Control techniques of diseases and insect pests of primrose

Primrose is a deciduous shrub of Oleaceae Jasminum, which is light-tolerant, slightly shade-tolerant, cold-tolerant, waterlogging-resistant, requires a warm and humid climate, loose, fertile and well-drained sandy soil, thrives in acidic soil, poor growth in alkaline soil, strong root germination, and branches are easy to take root. Let's take a look at the pest control techniques of primrose.

Mosaic disease

[symptoms] the whole plant disease caused by cucumber mosaic virus CMV is characterized by small and deformed leaves, dark green markings or yellowing, non-flowering, short flowers and speckled flowers. Peach aphid and cotton aphid are mainly transmitted by peach aphid and cotton aphid, and the source of infection is mainly infected plants of surrounding weeds.

[prevention and control] first of all, weeds should be removed in time to reduce the source of infection. Secondly, aphids should be prevented and controlled as soon as possible to eliminate virus transmission vectors.

Brown spot disease

[symptoms] Brown spot disease mostly occurs in the spring of the four seasons, and is caused by Alternaria of the subphyla. There are brown spots on the leaves of infected plants, and the way of transmission is that conidia are transmitted by wind and rain.

[prevention and treatment] at the initial stage of the disease, 70% chlorothalonil wettable powder 1000 times liquid and other fungicides were sprayed.

Grey mold disease

[symptom] Botrytis cinerea is one of the common diseases of primrose, which occurs all over the country. After the plant was infected, the whole plant yellowed and withered. The disease mainly infects leaves, tender stems, floral organs and other parts, and mostly occurs at leaf tip and leaf edge. At the beginning of the disease, the leaves appeared water-immersed spots, and then gradually expanded, turned brown and rotted. In the later stage, a gray-yellow mildew layer was formed on the surface of the lesion. After the stem was infected, the disease spot was brown and gradually rotted. After infection, the floral organ also became brown and rotted and fell off. Under moist conditions, a gray mildew layer appears in the disease, which is a major feature of the disease.

[prevention and control] planting density should be reasonable. Pay attention to ventilation and reduce air humidity. Diseased leaves and diseased plants are removed in time to reduce the source of infection. At the initial stage of the disease, 1500 times of 50% Sukeling or 50% Prohydantoin wettable powder was sprayed. It is best to apply alternately with 65% carbendazim wettable powder 500 times to prevent drug resistance.

Spot disease

[symptoms] the spot mainly harms the leaves of the plant, and the disease spreads from the lower part of the plant to the upper part of the plant. The spot is usually 3 to 4 mm in diameter and brown. In severe cases, the diseased leaves wither and die, resulting in fallen leaves. It is caused by Alternaria. The pathogen overwinters on the diseased residue in the form of mycelium or conidia, and the seeds can also carry bacteria and become the source of initial infection in the second year. It mainly depends on the transmission of conidia with the air and Rain Water, and its re-infection is frequent in the growing season, usually in warm and humid weather and partial application of nitrogen fertilizer, the plant is prone to disease. The disease usually begins in July and is prevalent from August to October.

[control] breeding disease-resistant varieties, strengthening fertilizer and water management, increasing application of organic fertilizer and phosphorus and potassium fertilizer, and avoiding partial application of nitrogen fertilizer. At the initial stage of the disease, 70% methyl topiramate was sprayed with 1000 times solution plus 75% chlorothalonil wettable powder 1000 times solution, or 1 Vera 100 Bordeaux solution.

Leaf spot disease

[symptoms] Leaf spot disease often occurs on leaves and receptacles, and water-immersed irregular spots appear along the veins at the initial stage, then yellowing, browning, enlargement, withering of the leaf margin, and death from the lower leaves in severe cases.

[prevention and control] strengthen cultivation management, cultivate disease-free seedlings, disinfect the soil of seedling bed, release air in time in greenhouse and reduce air humidity. Remove the remains of the diseased plant in time. After the attack, 50% copper succinate wettable powder or 72% agricultural streptomycin wettable powder 4000 times were sprayed.