First, prevent and control the harm of "knowing"
"Know it" is also known as the grasshopper. It is mainly produced by female adults on new shoots, causing the middle and upper parts of the branches to die. In particular, the threat to young trees is the greatest, and when the damage is serious, the rate of new and quiet damage can reach more than 50%, which is extremely unfavorable to the early results of the crown expansion of young trees. Adults begin to feather in mid to late June, with the peak of feathering in July. In the evening before the feathering, especially after the rain, if the old insects emerge from the soil, they crawl up the trunk and molt that night.
cicada
Adults can fly at rest for 2 to 3 hours after feathering. The peak period for females to lay eggs is from July to September. When laying eggs, the egg layer is pierced into the xylem under the epidermis of the new shoots, forming many cracks, and then laying eggs in them, each laying 4 to 8 eggs, and one branch can lay more than 100 eggs, resulting in the death of the middle and upper parts of the new shoots.
To prevent and control grasshoppers, we must focus on doing a good job in kindergartens. At present, there is no very effective method for the control of grasshoppers, but the following measures can be taken to reduce the degree of harm.
1. Intercept and catch climbing cicadas.
At the peak of adult feathering (July), plastic film bands are tied to the trunks of trees to intercept the feathering of the branches of the excavated cicadas.
The method is: the 5 to 8 cm wide plastic film belt, flat tied to the upper part of the trunk, when the night climbing cicadas out of the ground, climbing to the plastic film belt encounters slippage and obstruction, that is, catch. Especially after the rain, the capture effect is more significant;
2. Manual interference and capture.
The survey found that during the diligent management of orchards from July to August, grasshoppers were less harmful, which was due to the fact that people in the orchards often operated, and human activities invisibly interfered with grasshoppers. In addition, small kindergartens can be artificially harvested during the peak of adult feathering and egg laying to reduce the victimization;
3. Repel cicadas to lay eggs.
Small kindergartens can tie colored plastic strips about 3 cm wide and 50 to 100 cm long on the branches of fruit trees, 2 to 3 per plant. Because the plastic strips flutter with the wind, the flying cicadas dare not fall into the tree to lay eggs.
(1) Cut off the insect shoots, cut off the egg-laying shoots in time, burn them centrally, and eliminate the overwintering eggs.
(2) Cut down poplar trees near the orchard, and poplar trees near the orchard are easy to attract a large number of grasshoppers, which makes the apple trees seriously damaged. Where possible, it should be sung as much as possible.
Second, control boat-shaped caterpillars
The boat-shaped caterpillar is a leaf-eating pest that occurs late in the growth of new shoots. The larvae are about 50 mm long (old and young), the head is black and shiny, the body is purple-brown, the whole body has yellow and white long soft hairs, when it is stationary, the head, the tail is upturned like a boat, so it is called a boat-shaped caterpillar.
Funagata caterpillar
The eggs are spherical, about 1 mm in diameter, initially pale green, then yellowish brown, dozens of eggs are laid into egg blocks, boat-shaped caterpillars feed on the leaves by larvae, often feeding on dozens of clustered leaves, and the young larvae eat the leaves into a mesh shape, slightly larger can eat the whole leaves, leaving only the petiole. When the damage is severe, a large branch or a whole leaf can be eaten. Orchards with extensive management are more affected.
The worm occurs once a year. Adults are feathered from the first sentence of June to the beginning of August, and the feathering peak is in mid to late July. After the adults feather, they lay their eggs on the back of the leaves. The egg stage is about 7 days, after which the hatching larvae are pests. The peak period is from late July to August. Larvae are frightened and have a leaf drooping habit.
The focus of the control of boat-shaped caterpillars is to manage extensive kindergartens, and the control measures are as follows:
(1) Use the habit of clustering as a pest, and remove the insect leaves in time to eliminate the larvae. Or use the sagging habit of spitting to kill.
(2) When the harm is serious, it can be sprayed with 50% octylthion emulsion 100 times, or 20% kills permethrin 2000 to 25000 times, or 2,5% kills 2000 to 2500 times, or 80% of dichlorvos emulsion 800 to 100 times and other agents to kill.