Fund Project: Occurrence of Diseases and Pests of Bayberry in Suzhou and Prevention and Control Methods

Fund Project: Occurrence of Diseases and Pests of Bayberry in Suzhou and Prevention and Control Methods

Fund Project: Suzhou Agricultural Science and Technology Innovation Fund Project (SNG2018070).

_Huang Yinghong

Bayberry is one of the fruit trees with local characteristics of Suzhou, and its cultivation history is long, Su Dongpo once praised "Xiliang grapes, Fujian Guangdong lychee, not as Wuyue Bayberry". Bayberry is not only soft and juicy, colorful, sweet and sour, flavorful, rich in a variety of amino acids, mineral elements and vitamins beneficial to health, can provide consumers with delicious fruit, and its beautiful tree shape, evergreen, can also be used as a hilly mountain to conserve water, maintain water and soil, improve the ecological environment of excellent green tree species. With the increasing economic benefits of bayberry, the bayberry industry has been further developed in Suzhou, and fruit farmers have paid more and more attention to production, strengthening the management of bayberry diseases and insect pests. However, in the production process, many newly developed production areas do not know much about the occurrence of bayberry diseases and insect pests and control methods, and there are improper control or excessive control of diseases and insect pests, which cannot adapt to the general requirements of the current green production prevention and control of bayberry. The occurrence of the main diseases and insect pests and control measures of the current production of bayberry is introduced in order to provide a certain reference for the production of fruit farmers.

1 Suzhou main bayberry diseases and prevention methods

The diseases that harm Suzhou bayberry include bayberry carcinoma, brown spot disease, bayberry red cloth disease, bayberry wood rot, bayberry white rot, etc., but the main ones that occur more and are more widely harmful are bayberry cancer and bayberry white rot, and the others are only sporadic.

1.1 Bayberry carcinoma

1.1.1 Harmful symptoms. Bayberry cancer disease is mainly in the branches and trunks of bayberry, for the initial disease has a small milky white protrusion, its surface is smooth, and then gradually enlarged to form a rough surface tumor. After the twigs are killed, a small spherical tumor is formed, causing the branches above the tumor to dry up and die; after the trunk is killed, the surface is rough and uneven, and it evolves into brown or black brown wood-embolized tissue, which will cause the death of the whole plant when the tumor on the trunk is serious.

1.1.2 Occurrence. The pathogen is a disease-causing species of Pseudomonas lilacii arbutus. The germ overwinters in the cancerous tissue of the branches. In the spring of the following year, pus bacteria flow out of the surface of cancerous tissue, invade from leaf marks and wounds through rain, insects, air, etc., generally begin to invade at the end of April to the beginning of May, under the condition of 20 to 25 °C, after 30 to 35 days of incubation, symptoms appear, and occur more from late June to early August. In the arbutus orchards with poor drainage, as well as the older and weaker arbutus trees, the incidence of arbutus orchards with other crops is more severe.

1.1.3 Prevention and control methods. First, in 3-4 months, scrape off the spots with a sharp knife and apply 100 times the copper sulfate solution, and then apply it again after half a month. Or during the spring shoot extraction period, spray the arbutus branches evenly with 33.5% quinoline copper suspension 750 to 1000 times the liquid for 3 consecutive times, each time at an interval of 7 days. Second, after the summer typhoon, spraying should be sprayed to protect the tree body and prevent the invasion of germs. For the broken branches caused by the typhoon, it should be treated in time, and the wound should be coated with Bordeaux liquid and other protective agents. Harvest barefoot or wear soft shoes on tree harvesting during the harvest season to avoid damaging the bark and increasing wounds.

1.2 Bayberry white rot

1.2.1 Harmful symptoms. Bayberry white rot is commonly known as rotten bayberry. Generally in the middle and late stages of bayberry fruit harvesting and storage period for the harm to bayberry fruit, in the fruit surface to produce a gray-white mold layer, so that the flesh rot, resulting in the fruit surface depression, with the extension of time, the white rot area expands, generally less than 48h, will cause a large number of harmful fruits to land, the victim fruit can not be eaten, seriously affecting the yield and quality of the fruit.

1.2.2 Occurrence. The pathogen is semi-known bacteria subphylum ascomycete sclerotium disco, mainly penicillium and Trichoderma green, whose spores are colorless or pale gray. The more the fungus overwinters in the rotting fruit or soil, the more rain the fruit encounters when it ripens, the higher the ripeness of the fruit, and the more likely the fruit germ is to occur. At the beginning of the occurrence, only a few flesh columns wilt, as if the fruit was partially overridden and softened. In the later stage, due to the decrease in fruit resistance and acidity, the flesh column ruptures after absorbing water, spreading to half or whole fruit, the fruit is soft and rotten, and many white molds are produced in it [3].

