Key Technical Points for Summer Pruning and Pest and Disease Control in Peach Trees

Key Technical Points for Summer Pruning and Pest and Disease Control in Peach Trees

In summer, peach trees grow vigorous new shoots, and the new buds have the characteristic of early maturity, capable of sprouting 3 to 4 rounds of branches in a year, with a large and dense growth volume. Improper pruning often leads to reduced yield and weakened tree vigor; moreover, summer rainfall is heavy, with high temperatures and high humidity, making peach trees susceptible to pests and diseases. Timely summer pruning and pest and disease control in peach trees can ensure good tree growth and the quantity and quality of autumn fruit.

1 Summer Pruning

1.1 Pinching. Pinching is generally carried out after the new shoots have become lignified, and is done twice in summer: the first time between May 10 and June 10, mainly pinching the peripheral extension shoots; the second time between June 20 and July 10, pinching the still vigorously growing shoot tips.

1.2 Shoot twisting. Shoot twisting can convert vigorous water sprouts into fruiting branches and also improve the light environment of the tree. It is best done when the new shoots have grown to 25 to 35 cm and are not yet lignified, twisting at 10 cm from the base of the shoot. If the desired effect is not achieved, a second twisting can be performed.

1.3 Branch bending. The bending angle is generally kept at around 80, but the branch should not be bent to a horizontal position. Branch bending is generally carried out around June. The method can be applied flexibly, with gentle and even force. To avoid injuring the branch, soft material is usually placed at the bending point.

1.4 Thinning. This means removing competing branches, water sprouts, overly dense branches, dead branches, etc. Pruning should be carried out according to the age and growth vigor of the tree, taking care to thin where dense and retain where sparse, thin the strong and retain the vigorous, so that the layout among branches is reasonable.

1.5 Flower and fruit thinning. The object of flower thinning is varieties with a high fruit-setting rate, and the objects removed include upward-facing flowers, twin flowers, and leafless flowers, so that the retained flowers are evenly spaced and reasonably arranged. Reserve branches, main and lateral branch tips should not retain flower buds. During fruit thinning, the objects removed include withered yellow fruit, small fruit, pest- and disease-damaged fruit, and deformed fruit, while retaining good fruit that grows evenly on the middle and upper parts of the branch. Generally, the procedure is carried out from top to bottom along the branch, and from inside to outside. The principle for retaining fruit is to retain more fruit on the outer periphery and upper part of the canopy, and less fruit in the inner canopy and lower part. The amount of fruit retained should be appropriate for the tree, determined by considering tree age, variety, tree vigor and soil conditions.

2 Pest and Disease Control

2.1 Disease control. Focus on controlling anthracnose, brown rot, and peach bacterial shot hole. Options include 50% carbendazim powder at 600 times, or 70% thiophanate-methyl at 1 000 times, or 50% zineb at 600 to 800 times, or zinc sulfate lime solution (zinc sulfate 1 kg, lime 4 kg, water 240 kg), etc., used in rotation, sprayed once every 10 to 15 d, with no fewer than 2 disease control applications before bagging the peach fruit.

2.2 Pest control. Peach fruit moth, stinging caterpillar, leaf roller: spray 4.5% beta-cypermethrin at 1 500 times plus Lorsban at 2 000 times for control. Stink bug, scale insect, pear lace bug: can add beta-cypermethrin at 1 500 times, 60% dimehypo emulsifiable concentrate at 1 500 times; red spider mite, with a damage period roughly from April to October, worsening when temperatures are high. Spray 20% pyridaben wettable powder (dazhuoling, fenpyroximate) at 1 500 to 2 000 times solution, 2.4% abamectin at 6 000 to 8 000 times solution.

Overall, for summer pest and disease control in peach trees, before bagging the focus is on controlling peach fruit moth, stink bug, and scale insect; after bagging and before fruit ripening, the focus is on controlling stinging caterpillar, red spider mite, and pear lace bug, adjusted flexibly according to the actual occurrence that year and in that locality.