How to Get Rid of Whiteflies
Updated: May 23
Whiteflies are a major problem for greenhouse growers. These tiny moth-like pests congregate on the undersides of leaves and and suck the sap from the plant. They are transmit plant viruses.
Despite their name and appearance, whiteflies are neither moths or flies. In fact, they are distant cousins of aphids and leafhoppers.
In this article we're going to discuss:
Signs & symptoms of whitefly infestations
How to get rid of whiteflies
Garden cleanliness & pest prevention
Table of Contents
Whitefly Taxonomy
Early Signs of Whiteflies
Whiteflies on Plants
Whitefly Taxonomy
The initial signs of a whitefly infestation are very subtle and can be easy to overlook. Their surreptitious nature allows them to reproduce undetected until the infestation grows into something catastrophic.
Whitefly infestations resemble aphid damage. Plants lose vigor and leaves begin to droop before turning yellow and wilting.
Leaves may appear waxy with sticky honeydew or sooty-colored fungus that grows on the honeydew.
Adult whiteflies often resemble tiny specks of ash on the undersides of leaves.
Greenhouse whiteflies reproduce year-round.
One way to differentiate between an aphid or whitefly infestation is to shake the plant.
In the event of a whitefly infestation, a cloud of whiteflies will erupt from the plant when the leaves are agitated. If the plant is only infested with aphids, no such cloud will appear.
Aphids, also known as "plant lice," are soft-bodied, pear-shaped pests with long legs and antennae. A pair of tubelike cornicles or siphons project backward from the abdomen, almost like the tailpipe of a car.
Adult aphids are typically measure around 2mm and the rear end tapers to a pointed, tail-like caudum between the cornicles.
Aphids vary in color from black to green and some species of aphids are known to have paired bumps between the antennae on the head called "antennal tubercles."
The majority of adult male aphids do not have wings and are called apterae. Adult males that do have wings are called alatae, and their wings are much longer than their bodies.
These winged adults are called spring migrants and fly off to secondary hosts, such as cannabis.
Aphids attack cannabis plants by colonizing the stems and the undersides of the plant's leaves. They puncture the stems, branches, and leaves to suck the sap with straw-like mouths.
Aphids excrete a concentrated sugar solution called "honeydew" that attracts ants who heard and "farm" the aphids, thus protecting them from predators.