Did you find small, slender, winged insects on your plants? Have you noticed weird, distorted areas on the leaves and buds? Spot any black specks? If so, you might have thrips.
They might be tiny, but thrips can cause big problems. If you think you have an infestation, it’s time to take care of it before they take over your garden.
How do you get the situation under control? We’ll help you figure it out.
What Do Thrips Look Like?
Thrips are tiny and slender, typically only measuring about 2 mm long – super tiny! Most have two pairs of wings with fine hairs that you won’t be able to see without a microscope.
Thrips typically vary in color from pale yellow to light or dark brown, but they can be orange, black, or green as well.
Adult male thrips tend to be smaller and paler than their female counterparts. Their color can change, depending on the current temperature; they get darker when the temperatures are cooler.
Female thrips lay their translucent eggs in soft plant tissue. The eggs hatch and the larval form of thrips are similar to the adults in shape, but they’re even smaller – it’s hard to believe they can be smaller than 2 mm, but they are. Larval thrips also are paler in color and don’t have wings yet.
As they grow and hit the pupal stages, they’re similar in size to the adults, but they now have wing buds forming.
As you can tell, these insects are SMALL, but they can make a fascinating study if you have young kids. You can use a hand lens or a microscope to take a closer look at the details.
Here are some interesting – and worrisome – facts:
- Females don’t need males to reproduce – no fertilization is necessary. That means they can breed that much easier!
- The females make a slit into the leaf tissue to lay their eggs, damaging the plant.
- One female lays up to 50 eggs at one time, and the eggs only take one week to hatch.
- After hatching, it only takes the thrips three weeks to reproduce and mature fully. Imagine how fast their populations can grow!
Are Thrips Always Bad?
At times, some thrips are beneficial to have in your garden. Some kill other pests that like to destroy your plants. Finding some thrips on your flowers isn’t necessarily a bad thing.
If possible, try to identify the type of thrips you have in your garden. The beneficial ones eat plant-sucking pests, such as:
- Lace bugs
- Scale insects
The problem comes when they start to destroy your crops.
Predatory Thrips Are Different
Since they’re so small, it can be hard to identify specific types of thrips, but predatory thrips are the beneficial ones that you do want in your garden.
These little insects like to feed on other insects, sucking out their insides. While that’s gross, it doesn’t damage your plants. It’s the thrips that like to eat the buds and leaves off of your plants that you want to get rid of.
Predatory thrips are dark brown to black with white striped wings. They come from the family Aeolothripidae. See if you can get close enough to determine their specific markings.
If you find this type, leave them in place! They’re there to help your garden not damage it.
You can find predatory thrips hanging out in fruit-bearing trees, vegetables, and different plants throughout your garden.
Plants Typically Affected
Not all plants are bothered by these pests, but the most common include:
When thrips attack woody plants, the damage usually isn’t as severe as it is on soft-stemmed plants and herbs.
There are multiple kinds of thrips that attack different plants. For instance, the western flower thrip (Frankliniella occidentalis) is one of the more common ones. It eats herbaceous plants and veggies.
Citrus thrips (Scirtothrips citri) eat plants in the citrus family. Onion thrips (Thrips tabaci), you guessed it, favor plants like onions, garlic, leeks, and chives.
Bean thrips (Caliothrips fasciatus) reproduce in citrus plants and eat all kinds of veggies, while greenhouse thrips (Heliothrips haemorrhoidalis) will nibble on your ornamental and house plants.
Signs of a Thrips Infestation
The big question is how do you know if you have thrip damage in your garden. Since these insects are mini, it takes a major thrips infestation to do serious damage.
But since they can easily hide from humans, they can form a large population before you realize it.
They have piercing, sucking mouthparts that they stab into the surface of the leaves and flowers, sucking up the sap and juices. Sometimes, they conceal themselves inside of the flowers, making it even harder to spot them.
Some signs and symptoms of a thrips infestation include:
- Distorted leaves and fruit
- Spotting on flowers
- Yellow speckled spots on the leaves
- Silver-looking older leaves
- Black spots on leaves from excrement
- Small insects inside of the flowers or on the underside of the leaves
In most cases, the damage slowly progresses from one thing to the next. It typically starts with yellowing or bleached spots on the leaves or deformed leaves.
Over time, the symptoms move to a silvery look to the leaves and black spots, which are actually fecal matter from the thrips. The final stage involves the leaves wilting and dropping off of the plant.
How to Handle a Thrips Infestation in Your Garden
Assuming that you’ve determined you don’t have the beneficial kind in your garden, it’s time to take care of the problem.
Yes, you can use insecticides, but there’s an issue with that.
The insecticides that can be used to kill thrips also kill the beneficial predator insects in your garden. That’s not a risk most organic gardeners want to take.
Beneficial insects are prized in organic gardens, being far more efficient in the long run at controlling problems when compared to chemical choices.
So, the ideal plan starts with using control strategies that involve the least toxic methods while also using good practices, such as having a consistent watering schedule and removing diseased and dead plant material.
Here are some suggestions to help control and kill a thrips infestation.
1. Inspect Your Plants Regularly
When it comes to any pest infestation, catching the problem early will save you a lot of time and frustration. It’s a smart idea to take time each week, twice a week if possible, to carefully inspect your plants, looking for damage and potential pests.
The sooner that you catch the problem, the sooner you can get it under control. It’s easier to put out a small campfire than it is a brush fire, so get to the problem before it’s taking out your entire garden.
2. Trap Them
These pests don’t spend too much time flying around; their wings aren’t very strong. You can still try blue or yellow sticky traps near the plants; you’ll catch some of them.
Another option is to put a cloth underneath the plant and shake the branches, forcing the insects to fall off. Remove the cloth quickly and soak it in a bucket of water to kill them.
3. Prune Regularly
One good practice is to prune and get rid of injured or damaged parts of your plant regularly. Pests like to focus on damaged and vulnerable areas on the plant.
Rose growers, for instance, can go outside and inspect their plants as they begin to form buds. If the buds look discolored or deformed, trim them off.
If you keep at it, you’ll get rid of the pests and new, healthy buds will form.
4. Try a Mild Insecticide
Keep in mind that these aren’t cure-alls and they can still harm beneficial insects, so you should only turn to them if you’re really struggling to get an infestation under control.
5. Wash Your Plants with Soap
You don’t have to buy soap at the store for your plants. Instead, you can spray or wash your plants don’t with a homemade mixture of soap and water.
All you need is about two teaspoons of soap for each gallon of water – try using regular dish soap.
Gently wash down your plants with this solution, making sure to get it on all of the leaves and other areas of the plant. Don’t forget the underside of the leaves, which is where thrips love to go and hideout.
6. Hose Down Your Plants
If you’ve dealt with aphids, then you know this method. Take your hose and, using high-pressure water, focus on knocking pests off of the underside of the leaves.
This method works for aphids and thrips. You can use a blast of water as much and as often as your plant can handle it, but be careful. High-pressure water could damage leaves, so do so with the utmost care.
7. Don’t Shear Your Plants
Shearing, or dramatically cutting back your plant, isn’t a good idea if you’re dealing with thrips. The new growth will attract even more thrips, resulting in the complete opposite of your goals.
Pesticides Rarely Work for Thrips
It’s important to note that pesticides are rarely required and typically aren’t effective for thrips. Because they feed and their eggs are protected inside of the leaves, it requires multiple doses of pesticides to reach them.
If you find yourself struggling with thrips, using organic methods to decrease and control their population is your best bet. It’s rare that these pests kill plants, but they can cause problems. Insecticides and pesticides should be your last resort.