Chemical deratization

Chemical deratization is the most economical method in large-scale deratization. Pay attention to safety when using it to prevent poisoning accidents of people and animals. Chemical deratization can be divided into poison bait method and poison gas method, poison water method, poison powder method and poison paste method. 1. Commonly used rodenticides are mainly intestinal rodenticides, including acute rodenticides and chronic rodenticides. Acute rodenticides, or quick-acting drugs, only work once. Chronic rodenticide or slow-acting drug is called after taking it for several days. The former is mostly used in the wild and the latter is mostly used in residential areas.

(1) zinc phosphide (Zn3p2): It is a gray powder with obvious garlic smell, insoluble in water and lipophilic. It is stable when it is dry, slowly decomposes when it is wet, and quickly reacts with inorganic strong acid to release phosphine gas. It mainly acts on the nervous system and destroys metabolism. After poisoning, appetite decreases, activity decreases, hind limbs are often paralyzed, and finally they die. It acts quickly and is a quick-acting medicine. The concentration of prepared bait is generally 2% ~ 5%. The toxicity selectivity of this product is not strong, and the toxicity to human, poultry and livestock is similar to that to rats, so attention should be paid to safety. Mice that are not dead after the first poisoning are easy to refuse to eat when they meet again, and are not suitable for further use.

(2) gophacide (c14h13cl2n2o2ps): this product is white powder or crystal, almost insoluble in water, with no obvious odor, and relatively stable in dry state. Its main toxic function is to inhibit cholinesterase in nerve tissue and cells, which is highly toxic to rats and has low selectivity. Rats developed symptoms 4-6 hours after taking poison bait, and died about 10 hour. Poisonous rat phosphorus has good palatability to mice, and its refusal to eat is not obvious when it is encountered again. It has a good effect on both wild mice and domestic mice. Poisonous rat phosphorus is also highly toxic to people and livestock, but it is very weak to chickens. But it's strong for ducks and geese. Pay attention to safety when using. The common concentration of tetramine phosphate is 0.5% ~ 1.0%, which can also be increased to 1% ~ 2%.

(3) Warfarin (C 19H 16O4): This product is white crystal, insoluble in water, and soluble in alkaline solution to form sodium salt. Odorless and tasteless, quite stable. It is the most widely used anticoagulant rodenticide in the world and a typical chronic drug. The toxicity of rodenticide is closely related to the times of taking medicine. Taking medicine once can be fatal only when the dose is quite large; When taken many times, although the total amount of each dose is far lower than the lethal dose of one dose, it may also cause the death of rats. It mainly destroys the coagulation ability of rats, damages capillaries, causes internal bleeding, leads to anemia, blood loss and finally dies. The effect is slow. Generally, they die 4-6 days after taking the medicine, and a few individuals can die for more than 20 days. Increasing the dose will not accelerate death.

Because of the low dosage of rodenticide, good palatability, poison bait is easily accepted by rats, and its effect is slow, and it does not cause protective reaction, and the effect is generally good. However, the feeding amount must greatly exceed the acute bait, and the feeding period should not be shorter than 5 days.

The chronic toxicity of rodenticide to Rattus norvegicus is very strong, but it is slightly weak to Rattus norvegicus and Rattus flavipectus. Among poultry and livestock, cats and pigs are more sensitive, and chickens, ducks and cows have strong endurance. Generally speaking, it is one of the safest rodenticides at present.

The concentration of rodenticide is 0.025%. Because the dosage is small, the pure medicine is usually diluted to 0.5% or 2.5% mother powder or mixed with sodium salt solution with appropriate concentration, and then added to bait to make poison bait.

(4) diphacinone sodium salt (C23H 16O3Na): This product is khaki crystalline powder, odorless and tasteless, soluble in ethanol, acetone and hot water, and stable in nature. The diphacinone sodium salt (C23H 16O3Na) is yellow and insoluble in water. Their toxicological effects are basically the same as rodenticide.

