How to control the main pests and diseases of lilac? Detailed explanation of occurrence characteristics and control measures
What are the common pest and disease species of lilac? How to control them? Today the editor of Huinong Network will introduce a funded project mainly discussing the occurrence characteristics and control management of lilac pests and diseases. Interested farmer friends, hurry up and learn!
1 Diseases of lilac
1.1 Black spot disease
At the early stage of the disease, there are chlorotic spots on the leaves, which gradually expand to form round or nearly round lesions, 3 to 10 mm in diameter, brown or dark brown, with inconspicuous concentric rings. In the later stage, the lesions turn grayish brown and are densely covered with black mold spots, which are the conidiophores and conidia of the pathogen. The lesions connect with each other, causing a large part of the leaf to die and turn brownish yellow, and to shrink and even break apart. The pathogen of lilac black spot disease is a fungus of the genus Alternaria. Conidiophores are scattered or gathered in several strands, brown; conidia brown.
1.2 Brown spot disease
Brown spot disease mainly damages leaves, and can occur in both seedlings and mature trees. At the early stage of the disease, small lesions appear on the leaves, water-soaked, nearly round, grayish green, 3 to 12 mm in diameter. When humid, small mold spots are scattered on them. When the disease is severe, the lesions merge into large dead patches, grayish brown, covering the leaves, looking like fire from a distance, causing lilac leaves to dry up, and finally defoliating early, with only a few leaves remaining on the whole plant. The pathogen is a fungus of the genus Cercospora, which also infects camellia, pomegranate, Euonymus japonicus, crape myrtle, rhododendron and cockscomb, etc.
1.3 Powdery mildew
This disease can occur on both sides of the leaves, mainly on the upper side. At the early stage of the disease, scattered small powdery spots are produced on the diseased leaves, gradually expanding, and the powdery spots connect with each other to cover the leaf surface. In the later stage, the white powdery layer becomes sparse, appearing dusty, with small white particles appearing on it, and finally turning into black powdery dots - cleistothecia, which are the sexual stage of the disease, while the white powdery layer is the asexual stage. The disease of lilac powdery mildew is caused by Erysiphe syringae. Cleistothecia are spherical or flattened spherical, with appendages branching several times at the tip; multiple asci in the cleistothecium, elliptical to broadly elliptical; 4 to 6 ascospores, elliptical or ovate.
1.4 Pestalotia leaf spot disease
The lesions are small round spots 1 to 5 mm, white in the middle with dark brown edges, accompanied by purple halos. When humid, a large number of small black dots grow on the lesions, and the lesions penetrate both sides of the leaf. The pathogen is Pestalotia funerea. The black dots on the leaf spots are acervuli, conidia spindle-shaped, with 4 septa dividing into 5 cells, the middle 3 light brown, both ends colorless, with
3 flagella at the top.
1.5 Macrophoma leaf spot disease
The lesions are nearly round or irregular, 10 to 30 mm in diameter, and when at their largest can occupy more than 1/2 of the leaf area. The lesions are grayish brown, with a wavy purplish black band at the boundary between diseased and healthy tissue, on which a large number of small black dots are scattered, and in the later stage the diseased leaves become deformed. The pathogen mainly invades from the leaf tip. The pathogen is Macrophoma theicola. Conidiophores are small and unbranched. Conidia are elliptical, single-celled, colorless, 15.5 to 17.5 μm x 3.8 to 4.2 um in size. The small black dots on the leaf spots are the pycnidia of the pathogen, flattened spherical, 100 to 120 μm in diameter.
1.6 Corynespora leaf spot disease
It is reported that this disease once occurred in India. At the early stage, small water-soaked lesions appear on the leaves, up to 1 to 3 mm in diameter, with yellow halos at the edges, and the center clearly turning white. In most cases the lesions unite, showing typical leaf rot symptoms, and the leaf tip can wither up to half a leaf. The pathogen is a fungus of the genus Corynespora, Deuteromycotina. Conidiophores are erect and septate, growing in bundles on the underside of the leaf. They are branched, each branch can produce phialides, and finally produce conidia, club-shaped and multi-septate.
