Control of Main Grape Diseases (4)

Grape fan leaf disease

It mainly infects leaves, fruits and ears.

Symptoms

(1) Fan-shaped leaf

Fan-shaped leaf malformation is the most distinctive, but not only, foliage expression. Chlorotic speckling and a leathery texture commonly accompany leaf distortion. Shoots may be misshapen, showing fasciation (stem flattening), a zigzag pattern at the nodes, atypically variable internode lengths, double nodes, and other aberrations. Fruit set is poor and bunches are reduced in size. 

(2) Yellow mosaic

The yellow mosaic (chromatic) syndrome develops as a strikingly bright-yellow mottling of the leaves, tendrils, shoots, and inflorescences in the early spring. Discoloration can vary from isolated chlorotic spots to uniform yellowing. 

(3) Vein-banding

The third expression, veinbanding, develops as a speckled yellowing on mature leaves, bordering the main veins in mid- to late-summer.

Control

(1) Cultivating and utilizing disease-free propagation materials is the most fundamental measure to prevent fan leaf disease.

(2) Once the plant is infected, there is no treatment at present.

If the diseased plants are found in the field, they should be removed and destroyed as soon as possible, and the soil should be disinfected locally to eliminate the toxic source in the field.

(3) Increase the application of farmyard manure, scientifically determine the amount of fruit retained according to the growth of the grapes, and reasonably apply fertilizer to improve the disease resistance of the tree.

Sooty blotch

It won't cause the fruit to rot, but when the fruit grows and starts to soften, small black spots appear on the fruit surface, scattered like fly dung.

Aphids or whiteflies can aggravate the occurrence of diseases.

Chemical control

Insecticides: imidacloprid, nitenpyram·pymetrozine, sodium pimaric acid.

Chloroisobromine cyanuric acid, basic copper sulfate, mancozeb, chlorothalonil, thiophanate methyl, carbendazim.

Grape sour rot

It is a secondary infection disease, especially the fruits with wounds are more easily infected by fungi and bacteria, which will attract vinegar flies to lay eggs.

The fruit will rot, and there are pink flies around the rotten ears;

Have acetic acid taste;

There are white maggots in rotten and juicy rotten fruits;

The place where the juice flows through (fruit, stem, cob) will also rot;

After the fruit rot, it dries up, leaving only the peel and seeds of the fruit.

Control

(1) Select disease-resistant varieties in areas with severe disease, and try to avoid planting varieties with different maturity in the same orchard.

(2) The vineyard should be inspected frequently, and the diseased fruits should be removed in time and buried deeply; Increase the ventilation and reasonable close planting of orchards; Irrigation is not allowed at maturity.

(3) Reasonable use or not use hormone drugs to avoid peel damage and fruit cracking; Reasonable fruit thinning; Avoid too tight ears; Reasonable fertilization, especially avoiding excessive application of nitrogen fertilizer.

(4) Pay attention to control other diseases in the early stage, reduce wounds, use safe pesticides in young fruit stage, and avoid too tight or injured peel.

Grape fruit rust

Mainly caused by the harm of tea yellow mite. Mainly harmful to fruits.

Striped or irregular rust spots are formed, which are only limited to the surface of pericarp, and the epidermal cells are corked.In severe cases, the fruits cracks and the seeds are exposed.

Control

Spraying acaricides at the early stage of the onset.

Fenvalerate, bifenthrin, propargite, abamectin, pyridaben, fenpyroximate, fenpropathrin.