A ballcock (also balltap or float valve) is a mechanism or machine for filling water tanks, such as those found in flush toilets, while avoiding overflow and (in the event of low water pressure) backflow. The modern ballcock was invented by José Antonio de Alzate y RamÃrez, a Mexican priest and scientist, who described the device in 1790 in the Gaceta de Literatura Méxicana.[1] It consists of a valve connected to a hollow sealed float by means of a lever, mounted near the top of the tank. The float is often ball-shaped, hence the name ballcock. The valve is connected to the incoming water supply, and is opened and closed by the lever which has the float mounted on the end. When the water level rises, the float rises with it; once it rises to a pre-set level, the mechanism forces the lever to close the valve and shut off the water flow. This is an example of negative feedback and of proportional control. Ball Cock, Brass Ball Bibcock, Ballcock Valve, Toilet Ballcock Valve ZHEJIANG KINGSIR VALVE CO., LTD. , https://www.kingsir-valves.com
Pests in the prosperous period: For pests, the period of pest growth can be the period of egg hatching, the period of larvae, and the period of adult growth. In which period, the effect of drug control is most obvious, depending on the specific situation. In principle, it is necessary to grasp the living habits of pests, in the stage where the most harmful insects are easily killed and the damage can be effectively controlled. For example, in the control of armyworms, spraying at the peak of egg hatching, although the control effect on hatched larvae is good, it does not necessarily work for late hatching larvae, and when the larvae are at the peak of 2~3 years old, spraying drugs, once It can solve the pest problem. For example, when controlling cotton bollworm, the newly hatched larvae should be drilled into the bud bell in a short period of time. If the larva is used at the peak of 2 to 3 years old, the control effect is very poor, and the drug is used at the peak of egg hatching. The control effect is particularly remarkable; rice aphids and Spodoptera litura are also the same.
When controlling pests, it should generally be used before the peak of larvae 2-3 years old, and some should be used after the peak period of egg hatching. At this time, the application can get twice the result with half the effort. The main reasons are:
First, the younger pests are thin at the 3rd instar body, and there are many micro-hairs on the body wall. The epidermis of the micro-hair-forming part is very thin, and the agent can easily pass through this layer, and at this time, the insects Small body, large amount of food, light hazard, small range of activity, weak resistance to drug resistance (resistance), so determine the appropriate period of control of pests, should be used before the peak of 2-3 years of age, and some should be in the egg hatching The best control effect can be achieved by using the medicine before and after the peak period. When the pests reach 4-6 years old, the food intake and body wall thickness of the pests are greatly increased, and the thickness can reach 50-100 times of the 1st instar larvae, and the micro hairs on the body wall are also absent, so that the medicament is not easy to adhere. It is difficult to reach the body of the pest on the body wall and through the body wall. At the same time, the resistance (resistance) of the pest is also greatly increased, which greatly affects the insecticidal effect of the medicament.
Second, after the age of the pest increases, the amount of fat in the insect body also increases, and it has the function of accumulating and decomposing many pesticides. The higher the body fat content of the pest, the more obvious this effect and the stronger the resistance to the drug.
Third, the sensitive period of natural enemies: During the period when the natural enemies of the pests are sensitive to the chemical reaction, the medicine should be used as little as possible or not, so as to protect the natural enemies and maintain the ecological balance in the field.
The fourth is the disease-producing period: for diseases, the growth period of susceptible diseases is the best period of chemical control. If the seedling stage is most susceptible to bacterial blight, it can be mixed with fungicides before planting or sprayed at the seedling stage; if the flowering period is also the peak period of disease infection, therefore, it should be mastered during the flowering period. Prevention and control, control the occurrence and spread of diseases.
The fifth is the sensitive period of weeds: the application of herbicides should generally be controlled during the sensitive period of weeds. For weeds that are propagated by seeds, the germination and seedling stages are more sensitive to herbicides. Therefore, this period is often the time for herbicides. Generally, it is good to pre-emergence or weed 1-2 leaf stage after sowing. When using broad-spectrum herbicides, such as gram-free, glyphosate, and nutrient, it should be used when the weeds are more sensitive in the growing season, the herbicidal effect is significant, and the long-lasting effect is long. If weeds are used to control weeds in spring and summer, it is best to spray herbicides at the beginning of weeds.
Sixth is the fasting period of the rodent. In terms of effectively controlling the degree of rodent, the release of the drug lord should be better at the rodent fasting stage. Many years of experiments have proved that the best effect of rodent control in spring is because the winter storage of the rodent is depleted, and the feeding of poisonous cockroaches is more corresponding. At the same time, the rodent in spring can also reduce the cardinal number and protect the normal emergence and safe growth of spring-sown crops. .
Seven is the plant safety period. The safety of the agent to the plant is a prerequisite for determining the duration of the application. When applying pesticides, it is necessary to select the period during which the crop has strong resistance to the medicament, so as not to cause crop damage.
Eight is the security interval. During the application period of pesticides, it should also be applied according to the safe use standards of pesticides during the safety interval to avoid excessive pesticide residues and cause adverse consequences.
How to solve the problem of proper application of pesticides
The application of pesticides can not only save pesticides and reduce costs, but also improve the control effect, reduce drug residues, effectively control the damage of pests and diseases, and ensure the normal growth of crops. When determining the appropriate period of application, it should be considered from the following aspects:
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