With the rise in temperatures in March, our region's Spring Tea harvest has entered its peak period. Some areas have reported aphid infestations in Tea gardens, which are damaging young leaves and causing Bud shoots to curl, affecting both yield and quality. Based on the morphological characteristics, reproduction methods, and damage symptoms of tea aphids, as well as their occurrence patterns and causes, the National Tea Industry Technology System's Yibin Comprehensive Test Station proposes control methods to help tea enterprises and farmers manage their tea gardens effectively and control tea aphids.

I. Morphological Characteristics

There are three forms of tea aphids: eggs, nymphs, and adults. The eggs are long-elliptical and glossy black. Nymphs and adults can be winged or wingless. Winged adults are glossy dark brown with milky white wing buds; winged nymphs are brownish-red. Wingless adults are nearly egg-shaped, slightly plump, brownish-red, with many pale yellow transverse reticulate patterns on their surfaces; wingless nymphs are light brown or yellow.

(Images sourced from the internet)

II. Reproduction Method

Tea aphids reproduce through parthenogenesis and sexual reproduction. During spring and summer, they primarily reproduce rapidly through parthenogenetic viviparous reproduction. In autumn and winter, due to changes in photoperiod and temperature or a reduction in food supply, female tea aphids start producing male aphids, leading to mating and egg production. These eggs overwinter on the underside of leaves and hatch into female aphids in early spring. After birth, a new generation can emerge within 5-7 days, and the lifespan of tea aphids is about 3 months.

III. Damage Symptoms

Nymphs and adults cluster on tender stems and leaves, sucking sap and causing the buds and leaves to curl downwards, become wrinkled, and wilt. Growth may be stunted, and shoots may even die. Their excreted “honeydew” often triggers sooty mold disease, severely impacting tea yield and quality.

IV. Causes and Occurrence Patterns

(A) Causes

1. Climate Conditions: Temperatures between 18°C and 25°C, less rainfall, and relatively low humidity (

2. Agricultural Management: Excessive use of nitrogen fertilizers leads to excessive growth and an increase in carbohydrates, attracting tea aphids. Additionally, the widespread use of broad-spectrum insecticides reduces the number of natural predators such as ladybugs, lacewings, hoverflies, and parasitic wasps, making it harder to control the reproduction of aphids.

(B) Occurrence Patterns

1. They occur mainly during March to May in spring and August to October in autumn. There are around 30 generations per year, with more severe damage occurring in spring than in autumn. In southern Sichuan tea regions, they appear earlier, starting in late February. Early in the spring, most aphids are found on the lower tender leaves of tea plants, gradually moving up to the upper shoots as the weather warms. There are fewer aphids during hot summers, primarily at the lower parts of the plants. In autumn, the upper shoots are again heavily infested.

2. Tea aphids prefer tender shoots. The highest numbers are typically found on the first and second leaves below the bud, and they exhibit a strong attraction to yellow, light, and sweetness, while avoiding silver-gray. When shoots become older and tougher, or when food becomes scarce or environmental conditions are unfavorable, winged aphids emerge from the colony and migrate to new shoots to feed.

V. Control Methods

The best time for control is early spring when tea aphids first appear. Adhere to the principle of “preventing once you see them, early prevention and treatment,” using a combination of agricultural, physical, and chemical control methods.

(A) Agricultural Control

1. Timely Picking and Pruning: Spring tea picking should be done in batches and promptly, removing a large number of tea aphids and worsening their nutritional conditions, reducing their population. During summer and autumn, combine pruning to remove the upper branches and shoots of the tea plants, disposing of diseased and infested branches outside the tea garden to reduce the number of aphids.

2. Improved Fertilization Management: Apply amino acid foliar fertilizers 5-7 days before spring tea picking to enhance the plant's resistance. Increase the application of phosphorus and potassium fertilizers while scientifically controlling the use of nitrogen fertilizers to prevent excessive growth and carbohydrate accumulation that attracts aphids.

3. Winter Management in Tea Gardens: During winter, clear the garden by deeply plowing the soil (about 30 cm) and exposing it to sunlight. Use sulfur lime spray to kill overwintering eggs and reduce the number of tea aphids the following year. Apply whitewash to the trunks and main branches to prevent the laying of eggs and reproduction of tea aphids.

(B) Physical Control

1. Yellow Sticky Traps and Silver Gray Strips: At the end of February and beginning of March, place yellow sticky traps in the fields, coated with machine oil or pesticide for control. Replace the panels when they are full and reapply the coating. The height of the traps should be level with or slightly above the top of the crops, and the recommended density is 25 per acre. Additionally, hanging silver-gray plastic bags in the fields can deter aphids.

2. Sugar-Acetate-Alcohol Solution Traps: During periods of high tea aphid activity, place containers filled with sugar-acetate-alcohol solution (prepared in a ratio of 1:1:4:16 of brown sugar, alcohol, vinegar, and water) in areas with high aphid populations for trapping. Typically, 10-20 containers are placed per acre.

3. Tea Aphid Sex Pheromone Traps: Tea aphid sex pheromones can disrupt mating and reduce the overwintering population. Spraying sex pheromones in tea gardens in late autumn can reduce the number of aphids in the following spring and mitigate the impact on premium teas.

(C) Chemical Control

1. Spring Control of Tea Aphids: During the spring tea picking period, if there is a widespread outbreak of tea aphids, apply low-toxicity and safe biopesticides like matrine aqueous solution, polygalasaponins wettable powder, and pyrethrum soluble concentrate, alternating their use. Spray the upper tender shoots of tea plants, paying attention to the safety intervals for picking.

2. Autumn Control of Tea Aphids: At the end of July, apply pesticides to protect the autumn shoots. After the autumn tea harvest, apply pesticides again, increasing the dosage to prevent a resurgence of tea aphids the following year. Recommended pesticides for general tea gardens include buprofezin, flonicamid, and pirimicarb.