1.7 Die-back disease
This disease is mainly common in Sumatra and other places; it has not been seen in China so far. After infection, the bark and xylem of the branches turn reddish brown, small black dots can be produced, yellow mucus grows on them, and the surface of the diseased part becomes rough. Individual branches die back, and in severe cases the whole plant dies. The pathogen is caused by a fungus of the genus Cryptosporella. This is a wound parasite. The pathogen's pycnidia are scattered, with long necks, and conidia are filiform, yellow, single-celled, and can form masses. Asci are long without appendages, containing 8 spores, spores filiform, single-celled.
1.8 Bacterial blight
Lilac bacterial blight, also called bacterial flower spot disease, mainly infects leaves [8]. There are mainly 4 types of symptoms on leaves: first, spot blotch, which begins on lower leaves, forming chlorotic spots that soon turn brown, after which the center of the lesion becomes grayish white; second, starburst spot, in which one or several brown lines extend from a round lesion and connect with other small spot lesions to form a starburst shape; third, flower spot, in which the spot lesions continuously expand outward, forming concentric rings, with a grayish white center, and finally wavy lines are produced around the round spot, making the round spot resemble a flower; fourth, scorch, in which the whole leaf turns brown, dries and curls on the branches, looking like fire from a distance, and in severe cases the whole shrub dies. The pathogen of this disease is a bacterium, Pseudomonas syringae, belonging to Pseudomonas. The bacteria are single, rod-shaped, with 1 to 2 flagella at one end, able to swim in water, and without capsules. Gram stain reaction negative.
1.9 Algal leaf spot disease
The lesions are nearly round or irregular, 5 to 12 mm in diameter, initially purplish red, then the center becomes purplish black, while the edge remains purplish red. On the back of the lesions, a large number of golden yellow felt-like substances grow. The pathogen is a parasitic algal plant. The vegetative body of the pathogenic algae spreads on the lesions to form a dense nearly round felt-like substance, and later sporangiophores and zoosporangia grow. The tip of the sporangiophore swells, bearing 8 to 12 small stalks, each with an ovate, yellowish brown zoosporangium at the top, which releases biflagellate, elliptical zoospores when mature and exposed to moisture.
1.10 Root-knot nematode disease and root rot
They belong to root diseases. Nematodes can cause weak plant growth, yellowing of branches and leaves, and root galls; while root rot causes root decay. In mild cases, growth stops; in severe cases, the plant withers and dies.
2 Lilac insect pests
2.1 Scale insects
There are many species of scale insects damaging lilac, such as Icerya purchasi and Unaspis euonymi, etc. The pests mainly damage the branches and trunks of lilac, and in severe cases cause leaves to wither and black mold spots to grow on the branches and trunks.
2.2 Leaf-mining flea beetle
The leaf-mining flea beetle, also known as the privet flea beetle, belongs to Coleoptera, Chrysomelidae, and mainly damages lilac. In North China there are 3 generations per year. Adults mainly feed on leaf mesophyll, causing round or irregular small spots on the leaves, while larvae bore into the leaf epidermis, forming curved mining tunnels in the epidermis, causing leaf damage, and large numbers of leaves scorch.
In addition, pests damaging lilac also include aphids, leaf moths, etc.
3 Control and management of lilac pests and diseases
3.1 Chemical control
In early spring, spray protective agents such as Bordeaux mixture, zineb, and lime sulfur in advance for control. After the disease occurs, promptly spray fungicides such as chlorothalonil and carbendazim, or after lilac leaf expansion spray once every 15 d with 50% thiophanate-methyl 800 times solution, or use 50% carbendazim wettable powder 1 000 times solution for control, spraying 2 to 3 times is enough. It is also possible to spray 1:1:150 Bordeaux mixture before the disease or at the early stage of the disease to protect new leaves and increase disease resistance.
