by johnah on October 31, 2020
Whiteflies are insects which live in moist places like soil, leaves, flowers, and fruit. They feed on plant sap and cause damage to the plants’ growth. There are different types of whiteflies. Some species have wings while others do not have any kind of wings at all. These type of whiteflies usually attack only certain kinds of plants or specific parts of the plants such as petals or stamens. Other types of whiteflies are called non-flying whiteflies. These types of whiteflies do not feed on plants but they cause damage when disturbed.
Insecticides are used to kill these types of whiteflies and prevent them from attacking your crops. Insecticides work by killing the insects before they reach the crop.
When using insecticides, it is very important that you follow the label instructions carefully because some chemicals may harm other living organisms such as beneficials or pests. For example, some pesticides may affect beneficials such as bees and butterflies. You must read the label carefully before applying insecticides to your garden.
There are many types of insecticides available for use on plants. Most commonly used ones include pyrethrins (pyrethroids), organophosphates (OP) and carbamates (C).
Pyrethroids are extremely toxic to humans, pets and wildlife. They may also be toxic to beneficial insects. They are used to control sucking insects such as aphids, whiteflies and mealy bugs. But they do not provide long-lasting protection against whiteflies.
Organophosphates are used to kill whiteflies as well as other sucking insects. These chemicals are highly toxic to birds, fish and other wildlife.
Some of these insecticides may also be harmful if consumed by humans. These insecticides break down into another chemical namely organophosphate which affects the nervous system of animals.
In addition to using insecticides, it is necessary to manage the growth of whiteflies on plants. When pesticides are used for whiteflies, they should be thoroughly mixed with the leaves and flowers in sufficient amount to provide long-lasting protection.
Soap spray is an organic way to kill whiteflies on plants and flowers.
In the next section we will discuss benefits of using insecticidal soaps to kill whiteflies on plants.
Benefits Of Soap Spray
Soap spray can be used to control a wide range of insects infesting ornamental plants, vegetables, fruits and various kinds of crops. It can be used both indoors and outdoors.
It is an effective way to kill whiteflies fast and provides permanent control of these insects without affecting beneficial arthropods and animals.
It is an organic insecticide which is considered safer than chemical pesticides. If soap spray is applied properly, it does not cause any harm to the environment or animals and plants.
Soap sprays should be used with care when there are bees and other pollinators in the garden, as they may be killed if they come into direct contact with this insecticide.
In the next part of the article we will see how to use insecticidal soaps to control whiteflies.
Using Insecticidal Soap To Get Rid Of Whiteflies
Always buy a ready-to-use insecticidal soap or mix 1 teaspoon of pure soap powder in one liter of water for creating a solution of insecticidal soap. Different manufacturers use different types of soaps to make insecticidal soaps.
Some of the most commonly used soaps are:
Before applying insecticidal soap, it is necessary to remove all the diseased plants, as well as shed leaves, stalks and other plant parts from the garden. This will help prevent the disease from spreading to other plants in the garden.
When buying ready-to-use insecticidal soap or creating your own solution, make sure that the concentration of the soap is 8.8 % or less as concentrated soaps may damage some plants.
Soaps with concentration higher than 10 % can damage plastic pots and breed soil bacteria.
When spraying the plants, it is necessary to apply sufficient amount of insecticidal soap on the infected plants to completely cover all the infected areas. It is also necessary to spray the upper and underside of the leaves.
If whiteflies are present in large numbers, then it is better to spray the plants early in the morning or late in the evening, as whiteflies are not active at these time periods.
When using ready-to-use insecticidal soaps, make sure that you completely cover the plant with the prepared spray. While using homemade insecticidal soaps, it is necessary to apply at least 1 teaspoon of pure soap per liter of water.
Spray the plants thoroughly until the soil is moist. Do not apply more than 2 – 3 times every week.
Apply the spray in the late evening or early morning when it is cool and there is no wind.
Mix 1 to 2 teaspoons of pure soap for each litre of water in a spray bottle.
Soap sprays can be mixed and stored in plastic bottles for later use. Using a plastic bottle is preferable as it is lightweight and does not break easily.
Soap sprays should be used before the adult whiteflies reappear in large numbers.
Always store the prepared insecticidal soap in the refrigerator.
Insecticidal soaps should not be used for more than 2 to 3 weeks. If you are growing vegetables, herbs or flowers, do not use it for more than a week.
When using ready-to-use insecticidal soaps on large plants, it is necessary to cover the plant to prevent its direct spray.
Spray the underside of leaves first and then the upper surfaces.
Spray the plants until it is completely moist and shining.
Do not spray in the evening as the soap will burn the leaves.
Soap sprays do not provide immediate relief, therefore it is necessary to control pests such as whiteflies through other methods like physical removal and biological control. In large gardens it is necessary to keep checking the plants everyday for pest infestation and apply insecticidal soaps when necessary.
Soap sprays are effective only when used at the right time. It is necessary to reapply the sprays when the pest population increases.
While using ready-to-use soaps, it is not necessary to reapply after it has dried.
Biological control: Many natural enemies including predators and parasites attack whiteflies. They are present in all regions and environments where whiteflies are located.
These natural enemies need to be encouraged to prevent a large population of whiteflies from developing. Whitefly parasites, predators and pathogens are present in all regions and environments where whiteflies are located. It is necessary to encourage these natural enemies by maintaining the correct environment. The natural enemies of whiteflies can be encouraged by growing marigolds in the immediate neighborhood.
Yield losses from whiteflies can be prevented by encouraging their natural enemies such as lacewings, ladybugs and others.
Lacewings: They are a little bit expensive but effective. It is necessary to release them as soon as you notice whiteflies.
Bagworm: Bagworms are the larvae stage of a moth. The female moths lay their eggs in summer on the edges of leaves.
The eggs hatch and the young larvae start feeding on the edges of leaves. They build bag-like cases around themselves by weaving fibres around themselves. They stay fixed to one spot all through their life. The bags have a small hole through which the moth adult comes out to breed.
Hornworms: They are the larval stage of a moth. They are also known as tobacco hornworms.
The eggs of hornworms are laid by the female moths in clusters. The eggs hatch and the young larvae start feeding on the leaves. They grow larger and larger and feed on the leaves. They have a pronounced curve near their tail.
Sources & references used in this article:
Greenhouse whitefly by WS Cranshaw – Insect series. Home & garden; no. 5.587, 1999 – mountainscholar.org
THE PEST STATUS OF BEMISIA TABACI IN CHINA AND NON‐CHEMICAL CONTROL STRATEGIES* by REN Shun‐xiang, W Zhen‐zhong, QIU Bao‐li… – Insect …, 2001 – Wiley Online Library
Biological control of whiteflies with entomopathogenic fungi by LS Osborne, Z Landa – Florida entomologist, 1992 – JSTOR
Control of greenhouse whitefly (Trialeurodes vaporariorum) by thyme and peppermint by H Aroiee, S Mosapoor… – … APPLIED SCIENCE AND …, 2005 – li01.tci-thaijo.org