1.2.3 Prevention and control methods. First, through rain-shelter cultivation technology, rain-shelter cultivation facilities can be set up during the fruit change period until the end of picking. The second is to use pruning technology to improve the ventilation and light transmission conditions of the canopy, reduce the occurrence of diseases, and harvest fruits in time. The third is to spray 450g/L imidaminated water emulsion 2000 times liquid or 10% water emulsion 500 to 700 times liquid 1 to 2 times during the color transformation period of bayberry fruit, and the safety interval is 15 days.

2 Suzhou bayberry main insect pests and control methods

There are many types of insect pests in Suzhou bayberry, but the main insect pests that have a greater impact on production are vinyl whitefly, cypress oyster oysters, leaf curl moths, bayberry curl leaf moths, oil tung inchworms, black-bellied fruit flies and other insect pests.

2.1 Camellia oleifera vinyl whitefly

2.1.1 Symptoms of harm. Camellia oleifera vinyl whitefly is also known as small black whitefly. When harming bayberry, most of the larvae parasitize the back of the leaf, and in order to harm the leaves of bayberry, the needle is inserted into the leaf tissue to suck the sap. Arbutus trees that are seriously damaged often cause the leaves to fall early and the tree to weaken. The female adult is 2 mm long, the head and thorax are dark gray, the abdomen is orange-red, and the ventral opening is rounded. The male mater is wedge-shaped. The nymphs are oblong-oval, pale yellow at first hatching, and gradually turn reddish-brown. The 2nd instar larvae are rounded, with a pitch-black leathery back and a grayish-white ventral surface that is mesohusic.

2.1.2 Occurrence. The worm occurs in 1 generation per year in Suzhou, where it overwinters on the leaf back as an old mature larvae. Pupates in late March of the following year, feathering from early April to mid-May, and feathering at its peak in mid-April. Most of the eggs are laid on the back of the old and new leaves. In early to mid-June, nymphs hatch and feed on bayberry leaves with a needle. Peeling begins in mid-to-late July into 2 years of age, when a black shell is formed, then a colorless transparent glue begins to be secreted, and then develops under the shell to 3 years old until it pupates and no longer moves. The 2-instar larvae are the most harmful, not only directly harming the leaves of bayberry, causing poor leaf growth, but also inducing coal pollution disease, which in turn affects the growth of bayberry trees, and causes a large number of arbutus trees to fall flowers and fruits when serious, resulting in a decline in the yield and quality of bayberry.

2.1.3 Prevention and control methods. The first is to do a good job of pruning in the garden in autumn and winter to prevent the tree from being depressed and reduce or control the damage of vinyl whiteflies; the second is to spray the back of the leaf with 200 times the oil emulsion or 30% sodium terpine soluble powder 200 times liquid in early May or early July.

2.2 Cypress oysters

2.2.1 Harmful symptoms. Cypress oyster oyster alias juniper cypress oyster shield oyster, cypress oyster shield oyster, nymphs and female adults gather on 1 to 3 years old branches and leaf petioles and around the main vein, causing leaves to die and fall early, and in severe cases a yellowish patch. Female adults have a long or curved custard-shaped shell, narrow at the front and wide at the back, and are sauce-brown. The males have elongated shells and are brown or light brown. Nymphs are ovate.

2.2.2 Occurrence. In Suzhou 1 year occurs 2 generations, with fertilized female adults overwintering on branches or leaves. The first generation of eggs begins to emerge in mid-April, hatches from late April to mid-May, and occurs from late May to early June as the first generation of nymphs, mainly infested spring shoots. Female adults begin laying second-generation eggs in mid-to-late July, hatch in late July, and are in full bloom in the second generation of nymphs in early August, mainly in the summer shoots.

2.2.3 Prevention and control methods. One is to spray the garden with a 3°~5°Be stone sulfur compound in winter to cut off dead branches and branches with high insect population density; second, at the peak of the first generation of nymphs, it can be sprayed on the back of the leaf with mineral oil 200 times liquid or 30% sodium rosulinate soluble powder 200 times liquid.

