Insecticides play a vital role in modern farming by protecting crops from harmful insects that can reduce the yields and damage the overall health of plants and soil. With rising food demand and limited farmland, farmers rely on insecticides to protect crops, ensure healthy yields, and reduce losses. These insecticides (synthetic or natural) help to control pests. Modern farming techniques combine the use of insecticides with other practices like crop rotation and integrated pest management (IPM) to make farming more efficient and sustainable. In this blog, we will determine the major difference between the insecticides and their impact.
What are Insecticides?
Insecticides refer to chemical or biological agents that kill or restrain destructive insects that eat crops. Insecticides not only save crops but are also cost-effective and productive when used intelligently and with the right knowledge in modern Indian farming.
Insecticides are used to protect crops in vulnerable periods, such as seedling protection or flower protection. They are either systemic (entering the plant and killing the pest internally) or contact (killing pests on contact). From rice and cotton to vegetables and fruits, nearly every crop in India requires healthy harvesting and timely application of insecticides to generate greater revenue.
What Are Systemic Insecticides?
Systemic insecticides are those pesticides that are absorbed in the plant and move within the plant through the sap. This implies that the entire plant, including the leaves, stems, and roots, will be toxic to insects attempting to feed on it.
Instead of necessarily spraying these insecticides on the surface, they end up becoming a part of the internal system of the plant. This renders them particularly useful against pests that are easily overlooked or generally reside within the plant, such as sap-sucking insects.
How Systemic Insecticides Work
In the case of a systemic insecticide application, it enters the plant through the roots or leaves. Then, it travels through the vascular system of the plant, just like water and food.
An insect such as an aphid, whitefly, or jassid will suck the plant and, in the process suck in the insecticide. This destroys the pest even when it is hiding or not seen. These insecticides provide long-lasting protection, lasting several days.
Examples and Use Cases in Indian Crops
The following are some of the systemic insecticides commonly used along with their use by the Indian farmers:
- Imidacloprid: It was applied in cotton, rice, sugarcane, and vegetable crops to deal with aphid jassids and whiteflies.
- Thiamethoxam: It is very effective in cotton, chili and okra where sucking pests occur.
- Acephate: Used on pulses, cabbage, and brinjal to act against bugs such as thrips and leaf miners.
They are particularly helpful in the beginning stages of crop growth when the roots or sap begin to be attacked by pests.
Contact insecticide is a type of pesticide used to kill insects that involve direct contact between an insect and a pesticide. They do not enter the plant, and pests must come into contact with or be sprayed directly with the solution. They are most suitable for pests that inhabit the external areas of the plant, such as foliage, stems, or fruit, which can be easily reached using a spray bottle.
How Contact Insecticides Work
Each insect that comes into contact with the insecticide sprayed on the crop will be affected by the chemical entering its skin or body as it comes into contact with it and dies. The pest does not even need to eat the plant; contact is sufficient for damage.
However, this problem is that chemicals remain on the surface, and rain or irrigation can wash them off, so you may need to reapply the spray.
Examples and Use Cases in Indian Crops
These are some examples and common uses:
- Cypermethrin is applied to cotton, tomatoes, and chilies to control caterpillars and other leaf-eating insects.
- Chlorpyrifos is used in paddy fields against stem borers and leaf folders.
- Malathion is applied to fruit crops and vegetables to control fruit flies, chewing insects, and provide general pest control.
Contact insecticides are particularly useful during the flowering and fruiting seasons when pests begin to target the exposed parts of a plant.
Mode of Action
Systemic Insecticides: These act internally in the plant. Once applied, the chemical is absorbed by the plant and transported through its roots, stem, and leaves. Insects also ingest the insecticide by sucking the sap or chewing the parts of the plants, and they die off.
Contact Insecticides: These act on the surface. The insect must make contact or be in direct contact with the chemical and be killed. They do not access the plant's system and hence only spray them where they are located.
Application Method
Systemic Insecticides: They can be used in numerous ways: sprayed on leaves, applied to the soil, or even the seeds can be treated. When used, the plant itself will be poisonous to insects.
Contact Insecticides: These must be applied directly to the sections where the pests are found. One should spray the plant thoroughly, including the undersides of the leaves, where most pests tend to conceal themselves.
Duration and Effectiveness
Systemic Insecticides: They provide a better restraining effect. The chemical itself still has effects for several days and even weeks as it will still not be washed out of the plant.
Contact Insecticides: They are quite fast in acting but of limited duration. They can be washed or their effect diminished by rain or sunlight or irrigation, and repeated sprays can be necessary.
Target Pest Control and Limitations:
Systemic insecticides are the most effective in controlling sap-sucking insects, such as aphids, jassids, whiteflies, and thrips. They bite on the interior of the plant, and hence, systemic insecticides are more effective.
