The Harm and Control Techniques of Grape Erineum Mite Disease

Grape erineum mite disease is actually caused by the damage of a pest called the grape erineum mite (rust mite). Its damage symptoms resemble a disease, so people habitually classify it as a disease. So specifically, what harm does grape erineum mite disease cause? What control techniques are there?

1. What harm does grape erineum mite disease cause?

1. Damage characteristics

According to investigations, this pest mainly damages grape leaves. It begins to occur when the leaves unfold in spring and can continue to cause damage until leaf fall. Main damage symptoms: after the leaves are damaged, irregular pale-white lesions first appear on the underside of the leaves, irregular in shape and varying in size, with lesion diameters of about 2-10mm. Afterward, blister-like swellings form on the leaf surface, densely covered with felt-like down, resembling felt, hence the name. The down gradually changes from white to tea-brown, and finally to dark brown.

When the damage is severe, the leaves shrivel, the texture becomes thicker and harder, the leaf surface becomes uneven, and sometimes dries up and cracks, often causing early defoliation.

When the outbreak is severe, it can also damage young shoots, young fruit, tendrils, pedicels, and so on. The leaves of affected plants shrivel, seriously affecting leaf photosynthesis. As a result, the canes grow thin and weak, the clusters are small, the berries are small, yield decreases, and quality deteriorates, often causing early defoliation. This not only affects the yield of the current year but also weakens tree vigor and affects flower bud differentiation, thus also affecting the yield and quality of the following year.

2. Occurrence pattern

Grape erineum mite disease occurs 3 generations per year in Turpan. It begins to occur in mid-to-late April, causes severe damage in mid-to-late May and in September. The hot and dry weather in Turpan in summer is favorable to its growth and development, so it can cause damage throughout the entire grape growing season. Female adult mites begin laying eggs in early-to-mid April. In mid-October, adult mites lurk in the down of bud scales and in cracks of cane bark to overwinter, with the largest number of mites found in the down of the lower part of the canes and the bud scales of one-year-old young shoots.

When grapes bud in the following spring, they begin to move and migrate to the underside of young leaves to suck nutrients. The felt-like material is formed by the hypertrophy and deformation of the upper epidermal tissue of the grape after being stimulated by eriophyid mites, and it has a protective effect on the eriophyid mites.

2. What control techniques are there for grape erineum mite disease?

1. Use disease-free seedlings

Erineum mite disease can be spread with seedlings or cuttings, so it is best not to introduce seedlings from diseased areas. If seedlings must be introduced from diseased areas, they must first be disinfected before planting. A relatively simple method is hot water soaking. The method is to first place the seedlings or cuttings in warm water at 30-40°C for 3-5min, then move them into warm water at 50°C for 5-7min to kill the rust mites overwintering in the buds.

2. Strengthen fertilizer and water management

Apply more organic fertilizer, control the amount of nitrogen fertilizer applied, irrigate reasonably, and improve the grape's own resistance.

3. Strengthen vine management

When unearthing the grapevines, make sure the grape canes are not damaged. Otherwise, many pathogens can easily invade through the wounds. Remove the raised old bark on the stems and canes to increase the mortality rate of overwintering pests under the bark.

4. Chemical control

After grapes begin to sprout in early spring, before leaf unfolding, and after leaf unfolding when young shoots are 13-15cm long, spray 100-150 times 45% crystal lime sulfur mixture respectively to kill overwintering adult mites. Add 0.3% laundry detergent to the spray solution to improve the spraying effect. (Note: when spraying, it must be thorough and complete. The grape canes and leaves must be sprayed until wet; spraying is prohibited when the temperature is above 28°C. Otherwise, phytotoxicity is likely to occur.)

After grape leaves unfold, if damaged leaves are found, they should be removed immediately and buried deeply or burned. Also use acaricides such as Lorsban 1000 times solution, Luan Mantongsha 1000 times solution, or Saomanjing 2000 times solution.