2.3 Bayberry curl moth

2.3.1 Harmful symptoms. Bayberry leaf curl moth spits silk on the edge of the young leaf or at the end of the young leaf, and the leaves are interspersed with adult insect packets, and they sneak in the leaves to bite the leaf flesh, which is harmful to the young shoots of the bayberry and the tree is weak. Adults are yellow , with yellowish-brown scales on the head , and a well-developed lower lip that protrudes forward. The larvae are about 1.5 mm long when they hatch, and the end-age body length is 11 to 18 mm. The head is yellow at all ages except the first age black. The dorsal plate of the forebreast is yellowish, 3 pairs of pectoral feet are yellowish brown, and the rest are yellowish-green.

2.3.2 Occurrence. Occurs in 9 generations in 1 year, overlapping generations, with larvae overwintering in the curly leaves. The larvae appear from April to May each year, the larvae are lively, and when mature, they pupate in the curly leaves. Adults inhabit leaves during the day and fly at night, and adults prefer molasses and are phototropic.

2.3.3 Prevention and control methods. One is that during the larval stage, 5% methylaminoavermectin benzoate can be sprayed with 6000 to 10000 times liquid, and the second is that adult insecticidal lamps can be used to trap adult insects.

2.4 Tung inchworm

2.4.1 Symptoms of harm. The leaf of the tung inchworm is mainly based on larvae. Adults are grayish-white , 1st to 2nd instar larvae are grayish-brown , infested at the tip of the leaf , and at 3rd to 4th instars , they gradually turn blue and are infested inside the canopy. After 4 years of age, it varies with the environment (dark brown or grayish brown or bluish gray). 5 to 6 years old mature larvae, body length 60 to 70 mm, dense brown spots on the head. Pupae are dark brown.

2.4.2 Occurrence. In Suzhou 1 year occurs 2 to 3 generations. The first generation of larvae occurs between mid-May and late June, and the second generation of larvae occurs from mid-July to late August. The 3rd generation of larvae occurs from late September to mid-November. 1 to 2 instar larvae bite the midparaging edges and leaf tip epidermis. After 3 years of age, it bites the entire leaf. Its larvae are dominated by cloudy days and night eating.

2.4.3 Prevention and control methods. One is to spray 500 to 800 times liquid of Suyunjin bacillus with a suspension agent (containing more than 10 billion /mL of live spores) in May and September; the second is to trap adult insects with insecticidal lamps.

2.5 Drosophila melanogaster

2.5.1 Symptoms of harm. Black-bellied fruit fly for the fruit of the bayberry, when the fruit changes color, the flesh from hard to soft, the female adult worms begin to lay eggs on the surface of the fruit, hatching the larvae for the fruit of the bayberry, the affected fruit surface is uneven, the juice spills, the quality becomes inferior. Adults are small, pale yellow, with a black tail, 2 variants of red and white compound eyes, rounded antennae 3, transparent wings, 2 notches on the anterior margin, and a stubby abdomen. The egg is milky white, about 0.5 mm long, with a small mesh grid on the surface of the egg and 2 ovales at the front. The larvae are maggot-shaped, milky or yellowish-white, with a body length of 4.5 to 5.5 mm. Pupae are pupae, initially white and later gradually yellowish brown.

2.5.2 Occurrence. There are many algebraic occurrences in the black-bellied fruit fly. The egg stage is up to 57 days at 10°C, 18d at 15°C, and 6 to 4 days at 20°C. The generational calendar period is 12 to 15d at 20 to 25°C. The breeding rate is fast, and the first generation is only 4 to 7 d. The peak period occurs from mid-to-late June to early and late July. Old mature adults begin to escape the fruit from 8:00 to 9:00, burrow into the soil for 3 to 5 cm or pupate under dead leaves or in fresh bryophytes.

2.5.3 Prevention and control methods. One is to remove the rot between the garden and the garden, do not discard the rotten fruit between the garden during the picking, so as not to attract fruit flies, do not provide a breeding place for fruit flies, in order to reduce the harm; the second is that each tree can hang 1 yellow insect board from mid-April to late June, changing it once every 10d; the third is to hang sweet and sour liquid to trap fruit flies from mid-April to late July, and hang 1 to 2 per tree depending on the size of the tree.

3 Some precautions for the control of arbutus pests and diseases

Bayberry fruit has no peel, and its fruit safety should be paid special attention. The prevention and control of bayberry diseases and insect pests should adhere to the green control policy of "prevention first, comprehensive prevention", give priority to agricultural control, physical control and biological control methods for the prevention and control of diseases and insects, and carry out chemical control work in a timely and appropriate manner on the basis of the use of pesticides in the state registration and permits. Some time before the fruit ripens, the use of chemical pesticides is strictly prohibited