What are the main aphids that harm citrus?
There are many kinds of aphids that harm citrus, among which orange aphid, orange binary aphid, meadowsweet aphid, cotton aphid, peach aphid and so on occur most commonly and are most widely distributed geographically.
Aphids are clustered with adults and nymphs to suck sap on the new shoots, and the young leaves of the new shoots are curled, crumpled, shortened between nodes, and cannot be stretched normally, causing fruit drops and a large number of new shoots that cannot be withdrawn in severe cases.
The "honeydew" excreted by aphids can induce soot disease, affect leaf photosynthesis, and weaken tree potential. Orange aphids, cotton aphids and rusty chrysanthemums are also the main vectors of citrus recession viruses.
Aphid control methods:
1. Prune the insecticidal source
In winter, pruning is combined to remove egged or damaged branches to eliminate the source of overwintering insects. During the growing season, buds or hearts are removed to remove the damaged branches and irregular new shoots to reduce the feeding of aphids and lower the population base.
2. Yellow plate booby trap
3. Protect and utilize predators
There are many types of natural enemies of citrus aphids, ladybugs, aphid-eating flies, grasshoppers, spiders, parasitic bees, parasitic bacteria, etc. are very effective natural enemies, unnecessary medication should be avoided in orchards, and the method of pick-and-treat should be used as much as possible to protect and use natural enemies. If there are few predators in the orchard, they can also be collected for release.
4. Pharmaceutical prevention and treatment
When the hatching rate of overwintering eggs of spring aphids reaches 50% to 70%, or when the aphid rate of new shoots reaches more than 20%, pharmaceutical control should be carried out immediately. The agent can choose 10% imidacloprid wettable powder 2000 times liquid, 50% anti-aphid wettable powder 2000 times liquid, 40% Lesben emulsion 1000 ~ 2000 times liquid, 25% Aktai water dispersible granules 5000 ~ 6000 times liquid, 15% Jinhaonian emulsion 2000 times liquid, 3% acetamidine emulsion 1500 ~ 2500 times liquid, 2.5% rotenone emulsion 600 ~ 1000 times liquid, 0.3% matrine water agent 400 times liquid, etc.
What are the main types of leaf beetles that harm citrus?
The leaf carapace pests that harm citrus include malignant leaf beetle, citrus leaf carapace, yellow melon, black-winged ha leaf carapace, grape ten-star leaf carapace, double-banded square frontal carapace, citrus tortoiseshell, spot-tailed tortoiseshell, etc., of which the more serious harm is the malignant leaf carapace and the citrus latent leaf carapace.
Malignant leaf beetles are also known as black fleas, black leaf jumpers, soft worms, yellow sloth worms, yellow slipper worms, maggot worms and so on. Adults and larvae are used as pests of young leaves, young stems, flowers and young fruits of citrus, so that the leaves form missing holes and holes, secretions and feces contaminate the young leaves, so that the leaves become scorched black and withered, which is the most harmful to spring shoots. Citrus leaf-based beetle is also known as orange leafminer, red leaf jumper, red dog worm and so on.
Adult insects are harmful to citrus shoots and young leaves, and only the epidermis is left when they feed on the leaf flesh; the larvae submerge on the leaf flesh, causing a long curved tunnel, and the affected leaves wilt and fall off.
At present, it is mainly used to strengthen the management of orange orchards, remove potential overwintering sites such as lichens, mosses, dead branches and leaves on trees, as well as cultivate loose soil to reduce the population base of overwintering insects; before pupaling, trunks and bundles of grasses induce larvae and concentrate on elimination; adults and young larvae are used to control and control with 80% dichlorvos emulsion 1000 times liquid, 40% quetiphosphate emulsion 1000 or 20% cypermethrin emulsion 2500-3500 times liquid at the peak of adult and young larvae.
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