Identification of Cherry Blossom Pest and Disease Symptoms and Control Methods
SummarySymptoms of shot-hole brown spot disease: small purplish-brown spots appear on the leaves and gradually expand into circular shapes. Control methods for shot-hole brown spot disease: spray 3-5 degrees Baume lime sulfur mixture before new shoots sprout, and spray 160-fold Bordeaux mixture when the disease occurs. Symptoms of leaf blight: yellow-green circular spots appear on the leaves, then turn brown. Control methods for leaf blight: spray Bordeaux mixture before sprouting. Symptoms of crown gall disease: tumors develop at the affected sites. Control methods for crown gall disease: the cancerous tumors can be removed with a knife or saw.
I. Shot-Hole Brown Spot Disease
1. Symptoms
(1) For cherry blossom shot-hole brown spot disease, the peak incidence period is from May to June. When the disease occurs, small purplish-brown spots appear on the leaves and gradually expand into circular shapes in the later stage.
(2) After the diseased spots dry and contract, they form small holes. The pathogen prefers to overwinter on diseased branches and leaves, and the suitable temperature for its development is 25°C-28°C.
(3) It is generally spread by wind and often infects and causes disease during the plum rain season, leading to weakened tree vigor. It is also prone to occur when drainage is poor and ventilation and light penetration are insufficient.
2. Control Methods
(1) During the growth of cherry blossoms, planting management should be strengthened, timely pruning and branch training should be carried out, diseased shoot tips should be cut off, diseased leaves should be cleaned up promptly and burned with fire, creating a sterile growing environment for the plants.
(2) Before new shoots of cherry blossoms sprout, spray 3-5 degrees Baume lime sulfur mixture. During the disease period, spray 160-fold Bordeaux mixture, or 15% zineb 600-800-fold solution, or 50% benomyl wettable powder 1000-2000-fold solution.
II. Leaf Blight
1. Symptoms
In summer, yellow-green circular spots appear on the leaves, then turn brown, with scattered small black granules. Diseased leaves wither and die but do not fall off.
2. Control Methods
(1) When the disease occurs, remove diseased leaves and burn them with fire. Spray Bordeaux mixture before sprouting.
(2) From May to June, spray 65% zineb wettable powder 500-fold solution again. During this period, spray once every 7-10 days, and 2-3 consecutive sprays are appropriate.
III. Crown Gall Disease
1. Symptoms
(1) Crown gall disease mainly occurs at the base of the trunk, and sometimes also on the root collar and lateral roots. Tumors develop at the affected sites.
(2) In the early stage, the tumors are milky white or flesh-colored, and in the later stage they gradually turn brown or dark brown. They are spherical, with a relatively rough surface, uneven and covered with cracks.
(3) After infection, root development is poor, with very few fine roots, aboveground growth is slow, and tree vigor declines. In severe cases, leaves turn yellow, fall early, and even the whole plant dies.
2. Control Methods
(1) Cherry blossom seedlings infected with crown gall disease need to be gathered and burned with fire. Before planting, they can be soaked in 1% copper sulfate for 5-10 minutes, then rinsed clean with water before planting.
(2) When diseased plants are found, the cancerous tumors and other surrounding tissues can be removed with a knife or saw.
(3) For the soil around diseased plants, sulfur powder can also be applied at 50-100 grams per square meter for disinfection, and soil improvement can also be carried out at the same time.