The toxicity of diphacinone sodium salt to rats is stronger than rodenticide, so it can reduce the feeding times, but the risk to poultry and livestock increases accordingly. Its toxicity to houseflies and Rattus flavipectus is also stronger than rodenticide, and it has a good killing effect on Mongolian gerbils and other wild rats. The palatability of diphacinone sodium salt is not as good as rodenticide, especially at high concentration. Trichlorfon has good palatability. They are less toxic to chickens, ducks, sheep and cattle, but more toxic to cats, rabbits and dogs. It is also highly toxic to people and may lead to poisoning. According to the toxicity of diphacinone sodium salt, its concentration should be 0.0 1% ~ 0.0 125%, but in order to reduce the feeding times, 0.025% or even 0. 1% ~ 0.2% is often used to kill rodents in the field. But the higher the concentration, the worse the palatability, which will reduce the effect.

2. Baits and additives In addition to rodenticide, the quality of bait also directly affects the effect, so be sure to choose mice that you like to eat. There are several kinds of bait used to kill rats in a large area: ① whole grains or fragments, such as wheat, rice, naked oats, sorghum, broken corn, etc. ② Grain flour, such as corn flour and flour, is mainly used to make mixed bait. Generally, 60% ~ 80% corn flour and 20% ~ 40% flour can be used; (3) melons and vegetables, such as sweet potato slices and carrot slices, are mainly used to make poison bait, and now they are available.

3. Preparation of poison bait In order to ensure the quality, poison bait should be prepared centrally. There are three strict requirements: ① rodenticide and bait adhesive must meet the standards; (2) evenly mixing the bait, so that the rodenticide and the bait are evenly mixed; When using highly toxic rodenticide, it should be prepared into mother liquor or mother liquor with appropriate concentration before mixing with bait. The drug content of mother powder and mother liquor must be accurate; ③ The concentration of rodenticide is moderate, neither too low nor too high. Too high affects palatability, but reduces rodent control effect. For chronic drugs, increasing the concentration does not accelerate the onset of action accordingly.

4. Putting poison bait It is best to put poison bait by trained personnel. The feeding methods are as follows: ① hole feeding: suitable for wild rats with obvious holes; (2) According to the rat trail: it is not easy to find rat holes in most areas, but the activity place is easy to determine, so this method can be used for drug administration; (3) equidistant release: eliminate the wild rats in the open area, and put a bunch of poisonous baits at a certain distance in each row and column according to the chessboard mode; (4) Unified release: generally limited to wild rats, suitable for places with high rat density, vast territory and sparse population; ⑤ Strip application: Apply drugs in a straight line at regular intervals to kill wild rats. Bait can be released at night and collected during the day to avoid accidental injury to children, birds and animals; The method of poison bait box can also be used. The poison bait box can be made from local materials and adapted to the time. Generally, the bait box should not be placed for more than 5 days. If there are no mice in it for more than 5 days, you should change your position. When killing house mice, each household can put one or two poison bait boxes, but the location should be suitable, and fresh poison bait should be replenished in time when it is first used. After the rat density drops, check it once a month to ensure safety.

5. Scientifically use poison bait to kill rats.

1) If the number of rats is less than 65438+ this time, the drug selection should be changed to chronic rodenticide and fresh bait for killing. In principle, the rodenticide used for the first time should be cheaper or safer for people and animals, and the rodenticide used for the second time should be slightly more expensive or more dangerous for people and animals. Rats like plant seeds and pasta. Therefore, when killing rats, we often use acute drugs to stick millet or poison bait with tiny flour particles, and adopt the way of "fairy scattering flowers" to feed them in the place where there are 2 square meters left. The concentration of drugs used by mice is often 1- 10 times higher than that of Rattus norvegicus. When using rodenticide in rural areas and in the wild, we should pay more attention to the safety of livestock, poultry, cats and dogs, otherwise it will affect the relationship with the masses. Chickens and pig farms can accept salt with diphacinone, and chickens can tolerate 0.05% bait 2 kg; A pig weighing 30 kg can tolerate 5 kg of 0.05% poison bait. But not for cats and dogs. Cats can die if they eat 6 grams of 0.05% diphacinone sodium salt bait or dogs eat 10 grams of 0.05% diphacinone sodium salt bait. Poultry, pigs, cats and dogs are sensitive to chlorpyrifos, bromadiolone and Dalong. Killing them is dangerous for dogs and rabbits, but quite safe for pigs, chickens and ducks. Chlordimeform is relatively safe for poultry and birds. It can withstand the influence of various climatic factors in the field and remain in the soil for a long time.

