Rapeseed field black insects, also known as black shell insects, aphids. Black-shelled worms are the collective names of rapeseed triceratops and coccus beetles. The cocoon leafworms are divided into two species: big cocoon beetle and small cocoon beetle. The three are often mixed.
First, the harm symptoms and characteristics. Pests like to eat rapeseed seedlings and young leaves, rapeseed rapeseed field has just been looted, large rape seedlings are often eaten only leaves veins, like a broom, from afar there is a burning feeling, the victim is light Many holes were bitten on the leaves of rape, and some of the rape seedlings were snapped. According to surveys, low-lying and wet areas are heavier than high-lying areas. Late-planting fields are heavier than early sowing fields, and flood lands are heavier than hilly areas.
Second, retransmission reasons
(1) Over the years, rapeseed cultivation followed the tradition of sowing, with large seeding rate, high field canopy closure, and late seedlings, which provided good foodstuffs and suitable living environment for black worms. (2) For many years, the sown area of ​​rapeseed was large. Mild hazards did not cause people's attention, and most of them did not conduct timely prevention and control, resulting in a large base number of black insects. (3) The jump of three kinds of pests, suspended animation, and concealment of overwintering sites in overwintering conditions make the discovery difficult and prevention difficult. (4) Three kinds of pests are covered with hard shells, and it is difficult for common pesticides to penetrate the shells, causing repeated prevention and recurrence. (5) The three pests are miscellaneous and have a wide range of habitats. (6) The sowing date of rapeseed in some areas is more than rainy and the weather is suitable. In October, the weather is clear, and the temperature is 2-3°C higher than usual, which is conducive to adult oviposition and adult and adult larvae activities of black insects, and therefore heavy.
Third, control methods
1. Agricultural control: In autumn and winter seasons, through the thinning of rapeseed fields in the autumn and winter seasons, the crops will be cleared away and the leaves and leaves of the branches will be removed, and the living environment of the pests will be deteriorated and the living environment of the pests will be deteriorated. The density of overwintered populations will be reduced, or the adults will be allowed to inhabit under the dead leaves and wintering. The habit of setting up inducing reactors is to pile up weeds or picking cabbages on the ground to trap overwintering adults and collect and kill them.
2, for chemical seed dressing: before sowing can be used 5% Ruijin special clothing mixed oilseed rape seeds, according to Ruijin special 1 parts, seeds 10 parts of the ratio of seed dressing, stir evenly after sowing.
3, rational fertilization: cultivating strong seedlings to improve the resistance of rape seedlings, to control nitrogen fertilizer, phosphorus fertilizer, potash fertilizer and trace elements, timely set seedlings, changing the ecological microclimate of rapeseed fields.
4. Change sowing for seedling transplanting: Before transplanting, use 25% deltamethrin 1000 times foliar spray to transplant to kill invading pests.
5. Chemical control: Choose insecticides that have internal absorption and stomach toxicity, and re-spray the heart and leaves when spraying. Surface can not be ignored, when spraying in rapeseed fields to be sprayed in a row, can not miss the spray, weeds on the edge of the field to clear and spray control, the main agent is 50% sulfuric acid 800 times, 48% Losben 1000 times liquid, 90% crystal trichlorfon 800 times, 25% deltamethrin 1000 times or 2.0% rotenone 1000 times, spray evenly.