How to apply biological pesticides in tea production

Tea has vast production areas and numerous varieties in our country; it is an important daily consumer product for the people of our country, and at the same time a major agricultural product that earns foreign exchange through export. The current tea market, especially tea exports, has very high requirements for tea quality and safety.

At present, “pollution-free production” has already been implemented in Chinese tea production; integrated pest and disease management techniques are being vigorously promoted and popularized, greatly reducing the amount of chemical pesticides applied in tea production; some persistent and systemic pesticides (such as BHC, etc.) are prohibited in tea production; the use of pesticides and botanical pesticides, microbial pesticides that are low-toxicity, high-efficiency, low-residue, low water solubility and easily degradable is advocated; and a safety interval system for pesticides in tea production has been established. Biological pesticides, including microbial pesticides and plant-source pesticides, etc., will not cause pollution to tea or the environment, have very low toxicity to humans and livestock, and will not cause residual toxicity, so they are suitable pesticides for producing green food tea. In current production of Grade A green food tea, especially organic tea and Grade AA green food tea, the use of the following biological pesticides is worth promoting.

Rotenone. Also known as derris extract, it is a botanical insecticide with a long history of application. It decomposes easily in air, has low residual toxicity and is environmentally friendly. It has contact and stomach poisoning effects on pests. Its insecticidal spectrum is broad, and its residual period is short, generally 5~6 days, and only 2~3 days under summer sunlight. It can be used in the production of Grade A green tea to control tea geometrid, tea tussock moth, tea caterpillar, leaf-roller moths, bagworm moths, slug moths, small green leafhopper, black citrus whitefly and tea aphid, using 150~250mL of 2.5% rotenone EC per 667 m2, diluted with water to a 300~500 times solution for spraying. This pesticide cannot be mixed with alkaline pesticides. Rotenone is highly toxic to fish, so pollution of fish ponds should be prevented during use.

Matrine. Also known as sophorine, it is an alkaloid preparation made by extracting the roots and fruits of the Chinese herbal medicine Sophora flavescens with organic solvents such as ethanol. It degrades easily in the environment and basically leaves no residue. To control tea black tussock moth and tea tussock moth, during the 1st and 2nd instar larval stages, or at the peak of egg hatching, use 50~75mL of 0.2% matrine AS per 667 m2, add 50~75L of water, and dilute to a 1000~1500 times solution for spraying. It can be used in organic tea gardens to control tea geometrid; before the 3rd instar larvae, use 3.2% chongshajing EC per 667 m2.