2) After selecting the medicine, which bait to choose as the bottom bait refers to the one used by the unit and not used in the past. You can ask the mouse what food it has eaten. It is easy for the mouse to accept the poison bait made from this food. In hot seasons or dry places, poisonous baits can be prepared with fruits such as apples and bananas and vegetables such as radishes and sweet potatoes. Bait preparation containers, tools and baiting articles should be cleaned after use to prevent pollution and poisoning.

3) Feeding time should be at dusk.

4) Someone should lead the way when feeding. Poison bait should be placed in places frequented by rats. When there are rat holes and rat paths, it should be placed in rat holes and rat paths 10 cm, with 25g each. Mark it, check it the next day, and record the lost quantity. It is a chronic rodenticide. If it is found lost, the bait can be doubled until it is no longer reduced. Give acute poison bait, and you can continue to use fresh poison bait the next day until the mouse activity is no longer found.

5) Inform the customer about the performance and precautions of poisons, and hope to cooperate.

6) The collected rat carcasses should be packaged, recorded and sent to the clinical laboratory for registration.

7) Divide nests according to body length, weight and coat color. (If necessary, check the pregnant point and determine the number of rats. Check whether the number of rats counted in the inspection before deratization is consistent. Evaluate the rodent control effect.

8) Before and after deratization, the rat density was investigated in the same way. The investigation method is powder trail method or bait loss method, and the formula is as follows: deratization rate (%) = average rat density before deratization-average rat density after deratization/average rat density before deratization × 100%.

9) Write a deratization report and file it.

10) Follow up once a month to collect feedback and make records. Consolidate the rodent control effect.

6. Matters needing attention of poison bait deratization method

1) deratization plan

A) On-the-spot investigation of rodents: firstly, investigate the species, quantity, invasion route and habitat of rodents.

B) Formulation of prevention and control plan: According to the basic situation and biological characteristics of mice, formulate prevention and control plan.

C) Improve the environment: eliminate the breeding ground of rats, control the surrounding environment, and block the entry and exit of rats.

D) Give drugs in batches and stages, and kill rats as planned.

E) Check the effect of dead rats, detect the density of rats and judge the number of rats.

F) Regular inspection: check the consumption of poison bait, remove dead rats, find new rat paths and block them.

G) Consolidate the control effect, put in enough dosage, and regularly check the density.

2) Matters needing attention when killing rats

A) Where there is a rat hole, the rat poison must be put in the rat hole, so that the rat can eat the rat poison as soon as possible to avoid other poultry or livestock eating it by mistake.

B) Where there is no rat hole, put the medicine in the place where rats often haunt, and try to put it in a hidden place or corner, so as not to let children get it, and close the poultry and livestock.

C) Scattering or random scattering is strictly prohibited.

D) It is best to continuously apply rodenticide for at least two to seven days. Withdraw bait after one week, pay attention to picking up dead rats when killing rats, and record the number in the disinfection service record (dead rats are concentrated and buried deeply).

E) Rodenticide must be put on the premise of ensuring safety, and clearly marked.

F) Disinfected instruments and medicines should be cleaned and kept in a unified way.

G) When preparing bait, rodenticide should be sprinkled on the bait in proportion and mixed evenly. Workers must wear masks and gloves, and it is forbidden to work with bare hands.

H) Don't use moldy grains when preparing bait, so as not to affect palatability.

I) The bait should be put in time, carefully kept and not lost to avoid accidents.

J) After work, it must be cleaned with lye and put back. Workers should wash their hands and faces immediately after taking off their work clothes.

K) Never smoke, eat or talk less in the workplace to avoid accidental poisoning.

Use taboo

Acute toxic rodenticide can kill rats within minutes or hours after taking it. After rats ate acute toxic rodenticide, the symptoms were very serious and very painful. Rats die quickly, usually outside their nests. As everyone knows, this is just a "taboo". Rats are naturally alert. When a mouse falls to the ground after taking medicine, the same kind of mice will immediately scatter and never dare to touch this poison bait again. This is actually a "startle the snake", so that most mice can escape. Moreover, most of the mice who took medicine first were old, weak and sick, while the strong mice survived, artificially optimizing the mouse population, making the remaining mice grow better, the offspring stronger and the future more difficult. Therefore, acute toxic rodenticide is not provided in rodent control activities.

