What is rose rust and what are the control methods
What is rose rust? How to prevent and control it, please provide an introduction to the methods. Rose rust mainly damages the buds, leaves, young shoots, petioles, receptacles, pedicels and other parts of roses. It mainly occurs on buds and leaves. During the spring germination period, the base of diseased buds swells, and a large amount of orange-red powdery material grows within 1~3 layers of scales, like a small...
What is rose rust? How to prevent and control it, please provide an introduction to the methodsRose rust mainly damages the buds, leaves, young shoots, petioles, receptacles, pedicels and other parts of roses. It mainly occurs on buds and leaves. During the spring germination period, the base of diseased buds swells, and a large amount of orange-red powdery material grows within 1~3 layers of scales, like a small yellow flower; some become curved and deformed, and die after 15~20 days. After young leaves are damaged, yellow small dot-like spore containers first appear in clusters on the upper side of the leaves, and then orange-red spore piles form on the underside of the leaves. After axillary buds are infected by the fungus in autumn, most die after overwintering.
Rose rust is caused by the pathogen mainly overwintering as mycelium in diseased rose buds. In late March of the following spring, when the diseased buds germinate, the disease begins, producing urediniospores, which spread to the leaf surface and cause infection. Teleutospores on diseased leaves can also overwinter, and in the spring of the next year they germinate to produce basidiospores, infecting young leaves and tender shoots, then producing pycniospores and aeciospores. Aeciospores infect leaves and produce urediniospores again. Urediniospores can be produced many times, repeatedly expanding the infection, with the shortest incubation period being 7 days. Each year, leaves begin to develop the disease in late April. Late May to early July is the peak period of the disease. In August. When the average temperature is above 27 degrees, the disease does not develop; when the temperature is above 28 degrees, urediniospores do not germinate. After early September, only axillary buds develop the disease. In years with abundant and evenly distributed rain, the disease is more severe.
Rose rust can be prevented and controlled by the following methods:
(1) Remove diseased buds in time. Inspect from late March to April, and immediately remove and destroy diseased buds when found. Generally, the rate of diseased buds is less than 0.5%, and removal can prevent the spread of spores.
(2) Before the two peak disease periods in early April or late August, spray 1~2 times to control the development of the disease. You can choose 50% chlorothalonil 600 times solution; or 50% Tuzet 500 times solution; or 50% thiram 500 times solution; or 25% triadimefon wettable powder 1500 times solution. You can also spray 0.1 lime sulfur mixture before spring germination; or spray 0.2 lime sulfur mixture in the early stage of the disease.
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