For the control of bacterial diseases, spray 3% zhongshengmycin wettable powder 600 to 800 times solution, or 2% kasugamycin wettable powder 300 to 500 times solution, or 60% fosetyl-aluminum and copper wettable powder 500 to 700 times solution, or 20% bismerthiazol wettable powder 600 to 800 times solution, or 30% copper fatty acid wettable powder 400 to 600 times solution for control. When the disease is widespread, use 72% agricultural streptomycin sulfate soluble powder 2 000 to 4 000 times solution, or 88% oxytetracycline soluble powder 3 000 to 4 000 times solution, or 20% zinc thiazole suspension 600 to 800 times solution, or 25% copper ammonia complex aqueous solution 400 to 600 times solution, etc., spraying once every 5 to 10 d depending on the disease situation.
To control scale insects, spray lime sulfur on the trunk during the dormant period. Pesticides should also be sprayed in early spring, and from June spray once every 14 d, which can also control other fungal diseases. When the larval activity period is detected by investigation, immediately spray 80% dichlorvos 1 000 to 1 500 times solution or pyrethroid pesticides, and spray again after an interval of 14 d; repeating twice is enough, with remarkable effect. When female insects are fixed and damaging the branches and trunks, you can also use a knife to cut the epidermis of the stem and trunk, then apply pesticide, so that the plant absorbs the pesticide and kills the insects. Red spider mites damage leaves; use 0.2 to 0.3 Baume lime sulfur and 20% tetradifon diluted 500 times solution to spray and kill them. Mixing the two liquids gives a better effect; spray once every 5 to 7 days, using continuously 2 to 3 times.
When lilac is in weak growth condition, it occasionally also suffers damage from pests such as cotton aphid, flea beetle, and giant hornet, causing sap to flow from the wounds. Careful investigation should be carried out to detect and handle them promptly. You can choose 10% imidacloprid wettable powder 2 000 times solution, or 4.5% beta-cypermethrin emulsifiable concentrate 1 500 times solution + Haoshi 3 000 times solution, or 40% chlorpyrifos emulsifiable concentrate 1 500 times solution, or 20% diflubenzuron emulsifiable concentrate 3 000 times solution, 40% omethoate 800 to 1 000 times solution or abamectin spray for control. When using chemical pesticides for control, pay attention to alternating use.
3.2 Field management
3.2.1 Select superior varieties
When planting, selecting excellent disease-resistant varieties is also crucial for controlling diseases.
3.2.2 Reduce inoculum sources
Strengthen management after planting; in autumn and winter, clean the field, promptly remove dead branches, fallen leaves and diseased residues and burn them in a centralized manner to reduce pathogen infection sources.
3.2.3 Prune branches and trunks
Lilac should not be planted too densely and requires a great deal of pruning. If there are several forked main trunks, remove the weak and keep the strong, remove the slanted and keep the straight, retaining 1. During the growing period, timely pruning and shaping are needed to control branch and leaf density and facilitate ventilation and light penetration.
3.2.4 Strengthen drainage and irrigation
Young lilac has weak roots and is not drought-tolerant. For young trees under 3 a old, irrigation is needed in dry seasons; during the flowering and fruiting period, drought seasons easily cause flower and fruit drop, so irrigation is also needed; in the rainy season, attention should be paid to timely drainage of accumulated water to reduce humidity and prevent waterlogging.
3.2.5 Fertilization
Apply phosphorus and potassium fertilizers at the right time and in the right amount, apply less nitrogen fertilizer, and apply organic fertilizers such as barnyard manure or compost, mixed with an appropriate amount of superphosphate and plant ash.
3.2.6 Weeding and earthing up
Carry out weeding and earthing up from July to October each year. Lilac trees have shallow root systems; cover the plants with grass, taking care not to damage the roots, to prevent the occurrence of nematode disease and root rot. Fine roots should not be exposed on the soil surface; if exposed, cover them with 2 to 5 cm of fertile loose soil.
The above is all the content compiled by the editor for everyone today. Welcome every farmer friend in need to learn at Huinong Network!
