Efficient control of tea thrips
Tea thrips belong to the thrips family of Thysanoptera. It rasps the new shoots and tender leaves to make the tea stiff and brittle, which is the pest that has the greatest impact on the quality of tea.
1. Why is it difficult to control thrips？
a. Concealment: Thrips are photophobic, hide in the daytime and come out an night (sometimes hiding in the gap of soil layer). Harming plants on the back of the leaves and inside the flowers, which are difficult to detect;
b. Fast: Thrips are extremely small and difficult to detect. The nymphs can fly and jump, and once they appear, they spread quickly and are difficult to prevent;
c. Strong reproduction ability: Only 14 days from egg to nymph, generations alternate, 7-8 generations a year, there is a strong overlap of generations;
d. Temperature: in some periods, the temperature is more appropriate, which provides external conditions for the outbreak of thrips;
e. Strong resistance to pesticides: After long-term evolution, thrips have formed different levels of pesticide resistance to organophosphorus, carbamates, neonicotines, pyrethroids and microbial pesticides.
Both larvae and adults feed by piercing the tea plant tissue and sucking up the released plant juices. The injured leaves show two or more red-brown streaks on both sides of the main vein of the back of the leaves, and the front of the leaves bulges correspondingly. At the later stage, the buds and leaves shrink, the leaves roll longitudinally to the back, and become stiff and brittle, which seriously affects the growth of tea trees.
The front of damaged tea leaves
Back of damaged tea leaves
3. Regularity of occurrence
Many generations occur in a year. This insect mainly occurs in areas with suitable temperature, without obvious overwintering phenomenon, and adults and nymphs can still be found on tender shoots in winter. In the southern tea area, it usually takes about 10 ~ 15 days to complete one generation. Adults lay eggs in mesophyll on the back of leaves, and nymph feeds on the juice of bud leaves after hatching, especially at the second instar. The pupa is under the lower part of the tea bush or under the dead leaves near the soil. Adults are lively, good at crawling and flying short distances. In cool weather or in the morning and evening, they live in the shade of the lower layer of tea trees when the sun is direct, and there are more occurrences in nurseries and young tea gardens.
Pick tea in batches and in time. Part of the eggs and nymphs can be removed while picking tea, which is conducive to controlling the development of pest.
During the peak period of pests, spray emamectin benzoate series + diafenthiuron or tolfenpyrad for control.
In the early stage of occurrence, targeted drug prevention should be carried out in conjunction with the regular occurrence of previous years. For example, the use of imidacloprid and lambda-cyhalothrin for early control.
Clearing the garden:
Timely clear the garden in winter, remove the dead branches and leaves and burn them intensively to reduce the number of thrips in the coming year.
The occurrence and control of tea thrips are different due to different tea varieties, climatic conditions, growth environment and plant growth. The occurrence and control of tea thrips described above are for reference only, and comprehensive control should be carried out in combination with previous occurrence and drug resistance.