Most of the rodenticides banned by the state are highly toxic rodenticides, such as amide, sodium fluoroacetate, tetramine (also known as 424), tetramine and dichlorvos. Vendors of rodenticides usually call these rodenticides "no rat life", "three steps down", "smell them and die", "catch them all" and "Qiu's rodenticides", and people are buying, storing and using these rodenticides. For example, in Wangzhuang Village, Heze City, Shandong Province, an epileptic seizure characterized by nausea, vomiting, rolling eyes, foaming at the mouth, upper limb spasm and lower limb stiffness frequently occurs. Even livestock and poultry have similar symptoms, and the mortality rate is extremely high. Patients in the village keep happening, so many families have no choice but to move out. Investigation by local health department shows that villagers use some illegal rodenticide dealers to sell highly toxic rodenticide banned by the state.

Plants have a strong ability to absorb highly toxic rodenticides. If they fall into the vegetable garden or field by mistake, they will be absorbed, and people, livestock and poultry will do harm to them after using these plants. Studies have proved that this poison decomposes very slowly in nature. Even if it is buried deep underground for decades, the excavated soil will be used to cultivate plants, and pigs will still die of poisoning after eating it, which shows the potential harm of these highly toxic rodenticides. There are two kinds of poison gas for killing rats: one is chemical fumigant and the other is smoke agent. Commonly used chemical fumigants are aluminum phosphide and chloropicrin, as well as fuming agents with different formulations.

Fumigation and deratization Some drugs are easy to volatilize into toxic gases at room temperature or produce toxic gases through chemical reactions. These drugs are usually called fumigants. The method of inhaling toxic gas to kill rats is called fumigation. Advantages of fumigation to kill rats: mandatory, no need to consider the habits of rats; Food and other foods are not needed, and the effect is quick and generally good; It also has insecticidal effect; Safer for livestock and poultry. Disadvantages: it can only be used in closed places; High toxicity, quick action and easy poisoning due to careless use; Large dosage, sometimes high cost; When fumigating and killing rats in holes, it is necessary to find holes, put drugs and block holes, which is inefficient. The use of this method is limited. It is mainly used for rodent control in closed places such as warehouses, and can also be used for rodent control in caves.

There are two kinds of fumigants used: one is chemical fumigant, such as aluminum phosphide, and the other is rodenticide. Chemical fumigant and smoke agent have the same characteristics: mandatory, quick-acting, generally safe for non-target animals, no need to feed, but the cost is high, the work efficiency is low, and the effect on some mouse species is poor.

The selection conditions of chemical fumigant are: selective toxicity, convenient use, low price, good effect and antidote. Smoke is safer for non-target animals, but it may cause fire and needs to be lit before use. The fuming agent consists of main medicine, combustion improver and fuel, plus ignition part, and sometimes flame retardant is needed. General oral toxicity and fumigation toxicity, irritation and toxicity have no corresponding relationship. General pesticides are not toxic to warm-blooded animals. Visible smoke usually does not represent the total amount of smoke. These are all problems that should be paid attention to. There is no universally accepted formula.

When using the smoke agent, we should try to reduce the loopholes: if we can plug the hole first, it will be more economical if we only smoke and don't dig. Like the poison bait method, cigarettes cannot be used together. The main reason is that mice have the habit of adding hair to their front feet and bodies with their mouths. The prepared poison powder (generally more than 10 times the concentration of the poison bait) is scattered in places where rats often pass, or poison glue is applied around rat holes and corners of pipelines where rats often climb. This method is a good method for the residual stubborn rats (super rats) after deratization. It should be noted that toxic non-environmental rodenticide is prohibited in poisonous powder, otherwise it will bring disastrous consequences, such as rats carrying poisonous powder, walking through vegetables and grains and being eaten by humans. There are no similar concerns about the use of environmentally friendly rodenticides.