Main pests and diseases occurring on flowers and trees in autumn and their control
After entering autumn, temperature and humidity are moderate and light is good, creating favorable conditions for the breeding, reproduction and infection of some pathogens, often causing certain flowers and trees to suffer serious damage. The symptoms and control methods of several common pests and diseases are introduced as follows:
Brown spot disease
Mainly damages leaves. At the early stage of the disease, brown spots appear on the leaf surface, and later, as the disease continues to develop, the lesions gradually expand and merge into large spots. Because they are restricted by leaf veins, they are mostly irregular in shape. There is a faded halo on the outside. The edge is reddish brown, the center grayish white, and in the later stage black small dots (pycnidia) are produced in the middle of the lesions. When the disease is severe, the lesions fill the entire leaf. The leaves of affected plants fall off easily, and in severe cases, not a single leaf remains on the whole plant, forming a bare stem, and finally the whole plant gradually dies from bottom to top. Among these, flowers such as rhododendron, narcissus, jasmine, lilac, osmanthus, Chaenomeles speciosa, lotus, water lily, and photinia are seriously damaged.
Control methods: promptly prune diseased branches and leaves and burn them in a centralized manner to reduce pathogens. Before the disease occurs, spray 1:1:200 Bordeaux mixture once every 7--10 days, which can play a preventive role. At the early stage of the disease, spray 65% zineb wettable powder 500 times solution, or thiophanate-methyl 1000 times solution. You can also use 50% carbendazim 200 times solution to drench the roots.
Powdery mildew
Powdery mildew is mostly distributed on the upper side of Euonymus japonicus leaves, and also grows on the underside of leaves. Individual lesions are round, white, and after the lesions expand and heal with each other, they become irregular. When the superficial white powdery mycelium and spore layer are wiped off, the original diseased site appears as a yellow round spot. In severe cases, infection of new shoots can reach 100%. Sometimes diseased leaves shrink, and diseased shoots become twisted, deformed, and stunted.
Control methods: ① Properly thin branches to enhance plant permeability, and do not plant too densely when raising seedlings by cuttings; these are all issues that should be noted in controlling this disease. ② Chemical control: spray 20% triadimefon 2000 times solution, or 50% thiophanate, 50% carbendazim 500 times solution, immediately when the disease begins to appear, repeat once after about 10 days, spraying 4--5 times.
Anthracnose
The disease mainly occurs on leaves, and can also damage petioles, young branches, stems and flower buds and petals. After leaves are damaged, at the early stage small round pale white water-soaked spots appear, and later gradually expand, becoming grayish brown, with brown edges around them, slightly raised. Finally the central part of the lesion fades to grayish white to white, and this diseased part is extremely thin, semi-transparent, and easily perforated. In some cases, the disease starts from the leaf tip and then spreads inward into the leaf. The lesions can often reach 1/3--1/2 of the entire leaf surface, and finally the leaf dies. Some continuously fall off, and severely affected plants often have no leaves at all on the whole plant. When petioles are damaged, the diseased part turns brown, slightly sunken, and spreads to the leaf, extending to the main vein, branch veins and even the entire leaf turning brown. The lesions continue to spread downward, from the petiolule to the rachis, small branches, and even the stem turning brown and dying. Under humid conditions, pale red viscous substances often appear on the lesions, which are the acervuli produced by the pathogen. Affected plants, in mild cases, have normal growth and development affected and lose ornamental value; in severe cases, the whole plant dies. Flowers such as camellia, Chinese rose, Aglaia odorata, Michelia alba, lily, Magnolia grandiflora, nandina, Rohdea japonica, clivia, cactus, plum blossom, and orchid are prone to this disease.
Control methods: strengthen cultivation management, appropriately increase the application of phosphorus and potassium fertilizers, avoid partial application of nitrogen fertilizer, do not water too much, and do not let the potting soil become too wet. At the same time, enhance ventilation and light transmission performance and reduce humidity. When diseased leaves and diseased petioles are found, they should be immediately pruned and burned, and dead plants should be promptly removed. When the disease occurs, spray 50% thiram wettable powder 500 times solution or 70% thiophanate-methyl 1000 times solution, as well as 75% chlorothalonil 800 times solution, once every 10--15 days, continuously spraying 2-3 times. Alternating the agents can improve the control effect.
