They mostly appear in greenhouses and are particularly fond of infesting vegetables. Fortunately, whiteflies are easy to spot and, with the right tools, can be eliminated quickly.
What are whiteflies and how do you recognize an infestation?
The appearance of the whitefly is particularly typical. The insect is white in appearance and endowed with wings that fit very closely to the body. They are mainly found on the underside of the leaves of vegetable plants. But it doesn't stop at ornamental plants or trees either.
Their larvae, which are small and white in appearance, are also easy to recognize. They attach themselves to the leaves and pupate after a while. The cycle from larva to adult usually lasts three to four weeks.
However, there are different species of whitefly, each of which looks for other plants as a food source. This includes:
» Greenhouse Whitefly
The greenhouse whitefly (Trialeurodes vaporariorum) is mainly found in the greenhouse, where it settles on cucumbers, tomatoes or peppers. In addition, she also likes to go to various ornamental plants.
» Cabbage Whitefly
It is also known as cabbage whitefly or cabbage fly. The Aleyrodes Proletella mainly looks for vegetables such as kohlrabi, kale or Brussels sprouts and also sits in the savoy cabbage for the winter. In addition to the typical white coloring, it has gray spots on its wings.
The infestation is characterized by another feature, in addition to the larvae that sit on the leaves: the white fly emits a white waxy dust, which not only settles on the insect but also on the leaves in the form of deposits typical stains.
This causes a sooty mold infestation, which weakens the plant and causes it to produce malformed fruit. It is all the more important to prevent an infestation by the pests or to take the right measures as quickly as possible if it does happen.
Whitefly - Prevention
A natural balance of nature proves useful in control of whitefly. That means maninvites various beneficial insects into its garden. For this you hang up insect hotels, for example. Spiders or predatory beetles, which are the natural enemies of the whitefly, settle in these.
In the greenhouse you can release parasitic wasps, which are commercially available. They eat the larvae of the pests at the same time. To keep them in the garden, simply drill smaller holes in a log and place it in a suitable spot in the garden. In this way, the beneficial insects are preserved for the next year.
Fight whiteflies with long-term effects
If an infestation has already occurred, two things are important:
- The adult animals must be prevented from laying eggs.
- The existing larvae must be eradicated and reproduction prevented.
As a first step, it is helpful to remove the affected leaves and stems from the plant. They should be disposed of with household waste and not in compost, otherwise there is a risk of reinfestation. However, before throwing away the leaves, they are placed in a plastic bag and treated with soapy water. This softens the larvae and prevents them from evolving.
❶ Change in external conditions
Another helpful measure is to move the plant to another spot. This is particularly recommended for indoor and balcony plants. For example, placing the pot in a cool and very airy location will drive away the pests.
By the way, the same applies to cooler temperatures. With the first frost, the whiteflies have usually disappeared from the plants, as they cannot survive long below zero.
❷ Replace substrate
If the plant is okay, there is still a danger lurking in the substrate. Therefore, it is recommended to partially replace it. The best way to do this is as follows:
- Step 1: Remove the plant from the pot
- Step 2: Rinse root ball
- Step 3: Thoroughly clean the container
- Step 4: Equip the plant with new substrate
If the plants are garden plants, just remove the top layer of soil and replace it with fresh soil.
❸ Attach yellow boards
The so-called yellow boards are a very simple measure that is available in every hardware store or garden center. These are plates that appear yellowish and have a sticky surface. They immobilize the flies.
Our recommendation:
If you supplement this measure by shaking the plant several times a day, some of the pests can be caught. However, yellow boards should not be used as the sole measure.
❹ Home remedies for whiteflies
In addition to the methods already mentioned, there are special home remedies that can help to quickly reduce the whitefly infestation.
- Shower off the plant with cold water to remove larvae
- Use pesticides made from basil, nettles or garlic stock
Crafting each named spray requires a handful of the named plant, left in water for twelve hours. Then pour the brew into a watering can and treat the plant with it.
The effect is due to the odor emitted, which the whitefly dislikes.
❺ Controlling whiteflies with biological and chemical insecticides
Of course, the market also offers different preparations that can be used to eradicate whiteflies in other ways. The available means differ according to biological and chemical products. This is the best place to grab it:
biologicals
+ rapeseed oil
+ neem oil
+ other fatty acids
chemicals
+ potash soap
+ pyrethrum
In general, it is always advisable to use biological measures whenever possible, as these do not harm the environment.