What are the tea plant pests and diseases? Detailed explanation of common types
What should be noted during tea cultivation? Please refer to the following tea cultivation methods for your reference: 1. Field management of nurseries and young tea plantations: promptly clear away stones and other debris from nursery plots and young tea plantations, drain standing water, straighten tea seedlings, and use pruning shears to cut off the injured parts of damaged young tea seedlings; count as soon as possible...
What pests and diseases affect tea plants? How should they be prevented and controlled? Please adviseThe following are common tea plant pests and diseases:
1. Tea green leafhopper: This pest mainly uses adults and nymphs to pierce and suck the sap of tender tea shoots. Female adults lay eggs inside the stems of tender shoots, causing tea plant growth to be hindered. Damaged buds and leaves curl and harden, and leaf tips and margins turn reddish-brown and scorched. In low-mountain tea areas, this pest occurs 12-13 generations per year, with peak damage periods in May-June and September-October; in high-mountain tea areas, this pest occurs 8-9 generations per year, with peak damage periods in July-September. Adults overwinter on tea plants, leguminous plants and weeds. Adults mostly lay eggs in the tender stems between the second and third leaves of new shoots. Control methods: (1) Strengthen tea garden management, clear weeds in the garden, and promptly pick in batches and multiple times, which can reduce eggs and worsen nutrition and reproduction conditions, thereby reducing damage. (2) In severely affected tea gardens with a large overwintering pest population, from late November to mid-March of the following year, spray 50% phoxim or malathion at 1000 times dilution to eliminate overwintering pest sources. (3) During the picking season, according to pest forecasts, before the nymph peak, use the biological pesticide Tianba at 1000 times dilution or 80% dichlorvos at 2000 times dilution or 98% cartap at 1000-1500 times dilution.
2. Tea mites: Tea mites are an important group of pests on tea plants second only to leafhoppers in terms of damage. Because they are tiny, they are generally difficult to detect with the naked eye and can only be clearly observed under a 10x magnifying glass. The main species occurring in our city include pink citrus rust mite, tea rust mite, tea flat mite, coffee red mite and broad mite.
3. Pink citrus rust mite: This mite is relatively common in our city. It mainly uses adults and nymphs to suck the sap of mature leaves and tender leaves, causing damaged leaves to appear yellow-green, with main veins turning reddish-brown, losing luster, brown fine markings appearing on the underside of leaves, and buds and leaves shrinking. Adult mites are yellow or orange-red, carrot-shaped, with two pairs of legs at the front end; young and nymph mites are pale yellow to light orange-yellow. This pest occurs more than 20 generations per year, with the population mainly distributed on upper mature leaves and tender bud leaves. In environments with high temperature, drought, heavy rainfall and long rainy periods, the mite population in tea gardens is low and damage is light. There are two obvious peaks throughout the year, the first in May-June, and the second generally after the high-temperature drought period. Control methods: (1) After the autumn tea season ends, promptly spray 0.5 degree Beaume lime sulfur mixture before late November to reduce the overwintering population base. (2) Implement picking in batches and multiple times, which can reduce the pest population. (3) Before the occurrence peak, spray 20% pyridaben or 15% mie man ling at 2000-3000 times dilution or 25% buprofezin at 800-1000 times dilution.
4. Tea broad mite: Also known as broad mite, tea semi-tarsal mite. Adults and nymphs inhabit the underside of tender tea buds and leaves, sucking sap and causing damage. The underside of damaged leaves develops rust color, hardens and thickens, and leaf tips twist and deform. Buds and leaves shrink. This mite occurs 20-30 generations per year, with female adults overwintering on residual buds and leaves, scales, petioles, crevices and weeds. High-temperature and drought climate conditions favor its occurrence. Generally, summer and autumn tea is more severely affected. Control methods: Refer to pink citrus rust mite.
5. Tea rust mite: It mainly damages mature leaves and old leaves. Damaged leaves lose luster and turn bronze-colored, with dense white dust-like waxy molted skins along the veins on the leaf surface. Leaves become brittle and easily split, and in severe cases a large number of leaves fall. This mite occurs more than 10 generations per year, with adults overwintering on the underside of tea leaves. High-temperature and drought seasons favor its occurrence, and it is most prevalent from July to October throughout the year. Control methods: Refer to pink citrus rust mite, but picking in batches and multiple times is ineffective against it.
