What are the latest control measures for grape black pox?

Grape black pox, also known as scab, and in some areas called “bird's eye disease”, can damage most of the green tender tissues of the grapevine, mainly affecting the fruit, fruit stalks, leaves, petioles, new shoots and tendrils. Black pox is one of the common diseases in the grape growing process; its occurrence greatly affects the commercial value of grapes and brings certain economic losses to grape growers. So how should we control black pox? Today Qinnong Web will introduce the control measures for black pox.

I. Symptoms of black pox

The onset period of grape black pox is most concentrated in spring and early summer, and it is also the earliest disease to appear during the grape growing season. When young leaves are infected, needle-head-sized brown spots appear on the leaf surface; after the spots expand, there is a yellow-brown halo around them, and they gradually become irregular in shape; the center of the spot turns light brown or gray-white, and the edge is dark brown; later the tissue at the center of the spot dies and falls off, forming holes. The spots are fairly uniform in size, with a diameter of 2—4mm. When new shoots, petioles and tendrils are infected, round or irregular brown small spots appear, later turning gray-black, with the edge of the spot dark brown or purple-brown and the center sunken and cracked. In severe cases, several spots often join into one patch, causing the diseased shoot and tendril to die because the spots girdle them. When young fruit is infected, round brown small spots first appear, then the center of the spot turns gray-white, the edge purple-brown, slightly sunken, resembling a “bird's eye”; later the spot hardens or cracks, and the diseased fruit is small and deformed, with no edible value. When growing berries are infected, the berries can still enlarge, the spots have no obvious sunken areas, and the taste is sour. When the air is humid, a gray-white sticky substance (conidial masses) forms on the spots. When the rachis is infected, it often causes partial clusters or even the whole cluster to develop poorly, or even die.

II. Control methods for black pox

The control of black pox also follows the concept of giving priority to prevention and supplementing with treatment, first eliminating the possibility of disease occurrence from the source. Qinnong Web here introduces four control methods for everyone; among them, only the last one uses pesticide control, while the first three still focus on daily care. Let's take a specific look below:

1. Eliminate overwintering sources of the disease

Prune carefully, cutting away diseased branches, diseased fruit clusters and tendrils completely; bury fallen leaves deeply, remove diseased residues in time, and bury them deeply or burn them; when the buds sprout, carefully spray 3-5 degrees Baume lime sulfur mixture or 45% crystalline lime sulfur mixture at 30-40 times dilution, or 100 times sodium pentachlorophenate to eliminate overwintering pathogens.

2. Choose drip-free anti-fog film to cover the facility

Cover the entire ground area inside the facility with plastic film, and pay attention to ventilation and dehumidification to reduce the air humidity inside the facility, keeping the relative air humidity below 80%, inhibiting spore germination and reducing infection.

3. Deep plowing and soil improvement

Deepen the live soil layer to promote root development; increase the application of organic fertilizer, phosphate fertilizer, potassium fertilizer and trace element fertilizer; appropriately reduce the amount of quick-acting nitrogen fertilizer to improve the plant's own disease resistance. Reasonable density, scientific pruning, appropriate retention of branches, reasonable load, maintaining vigorous growth, improving field light conditions, and reducing air humidity in the microclimate. Bag the fruit clusters to eliminate infection of the clusters by pathogens.

4. Chemical control

Protectants: 78% Kebo 600-800 times, 80% Bibei 400 times; 80% Dacotech M-45 or 80% Penke 600-800 times, 1:0.5:200 Bordeaux mixture;

Therapeutic agents: 5% Meiningling (imibenconazole, amide azole) 800-1000 times, 10% Shigao (difenoconazole) 1500-2000 times, 12.5% Subaoli (diniconazole) 3000-4000 times, 40% flusilazole (Fuxing) 8000-10000 times; 50% carbendazim 600-800 times, 70% thiophanate-methyl 800-1000 times.

The above are the control measures for grape black pox brought to you by Qinnong Web. As a common disease harming grapes, the control work for black pox is of great significance for grape cultivation. We hope this article can bring some reference value to the vast number of grower friends.