🌬 Plant Protection Equipment

Sprayer and Dusters

Need for Plant protection equipment

These days more fields remain covered under crops for longer duration of time due to multiple cropping and various methods employed for increasing the efficiency of crop production.
Because of these reasons, it has become necessary to use pesticides and fungicides for controlling pests and diseases.
These chemicals are applied in the form of spray and dust.
There are many types of dusters and sprayers that are available for plant’s protection.

Based up on the volume of liquid handled, sprayers may be classified into:
- High volume spray (more than 400 liters /ha) ^{IBPS AFO}
- Low volume spray (5 to 400 liters/ hectare)
- For aerial dose: 15-75 liters/ha (used in fruit crops)
- For ground dose: 100 – 120 liters/ha (used in field crops)
- Ultra-low volume sprayer (ULV) spray (less than 5 liters /ha). One hectare of crop can be treated in around 2.5 hour.
- ULV spraying can be defined as plant protection in which total volume of liquid applied amount to a few milli litre per acre. It is mainly used in aircraft.
Most commonly used sprayers are low volume and ultra-low volume sprayer.
Nozzles on field sprayers have angle ranges of 60 to 90° but pressure nozzles have smaller angles.

Sprayers are of three types:
- Manually operated
- Engine operated
- Airplane operated
Manually operated sprayers are classified as follows:
- Hand atomizer type
- Stirrup pump type
- Knapsack type
- Bucket type
- Hand compression sprayer
- Rocket sprayer
- Foot sprayer
Engine operated sprayer is classified as follows:
- Knapsack mist sprayer duster
- Power sprayer

This sprayer is also ideally suited for home gardens and small fields.
It consists of a container of 0.5 to 3.5 lit capacity a built in air pump, pressure gauge, nozzle and flow cut-off lever. The tank is to be filled with 3/4^th volume.
The pump is operated to build pressure in the tank of 0.15-0.3 kg/cm².
When the flow cut-off lever is pressed, the fluid passes through the nozzle and spraying is done.
The application rate ranges from 45 to 100 litres/ha.

It is suitable for applying chemicals for field crops and lawns.
The pump is operated to pump air in to the tank to build pressure up to 2.0 — 3.5 kg/cm².
When the flow cut-off lever is pressed, the fluid passes through the nozzle and spraying is done. The sprayer is carried on the shoulder of the operator.
The application rate ranges from 45 to 100 liters /ha.

This sprayer is suitable for applying chemicals to several field crops.
It has a flat or bean-shaped tank of 10-15 liters capacity.
A hydraulic pump fitted inside the tank, a handle to operate the pump, agitator, fitter, delivery hose, and spray gun with nozzle and flow control lever.
The tank is made of either brass or PVC material.
The pressure developed in these sprayers depends on the pump and varies from 3 to 12 kg/cm² the application rate is 500 lit/ha.
The coverage is 0.5-1.0 ha/day.

Rocker sprayer is mainly used for spraying fruit trees in orchards, coconut and areca nut trees, flower gardens, and cotton and tapioca fields, the pump builds up a pressure up to 14-18 kg/cm² which facilitates the use of the sprayer for tree spraying.
The output of the sprayer is 70-90 lit/hr with one nozzle.
Coverage is about 1.5 ha/day.

The foot or pedal sprayers, as they are commonly called, consist of a plunger assembly, stand, suction hose, delivery hose, spray gun with a nozzle etc.
Constant pedaling is required for continuous spray.
It develops a pressure of 17-21 kg/cm².
The discharge rate with one nozzle is 110-135 L/hr and coverage is 1.0 ha/day.

Power sprayers are operated usually with internal combustion engines.
It can be powered by a 3 HP engine or electric motor.
The pressure pump is operated by a small power unit ensuring a constant steady pressure.
They are operated at pressure from 20 to 55 kg/cm².
These machines are usually portable type.
A power sprayer consists of the following parts:
- Prime mover
- Tank
- Agitator
- Air chamber
- Pressure gauge
- Pressure regulator
- Strainer
- Boom
- Nozzles

👉🏻 There are three types of pumps that are used for spraying:

Piston or plunger pump (well suited for high pressure spraying. The volumetric efficiency of this pump is as high as 90%)
Rotary pump (used for low pressure sprayers)
Centrifugal pump (pump working on high speed having high volume discharge)

Duster is a machine to apply chemical in dust form.
Dusters make use of air streams to carry pesticides in finely divided dry form on the plants.
Types of duster:
- Plunger type
- Knapsack type: 2.5 to 5 kg
- Rotary type
- Power operated duster