What are the diseases and insect pests of pear trees? How to prevent and cure it?

Pear tree is a perennial deciduous fruit tree of Rosaceae, and its cultivated area and yield are second only to apple trees. In its growing period, pear trees may suffer a lot of diseases or insect pests. How to prevent and cure it?

What are the diseases of pear trees? How to prevent and cure it?

The main diseases of pear trees are rot, dry rot, ring streak, anthracnose, brown spot, scab, black spot and so on.

1. Rot disease

Symptoms: harm to branches; at the initial stage of the disease, the disease is reddish brown, oval or irregular, waterlogged, slightly swollen, pressed with fingers, sunken, diseased tissue rotten, sometimes overflow reddish brown juice, give off the smell of distiller's grains, when the disease is serious, part or all of the tree dies.

Prevention and treatment: pruning and thinning in time, ventilation and light transmission, improve plant resistance; use a bottle of mother liquid of tree protection general to add 30 kg water diluent before the disease, spray the tree body and ground disinfection comprehensively, and use medicine once every 15 days; cut off the diseased plant and burn it in time after the disease, reduce the pathogen.

2. Dry rot

Symptoms: damage to branches and fruits; brown disease spots appeared in the cortex at the initial stage of branch disease, and the upper part withered when the disease spots extended to more than half a circle of branches; at the initial stage of fruit disease, there were wheel spots on the fruit surface, and then fruit rot; seedlings were infected, and the bark showed dark brown wet spots, the leaves wilted and the branches withered.

Prevention and treatment: strengthen the management of young trees to make them grow healthily and enhance their disease resistance; scrape and treat disease spots in time and smear them with Kuifuling solution; combined with winter and summer pruning, remove diseased branches and fruits in time and burn them centrally.

3. Wheel streak disease

Symptoms: harm to branches and fruits; in the early stage of the disease, dark brown watery spots were formed with lenticels as the center, gradually enlarged, round or flat, raised in the center, verrucous, hard, diseased trees grew weak, branches withered; in the early stage of fruit disease, brown water stains were formed with lenticels as the center, gradually expanding, showing dark reddish brown to light brown, with clear concentric patterns, and the diseased fruit rotted quickly and gave out a sour smell.

Prevention and treatment: do a good job of clearing the garden in winter to reduce and eliminate the source of infection; scrape and burn the disease spots on the branches before germination to reduce the source of primary infection of bacteria; spraying eradication agents during dormancy can directly kill bacteria; fruit bagging can effectively prevent rotten fruit.

4. Anthrax

Symptoms: harm to fruits and branches; at the initial stage of the disease, small round spots in the shape of light brown water stains appear on the fruit surface, and soft rot is sunken; when the disease is serious, most or the whole fruit rotates, causing fruit to fall or dry to shrink into a stiff fruit; the branches appear small round dark brown spots at first, then develop into oval or elongated shapes, dry and sunken in the middle of the disease spot, and the cortex and internal tissue of the diseased part gradually wither and show dark brown.

Prevention and treatment: no partial application of nitrogen fertilizer, increased application of phosphorus and potassium fertilizer, cultivation of strong seedlings, in order to improve the disease resistance of the plant itself; disease period, timely removal of diseased plant residues, diseased fruits, diseased leaves, diseased branches, etc.; thoroughly remove diseased leaves and residues after pulling seedlings.

5. Brown spot

Symptoms: harmful leaves and fruits; black-brown herpes and needle-like fine lines appeared on the front of the leaves in the early stage, and yellowing and shedding of the diseased leaves in the later stage; dark brown spots appeared on the fruit surface at the initial stage of the disease, gradually expanding and sunken on the surface, forming round or oval black spots.

Prevention and treatment: reasonable pruning, strengthening the tree potential, improving ventilation and light transmission; in the early stage of the disease, Aolikezujing 50ml + Jinbei 40ml, 15 kg of water, 5 Mel once a day for 2-3 times; remove fallen leaves and eliminate the source of infection.

6. Scab

Symptoms: harm to young leaves, tender shoots, young fruits; leaf symptoms, polygonal or nearly round discolored macula on the front, radiant mildew layer on the back of the leaves, resulting in a large number of fallen leaves when the condition is serious; new shoot infection, primary fusiform disease spots, late diseased part cortex cracking scab; young fruit infected, mostly early fall or diseased part lignified to form deformed fruit.

Control: select disease-resistant varieties; remove fallen leaves and fruits in late autumn and early winter, remove diseased shoots before early spring pear germination, remove diseased shoots and diseased flower clusters at the initial stage of disease, or promote flower buds to form ringed branches in the middle of May; spray with 400rel 600 times solution.

