Main insect pests and control methods of Fritillaria thunbergii

Fritillaria thunbergii in planting mainly has the following diseases and insect pests, such as gray mold, black spot, soft rot, dry rot, grub, bean turnip, golden needle worm, onion mite, Xiaobian introduces you one by one, at the same time, there are corresponding control methods.

(1) Grey mildew:

Is a disease caused by fungi. After the onset of the disease, light brown spots appeared on the leaves first, and then expanded into oval or irregular disease spots, with obvious watery rings on the edge, constantly expanding to form gray spots; after the flower was killed, the flower shrunk could not blossom, and the flower stalk shrunk, showing light green; the young fruit was killed in dark green and dry, and after the larger fruit was killed, there were dark brown spots on the pericarp and wings, constantly expanding and gradually withering. The injured part can grow gray mildew under the condition of suitable temperature and humidity. Generally, it began to occur from late March to early April, and occurred in mid-April, causing serious harm. The disease overwintered with conidia on the stump of the diseased plant or produced sclerotia and fell into the soil, which became the source of the first infection in the second year.

Prevention and control methods:

After harvest of ① Zhejiang shellfish, the damaged plants and diseased leaves should be removed and burned so as to reduce the pathogen of overwintering.

The land with serious incidence of ② is not directly replanted.

③ should strengthen field management, apply fertilizer reasonably and enhance the disease resistance of Fritillaria thunbergii.

Before the onset of ④, Bordeaux solution was sprayed with Bordeaux solution at the end of March, once every 7 to 10 days for 3 consecutive 4 times. In the initial stage of the disease, 25% wettable powder carbendazim can be sprayed with 100g / mu 500 × 1000 times of carbendazim per mu; re-spray once after 7 days, twice in a row. Or spray 50% methyl topiramate 1000 times during the onset of the disease. In the prevention and control of soft rot and dry rot, attention should be paid to digging drainage ditches during the summer; soaking seeds with 1000 times solution of 50% benzimidazole for 15 minutes, drying and then planting; selecting disease-free insects and pain scar phosphorus stems as seeds. In case of harm to bean turnips, spray with 1500 times of 90% crystal trichlorfon or 800-1500 times of 40% dimethoate emulsion.

(2) Black spot: disease caused by a fungus. The disease begins from the tip of the leaf, the color of the leaf becomes lighter, and there are water-stained brown disease spots, which gradually spread to the leaf base. some of them do not develop to the base of the leaf because of the environment, and there is a clear boundary between the disease part and the healthy part. generally, the damage began to occur in late March until the underground part of Zhejiang Fritillaria withered and died. For example, the damage was more serious when the spring rain continued before and after the Qingming Festival. Zhejiang shellfish black spot overwintered on the damaged plants and diseased leaves with hyphae and conidia, and was infected again in the second year.

Prevention and treatment: the same as gray mold.

(3) soft rot: a disease caused by pathogenic bacteria. The damaged part of the bulb begins to look like a brown water stain and spreads very quickly. After the damage, the bulb turns into a dreadful bean curd or a sticky "snot"; sometimes it stops harming, and when the surface loses water, it becomes a hole that looks like an insect bite. The boundary between the rotten part and the healthy part is obvious. The epidermis often does not suffer, after the internal soft rot shrinks, leaving an empty shell, the rotting bulb has a special sour taste of wine.

Prevention and control methods: comprehensive control measures must be taken for the prevention and control of rot and soft rot.

① chose robust and disease-free bulbs as seeds. If the soil is stored for the summer, it should be divided into stalls, spread out and stored.

② chooses to plant on sandy soil with good drainage and creates good summer conditions.

③ chemical control: with the use of various fungicides and acaricidal Liu, soak the seeds before seeding. For example, soaking seeds with 20% wettable triclofenac 800 times plus 80% dichlorvos emulsion 2000 times and 40% Kemiansan emulsion 1000 times mixture for 10 minutes before seeding has a certain effect, but the experiment needs to be continued to find more safe and effective chemical control measures.

④ control mites, grubs and other underground pests, eliminate vectors, prevent transmission of bacteria, in order to reduce the harm.

(4) dry rot:

It's a disease caused by fungi. During the summer from June to August, the bulb occurred in the dormant period of Fritillaria thunbergii bulb and soil drought. The bulb base was honeycomb after being damaged, and the scale was brown wrinkled after being killed. After the bulb is planted, the root is dysplastic, the plant withered early, and the new bulb is very small. The main manifestation of dry rot in the suburbs of Hangzhou is that the base of the damaged bulb is bluish black, the inside of the scale rotts to form black spot cavity, or the black brown and cyan spot cavity is formed on the scale. Some vascular bundles of bulbs were injured, and brown dots could be seen in the cross section of the scales.

Control methods: during the summer conservation period, Fritillaria thunbergii is not suitable for interplanting on the ground or dug up too early, so it should be planted reasonably to create a cool, ventilated and dry environment for dormant bulbs; to control underground pests and avoid diseases caused by pests; for diseased species, soak the seeds with 50% carbendazim 400 times 600 times solution for 10 minutes before planting, slightly dry and transplant bulbs.

Insect pests:

The main underground pests are grubs, golden needles and so on. For the damage period is the dormancy period of the seed stem, 90% trichlorfon 1000-1500 times liquid can be used to irrigate.

(5) grub: it is a beetle larva, also known as "white silkworm". Body white, head yellow or yellowish brown. The main damage to the bulb of Fritillaria thunbergii is the larva of Anomald corpulenta motschulsky. Other beetle larvae are also harmful.

The adult copper green beetle is 1.8 cm 2.1 cm long, copper green, the edge is yellow, the base of the foot is yellow, there are two teeth on the outside of the tibial segment of the forefoot, and there are no teeth on the claws; the mature larva is 2.3 cm long, the head is yellow brown, the chest and abdomen is milky white, the anus is zigzag, one groove is cracked, there are two bristles in front of the center, and there are many irregularly arranged bristles around. Big black beetle larva anus three-lobed, in front of a group of flat shape. Bristles with hooked ends. The black velvet beetle larva has a longitudinal anal fissure with a row of slightly curved setae in front of it.

The grub began to harm the bulb of Zhejiang shellfish in the middle of April, and the damage was the most in the overrecovery period, and stopped after the middle of November. The killed bulb is dotted or rugged, like a rat gnawing on a sweet potato. Sometimes the bulbs are bitten to pieces. The adults appear in the middle of May and are active in the evening. The eggs are scattered in the wetter soil and like to lay eggs on the immature barnyard manure.

Prevention and control methods:

① clears weeds in winter, turns deep into the soil, and eliminates overwintering insects.

② applied rotten barnyard manure, compost and soil cover manure to reduce adult oviposition.

The larvae were picked up as feed for chickens and ducks when ③ was turning over the ground.

④ lit a lamp to trap and kill adult beetles.