Graphium sarpedon
Mainly damages camphor tree, nanmu, laurel, Michelia alba, Michelia figo, Cinnamomum burmannii, avocado, citrus, etc. Newly hatched larvae first eat the egg shell, then feed on the leaf mesophyll on the underside of young leaves. After the 3rd instar, food intake increases, and they can eat all the leaves. Young trees 2--3 years old suffer the most severe damage. This seriously affects plant growth, development and ornamental value.
It occurs 2--3 generations per year, overwintering as pupae hanging on the branches and leaves in the middle and lower parts of the host. From mid-April to late May they emerge successively. The larval periods of the overwintering generation and the first to third generations are respectively from mid-May to mid-June, early July to mid-August, and late August to late September. Adults emerge at night, and 1--2 days after emergence fly among the forest, seeking flower nectar as supplementary nutrition. After several days they seek mates, copulate and lay eggs. They lay 1 egg at the tip of a young leaf, occasionally 2 eggs. Each female lays 18--34 eggs. Larvae have 5 instars and molt once every 4 days. The body grows with the instar, and the 5th instar larva has the largest food intake; each larva feeds on 1--5 camphor leaves per day. When mature, the larva crawls to the back of hidden small branches and leaves, fixes the tail with silk, and pupates in 2--3 days. The egg stage is generally 4--6 days, the larval stage about 20 days, and the overwintering pupal stage about 90 days. The suitable temperature for larval development is 20--28°C.
Control methods: ① During the adult egg-laying period, inspect the camphor seedlings in the nursery and promptly remove the eggs laid at the tips of the shoots. ② At the early stage of larval occurrence, spray 40% isocarbophos emulsifiable concentrate 1500 times solution. ③ In combination with winter management, remove overwintering pupae.
Crape myrtle felt scale
Mainly damages crape myrtle, pomegranate, mulberry, etc. Adults and nymphs pierce and suck on bud axils, leaves and branches, secreting honeydew, causing branches and leaves to turn black, leaves to fall off, affecting growth and losing ornamental value.
It occurs 2--3 generations per year. It overwinters as nymphs in the crevices of branches and trunks. The following year it continues to feed and cause damage. In April, mature male nymphs pupate and emerge, and mate with females, dying shortly after mating. Female adults begin laying eggs in early May. First-generation nymphs hatch from late May to early June. Second-generation female adults lay eggs in large numbers in early to mid-August. From late August to early September, nymphs hatch in large numbers, and development is uneven. There is a phenomenon of overlapping generations. The insects are mostly distributed in branch and trunk crevices and depressions. A few are distributed at the base of the underside of leaves. On branches, there are more on the shady side than on the sunny side.
Control methods: ① Use a bamboo strip or brush to scrape off insect-infested branches on the trunk and branches. ② At the end of nymph hatching, spray continuously 2--3 times, choosing 25% phosmet 600--800 times solution, 40% monocrotophos emulsifiable concentrate 1500--2000 times solution. ③ In combination with pruning, remove and burn insect-infested branches.
Slug moths
There are yellow slug moth, Parasa consocia, Thosea sinensis, etc. They mainly damage Bischofia polycarpa, poplar, willow, elm, black locust, cherry blossom, red maple, crabapple, wintersweet, crape myrtle, osmanthus, Euonymus japonicus, etc.
It occurs 2 generations per year, overwintering as larvae in cocoons in shallow soil. Adults hide during the day, fly and move at night, and are phototactic. Adults copulate and lay eggs. Eggs are often laid in groups of dozens on the underside of leaves, arranged like fish scales. The egg stage is 5--7 days. Newly hatched larvae do not feed; after the 2nd instar they feed on the molted skin and leaf mesophyll; after the 3rd and 4th instars they eat through the leaf epidermis; after the 6th instar they nibble inward from the leaf edge.