7. Black spot

Symptoms: harm to the fruit, leaves, new shoots; fruit damage, the appearance of one to several black spots on the fruit surface, the late onset of the disease fruit deformity, cracking, causing fruit drop; leaf damage, young leaves first onset, brown to dark brown round spots, and then gradually expand, severe diseased leaves namely scorched, deformed, early shedding; new shoot disease, disease spot round or oval, spindle-shaped, light brown or dark brown, slightly sunken, easy to break.

Prevention and treatment: select varieties with strong disease resistance; fertilize reasonably to enhance tree potential and improve disease resistance; after defoliation to before budding, clear the fallen leaves and fruits in the orchard, cut off the diseased branches and burn them deeply; when the disease occurs, use Sujing diluted and sprayed with 500 times liquid, once every 7 days.

Second, what are the pests of pear trees? How to prevent and cure it?

The main pests of pear trees are pear aphid, pear weevil, pear longicorn beetle, pear heart borer, pear star caterpillar, pear Shifeng and so on.

1. Pear aphid

Symptoms: harm to buds, leaves, shoots and stems; adults and nymphs gather sap on buds, leaves, shoots and stems, and both sides of the injured leaves roll vertically into a tube, which is easy to fall off in the early stage.

Prevention and treatment: early removal of damaged rolled leaves and centralized treatment; 3000 times of parathion EC, 2000 times of 40% dimethoate and 1000 times of 50% dichlorvos emulsion can be sprayed after the aphid eggs hatch.

2. Pear weevil

Symptoms: harm to young shoots, flowers and fruits; when pear buds sprout and sprout, adults feed on tender shoots and flowers; after the formation of young fruits, the fruits become wide strips and bite the stalks; they lay eggs in the fruit, and the larvae eat in the fruit after hatching, resulting in early fruit drop.

Prevention and control: pick up the fallen fruit on the ground in time and beat down the injured fruit, and kill the larvae; during the peak period of adult occurrence, the medicine is sprayed once every 10 murals for 15 days, twice in a row, and the effective agents are 80% dichlorvos 800 times, 50% phosphoamine emulsion 2000 times, 90% trichlorfon 1000 times.

3. Pear eye longicorn beetle

Symptoms: harm to leaves and branches; adults feed on the skin of leaves, petioles, leaf veins, leaf margins and twigs to supplement nutrition; larvae eat the xylem of branches, and damaged branches are easily broken by the wind.

Prevention and treatment: at the initial stage of egg hatching, spray 50% parathion EC or marathon EC or monocrotophos EC and the conventional concentration of various pyrethroid pesticides; during adult Eclosion, spray 1500 times parathion EC; cut off the insect branches in time, burn them or bury them deeply.

4. Pear heart borer

Symptoms: harm to pear buds, tender leaves of new shoots, petioles and fruits; the first generation larvae mainly damage pear buds, tender leaves and petioles of new shoots, and a few are harmful fruits; the second generation larvae are harmful to fruits, and the third generation fruits are the most harmful.

Prevention and treatment: scraping the warped skin from the tree in spring, the overwintering larvae can be eliminated; the fruits of the pests are removed in time and destroyed centrally; in the orchard, sugar and vinegar (brown sugar: vinegar: liquor: water = 1, 4, and 1) are added, and a small amount of trichlorfon is added to kill adults; 2.5% deltamethrin EC is sprayed 2500 times.

5. Dendrolimus punctatus

Symptoms: harm to flower buds and leaves; damage to flower buds, buds and leaves by larvae can occur twice a year.

Prevention and treatment: scrape the skin of the old wings in early spring to eliminate the overwintering larvae; the overwintering larvae spray 1000 times the liquid of crystal trichlorfon during the dormancy period.

6. Li Shifeng

Symptoms: harm to the fruit; the larvae initially feed in the inner circle at the base of the calyx, and then eat into the heart of the fruit after blackening, so that the young fruit dries up and falls off, and the larva climbs out before falling fruit, causing damage to other young fruits.

Prevention and treatment: artificial removal of oval flowers and young fruits with insects during the spawning period; ground spraying with 300 times of 25% parathion, 300 times of 25% phoxim or 600 times of 40.7% Lesben EC when adults are unearthed.

Summary: the main diseases of pear trees are rot, dry rot, ring rot, anthracnose, brown spot, black spot, black spot, etc., and the main pests are pear aphid, pear weevil, longicorn beetle, pear small heart borer, pear star caterpillar, pear Shifeng and so on.