Detailed Explanation of Pollution-Free Control Techniques for Tea Plant Pests and Diseases

The main pests currently occurring in tea gardens include the tea green leafhopper (Empoasca vitis), the pink tea mite (Acaphylla theae), and the tea geometrid (Ectropis obliqua); diseases include anthracnose and tea brown leaf spot. Tea farmers should strengthen tea garden surveys and carry out timely pest and disease control. For tea gardens with multiple concurrent pests, combine primary and secondary control, select high-efficiency, safe, pollution-free pesticides and biological pesticides, mix them rationally, reduce the number of sprayings, and ensure tea yield and quality.

Because the overwintering base of the tea green leafhopper was relatively high last winter and this spring, as temperatures rise, it has now occurred widely in tea gardens throughout the county, and insect numbers have risen rapidly since mid-May. According to a survey by the station on June 14, the number of insects per 100 leaves reached 37, of which nymphs accounted for 89.2%. The plum rain season is about to begin, which is very favorable for the growth and occurrence of this insect. Insect numbers are expected to continue increasing, which will have a certain impact on future tea production. Tea farmers should strengthen surveys in the gardens. In production, they should pick frequently in batches, which can carry away large numbers of eggs and young nymphs with the buds and leaves, and is an economical and effective method of controlling this insect. For tea gardens with more than 6 insects per 100 leaves, pesticide should be applied for control when sunny weather can be seized. For control, 60 mL/mu of Lülang emulsifiable concentrate can be selected. According to feedback from Miaogaozhuang Mountain Tea Farm, using 60 mL/mu of Lülang emulsifiable concentrate diluted with 50 kg of water for spraying kills the insects as it sprays, with extremely strong knock-down ability; three days after treatment there were no pests in the tea garden. Because Lülang is a pure plant insecticide, pollution-free, and free from resistance problems, it is a very good choice for tea gardens in the county that have been unable to control pests due to long-term use of imidacloprid-type pesticides.

The pink tea mite is a frequently occurring harmful mite in the county's tea gardens. Adults and young and nymph mites pierce and suck the sap of tender leaves, causing the leaves to lose their luster and brown rust spots to appear on the underside, which seriously affects tea yield, quality, and tree vigor. According to a survey by the agricultural plant protection department on June 14 at the county tea and fruit farm, the rate of mite-infested leaves was 96.67%, with an average of 24.1 mites per leaf and a maximum of 65 mites per leaf. Tea farmers should, according to the actual conditions of local tea gardens and in conjunction with control of pests such as the tea green leafhopper, spray for control in tea gardens averaging 17 mites per leaf. The application method should use low-volume sweeping spray over the canopy. For control, a 2000-fold dilution of 73% propargite emulsifiable concentrate can be selected. The safe interval before tea picking is 10 days (spraying should avoid the scorching sun).

For other pests such as the tea geometrid, tea farmers should closely monitor occurrence dynamics and carry out timely control. To control the tea geometrid, Lülang or Saidan can be selected; to control the tea black tussock moth, Lülang, dichlorvos, or Tianshengxing can be used. The safe interval is 7 days for all.

For tea gardens where leaf diseases such as tea brown leaf spot and anthracnose occur, in the early stage of the disease, 75 g/mu of 70% thiophanate-methyl or 100 g/mu of 75% chlorothalonil can be selected for control. The safe interval is 10 days.