Control methods: ① Based on the clustering behavior of newly hatched slug moth larvae and the transparent dead spots on damaged leaves, which make the target obvious, organize manpower to remove the insect-infested leaves. ② Use lights to trap and kill adults of various slug moths to prevent egg laying. ③ Spray pesticides before the 3rd instar larvae of slug moths. You can use 20% diflubenzuron suspension 10000 times solution, 50% phoxim emulsifiable concentrate 2000--3000 times solution, or 50% malathion emulsifiable concentrate 1000 times solution. ④ In combination with winter pruning, cut off pupae and cocoons and burn them in a centralized manner, and in combination with measures such as loosening the soil under the tree canopy and fertilizing, dig out other slug moth cocoons underground to eliminate them.
Euonymus looper
Mainly damages Euonymus bungeanus, boxwood, Euonymus, elm, poplar, willow, etc. Larvae gather on leaves to feed. After eating all the leaves, they gnaw the bark of young branches, causing the whole plant to die.
It occurs 2--3 generations per year, overwintering as pupae. Adults rest in hidden places among branches and leaves during the day, and come out at night to move, copulate and lay eggs. Eggs are laid on the underside of leaves, arranged in double rows or in masses. Egg masses contain dozens to more than a hundred eggs. Eggs mostly hatch in the morning from 5:00--8:00, and the larvae gather on the underside of leaves to cause damage, chewing leaves and the bark of young branches. Mature larvae spin silk and drift down into the soil to pupate. Adults have weak flying ability and strong phototaxis.
Control methods: ① During the adult emergence period, use lights to trap and kill them. ② Taking advantage of the adults' weak flying ability and their habit of gathering on the upper and lower parts of host plants in the morning and evening, capture and kill them with simple tools. ③ During the larval damage period, spray 50% phosmet emulsifiable concentrate 200 times solution, 50% fenitrothion emulsifiable concentrate 500 times solution, 25% carbaryl wettable powder 300--500 times solution, with good control effect. ④ At the peak of adult egg laying, remove egg masses and newly hatched larvae on weeds around the root zone, and plow the soil around the root zone in winter, which can kill overwintering pupae.
Common pests and diseases of wax apple and control measures
Wax apple mainly grows in southern regions. Wax apple can flower and bear fruit multiple times in its lifetime. Because of this particularity, it is loved by many people. So during the planting period, what are the common pests and diseases of wax apple and what are the control measures?
Main diseases of wax apple
1. Anthracnose
It is the most important disease in production. In addition to damaging fruit, it can also infect leaves, forming dry-type lesions and becoming an infection source. Whether field management is good or not has a great relationship with the control of this disease. For control methods, you can use 56% thiabendazole wettable powder, 50% carbendazim wettable powder and 43% kasugamycin wettable powder. Other optional agents include 50% thiram, 40% folpet, 50% anilazine, 50% thiophanate and 75% chlorothalonil. In addition, do a good job in fruit tree management, prune diseased branches and excessive vegetative branches to make the fruit tree well ventilated, which can not only prevent disease occurrence but also facilitate uniform distribution of the pesticide. Bagging is also a good protective measure. On young wax apple fruit (bell stage), first apply pesticide to prevent infection, and bag immediately at the same time, which can also achieve a good control effect. Diseased branches, fallen leaves and fallen fruit in the field must be burned in a centralized manner or moved out of the orchard to reduce pathogen density and reduce disease occurrence.
2. Fruit rot
Pestalotia is one of the important pathogens in tropical regions, with many hosts. Many fruit trees such as areca, coconut, mango, and guava can all be damaged, mainly on leaves or fruit. Diseased fruit initially forms water-soaked color spots, the lesions expand with black dots on the surface, and finally the fruit turns dark purple or black, hangs on the branch, dehydrates, dries up and falls. Chemical control can use zineb, fosetyl-aluminum, metalaxyl, etc.; physical control can use bagging to block pathogen invasion; isolate suspicious hosts: avoid mixed planting or adjacency of multiple fruit trees. If already mixed planted, pesticides should also be applied to other fruit trees at the same time to reduce pathogens and reduce disease occurrence; clean the orchard to avoid spread of infection.