6. Tea flat mite: Adults and nymphs pierce and suck the sap of mature leaves or old leaves, causing leaves to lose luster. Purple patches often appear on the underside of leaves, and main veins and petioles turn brown, later becoming moldy and rotting, causing a large number of leaves to fall. This mite occurs about 10 generations per year, mainly with female adults gathering in the soil 1-6 cm below the surface at the root collar of tea plants to overwinter, with a few overwintering on the underside of leaves, axillary buds and fallen leaves. Most mites in tea gardens are female and reproduce by parthenogenesis, mainly inhabiting the underside of leaves to cause damage. Throughout the year, damage is severe during the high-temperature drought season from July to September. Control methods: (1) Do a good job in drought resistance in tea gardens, clear fallen leaves and weeds in tea gardens, strengthen management, enhance tree vigor and improve stress resistance. (2) After the autumn tea season ends and before the pest mites overwinter, spray 0.3-0.4 degree Beaume lime sulfur mixture for control. (3) Before the pest mite occurrence peak, spray 20% pyridaben or 15% mie man ling at 2000-3000 times dilution or 73% propargite at 2000 times dilution or 25% quinalphos at 1000-1500 times dilution for control.
7. Coffee red mite: This mite uses adults and nymphs to suck and damage mature leaves. Damaged leaves partially turn red, then develop dark red spots and lose luster. When dew has not dried, a layer of fine spider silk can be seen on the leaf surface. When pinching leaves with many mites, blood-red spots stain the fingers, and on closer inspection red mite bodies can be seen crawling on the leaves, with many white molted skins and egg shells near the mite bodies. It occurs 10-20 generations per year, with overlapping generations. It mostly inhabits the leaf surface to cause damage. Eggs are scattered on the upper surface of leaves, mostly on both sides of the main and lateral veins and in depressions. Damage is severe in early spring, autumn and winter. Control methods: Refer to tea flat mite.
8. Tea aphid: A common but easily controlled pest in tea gardens in our city. Tea aphids mostly gather on the underside of new shoot leaves, and are most numerous on the first and second leaves below the bud. They use mouthparts to pierce into tender leaf tissues and continuously suck sap, causing buds and leaves to shrink, elongation to stop, and even bud shoots to die. Their excrement, "honeydew," not only contaminates tender shoots but can also induce sooty mold. It occurs more than 20 generations per year, all overwintering as eggs or wingless aphids on the underside of leaves. In early spring, the population is mostly on tender leaves in the middle and lower parts of tea bushes, gradually moving to buds and shoots in the middle and upper parts after warm spring weather. In hot summer, the population is smaller and mostly in the lower parts, while in autumn it is mostly on buds and shoots in the middle and upper parts. Control methods: (1) Prompt picking in batches and multiple times. (2) For chemical control, usually use 40% dimethoate, 50% phoxim or 80% dichlorvos at 2000 times dilution, especially ensuring the underside of leaves is sprayed wet.
9. Black citrus whitefly: It causes serious damage in some tea areas of our city. Larvae gather on the underside of leaves, fix themselves and suck sap, and excrete "honeydew," inducing sooty mold. Damaged branches and leaves turn black, and in severe cases a large number of leaves fall, weakening tree vigor and affecting tea yield and quality. This pest occurs four generations per year, with mature larvae overwintering on the underside of leaves, pupating in March of the following year and emerging in early to mid-April. The larval occurrence periods of each generation are respectively late April to late June, late June to early July, mid-July to early August, and early October to December. Adults lay eggs on the underside of leaves, and newly hatched nymphs, after crawling, immediately fix themselves and suck sap to cause damage. Control methods: (1) Strengthen tea garden management: combined with pruning, collar pruning, mid-tillage and weeding, improve ventilation and light conditions in the tea garden and inhibit its occurrence. (2) Biological control: Apply Verticillium lecanii powder at 0.5-1.0 kg/mu by spraying, or use the fungus branch hanging method, that is, hang branches with Verticillium lecanii around the tea bushes, 5-10 branches per square meter. (3) Chemical control: According to pest forecasts, spray 25% buprofezin at 800 times dilution or 25% bifenthrin at 1000 times dilution or 50% phoxim at 1000 times dilution at the peak of egg hatching, and be sure to spray the underside of leaves wet.
