Rose black spot is a worldwide disease. It was reported for the first time in Switzerland in 1815. In 1910, China reported on this disease on the rose plants. At present, almost all regions in China that have planted rose have this disease. When the disease occurs seriously, the yellow leaves of the leaves fall off as "light poles" and become an important issue for the production of rose.
Symptoms The bacteria invade the leaves, shoots, and pedicels. At the onset of the onset of the leaves, purple brown to brown dots appear on the front, gradually expanding into round or irregular dark brown lesions, with a diameter of 1 to 12 mm and radial edges of the lesions. This is a typical symptom of melasma. Yellowing of the late leaves, black spots on the lesions, this is the conidia of the bacteria. Some rose varieties often have yellow halos around the lesions; some species are often linked to yellow lesions in several lesions, and the edges of lesions are still green, known as the "green island." Young shoots and peduncle infections produce purple-brown to dark-brown bar spots that subside. When the disease is serious, the middle and lower leaves of the plant fall off completely, leaving only the top few green leaves.
Diseases The original pathogen (Actinonema rosae) is infested by the semi-known fungus subsporidia, cochlophytes, black-sphaeropsis, black-spotted, and actinomycetes of E. rosacea. The sexual generation is Diplocarpon rosae Wolf. The growth temperature of the bacteria ranged from 10 to 35°C, and the optimum temperature was 20 to 25°C. The optimum temperature for invading the rose was 19 to 21°C.
Disease characteristics? Rose black spot pathogens mycelia or conidia in the plant bud scales, leaf marks, shoots and leaves overwintering. In the following spring, conidia are produced after rainfall, which is transmitted by wind and rain, splashing water and directly invaded by the host epidermis. Under suitable conditions of temperature and humidity, the incubation period can be 3 to 6 days. Symptoms can occur until the leaves fall off approximately 8 to 32 days. The higher the temperature, the more easily the diseased leaves fall off. Every year from late March to early June and late September to November is the peak of onset. Rainy, foggy, and sultry after the typhoon rain, poor ventilation and light transmission conditions, weak and old strains, the incidence is more serious. All rose cultivars can be infected. The old leaves are more resistant to disease and the new leaves are more susceptible to disease. The leaves that are 6 to 14 days old are the most susceptible to Zibo. In general, the colors are light, the flowers are small and the erect varieties are susceptible, and the disease-resistant ones are “Elizabeth†and “ "Black Melaleuca", "Isbel", "King of the Tropics", "Molong", "Sunflower Sunny" and so on. Foreign reports of "David", "Moon Flower", "Golden Flawless", "Yellow Flawless", and "Pink-no Beggar" were highly resistant to the species, but no immunized species were found.
Control methods
1. In the seasons of winter and early spring, the diseased leaves on the plants and the fallen leaves on the ground are completely removed, and the knots are trimmed to remove the diseased branches so as to reduce the overwintering pathogens. Clean the leaves at any time during the growing season.
2. Improve the cultivation and management measures, and use local rose varieties with strong disease resistance. The susceptible varieties are best planted with disease-resistant cultivars at intervals, so as to reduce the spread of disease and spread, to pay attention to the spacing between the plants, not too dense, the watering time should not be too late, and should not be watered above, and root irrigation should be adopted to avoid The spores of the germs are not spilled to the adjacent leaves. Pay attention to ventilation and ventilation, control the temperature, reasonably maintain, and cultivate plant resistance.
3, chemical control. In the spring of the following year, in the Chinese rose and rose germination, crystal lime sulfur was sprayed 100 times. Alternately spray 75% chlorothalonil wettable powder 1000 times, or 45% Thiabendazole (Tecdo) suspension 500 to 600 times, and 40% fluorosiliconazole or 25% myclobutanil 800 times. Or 40% polysulfide suspension or 50% anthraquinformamide WP or 50% compound thiophanate WP 800 times, 70% thiophanates 700 to 1000 times, 50% eutectic 800 To 1000 times the liquid, spraying once every 7 days in the rainy season, spraying once every 7 to 10 days during the normal growing season and the rainy season, and even spraying 4 to 5 times to control the spread of the disease.
With the capability of precise milling and multiple application, the multifunctional Dental Milling Machine provide a simple, efficient, and powerful dental CAD/CAM solution, make it the best choice for your dental lab or clinic. Featuring Demetdent famous reliability and product support, it's the ultimate in affordable and dependable milling technology.
Multifunctional Milling Machine
Dental Laboratory,Dental Suction Unit,4 Axis Milling Machine,Glidewell Dental Laboratories
Shandong Carved Intelligent Technology Group Co.,Ltd , https://www.demetdent.com