3. Phytophthora blight
Mainly damages mature fruit. It first forms faded lesions, and the affected part rapidly expands and is covered with white filaments. In about 2-3 the whole fruit will rot, with a strong sour smell, attracting fruit flies, which helps spread the pathogen. In controlling Phytophthora blight, field sanitation is the top priority, and removing the pathogen is the primary measure, such as removing diseased fruit. At the same time, avoid compost being together with Phytophthora blight fruit and diseased fruit, to reduce pathogen density and shorten the pathogen survival period. Use chemical agents to kill residual Phytophthora pathogens on the soil surface and reduce reinfection. Wax apple fruit should be avoided on branches that are too low, so branches near the ground should be pruned. The orchard should use grass cover to prevent rain splash and block infection. When the orchard disease is severe, fungicides can be sprayed on the ground surface within the tree canopy range and below 1.5 meters on the trunk to inhibit spread. Available fungicides include metalaxyl, fosetyl-aluminum, thiophanate-methyl, etc.
Main insect pests of wax apple
1. Oriental fruit fly
The top pest of wax apple is the oriental fruit fly. Females lay eggs on the fruit surface, larvae bore into and feed on the fruit, causing nearby flesh to rot and promoting fruit drop. Mature larvae crawl out from the flesh, spring to the ground and pupate. For control methods, during the fruiting period you can hang toxic methyl eugenol, insect traps or fiberboard traps to kill male flies, which is ineffective against females, and nearby orchards need to hang them at the same time, otherwise the effect is not good; chemical control can spread 25% malathion wettable powder or 5% fenthion emulsifiable concentrate 200 times mixed with protein hydrolysate (or 3% brown sugar water), spraying once every 7 days, spraying small trees and spraying the canopy, grass clumps or tree clump leaves near the orchard; clean the orchard, pick up fruit and bury it deep in soil or submerge it in water; bag the fruit.
2. Thrips
There are thrips that damage leaves, such as Thrips abdominalis, and flower thrips that damage floral organs, etc. The former is more common in the dry season. Adults and nymphs both feed on leaves and secrete excrement that fouls the leaves, causing leaves to rust, curl and fall, affecting photosynthesis. The latter damages floral organs during the flowering period, causing deformed fruit, rusty fruit spots, etc. For control, you can choose 25% tau-fluvalinate emulsifiable concentrate 3000 times solution, 28% lambda-cyhalothrin (Kung Fu) emulsifiable concentrate 2000 times solution, 2.8% deltamethrin (Decis) emulsifiable concentrate 1500 times solution, alpha-cypermethrin emulsifiable concentrate 1000 times solution, or 48.34% carbosulfan (Haonian Dong) emulsifiable concentrate 1500 times solution. For lambda-cyhalothrin, deltamethrin and alpha-cypermethrin, stop applying 6 days before harvest; for tau-fluvalinate, stop applying 18 days before harvest; for carbosulfan, stop applying 25 days before harvest.
3. Green leafhopper
It occurs more in dry seasons and when new leaves emerge. Adults and nymphs suck on young leaves and young shoots, causing young leaves to curl and growth to be hindered. The pesticides used to control thrips can effectively control green leafhoppers. You can also choose 50% parathion 2000 times solution.
The above are the control measures for common pests and diseases of wax apple. If there is anything you do not understand or you want more knowledge about pests and diseases, welcome to follow China Pesticide Network. In addition, note that wax apple likes warmth and fears cold, and the most suitable growth temperature is 25-30°C. There is no frost damage in winter; at 7°C flower buds and young fruit suffer cold damage and fall off; at 10°C fruit close to harvest will also be damaged and fall off. Wax apple has high water requirements and strong adaptability to different soil conditions. Wax apple prefers moist soil and needs sufficient water supply throughout the year. Wax apple near water always grows vigorously and also has strong tolerance to waterlogging, and areas often flooded also grow and flower and fruit normally. At the same time, it has low requirements for soil conditions; sandy soil, clay, red soil and slightly acidic or alkaline soil can all be planted, and for economic cultivation slightly alkaline clay loam with good irrigation conditions is best.