10. Tea weevil: Also known as tea small black snout beetle. It causes serious damage in some tea areas of our city. Larvae feed on fibrous roots in the soil, and mainly adults bite and feed on leaves, causing arc-shaped notches on leaf margins. In severe cases, the whole garden is left with damaged leaves and bare veins, greatly affecting tea yield and quality. It occurs one generation per year, with larvae overwintering in the soil under the tea bush canopy, pupating successively from late March of the following year, beginning to emerge and come out of the soil successively in early April, and May-June is the peak damage period for adults. Adults have a death-feigning habit and retract their legs and fall to the ground when disturbed. Control methods: (1) Plow and loosen the soil, which can kill larvae and pupae. (2) Take advantage of the adult death-feigning habit by laying plastic film on the ground, then vigorously shaking them down to concentrate and eliminate them. (3) Before adults emerge from the soil, spread Beauveria bassiana 871 powder, using 1-2 kg of powder per mu mixed with fine soil and applied on the soil surface. (4) Before the adult emergence peak, spray 2.5% bifenthrin at 800 times dilution or 98% cartap at 800 times dilution or mix with 871 powder at 0.5-1.0 kg/mu.
11. Tea leaf roller: Commonly known as "leaf-wrapping worm" or "leaf-rolling worm." Larvae roll and tie tender shoots and new leaves or glue several leaves into a bract, up to 4-10 leaves, and the larvae hide inside to feed and cause damage. In severe cases, tea quality and yield are greatly reduced. This pest occurs 6 generations per year, with mature larvae overwintering in the worm bracts. The first appearance periods of larvae of each generation are often late March, late May, late July, early August, early September and early November, with overlapping generations, and larvae have six instars in total. Adults are phototactic, and eggs are laid in masses mostly on the leaf surface. Control methods: (1) Pick off egg masses and worm bracts by hand at any time, and pay attention to protecting parasitic wasps. (2) Use light traps to kill adults. (3) Control by spraying during the 1st and 2nd instar larval stages. You can choose 80% dichlorvos at 1000 times dilution or 2.5% bifenthrin or 25% quinalphos at 800 times dilution.
12. Tea branch clearwing moth: Also known as branch-boring worm, distributed in all tea areas of our city. Larvae bore into and feed on branches, often boring into main branches. In the early stage, buds and leaves on the branch stop elongating, and later all branches and leaves above the hollowed part of the bored branch die. This pest occurs one generation per year, with larvae overwintering in bored branches. Pupation begins in late March of the following year, with the peak pupation period in late April and the peak adult period in mid-to-late May. Adults lay eggs between the second and third leaf nodes of tender shoots. Several days after larvae bore into tender shoots, the buds and leaves above wither. After the third instar they enter the branches and eventually bore near the ground. The boring tunnel is relatively straight, and at certain intervals they bite through to the shaded side to make nearly circular excretion holes, with flocculent debris accumulating below the holes, and dark yellow short cylindrical fecal pellets scattered on nearby leaves or the ground. Control methods: (1) During the peak adult emergence period, use light traps to kill adults. (2) After the autumn tea season ends, cut off the pest branches 5 cun below the lowest excretion hole and kill the larvae inside the branches.
13. Moss and lichen: Moss is a higher green plant that lives in shady and humid places. Lichen is a symbiosis of fungi and algae and is divided by shape into foliose, crustose and fruticose lichens. They can all spread upward from the root collar of tea plants, causing the tea plant bark to brown-rot and growth to gradually weaken, seriously affecting normal growth and development. In continuous rainy spring or plum rain season, they grow fastest; in hot summer and cold winter, they stop growing. Control methods: (1) Strengthen field management, promptly carry out mid-tillage and weeding. In slack agricultural seasons, after rain, use bamboo slices and other tools to scrape them off and remove them from the garden. Keep the tea garden clean, apply fertilizer reasonably, and cultivate vigorous tree vigor. (2) Spray with 1% lime equal-amount Bordeaux mixture, with an effect of up to 90%. In winter, apply boiled and concentrated wood ash extract by brushing, which also has a very good effect.
2. What are the main diseases of tea plants? How to scientifically prevent and control them?
1. Tea white star disease: (1) Symptoms: Mainly damages tender leaves and new shoots. Initially small brown spots the size of a needle head appear, then gradually expand into small round lesions less than 2 mm in diameter, with a sunken center appearing gray-white and a brown raised line around the edge. Later, small black granules are scattered on the lesions, with more than a hundred lesions on a single tender leaf. (2) Occurrence pattern: This disease is a low-temperature and high-humidity type disease. Mycelium overwinters on diseased branches and leaves. In spring of the following year, when the temperature rises above 10°C, under high humidity conditions, conidia form on the lesions and spread by wind and rain, infecting young tender shoots. The low-temperature and rainy spring tea season is most suitable for spore formation and causes disease epidemics. High-mountain and young tea plantations are prone to the disease. Poor soil, excessive application of N fertilizer and improper management all make the disease more likely. (3) Control methods: (1) Strengthen management, increase the application of phosphorus and potassium fertilizers, enhance tree vigor and improve disease resistance. (2) Spray for protection during the spring tea germination period. You can use 70% thiophanate-methyl or 50% carbendazim at 1000 times dilution, and spray again after about 7 days.
