Indoor Residual Spraying
1.1Terms and definitions
1.1.1 Indoor residual spraying
A way of chemical spraying that mainly covers the surface of the target in the form of powder particles or pesticide membrane in order to maintain its lasting efficacy.
1.1.2 Target
Objects such as walls, curtains, etc. to be disposed.
1.1.3 Hang but not flow
By the method of spraying, the liquid is sprayed on the surface of the target object, showing a uniform layer of liquid droplets that do not flow.
1.1.4 Dosage
The amount of effective components of insecticides per unit spraying area(g/m2)
1.1.5 Water absorbing capacity
The amount of water required from spraying to hanging flow on the surface of the target object per unit area (mL/m2).
1.2 Sprayer selection
1.2.1 Principle
1.2.1.1 Compression sprayer or motor pump sprayer should be selected; single or dual use can be selected according to the size or height of the area to be treated, or knapsack manual sprayer or pedal sprayer can be selected.
1.2.1.2 The sprayer should be equipped with a barometer to show the spray pressure.
1.2.1.3 When the surface of the target object is flat, the fan-shaped spray nozzle should be selected. In addition, when dealing with holes, cracks or apertures, a single beam nozzle should be selected.
1.2.2 Parameters
1.2.2.1 Spray pressure range: 170-380 kPa.
1.2.2.2 Spray nozzle angle≥80°.
1.3 Insecticide selection
1.3.1 Principle
1.3.1.1 The pesticide has persistent activity and killing effect.
1.3.1.2 The insecticide is sensitive to the mosquito.
③The pesticide form should be selected according to the surface properties of the target object:
A. Wettable powder can be selected for absorbing surface, such as ash surface and cement surface.
B. For semi-absorbing surface, such as paint surface, wood surface and wallpaper surface, it can choose suspending agent.
C. For non-absorption surface, such as silicate glass surface, marble surface, or specific places it can choose microemulsion and so on.
(2)Common insecticide
The common insecticides and promotional doses that can be used for mosquito (mainly for Anopheles) vector residual spraying are shown in Table 6-1.
Note: a. C stands for carbamate insecticides; OP stands for organophosphate insecticides; PY stands for pyrethroid insecticides.
b. II indicates moderate hazard; III indicates mild hazard; U indicates that there is no possibihty of hazard if _in normal use___________________________________________________________________________.
4. Operation method
(1)Equipment preparation
①Check that the sprayer or sprayer parts should be complete, the function should be normal, and the installation should be correct. Before charging the knapsack sprayer, apply appropriate amount of lubricating oil at the sprayer leather bowl and rocker shaft (the sprayer built in the air chamber should be at the sliding sleeve and piston). Before using the compression sprayer, make sure that the spool of the safety valve is flexible and the exhaust hole is unobstructed. The pressure regulating valve of the motor sprayer should be flexible and reliable.
②Add clean water to the normal allowable capacity in the medicine box and press it to ≥ 170kPa. The test spray nozzle should be atomized well. In addition, there is no leakage at each connection. In addition, there is no dripping or blockage of the nozzle and switch valve. Sprayer or motorized sprayer should have no air leakage or liquid leakage.
③Put the nozzle into the wide mouth (≥ 2L) metering container, accurately spray continuously for 1 minute without leakage, measure the spray volume of the nozzle and record it. Repeat more than 3 times and calculate the average as the amount of spray of the sprayer or sprayer head. Calculate according to Formula 6-1:
In this formula:
X—Spray quantity(mL/min)
V—1 min measured spray quantity(mL)
n—Repetition times
(2)Spray preparation
①According to the surface properties of the target to be treated, three surfaces with the same area are delineated respectively. Press to ≥ 170kpa, spray to hanging flow. Accuratdy timing and calculate the water absorption on the surface of the target object according to Formula 6-2.
②According to the surface properties of the target to be treated, three surfaces with the same area are delineated respectively. Press to ≥ 170kpa, spray to hanging flow. In addition, accurate timing, calculate the water absorption on the surface of the target object according to Formula 6-2.
In the formula:
L—Water absorption (mL/m2)
X—Spray intensity (mL/min)
t—Spraying time (min)
S1—Treatment area (m2)(https://www.daowen.com)
③Practice of spraying skills: obtain the spraying skills by training, make sure that the spraying speed of sprayers match the applied dose with the water absorption on the surface of the target object. On the wall of the building, choose some area with the height being 3 m and the length 6.35m. Divide it into 9 pieces, with the first piece being 75 cm and the rest 70 cm wide. Spraying starts from the bottom of the wall, moves up to the top at the same rate, takes a step to the right, continues spraying the next one, sprays from top to bottom and Continue until the whole area is overlaid by pesticide. Each painting takes 6 to 7 seconds and 9 paintings take 1 minute, as shown in Fig. 6-1.
