Practically all plants are susceptible to some sort of invasion, whether that’s from an animal, fungus, or insect, such as thrips. Basil is no exception, and its tender stalks and leaves are no match for a swarm of hungry insects. Luckily, thrips are easy to treat, and plants can often make speedy, full recoveries if treated early.
What Are Thrips?
Plant-eating thrips are very small insects that feed on the contents of plant cells, ultimately causing the tissue to die off. These creatures are minuscule, often only around 1/63 of an inch long.
Types of Thrips
Not all thrips are cause for concern as some species actually hunt other thrips and pest insects such as aphids. Some of the most common thrip types are:
- Recycler thrips. These insects eat decaying matter and help to break down garden waste
- Predatory thrips. Thrips in this category prey on other insects as opposed to plants.
- Fungus-eating thrips. As the name suggests, these guys will feed on fungus.
- Pollen thrips. These thrips have a taste for pollen from flowers in your garden. This is beneficial as these thrips contribute to pollination.
The only time you need to worry about thrips is when they show themselves through plant damage, which we will cover below.
How To Identify Thrips
Because of their quick movements and tiny size, thrips can be hard to identify solely by observation. A jeweler’s loupe is a great tool in the arsenal of gardeners and makes spotting thrips much easier.
Thrips are black and have a long, narrow shape as adults with folded wings on their backs. Pupae have a translucent tan color and have a thicker look — kind of like a tiny, beige grain of rice.
Thrip damage is fairly straightforward to identify and can be spotted by dead, silver-gray areas on the plant. They also leave behind very small green circles that are created by their waste as they feed.
Thrip Life Cycle
Thrips can be a real nuisance to indoor and greenhouse gardeners because eggs are able to overwinter. This means that infestations can be a recurring problem if not dealt with.
The first stage after hatching for thrips is a larvae form. They will then feed and molt again into the second stage of larvae. After this second stage, they will fall to the ground and pupate into their adult form. This is a similar process to what butterflies go through.
Where Do Thrips Come From?
Adult thrips have wings, which gives them the ability to move to different locations and settle on suitable food sources where they find them. They can also be carried by the wind, meaning their spread can be greatly increased.
Thrips in Soil
Because thrips drop to the ground during their life cycle, they can be found on low leaves and in the soil. For this reason, they can contaminate other areas through the transfer of soils. In general, unless you are buying certified soils from landscaping companies or nurseries, you should not move outside soil to your garden.
Why Thrips Are Attracted to Basil
Thrips are drawn to plants that have green, tender leaves. This definitely includes basil. This is the reason why thrips may be choosing your basil over other plants.
Can Plants Recover From Thrips?
Yes, plants can definitely recover from a thrip attack, but there’s a catch. Remember that thrip damage results in dead tissue, so the more your plant is attacked, the more your plant will die. For heavily affected plants, it will take a lot of energy to grow back to their original state.
How To Get Rid of Thrips
Fortunately for gardeners, thrips can usually be managedeasily. Unlike the chemical solutions on commercial farms, home growers have many different natural and family-safe options at their disposal. The list below will give you all the most commonly used methods for stopping and discouraging thrips.
1. Strong Spray of Water
A good first measure of dealing with thrips can be to use a spray bottle or gentle spray from a hose to spray the underside and tops of leaves, knocking off insects. This, however, is definitely not a permanent or super-effective solution. Care should also be taken not to damage the basil plant, which can be delicate.
2. Soapy Water
Soapy water is increasingly becoming the go-to control method for a wide variety of garden insect pests, including thrips. Soapy water permeates the skin of thrips and kills them on impact. The downside to soapy water is that it stops being effective when dry, and it does not kill thrip eggs.
3. Neem Oil
Neem oil is a safe and effective solution for controlling a wide variety of insects. It is a recognized organic pest control option and will do a great job at destroying thrips while keeping your basil safe to eat. I use this organic cold-pressed neem.
For thousands of years, gardeners have known about the beneficial insecticidal properties of chrysanthemum flowers, which is what pyrethrin is extracted from. This chemical is highly effective at destroying and keeping away thrips and other pests, and there are many pre-made, organic products of this chemical available, like this one.
You can also grow chrysanthemum flowers yourself, and besides their insect-repellent qualities, these daisy-like flowers are also very attractive.
5. Insecticidal Soaps or Oils
For a readily available and formulated version of homemade dish soap, insecticidal soaps can be useful alternatives. These products offer gardeners the convenience of a pre-made product that has been designed to kill many kinds of insects. The drawbacks of these products are that they are often harsher on plants as well as animal life in your garden and they import unnecessary chemicals into your food and soil.
6. Sticky Traps
Sticky traps can be useful for controlling the number of thrips on your basil, but they are not a long-term solution. Rather, this can be employed in addition to other methods such as soapy water or neem oil.
7. Remove Infested or Damaged Plant Parts
This is a step that is most beneficial after a thrip infestation has been dealt with. You do need to be careful, however. If you remove too much of the foliage while thrips are still present, they will move to the healthy leaves and completely destroy your plant.
8. Remove Plant Debris From Soil
Removing the very top layer of debris can be a good way to maintain a healthy garden, but it should be done sparingly. This layer is essential for soil to retain moisture, and taking it away will mean a less efficient ecosystem.
Unheard of in most home-grower circles 10 years ago, ladybugs are finally receiving the attention they deserve. These charming little fellows can be bought online (find them here) ready for release at home and are top-notch thrip hunters. They also love to feed on all sorts of insect pests and are safe for plants, pets, the family, and your home.
Ladybugs are also very affordable and are a real treat to release. The only downside is that they will move on once almost all of the thrips are gone, so they will not eradicate them, but that’s still a good tradeoff for them doing all of the work.
10. Sodium Bicarbonate
Baking soda (not baking powder) is an absolute powerhouse when it comes to natural, daily applications, and the garden is no different. A simple solution of sodium bicarbonate, eco-friendly dish soap, neem oil, and water is enough to kill thrips in all stages except for the eggs. This simply means that you will need to spray once a week until they disappear.
Use this recipe for creating your own thrip spray:
- ¼ gallon of water
- 2 teaspoons of sodium bicarbonate
- 1 teaspoon of neem oil (can be substituted with vegetable or olive oil)
- ½ teaspoon of eco-friendly dishwashing soap
How To Prevent Thrips
Thrips are the result of a natural process. They are insects looking for food, and they just happened to land on your patch. Oftentimes, there are no preventative measures that you can put in place. Your best bet is to raise healthy plants so that if an attack does occur, your plants will recover quickly.
Adding plant diversity and habitat for animals and insects is also a great way to slow or prevent any pest infestation in your garden.
Thrips in the garden can be a concerning discovery, but it is not a reason to panic. The solutions we have outlined are sure to help you control and even eradicate plant-eating thrips.
Sprays that immediately kill thrips, like dish soap, neem oil, pyrethrin, and sodium bicarbonate, should be applied weekly to control thrips. Alternative methods, like releasing ladybugs, can be used in conjunction with these methods.
With the solutions outlined, you can definitely keep thrips within manageable levels so that your basil continues to grow and provide you with lots of fresh, tasty leaves.