Pest and Disease Control Methods and Techniques for the Chinese Medicinal Herb Fritillaria thunbergii
Diseases
Soft rot: Occurs during the summer dormancy of the bulbs from June to August. It initially appears as brownish water-soaked lesions, quickly turning into a tofu-dregs-like or paste-like rot with a sour, alcoholic odor.
Control methods: Dig drainage ditches properly during the summer dormancy period; soak the seeds in 50% benomyl 1000x solution for 15 min, then dry them before planting, which gives relatively good results.
Dry rot: Generally occurs during the summer storage period for seed bulbs, and is severe when the soil is dry. It mainly damages the base of the bulbs. Dry rot has two symptom types: one is that the affected bulb becomes honeycomb-like, with the affected scales appearing brown and wrinkled; the other is that the base of the affected bulb turns bluish-black, and the scales rot to form cavities or form dark brown or bluish cavities of varying sizes. The vascular bundles of the bulb are affected, and a brown ring appears on the cross-section.
Control methods: Control methods: Select robust, disease-free bulbs as seed; practice rational intercropping during the summer storage period to create a cool, ventilated environment; before planting, soak the affected seed bulbs in 50% thiophanate-methyl 300-500x solution for 10-20 min.
Fritillaria dry rot: 1. Cross-section of a healthy bulb 2. Healthy bulb 3. Cross-section of a diseased bulb
4. Diseased bulb 5. Pathogen
Gray mold: Also known as "early blight" and "green rot." It generally occurs from late March to early April, with peak incidence in mid-April, damaging the aboveground parts. After infection, the leaf lesions are light brown, long-oval or irregular in shape, with water-soaked halos at the edges. When humidity is high, gray mold-like growth appears; the stem lesions are gray, the flowers shrivel and fail to open, and the young fruits dry up and turn dark green.
Control methods: Practice crop rotation; increase P and K fertilizer application to enhance disease resistance; prevent waterlogging to reduce field humidity; before disease onset, spray 1:1:100 Bordeaux mixture as a preventive measure; remove and burn diseased plant debris and leaves; at disease onset, spray 50% carbendazim 800x solution or 50% thiophanate-methyl 1000x solution.
Black spot: First appears in early April, and is especially severe when there is abundant rain. It damages the leaves.
Control methods are the same as for gray mold.
Pests
White grubs: The larvae of the copper-green chafer. They damage the bulbs, beginning in mid-April, with the most severe damage during the summer dormancy period.
Control methods: Practice paddy-upland rotation; clear weeds in winter and plow the soil deeply; use light traps to kill adult copper-green chafers.
Onion mites: They damage Fritillaria thunbergii bulbs, mainly during the summer dormancy period.
Control methods: Select seeds strictly, and pick out the rotting, mite-infested bulbs; after harvesting, store the bulbs spread out indoors for 7-10 days, so that the mites die in the dry environment or leave the bulbs. Before sowing, soak the seeds in a mixture of acaricide/insecticide and fungicide; the method is the same as for dry rot and soft rot.
Saw-horned bean blister beetle: The adults bite and eat the leaves, and in severe cases the leaves of whole patches of plants are eaten bare. Control methods: Taking advantage of the adults' gregarious behavior, capture them promptly with nets; spray with 90% crystalline trichlorfon 1500x solution or 40% dimethoate emulsifiable concentrate 800-1500x solution, or use 5% carbaryl powder.
The grooved wireworm is commonly called the "click beetle." Its body is flat and leathery, needle-like, with a forked and slightly upward-curved anal segment, and a longitudinal groove down the middle of its back, hence the name grooved wireworm. The grooved wireworm damages bulbs in the soil, and holes about 0.2 cm in size are commonly seen on the scales.
Control methods: Change the living conditions of soil pests, turn the pests out onto the soil surface so that they die from natural enemies and environmental influences. When wireworms pupate, destroying the pupal chambers can cause mass mortality.