A closer inspection with a magnifier confirms a worrying infestation of minuscule-winged insects – thrips. If you are an organic gardener, there are many natural ways to get rid of this pest problem.
Damage results in scars and discoloration. The plants no longer look healthy, and silver and black specks have appeared on the leaves, which cause them to look discolored and crinkled.
The fruit and vegetable patches are not thriving either, and those lovely flowers just starting to burst into color are looking rather wan too.
Here’s how to get rid of thrips naturally.
1. Soap and Water
A quick, easy way using a solution of a little organic liquid soap in a spray bottle and topped up with water.
Mix 5 tablespoons of liquid soap in a gallon of water. Spray it all over indoor or greenhouse plants.
For outdoors, a pump sprayer may work better if the infestation is far along. Pour any leftover solution around the base of plants to kill off developing nymphs.
This biological insecticide is processed from a naturally-occurring bacterium found in the soil and used today by farmers for large-scale pest control.
Spinosad is usually combined with other compounds and sold dry or in a dilutable liquid form and is effective against thrip bugs (Thysanoptera).
3. Neem Oil
This is an old established method of destroying many pests, favored by organic gardeners and farmers worldwide. Neem is a natural pest repellent derived from the seed of the neem tree.
The oil has many beneficial properties and is used in a wide variety of pest-repelling gardening products. It has an additional use as a fungicide and helps produce glossy leaves and healthy plants.
Combine 4 teaspoons of neem oil with 2 teaspoons of liquid soap in a gallon of water. Spray liberally.
4. Diatomaceous Earth
Another age-old method of dealing with a multitude of pests and diseases in the house and garden.
Unlike Neem though, it is a preventative or long-term answer to the problem. The white silicon-based powdery substance is from the crushed fossils of microscopic marine creatures.
Diatomaceous earth is sharp and abrasive to the exoskeleton of many insects. It has a dehydrating effect on the pests, which kills them overtime when they fall to the ground.
Sprinkle it around plants and spread it on the soil, in pots, or on the lawn over the winter to disrupt the life cycle of thrips. However, after rain or watering the garden, you will need to reapply it.
5. Sticky Traps
Different colors of these sticky strips attract different types of insect pests (blue for thrip insects).
These can be purchased readily from garden centers, shops, and online. Besides, they are easy to hang near any infected plants — inside or outside the house.
These critters and other insects will immediately become stuck to the traps and die rapidly without a food source. Afterward, dispose of the strips with the pests.
6. Pyrethrum (Pyrethrin)
This is an organic compound derived from chrysanthemum flowers and toxic to many pests.
Pyrethrin is usually combined with other insecticides and available in commercial sprays. Look at labels to be sure of an organic product.
7. Beneficial Insects
One of the successes of organic gardening is in being able to attract beneficial garden insects that remain unharmed by natural pesticides.
Along with lacewings, mites, and other insects, the star of these predators is the ladybug. Although small and pretty, the lady beetle is, in fact, a merciless killer, devouring up to 60 aphids and assorted pests per day.
Besides, the thrips predator (Cucumeris) eats the eggs and larvae.
Pollen and nectar make up the diet, so planting attractive flowers like marigolds and nasturtiums or aromatic herbs will invite these helpers to your garden.
8. Essential Oils
A few drops of essential oil such as peppermint, lemongrass, rosemary, etc., diluted with water is a powerful spray against all types of bad insects.
A standard recipe is 1 to 2 ounces of essential oil in a gallon of water. Spraying the plants thoroughly should kill the pests on contact.
Research into this means of thrip control is ongoing, but plant oils from aromatic herbs seem most successful.
Thunderflies are so lightweight that gusts of wind transport them from plant to plant. Therefore, it is relatively easy to remove them with a vacuum cleaner that will suction them into a disposable dust bag.
Running a small hand-held cleaner gently along and under the stems and leaves of plants will draw up large numbers of the pests.
10. Eliminate Grass and Weeds
Keeping a clean garden is one way of reducing infestations from unwanted insects.
As a result, regular cutting and weeding, and clearing up dead leaves or debris will help keep the numbers down.
11. Kaolin Clay
This natural mineral leaves a grainy residue when puffed onto leaves and fruits, which thrips cluster around.
The critters pierce into plants and suck the sap, causing a great deal of damage. Consequently, kaolin clay will help deter them from feeding in this way.
Thrips multiply and spread rapidly, feeding on all kinds of fruit, vegetables, and ornamental plants.
They can cause leaf damage, harm stems, and buds, so an infestation might require you to take some fairly radical action.
You may be waiting for those blooms to burst into flower, but pruning hard to cut off the invasion may mean healthy plants, late season.
13. Use the Hose
Another simple home remedy for getting rid of thrips is using the hose.
These bugs are not good flyers and find it even more difficult in moist air. As a result, using the hose to produce a fine mist can restrict their movement.
There are at least 4,500 species of thrips recorded today and possibly the number is as high as 6000. Some are even beneficial in that they kill and eat other pests, but most are a nuisance to gardeners.
Using these natural methods may mean that next season you will be able to enjoy vibrant plants again.