Contact Insecticides: Best suited when dealing with chewing insects such as caterpillars, beetles, and borers. Most of these pests can be spotted and seen on the surface of the plant so that contact sprays can be applied directly to them.
Limitations:
Systemic insecticides may not be effective against pests that remain on the exterior or feed on exterior sections.
Unless carefully applied, contact insecticides would not reach the hidden pests (or pests feeding within the plant).
When to Choose Which: Practical Tips for Indian Farmers:
The type of insecticide is also very important, as it helps protect your crop, saves money, and reduces the amount of pesticides. It is also dependent on the crop, its growth stage, the nature of the pest targeting the crop, and even the weather conditions.
Type of a Crop and Crop Growth Stage:
There are a variety of crops and different growth stages of a plant that attract different kinds of pests. It is also better to understand when to apply systemic or contact insecticides to manage these pests:
Initial Stage of Crop (Seedling to vegetative): Apply systemic insecticides. Chemicals are readily absorbed by young plants and sap-sucking pests (such as aphids, jassids, and whiteflies), allowing for easy control at an early stage. Example: Imidacloprid in cotton and okra.
Flowering and Fruiting Stage: Contact insecticides can be applied. At this stage, leaves, flowers, and fruits are consumed by pests such as caterpillars and borers. They live on the outside; thus, contact sprays are more effective. An example is that of cypermethrin in chili and tomato crops.
Root Crops (such as sugarcane, onion, and potato): Systemic soil-applied insecticides (such as thiamethoxam) are more effective when pests exist in the soil or underground, or they attack underground portions of the plant.
Season and Pest Behavior:
Knowledge of the type of pest that is destroying your crop and at which season assists in choosing the necessary insecticide:
Sucking Pests (aphids, whiteflies, jassids, thrips): may take systemic insecticides because they feed on plant sap. The chemical kills the pest as it eats when the chemical travels within the plant.
Chewing Pests (caterpillars, beetles, borers): Use contact insecticides. These are external feeders that may be sprayed directly to gain quicker control.
Dry Season (Summer or Winter): Systemic insecticides are more effective, as they cannot be rinsed and can provide protection over a long period.
Rainy Season (Monsoon): Contact insecticides can be washed out during a rain shower. When spraying is necessary, do it during a dry spell or use systemic options that remain within the plant.
Weather and Irrigation Solutions:
Weather and water management also influences the effectiveness of your insecticide:
Before Rain or Flood irrigation: Do not use contact insecticides as they are easily washed away and rendered useless. Systemic insecticides are safer since, once they enter the plant, they continue to work.
Hot Sunny Days: Sunlight can cause quick evaporation of contact insecticides. To prevent wastage, spray them in the early hours of the morning or late at night.
Drip or Sprinkler Irrigation Farms: Fertigation Systemic insecticides can be applied by water using the fertigation technique, which administers the chemical directly at the roots of the plant.
In this way, the insecticide reaches the plant's roots and is absorbed effectively. It exerts excellent control over sap-feeding or root-feeding insects and does not require manual spraying.
Safe Usage Practices for Both Types
In the case of both systemic and contact insecticides, handling and application are crucial, not only for controlling pests, but also for maintaining your health, practice, environment, and crop safety. The following are some of the safety strategies every farmer must adhere to:
Look at the Label and Instructions:
Be sure to follow the directions on dosage, dilution, and method of application provided by the manufacturer. An excessive portion can damage the crop; an insufficient portion may not even kill the pest.
Use Protection Equipment:
When operating insecticides, use gloves, masks, long-sleeved clothes, and goggles. This guards against accidental exposure to skin or breathing.
Avoiding Spray in Wind or Sunshine:
Apply in a windless condition (preferably early morning or late evening) to avoid chemical drifting and evaporation. Do not spray during high, windy weather or in sunshine.
Keep Animals and Children Away:
Do not permit children or livestock to enter the sprayed area until it is safe (usually within a few hours or as recommended on the product label).
Stocking of Chemicals in Stores Keep properly:
Never store insecticides near food, feed, and water sources, and store them in a cool, dry location. Pesticide containers should never be re-used to store other liquids.
Observation of the Waiting Period:
Follow the stipulated days of harvesting crops after spraying. This makes sure that the pesticide residue has been destroyed and that the produce is safe to eat.
Conclusion
Insecticides play a crucial role in the modern farming process, enabling Indian farmers to protect their crops against harmful pests that can impair harvests and profits. The choice between systemic and contact insecticides depends on the type of crops, the behavior of the organism, its stage of development, and the prevailing weather conditions.
Systemic insecticides act inside the plant and are most suitable for sap-sucking pests, whereas contact insecticides are topical and most effective against chewing pests. They can be used effectively, on schedule, with proper practices, and safely, to yield healthy crops, improve pest management, and enhance profits. The current concept of successful and sustainable farming practices relies on the innovative and safe use of insecticides.
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