Bacillus thuringiensis is abbreviated as bt, also known as Bacillus thuringiensis, a low-toxicity insecticide of microbial origin, including many variants of a class of crystal-producing bacillus. The bacteria can produce two major types of toxins, namely endotoxins (with cytocrystals) and exotoxins, after the pest feeds, under the action of the intestinal alkaline digestive juice, the bacteria release toxins, the pest poisoning and stop feeding, and finally the pest dies of starvation and blood and nerve poisoning. It is used to control a variety of pests of Orthoptera, Coleoptera, Diptera, Hymenoptera, especially Lepidoptera. It is currently the most in-depth research in the world, the most widely used microbial insecticide, non-toxic to humans and livestock, does not harm the natural enemies of pest control groups, does not pollute the environment, is an important part of biological control of pests, and is more suitable for the integrated control of crop pests.
Physicochemical properties: the original drug is a yellow-brown solid, is a bacterial insecticide, belongs to the gaseous waxy bacillus flora, in the sporangia produce crystals.
Toxicity: Thuringiensis is slightly toxic to humans and animals; rats are administered by oral administration of 2×l022 live spores, no poisoning, no death, no side effects of skin smearing; no trisymology; very safe for fish, bees, livestock and natural enemies; great toxicity to silkworms.
Main dosage forms: 8000iu/μl suspension, 16000iu/mg, 32000iu/mg wettable powder, 15000iu/mg water dispersible granules, 2000 IU/μl suspension, 10 billion live spores/ml suspension.
Morphological characteristics
Culture at 30 °C on beef paste peptone solid medium, sample at different times, and observe under a microscope after staining. b-hm-16 vent cells are rod-shaped, thick, and 1. 2～1. 5μm×3. 6~4. 5μm; Culture for 30h can form a thicker sporangia than the vegetative body, after staining, you can see that one end is dark red, the other end is not colored; the culture of 36~38h sporangia rupture, releasing ovoid spores and blunt diamond-shaped crystals, the crystal size is 1. 0～1. 2μm×1～2. 0μm。
Mechanism of action
Suyunjin bacillus preparation is a kind of gastric agent, after entering the digestive tract of insects, the accompanying spore crystals (the main component is protein) are destroyed by the alkaline intestinal fluid of insects into smaller units of δ-endotoxin, so that the midgut stops peristalsis, paralysis, midgut epithelial cells dissociate, stop eating, spores germinate in the intestine, through the destroyed intestinal wall into the blood cavity, large multiplication, so that the pests have sepsis and die, the body of the dead larvae is paralyzed, black. There are more than 30 known variants of Thuringiensis, and some variants produce β-exotoxin during logarithmic growth, are heat-resistant, are adenine nucleotides, and also play an insecticidal role.
Main features
Thuringiensis is currently the largest yield and the most convenient insecticide to use, which has the characteristics of insecticidal specificity, high efficiency and low toxicity and has attracted people's attention. Suyunjin bacillus is very widely used in crops, widely used in vegetables, melons, fruits, tobacco and other crops, insecticidal effect is good, insecticidal widely, for lepidoptera, Coleoptera, Diptera, Hymenoptera, Hymenoptera and other insects, as well as animals and plant nematodes, ticks and other arthropods have specific toxin activity. This pesticide is non-polluting to the environment and water sources, and has no harm to people and animals.
Scope of prevention and control
Thuringiensis has a wide range of insecticidal spectrums, can control hundreds of pests, and is particularly effective against Lepidoptera larvae. It is mainly used for the control of Lepidoptera pest larvae, such as cabbage worms, small cabbage moths, beet nocturnal moths, twill nocturnal moths, kale nocturnal moths, smoke green worms, corn borers, rice longitudinal leaf borer, dimorphic borer, pine caterpillars, tea caterpillars, tea inchworms, corn stickworms, bean pod borers, silver-striped nocturnal moths and other hundred kinds of insect pests, which are the most widely used microbial insecticides.
Suitable for crops
It is widely used in cruciferous vegetables, nightshade vegetables, melon vegetables, tobacco, rice, corn, sorghum, soybeans, peanuts, sweet potatoes, cotton, tea trees, apples, pears, peaches, dates, citrus, bananas, mangoes, lychees and other crops and forests and grasslands.
How to use
(1) Control of small cabbage moths, cabbage worms, beet moths, twill moths, etc., in the peak period of egg incubation, use 10 billion live spores / g wettable powder 1000 times liquid, or mu with 16000iu / mg water dispersible granules 50 ~ 75 grams or 10 billion live buds full / ml of 100 ~ 150 ml of solid floating agent, sprayed with water.
(2) Control tea caterpillar, tea black poison moth, tea thorn moth mu with 10 billion live spores / g wettable powder 100 ~ 150 g, control of tea inchworm, tea small leaf curl moth mu with 100 ~ 200 grams, water 50 ~ 75 kg, foliar spray.
(3) Control of fruit tree pests, generally with 10 billion live spores / g wettable powder or suspension agent 200 times liquid uniform spray, can control the northern fruit trees of the inchworm, heartworm, citrus stinger moth, leaf curl moth, leafminer moth, banana leaf curlew and so on.
(4) For the control of lepidoptera pests such as pine caterpillars, ruler moths, poisonous moths, stinging moths, and small curl moths, it is generally sprayed with 10 billion live spores/ml suspension 150 to 200 times liquid or 80001u/mg wettable powder 100-200 times liquid spray.
(5) Control of cotton bollworms, strong killing power of hatching larvae, generally mu with wettable powder or suspension agent 200 ~ 300 grams, spray on water. In large occurrence years or heavy plots, chemical pesticides are applied again on the third day after spraying Bacillus thuringiensis, and the field larvae have been infected with the disease, which can significantly improve the prevention effect of chemical pesticides.
(6) Control of corn borer, can be used 20001u / mg granules 00-400 grams per acre, heart leaves sprinkled. Or mu with 160001u / mg wettable powder 50 ~ 100 grams, or 20001u / microliter suspension 300 ~ 400 ml or 10 billion live spore / ml suspension 150 ~ 200 g, add fine sand mixing and then irrigate the heart leaves.
(7) Control of tobacco green insects, generally mu with 160001u / mg wettable powder 50 ~ 100 grams or 20001u / microliter suspension 400 ~ 500 ml, or 10 billion live spore / ml suspension agent 200 ml, spray on water.
(8) Control of rice longitudinal leaf borer and rice bracts, generally mu with 80001u / microliter suspension agent 200 ~ 400 ml or 160001u / mg wettable powder 100 ~ 150 grams or 10 billion live spores / ml suspension 200 ~ 400 ml, spray on water.