Whiteflies are a popular greenhouse and garden pest that’s difficult to get rid of totally.
Whitefly infestations can damage flowers, vegetables, and fruits.
What causes whitefly infestation
Plants suffering from water stress are more prone to whitefly infestations. If you reside in an area whose summers are mainly hot and dry, or you keep failing to water your plants, it’s most likely that your plants are dehydrated.
High temperatures are the perfect breeding environment for whiteflies.
Further, because of their piercing and sucking mouthparts, whiteflies naturally flourish in dry conditions.
Drought also inhibits the survival of the ladybug larvae, a natural whitefly predator. When ladybugs decrease in your garden, brace yourself for a whitefly infestation
Excessive insecticide use
Most insecticides do not target specific insects. Spraying your garden with large amounts of pesticide will eventually wipe out all bugs around, including those that are natural predatory species, such as spiders, parasitic wasps and ladybug beetles.
Excessive use of nitrogen fertilisers
Although fertilisers rich in nitrogen improve your plants’ health, their excessive use causes high concentration levels of nitrogen in plant tissues. These high levels overstimulate the succulent growth of your plants, prompting rapid reproduction of some aphids.
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How to prevent whitefly infestations
Here are a few natural ways to prevent and get rid of whiteflies:
Routinely check under the leaves of your plants. If you notice any whiteflies, hose them down to get rid of little white bugs on plants. Early detection will decrease the chances of an infestation.
Place yellow sticky traps close to your plants to catch the whiteflies and prevent them from attacking your plants.
Sticky traps also help to monitor the population of the whiteflies without closely inspecting the plants.
The trap’s yellow colour attracts whiteflies. You can also make your sticky traps using yellow cards and then use a sticky coating like petroleum jelly, tanglefoot or mineral oil to coat them.
Use a vacuum cleaner
Use a handheld vacuum cleaner to remove the whiteflies from the plants.
Use the cleaner to vacuum the underside of the leaves until there are no more whiteflies remaining.
Dispose of where the whiteflies will not be able to reaccess your garden.
Neem oil provides an alternative for chemical pesticides that’s non-toxic.
Spray this extract on the leaves of your fruit trees, vegetables, and flowers weekly to significantly reduce whitefly populations.
Mix 1 oz of oil to 1 gallon of water, then spray all leaves until they are coated completely to kill whitefly eggs, larvae and adults.
Alternatively, you can coat the leaves and stems of your plant thoroughly with neem oil.
Ensure you cover the whole plant with the oil for it to work effectively. Neem oil acts as a repellent and also minimises the whiteflies feeding, making them starve to death.
Releasing large numbers of predators into your garden is effective in controlling whiteflies.
Ladybugs, green lacewings, and parasitic wasps such as Encarsia Formosa are examples of natural predators. Purchase these beneficial insects and release them into your garden.
These insects feed on whitefly eggs as well as adult whiteflies, controlling any infestation in your garden.
Use organic fertiliser
Organic fertilisers slowly release nutrients to the plants, moderating the succulent growth of plants which does not prompt any rapid reproduction of aphids.
Use insecticidal soap
Whiteflies die on contact with insecticidal soaps. Spray the underside of leaves with soap for effective control of whiteflies.
To make the soap, mix water with liquid dish soap. Put the mixture in a spray bottle and spray the affected plants every three to five days until all whiteflies are gone.
You can also make insecticidal soap by mixing rubbing alcohol, water and liquid soap in the ratio of 2:5:1. Put this mixture in a spray bottle and use it to spray your plants’ foliage that is already affected.
Spray when the temperature is cooler in the evening.
If you experience a heavy whitefly infestation, prune the leaves and branches most affected and dispose of them.
Enclose them in a bag or burn them to inhibit the spreading of the whiteflies.
Use horticultural spray oils
These oils will control whiteflies and have minimal adverse effects on natural predators.
Mix the oil with water and spray at the base of your plant.
You can intercrop other plants with your vegetables to deter whiteflies.
Plants that repel whiteflies are:
- Plants with strong scents like
- Aromatic plants
- Pineapple sage
- Hummingbird bush
- Bee balm
Will vinegar kill whiteflies
Vinegar, when diluted with water, is effective in killing whiteflies. Use this mixture to spray on the leaves.
You can also use it alongside baking soda and dish soap to make an insecticidal soap that will kill whiteflies.
To make this whiteflies home remedy, use two teaspoons of each ingredient and mix with one gallon of water to make the insecticidal soap.
Spray the soap on the underside part of the leaves because it’s where the whiteflies reside.
The whiteflies die upon contact with the soap. To maintain control over the flies, spray routinely- every 3 to 5 days.
Whiteflies develop resistance to pesticides quickly, making their control difficult.
Repeatedly applying chemical pesticides leads to the growth of a strain of whiteflies resistant to pesticides.
Ensure that the pesticide you use is not harmful to whitefly natural predators by washing your plants before releasing the predators into your garden.
Effective pesticides should contain active ingredients from neonicotinoid compounds such as dinotefuran, imidacloprid, clothianidin and thiamethoxam.
Using different family insecticides will inhibit tolerance building to the product.
Are whiteflies harmful to humans
Whiteflies are harmless as they are not known to bite humans.
Large populations of whiteflies in your garden will cause severe damage to your plants.
Be on the lookout for the earliest sign of whiteflies to be able to control them effectively.
Take action immediately when you notice the whiteflies in your garden.