July 21, 2023

How to Get Rid of Whiteflies?

What are Whiteflies?

Whiteflies are not your typical ''flies'' but are sap-sucking insects related to Aphids, Scale Insects and Mealybugs. They are small, hard to catch insects that breed rapidly and suck plant sap whilst producing honeydew.

These bugs are also known as ''flying dandruff''; they can be seen flying around plants but are so small human eyes struggle to see them.

There are over 100 species of whiteflies in Australia, but the most common is the native strain of Silverleaf Whitefly.

Cluster of whiteflies and their eggs on the underside of a green leaf

Whiteflies are often found in clusters on the undersides of leaves. They are active during the day and scatter when disturbed, turning into ''flying dandruff''.

What do whiteflies look like?

Adult whiteflies are usually white or pale coloured. They are smaller than a pinhead, around 1.5 mm long, and have four delicate wings. Up-close, these insects look like tiny moths, but they're tiny white specs flying around plants to the human eye.

The name ''whitefly'' comes from the white, waxy substance coating their bodies. Most species of whitefly have triangular shapes bodies and can be found in clusters on the undersides of leaves.

Whiteflies use their piercing mouthpieces to suck up plant sap and turn it into a sticky substance known as honeydew. Honeydew can cause fungal diseases known as sooty mould. Sooty mould interferes with photosynthesis which prevents plant growth and health; this can be whipped clean with a warm cotton cloth but, if left untreated, can spread and infect the plant.

The lifecycle of whiteflies.

All whiteflies have similar lifecycles. They develop from eggs and grow into adults through four nymphal instars. Male and females are identical in this insect species, except females are usually larger.

Female whiteflies lay their eggs in circular patterns on the undersides of leaves. These eggs resemble scale insects with their hard outer shell. Once hatched, the crawlers of about 0.3mm long emerge from eggs and wander over the plant's surface seeking delicate plant matter.

Within one week, the crawler settles and remains stationary for the final stages of growth. They morph from flat and oval larva (like scale) into nymphs that appear yellowish or black. Here the nymphs remain fixed to the leaves' surface whilst they suck the plant's sap for nutrients. Before transforming into adults, the final stages change the insect to pale green in a scalelike appearance whilst developing their legs and wings for adulthood.

The winged adults emerge from their final stage. First appearing as pale green or yellow, they quickly secrete a white, waxy coating. Whitefly populates can quickly develop in warm weather as their entire lifecycle can be completed in 18 days.

During the entire lifecycle, whiteflies depend on sucking plant juices from leaves and ensuring enough nutrients to grow.

Where are whiteflies found?

Whiteflies enjoy warmer weather; they do not survive in freezing winters or colder months. They want greenhouse environments where it's humid with plenty of plant food. Whiteflies can become seasonal outdoor pests if not properly treated, so always inspect plants before bringing them home!

In Australia, whiteflies are typically able to reproduce throughout the entire year. As a result, they can cause indoor and outdoor plants problems. In addition, the numbers will jump up during the mid to late summer due to the warm, humid months.

Which plants are susceptible to whiteflies?

Whiteflies can be found in various plants, from indoor plants to summer vegetables. They typically enjoy tomatoes, eggplants, peppers, sweet potatoes, and even citrus trees. Whiteflies will feed on anything with soft, smooth leaves. We've even found them on our elephant leaf plant!

Herbs, weeds, flowers, fruits and vegetables can all be acceptable to whiteflies.

Whitefly damage

Adult whiteflies and nymphs feed on plant sap by puncturing the plant service and sucking upwards. By congregating on the underside of leaves, they are protected from the sun and wind whilst finding tender leaves.

From feeding on plant sap, whiteflies produce large amounts of sweet, sticky honeydew, covering entire plants. This honey due then turns into a sooty mould. Sooty mould interferes with photosynthesis which prevents plant growth and health.

How to identify if you have whiteflies?

If you are unsure if you have whiteflies look for two things.

Look out for flying dandruff – small white dots flying around your plants or on the underside of their leaves.
Watch for sooty mould. You'll see sticky honeydew developing on your leaves, potentially going black; this is an excellent indicator that you have a whitefly infestation.

How to prevent whiteflies?

There are a few great remedies to preventing whiteflies.

Remove any unnecessary plant matter that may attract them, i.e. weeds.
Thoroughly check plants before taking them into your home jungle. If you can prevent them from coming in, you've saved the day and your plants.
Invest in neem oil, as it's a natural repellent for whiteflies. Neem oil is a tremendous biological product that will reduce the number of whitefly larva. Spray regularly on leaves and soil to prevent several plant bugs.
Sticky traps for adult whiteflies. Sticky traps are a fantastic way of capturing flying adult pests. Once they've landed on the sticky trap, they can no longer continue to breed and spread.
The natural enemies of whiteflies are the tiny parasitic wasp. Lacewings, ladybirds, and hoverfly (syrphids) larvae are other enemies.

Whiteflies can quickly develop insecticide resistance, so using natural remedies like neem oil and other insects is a fantastic way to keep the larvae and population under control throughout the entire year.

Treatment for small whitefly infestations

Start by spraying the whiteflies with a hose or spray bottle; this will cause them to scatter and dislodge nymphs and eggs from plants.
Spray neem oil and insecticide soap to prevent re-landing on the infested plant. Repeat two or three times weekly or as necessary.
Set up traps for adult flies. Once they've lost their hold on a plant, they're going to search for their next home. By setting up traps, the adults will be attracted to them and prevent further spreading.

If you have any more questions about whiteflies, please message me. Or if you've developed any at-home natural remedies, we'd love to hear about them.