Causes and Control Countermeasures of yield reduction of Walnut Fruit drop

We all know that walnut is not too strict in the growth environment, and it is more tolerant to the barren and dry growth environment, but if it is not well mastered in management, it is prone to fruit drop, which leads to a reduction in yield and harvest, which directly affects the harvest and planting enthusiasm of fruit farmers. Therefore, the causes and solutions of walnut fruit drop are summarized as follows:

First, the cause of walnut fruit drop.

1. Improper selection of varieties. Varieties should be selected in accordance with local conditions, and varieties suitable for local climate and soil conditions should be selected. Generally, thin shell varieties with strong growth, strong stress resistance, high quality and high yield should be selected. Walnut is a monoecious plant, so it is best to select 2 or 4 main varieties with similar or complementary florescence, or suitable pollination varieties when setting up the garden. The ratio of main varieties to pollinated varieties was 4 ∶ 1. The main varieties can be selected as Xiangling, Liaohe No. 4, Yuanfeng, Fenghui and so on.

2. Rain or low temperature during flowering leads to poor pollination. The young fruit without fertilization usually falls 20 days after anthesis, which is one of the main reasons for a large number of walnut fruit drop.

3. Lack of nutrients. Many people think that walnuts can bear fruit with little or no topdressing. Due to the lack of fertilizer, the consumption of nutrients at flowering stage is large, resulting in nutrient deficit, weak tree potential and fruit drop.

4. Lack of trace elements. When the walnut orchard is deficient in boron, zinc and copper, fruit drop is also easy to occur.

5. Excessive or partial application of nitrogen fertilizer. Excessive use of nitrogen fertilizer or partial application of nitrogen fertilizer will cause the tree potential to be too prosperous, resulting in the loss of balance between vegetative growth and physiological growth, resulting in flower and fruit drop.

6. Fruit drop caused by diseases and insect pests. The main disease of walnut is anthracnose, which mainly harms the fruit and directly causes fruit rot and fruit drop.

2. Control measures of walnut fruit drop

1. Apply fertilizer in time to strengthen the tree. Generally speaking, topdressing should be done once in autumn and spring, and 1000-1500 kg of soil and miscellaneous fertilizer should be applied per mu. According to the age of walnut, each tree should also apply no-tillage fertilizer or ordinary nitrogen, phosphorus and potassium fertilizer 1-1.5 kg. 4000-fold liquid Shuofeng 481 and 1000-1500 times liquid available boron were sprayed on the leaves before and after flowering. The use of available boron can effectively avoid the bad phenomena of walnut trees, such as bud without flower, flower without fruit, fruit drop, fruit deformity and so on, caused by boron deficiency.

2. Strengthen the prevention and control of anthrax. In order to prevent rotten fruit or fruit drop caused by anthracnose, 400 × 600 times liquid Bangjiawei (80% mancozeb) can be sprayed once in mid-May, early June and early July, and 4000 times liquid Shuofeng 481 can be added to prevent it.