Prevention and Control of Fruit shrinkage Disease of growing Apple

Apple fruit shrinkage disease is a physiological disease caused by boron deficiency, which has been aggravated in early ripening apple varieties such as American No. 8, Gala and late ripening apple Qin Guan in recent two years.

I. symptoms of the disease:

The main symptoms of fruit can be divided into three types: dry spot type, cork type and rust spot type.

1) dry spot type: the symptoms appeared early and mostly occurred in the early stage of young fruit development, with dark green or dark red edema spots on the fruit surface, flesh browning to dark brown, gradual necrosis, dry shrinkage, hardening, subsidence and deformity. The seriously diseased fruit becomes smaller or dehiscence at the dry spot, and it is easy to fall early.

2) Cork type: mostly occurred in the later stage of fruit growth, the diseased fruit pulp appeared water-stained spots, usually spread along the core line, distributed in strips, and the pulp turned brown and spongy. The appearance of the diseased fruit does not change much, only the fruit surface is uneven, and there is a sense of softness when pressing with hands. When the disease occurs in the young fruit stage, the fruit becomes smaller, deformed and easy to fall early. In the later stage of growth, the fruit is infected and the fruit surface is uneven. Red varieties coloring early, easy to fall early, most of the seriously diseased fruit is spongy, can not be eaten; mildly diseased fruit, local discoloration and necrosis of pulp, light taste and poor quality.

3) Rust spot type: the symptoms are mostly manifested in Marshal and other varieties, after the disease, the fruit is oblate or long tube-shaped, brown and fine horizontal stripes are produced along the fruit stalk around the fruit stalk, these markings often crack, there is no necrotic lesion on the fruit surface, and the pulp is soft.

When the disease is serious, it is also shown on the shoots, the symptoms are: withered shoots in summer, new shoots gradually dry up from the top to the bottom. Sometimes diseased branches die quickly after not sprouting or spreading leaves in spring, and many thin clumps grow under the withered branches.

Second, reason analysis:

Boron is an essential trace element for plant cell division and tissue differentiation, and plays an important role in promoting the reproductive process of fruit trees. boron deficiency occurs when the content of boron in soil is low (less than 10mg/Kg). The main reasons for boron deficiency are as follows:

The main results are as follows: 1) the bad weather in early spring, excessive dryness and hardening of soil, poor root development of fruit trees, affecting nutrient absorption and boron deficiency.

2) the partial application of nitrogen fertilizer increased the growth of fruit trees, thus increasing the requirement of boron, but the supply of boron could not keep up with that of boron deficiency.

3) the soil is barren or alkaline soil is easy to lack boron.

4) there are great differences in sensitivity to boron deficiency among varieties. American No. 8, Gala, Qin Guan and other varieties have a serious disease.

III. Prevention and control methods

The main results are as follows: 1) combined with autumn fertilization of fruit trees, trace element fertilizers are applied to the shopkeeper of elements. the amount of application is about 20 jin per mu (0.7 jin per tree) for fruit trees in full fruit period. Big shopkeeper is a kind of medium and trace element fertilizer, which contains many kinds of medium and trace elements, such as boron, iron, zinc, manganese, magnesium, sulfur and so on. It can not only prevent apple fruit shrinkage disease, but also prevent leaflet disease, yellow leaf disease and bitter pox disease, promote fruit expansion and coloration, increase yield and improve quality.

2) foliar boron spraying: 1500-2000 times of Gale boron or 1000-1500 times of cardine boron can be sprayed before, during and after flowering, respectively, and 4000 times of Aiduo liquid can be added to promote the effect of correction and control.

3) strengthen the management of water and fertilizer. Increase the application of organic fertilizer, improve the soil, and irrigate in time during drought.