with brown edges. Infected flowers produce white or light yellowish-brown lesions, which as the lesions rapidly expand cause the flowers to fall off or turn brown and dry up. Under humid conditions, the diseased parts produce a gray mold layer, which is the conidia of the pathogen. When the bulb is affected, the whole plant becomes dwarfed, the stem base and outer scales of the bulb rot, and many light black or dark brown sclerotia are produced.

Pathogen: The pathogen is Botrytis tulipae Lind., belonging to the fungi of the subdivision Deuteromycotina, class Hyphomycetes, order Moniliales, genus Botrytis.

Disease pattern: The pathogen overwinters in the soil as sclerotia, and when conditions are suitable the following year, it produces conidia that infect new plants. High air humidity is the main condition for the occurrence and spread of the disease.

Control: ① Reduce infection sources: Remove diseased bulbs before planting. During the growing period, promptly prune diseased flowers and leaves when found, and destroy them in a concentrated manner. ② Bulb treatment: Before planting, soak the bulbs in 0.3%-0.4% copper sulfate solution for 30 min, then wash with water, dry, and plant. ③ Chemical control: During the growing period, spray 50% benomyl wettable powder at 2500 times dilution, or 50% colloidal sulfur at 200 times dilution, once every 10-15 days, spraying 2-3 times.