Control techniques of Violet Diseases and insect pests

Violet is native to southern Europe and the Mediterranean coast. It is often introduced in big cities in southern China. In the north, it is planted in garden flower beds or greenhouses for ornamental use. It is often harmed by diseases and pests in cultivation. The main diseases are Violet Fusarium wilt, Violet Verticillium wilt, Violet white rust and Violet mosaic disease. Let's take a look!

Downy mildew

[incidence characteristics] Violet downy mildew was found in Zhongshan Park in Shanghai, which caused leaf sagging and even the whole plant to die. There are green spots on the surface of the diseased leaves, and then they turn into yellow thieves, without obvious edges, and become angled members limited by the veins of the leaves. There is a white frost layer on the back of the corresponding leaves. Tender shoots and flowers can also be infected, resulting in plant dwarfing or deformity. The pathogen overwintered with eggs in the soil and in the residual tissue of the diseased plant. The next spring began to germinate and the first infection was carried out. Too dense sowing and poor drainage are easy to cause serious disease.

[prevention and control methods] to avoid cutting Huan for too long to remove diseased plants in time, Shanghai pesticide widely trial-produced a new fungicide subpound acid ethyl A3, the concentration is 2-3 grams per liter of water.

Fusarium wilt

[characteristics] Fusarium wilt is caused by Fusarium oxysporum. The main symptoms are plant dwarfing and wilting. The young plants produced obvious veins on the leaves and caused the leaf sagging on the larger plants.

[control method] the seeds can be soaked with 50-55 ℃ warm water for 10 minutes, which can kill the germs carried by the seeds. The soil used for planting violets should be disinfected and reused. The medicament can be used with 1000 times potassium permanganate solution. If seriously infected plants are found, they should be removed and burned immediately to prevent transmission to other healthy plants.

Verticillium wilt

The symptoms were yellowing and wilting of the lower leaves of the plant. The diseased plant was seriously dwarfed and the tissue of bundle management changed color rapidly.

[control method] same as Violet Fusarium wilt.

Violet white rust

[characteristics of the disease] caused by white rust, the diseased part of the Violet plant turned yellow after infection and brown in the later stage. Chains of colorless spores are produced under the epidermis of the leaves.

[control methods] Violet white rust is also seriously harmful to other cruciferous plants. If violets are placed together with other cruciferous plants, they will infect each other, so the weeds of Cruciferae should be eradicated and isolated from other cruciferous plants. Violet plants should be sprayed with Baume 3-4 degrees stone-sulfur mixture to prevent the disease, and 65% zinc wettable powder 500-600 times should be sprayed according to the growing season. Or rust sodium 250 times 300 times the solution to control.

Mosaic disease

[characteristics] Mosaic disease is caused by Daphne genkwa mosaic virus, also known as cabbage virus 1. The virus is transmitted by 40 and 50 species of aphids, mainly peach aphids and vegetable aphids, and can also be transmitted through juices. The virus can harm many cruciferous plants and other non-cruciferous plants. Therefore, it should be isolated from these plants.

The paging symbol [control method] should be isolated from other poisonous plants, and aphids should be eliminated in time. 1.2% nicotinine 2000-4000 times or 10% imidacloprid 2000 times can be sprayed and controlled.

Violet blight

[disease characteristics] Violet leaves show large round disease spots, soft rot when wet, bluish white when dry, and easy to crack late. The disease of the stem is watery and dark green, and the diseased part is generally constricted, but the vascular bundle does not change color, and the leaves above the affected part wilt. If there are several stem diseases in the plant, the whole plant will wilt and wither quickly. The seedlings are susceptible, the growth point is often dark green, water stains, and dry tip after soft rot.

[control methods] in addition to the selection of disease-resistant varieties and rotation cultivation and management, the use of drugs for the disease should be emphasized in time, and the central disease plants should be used immediately.

Leaf spot disease

[incidence characteristics] Leaf spot is caused by continuous cropping, poor ventilation, high humidity and so on.

[control methods] remove the remains of diseased plants, reduce infection sources, select disease-resistant varieties, appropriately increase phosphorus and potassium fertilizer, improve plant disease resistance, carry out crop rotation, irrigate along the soil surface, and avoid spraying water on plants. Spray 1% Bordeaux solution or 25% carbendazim wettable powder 300 times 600 times solution, or 50% methyl thiophanate 1000 times solution, or 80% mancozeb 400 times solution 600 times.

Cataplexy

[incidence characteristics] quenching disease is mainly transmitted by soil and fertilizer, and it is easy to occur when the humidity is too high, the soil temperature is too high, the sowing is too dense, the seedling growth is weak and so on.

[control methods] the diseased plants were pulled out in time, the soil was disinfected, the seedlings were unearthed in the early stage, watering was properly controlled, and at the initial stage of the disease, the diseased plants were irrigated with 1000 times of 50% Dysenammonium solution or 1000 times of methyl topiramate wettable powder.

Rot disease

[characteristics of the disease] the rot is mainly caused by high humidity, insufficient light and poor ventilation.

[prevention and control methods] proper control of moisture, light transmission and ventilation.

Pest control

[hazard characteristics] the insect pests are mainly aphids, which accumulate on leaves, buds and flower buds, and pierce the plant tissue with piercing mouthparts to absorb juice, resulting in macular or black spots in the damaged parts, shrinking and shedding of damaged leaves, atrophy or abnormal growth of flower buds, and death of plants in severe cases. Aphids can secrete honeydew, leading to bacterial growth, soot disease and other diseases.

[control methods] to eliminate by removing nearby weeds, spraying 40% dimethoate or omethoate 1000-1500 times, or killing permethrin 2000-3000 times or 80% dichlorvos 1000 times, etc.