What is the cure for citrus spot macular disease?

Citrus lipid spot macular disease is also known as macular disease, lipid spot disease, brown small round star disease, etc. It occurs in citrus producing areas across the country. It is more common in Zhejiang, Jiangsu, Guangdong, Taiwan and southwestern provinces.

The symptoms of citrus lipid macular disease are divided into three types: lipid macular type, brown small round star type, and mixed type.

Dippy-spotted macular type: mostly occurs on 2-year-old leaves. At the beginning, it presents irregular pale yellow spots on the back of the leaf, translucent, and then expands into yellow spots of different sizes, and small blister-like yellow protruding dots appear on the back of the leaf, several or dozens of groups grow together, and later grow with the leaves; In the later stage, the lesions gradually expand and age, the edges are not obvious, and the color becomes darker, becoming brown to black-brown lipid spots.

Irregular macula is visible on the front of the leaf corresponding to each lesion, with pale brown to black-brown granular dots in the middle. This type occurs mainly on spring tip leaves and often causes a large amount of defoliation.

Brown small round star type: russet sesame seeds appear on the initial leaf surface with nearly circular spots, and later slightly expand to round or oval, with a diameter of centimeters, the edge of the lesion is convex, the color is dark, ** concave, the color is light, and then it becomes grayish-white, and the small black spots on it are conidia. This type mostly occurs on autumn shoot leaves.

Mixed: Presence of both yellow-spotted and brown star-shaped lesions on the same leaf.

The fruit can also be damaged, after the lesion often occurs on the fruit surface of the sunny part, the initial stage is a small herpes-like light yellow protrusion or like oil spots, after the lesion expands and ages, the color of the spot becomes reddish-brown, and the lipid gelatinous hyalitrope secreted from the lesion is oxidized to dirty brown, forming a large lipid spot with no obvious boundary of 1 2 cm of diseased tissue, and the lesion does not extend to the fruit.

The spots no longer spread. Citrus lipid spot macular disease. The control effect is very good with 1000 times 50% carbendazim wettable powder, or 500 times 50% thiophanate-methyl wettable powder, or 700 times 30% copper oxychloride suspension, or 300 times 14% glucosamine copper aqueous solution, or 2000 times 50% benmonyl wettable powder, 600 times 80% zepzeb wettable powder, or 1500 times 10% difenoconazole aqueous solution, or 800 times 80% mancozeb.

The prevention and control of citrus lipid spot yellow spot disease should first strengthen cultivation management to improve the disease resistance of plants, especially for seriously diseased old trees, which should be shortened and renewed, and organic fertilizer should be applied to enhance tree potential. At the same time, do a good job of clearing the garden in winter, combine pruning and pruning to remove seriously diseased branches, sweep away fallen leaves and stump branches on the ground, and concentrate on burning. In addition, the new shoots should be combined with the prevention and control of other pests and diseases before the leaves turn green, and the pesticide control should be carried out to protect the new shoots from harm. For unfruitful trees, spray pesticides at the beginning of spring leaves; For fruiting trees, start spraying the first agent at 2 3 o'clock and spray again 20 days apart.

In areas where the disease has been severe, the second spray is sprayed 30 days after the third spray. The agent can be selected with 800 1000 times of 50% carbendazim wettable powder or 800 1000 times of 70% thiophanate-methyl (methyl tobuzin) wettable powder, and 500 700 times of 75% chlorothalonil wettable powder. It is also possible to spray carbendazim and chlorothalonil mixture (mixed in the ratio of 6 4) 600 800 times 2 3 days before the rainy season and 1 month apart, or 500 times of 70% mancozeb wettable powder or 500 800 times of 77% copper hydroxide (killable) 2000 type.

Yes, citrus lipid spotted macular disease, which occurred sporadically in the early years, then occurred in small areas, and now it occurs throughout the orchard. When the disease is severe, the leaves of the autumn shoots are almost finished, and the tree weakens. Autumn shoots that have fallen leaves do not bear fruit and do not bud.

Symptoms: The dorsal surface of the initial diseased leaves appears pale yellow or yellowish brown oil-impregnated small particles, showing irregular pale yellow spots, several or a dozen clusters together, and the edges are not obvious. Later, the lesions expand and age, and the color becomes darker, forming irregular yellow-brown to black-brown lipid spots.

It is recommended to use 45% fluconazoxystrobin compound diluted 2500 times or 40% phenyletheroxystrobin compound diluted 2000 times or tebuconazole oximestrobin compound diluted 2000 times to 3000 times, and agents 7 to 10 are rotated.