2. Tea blister blight, also known as tea leaf gall disease, often occurs in high-altitude tea areas and damages tender leaves, tender shoots and petioles. Tea made from diseased leaves tastes bitter and breaks easily. (1) Symptoms: In the initial stage, light yellow water-soaked small spots appear on leaves, then gradually expand into light yellow-brown lesions with obvious edges, sunken on the upper surface and protruding in a blister shape on the underside, with gray-white powdery material on top, later turning into dark brown ulcer-like lesions. (2) Occurrence pattern: Mycelium overwinters or oversummers in diseased leaves. Temperatures of 15-20°C and relative humidity above 85% make the disease likely. Generally, damage is severe from March to May and September to October. In sloping tea gardens, the shady side is more prone to the disease than the sunny side. Tea gardens with extensive management, overgrown weeds, improper fertilization and shade are also prone to the disease. (3) Control methods: (1) Tea blister blight can spread during tea seedling transport, so quarantine should be strengthened. (2) Frequently remove weeds and prune appropriately in tea gardens to promote ventilation and light transmission, which can reduce disease occurrence. (3) Increase the application of phosphorus and potassium fertilizers to improve disease resistance. Removing diseased leaves in winter or early spring combined with tea garden management can effectively reduce the pathogen base. (4) In picking tea gardens, spray 70% thiophanate-methyl or 20% triadimefon at 1000 times dilution in the early stage of disease, and spray again after 10-15 days.
3. Tea anthracnose (1) Symptoms: Mainly damages mature leaves or old leaves. Lesions mostly arise from leaf margins or leaf tips, initially water-soaked; dark green and round, then gradually expand or become irregular large lesions, yellow-brown or light brown in color, finally turning gray-white, with scattered small black granules on them. There are no concentric rings on the lesions, and there is a yellow-brown raised line at the edge, clearly demarcated from healthy tissue. (2) Occurrence pattern: Mycelium overwinters in diseased leaves. In the following year, when the temperature rises to 20°C and relative humidity is above 80%, spores form and spread by rainwater. Temperatures of 25-27°C and high humidity are most favorable for disease occurrence. Throughout the year, it is most prevalent in the plum rain season and autumn rain season. Cutting tea gardens and collar-pruned tea gardens have tender leaves with high water content, which favors disease occurrence. Tea gardens with excessive N fertilizer also have severe disease. (3) Control methods: (1) Strengthen tea garden management, increase the application of P and K fertilizers, and improve tea plant disease resistance. (2) In the early stage of disease, spray 70% thiophanate-methyl at 1000-1500 times dilution or chlorothalonil at 500-800 times dilution.
4. Tea cloud-pattern leaf blight mainly damages old leaves, and can also occur on tender leaves, fruits and branches. Lesions mostly occur at leaf tips and leaf margins, semicircular or irregular in shape, initially yellow-brown and water-soaked, later turning brown, with wavy concentric rings on them, resembling cloud patterns. Finally, the lesions turn gray-white from the center outward, with gray-black small granules on them arranged along the concentric rings. This disease is most prevalent under high temperature (above 20°C) and high humidity (relative humidity above 80%). Tea gardens with weak tree vigor, poor management, and damage from freezing or pests also have severe disease. Control methods: Refer to tea anthracnose.
5. Tea ring spot disease occurs more on mature leaves and old leaves. It first produces yellow-green small spots from leaf tips and leaf margins, then gradually expands into round, semicircular or irregular lesions. The lesions are brown with obvious concentric circular rings, and later the center turns gray-white, with dense black relatively thick small granules on them arranged in rings along the concentric rings. There is often a brown raised line at the edge of the lesions. The pathogen invades tea plant tissues from wounds to produce new lesions. It occurs more in summer and autumn with high temperature and high humidity. Pruned or machine-picked tea gardens and tea gardens with frequent pest outbreaks have more severe disease. Tea gardens with weak tree vigor and poor drainage also have severe disease. Control methods: Refer to tea anthracnose.
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