Control methods of Rose Leaf Blight

Leaf blight is one of the common diseases of rose, infected rose will first appear from the top or edge of the leaf spots, with the occurrence of disease spots will be small to large irregular shape, color will be from reddish brown to taupe, finally the spots will be contiguous into large withered spots, if the disease is serious, will cause the death of rose plants, let's take a look at the prevention and control methods of rose leaf blight!

hazard symptom

Rose leaf blight often causes the leaves of nursery and potted roses to dry and fall off. The pathogen mostly invades from the leaf tip or leaf edge, initially yellow spots, then rapidly expands into irregular large spots, seriously damaged whole leaves dry up to 2/3, the diseased parts fade green and yellow, brown dry and fall off, and sometimes the leaves are sparsely black spots.

occurrence regularity

Leaf blight fungi belong to the order of Coelassia, and the small black spots on the leaves are the conidia of the pathogen. The conidia are spherical or subspherical, light brown, with an orifice at the top, initially buried in the leaf tissue, and then exposed through the epidermis, producing many conidia to infect and harm. The disease was most severe in July to September when the temperature was high and humidity was high.

control methods

1. Agricultural control: remove sick leaves on the ground and underground, and eliminate overwintering pathogens. If the diseased leaves are removed in time during the disease onset, the disease extension can be effectively controlled.

2. Chemical control: spray 75% chlorothalonil 600~800 times solution or 25% carbendazim 500 times solution during the disease period.