Fig. 6-1 Schematic diagram of residual spraying training for building walls
④Practice of spraying distance and spray amplitude
The nozzle remains 45 cm from the wall. The spray rod can be tied together with a wooden stick or an other rod with a rubber band or rope. As a result, the distance between the nozzle and the top of the rod is 45 cm (see Fig. 6-2). The person tilts forward slightly. When moving the right arm up and down, the top of the pole always touches the wall.
Fig. 6-2 Nozzle injection mode
⑤According to the water absorption or dosage of the target surface area and its unit area, the liquid demand (formula 6-3) and the insecticide demand (Formula 6-4) can be calculated.?
V=S2L……………(Formula 6-3)
In the formula:
V—Liquid demand (mL)
S2—Surface area of target object (m2)
L—Water absorption per unit area (mL/m2)
In the formula:
W—Required drug dose (g or mL)
S2—Surface area of target object (m2)
Y—Dose to be retained for spraying (g/m2)
w—Mass fraction of insecticide (%)
⑥Dispensing solution
A separate mixing container can be used in order to ensure that the solution can be fully mixed. After fully mixing with quantitative clean water and insecticides, pour it into the sprayer, add water to the required dose, mix well again and then use. The solution should be used immediately.
(3)Spraying technology
①Plane spraying
A. Adjust the working pressure of motorized sprayer to 280kPa. The pressure of the compressed sprayer is 380kPa after the liquid is added and it is closed; when there is no pressure gauge, press according to the instructions. In the spraying process, pump gas intermittently to maintain the pressure in the barrel.
B. The fan-shaped spray nozzle is used when spraying, the nozzle is 45 cm away from the wall. There should be 5 cm overlap on each spray amplitude. First spray from the roof to the ground from top to bottom, then step to one side and spray from the ground to the roof from bottom to roof. Move in the same direction as shown in Fig. 6-3 repeatedly until the target surface spraying is completed.
C. When spraying to the top of the wall, the body should lean forward and retract and stand upright when the nozzle moves down.
D. Selective or comprehensive residual spraying should be taken according to the breeding, hiding and habitation habits of mosquitoes.
Fig. 6-3 Schematic diagram of residual spraying
②Ceiling spraying
Using fan-shaped spray nozzles, the length of the handle should be adjusted according to the height of the house so that the sprayer can freely keep 45 cm distance between the nozzle and the ceiling surface. Select the ceiling of one side of the wall as the starting point, start spraying from the beginning of the ceiling adjacent to the wall, to the end of the opposite terminal. Step towards the unsprayed direction and turn the direction to spray the next one. Each should have 5 cm overlap. This is repeated until the surface spraying of the target object is completed.
③Spraying holes, cracks and apertures
Use a single-beam nozzle to spray directly into holes, cracks or apertures until the liquid is moist and does not overflow. Spray from top to bottom and move in the same direction until the whole target surface is sprayed.
(4)Matters needing attention
A. The residents should be informed of the function and protective effect of the insecticide. Evacuate the working area in time as required before spraying. Cover food that may be contaminated by spraying and move pets and ornamental fish to a safe area. Move, cover or remove furniture to facilitate wall spraying. Target objects with stains or dust should be cleaned before treatment.
B. Operators wear wide-brimmed hats, rubber gloves, protective goggles and protective masks, long-sleeved overalls and rubber shoes.
C. Not smoking, drinking or eating during operating. If the splashing liquid touches the skin unexpectedly, they should immediately wash the contaminated skin with soap or skin cleanser and water.
D. At the end of the work, wash exposed skin and protective clothing with soap or other washing products and clean water.
5. Effect evaluation
(1)Methods
Investigate according to the investigation method of mosquito density and fill in the investigation records before carrying out residual spraying. After the completion of residual spraying, the same density investigation method shall be used every other period of time to compare the reduction rate of mosquito density before and after. Evaluate the control effect.
(2)Calculation
The decrease rate of mosquito density is calculated according to Formula 6-5.
In the formula:
P—Density reduction rate(%)
Tb—Average density value before treatment
Ta—Average density value after treatment
(3)Evaluation criteria
The evaluation cut-off point of the reduction rate of mosquito density is 70%. When the density decline rate is less than 70%, the treatment effect is not obvious.