Black Gnats on Tomato Plants + [What To DO And How To Keep Them Away]

Growing tomatoes is a bitter-sweet experience. You face many problems, ranging from diseases and environmental issues to pests. Most importantly, pests are the worst because they can cause infections. For instance; black gnats.

But, what are the black gnats on tomato plants?

Don’t mistake them for fruit flies. These fungus gnats are either already in the soil or come with the potting soil. After laying eggs, they produce larvae that damage your seedlings and growing tomatoes. Usually, the larvae do the damage, not the adult black gnats.

So, it’s essential to recognize what’s eating your tomato plant and learn how to manage the situation. These little black gnats may not seem like a problem but can cause severe damage if left unattended. Read on.

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Black Gnats on Tomato Plants

These mosquito-like insects are an eighth of an inch in size. Usually, they don’t fly a lot, so you’re likely to see them on the tomato leaves or potting soil.

Because they are tiny, getting into your in-house garden is not an issue- through narrow openings. However, they often come as eggs in potting or in the infected soil of outdoor plants. They reproduce so fast that it only takes a few of them to destroy your garden wholly and quickly.

Knowing the lifecycle of black gnats help control their population, especially when feeding aggressively.

Black gnats lay eggs in between cracks on the soil surface. After about six days, the eggs hatch into larvae and start to feed immediately on the roots. After two weeks of active feeding, they emerge above the soil as adults. The lifecycle begins all over again.

The reason they reproduce so fast is that they hatch to primarily females. A single female lays an average of 100 to 300 eggs.

How Do You Get Rid Of Black Fungus Gnats?

There are three best methods of controlling fungus gnats.

1.     Observe and Eliminate Adult Fungus Gnats

Typically, it’s hard to know the exact population of black gnats, given that they reproduce quickly. But, it’s not impossible.

Buy and use yellow sticky cards. There’s adhesive on each side of the small yellow cards.

Ensure you put the cards facing upright on the soil surface. Since the yellow attracts and lures the adult fungus gnats, they will fly towards the cards. The adhesive captures many gnats allowing you to know the estimation of black gnats available in your garden and eliminate them.

2.     Practice Good Housekeeping and Maintain Suitable Soil Conditions

To grow your tomatoes in a greenhouse, ensure thorough cleaning before planting new seedlings. Usually, scattered weeds and soil on the greenhouse floor attract fungus gnats.

Aside from attacking your tomato plant roots, the black gnats also feed on the organic matter in the soil. That’s why it would be best not to use potting soil mixed with fresh compost since it contains high microbial activity.

Moreover, fungus gnats thrive better in moist soil. Thus, use a potting mix that drains well and don’t overwater – wait until it dries completely before watering again. Remember to be cautious not to allow the soil to dry out over a day to prevent killing your seedlings with drought conditions.

Most importantly, be very careful with potting mix left outdoors for some time. You’ll probably find it wet and highly has fungus gnat larvae.

3.     Use Biological Methods to Manage Black Gnats

You can slice and place a potato on the soil to attract the active-feeding gnat larva. The potato slice helps attract the larva and alert you on when the feeding occurs. This way, you can use control measures at the right time. Ensure the potato slices stay fresh without drying out.

There’s also fungus gnats control that involve the use of living organisms. The fungus gnats must feed on these organisms, emitting a toxic bacterial that destroys the gnats from inside.

You’re unlikely to find this type of black gnat control over the counter. Mostly, you’ll have to order from specific garden centers.

Shelf gnat insecticides work best on adult fungus gnats, especially those with pyrethrins. Still, you’ll need to use it severally to see desired results.

What Are The Small Black Bugs On My Tomato Plants?

Usually, the black bugs are a species of aphid. These tiny pests can quickly rain havoc on your tomato plants and even infect a deadly virus. They also suck the sap, drying out the plants and leaving behind a substance that grows into a fungus. When the fungus starts to grow, it covers the plant, blocking sunlight which stunts growth.

The female black bugs can reproduce without needing a male. So, each growing season gets many black bugs attack the tomato plants. Hence, more plants get the deadly virus which is hard to stop once it begins.

Though devastating, removing and discarding the infected tomato plants is the only favorable solution for controlling the black bugs. Besides, it’ll save the uninfected plants.

How Do You Get Rid Of The Black Flies On Tomato Plants?

As an expert gardener, you probably know the black flies and the amount of destruction they cause. But as a beginner, it would be best to start understanding what is at hand to help you fight successfully.

Black flies can destroy your tomato garden quickly. But, how do you eliminate the black flies without destroying your tomatoes?

There are several ways to handle this problem without harming your tomato plants. But as observed, if the fungal growth is extreme, the only way is to remove and dispose of the plants. Better still, burn the plants to avoid the fungus and virus remaining in the soil.

Let’s go through different control methods to get rid of the black flies on the tomatoe plants;

1. Water

Washing off the black flies is a simple but effective way of removing them from your tomato plants. Use your hose pipe and rinse them off after a few days consecutively until you clear the infestation.

But, remember not to use so much water pressure as this may damage the delicate tomato plants.

2. Essential Oils

Essential oils are a product of plants. But, they can help eliminate an outbreak of pests like black flies.

Some essential oils that work best for this situation are thyme, clove oil, peppermint, and rosemary. These are the strong types.

Use about four drops and mix with water in a spray bottle. Spray on the whole affected plants, including under the foliage. This mixture is sure to kill the black flies and their eggs.

3. Bird Bath

Another effective natural method of killing the black flies is to invite predators. Birds love pests and would help eliminate an infestation but only if you encourage them to your garden.

Installing something like a bird bath attracts the birds to the garden. Once the birds come, it’ll be easy to spot the black flies on your tomato plants. From there, the black flies become history.

4. Crush Them

Probably obvious and a lot of work, but crushing the black flies is also very effective. Just pick the plant and use your thumb and forefinger to squash the black flies.

This method takes time if the infestation is significant in a tomato garden. But the results are incredible!

How to Prevent the Black Gnats on Tomato Plants

Getting the best out of your tomato garden can be far-fetched but possible. Preventing pests like black gnats is the first and best way to start. So, take preventive measures if you’re yet to get an infestation.

For starters, it would be best to diversify your garden. Planting a wide range of plants helps attract different predators. Because these tiny insects are low in the food chain, their chances of survival are minimal.

Also, avoid excess application of nitrogen-rich fertilizer. Nitrogen fertilizer helps your plants thrive better. This means more and better production of sap. Consequently, this fluid attracts these pests to feed on and suck the life out of your tomato plants.

Frequently Asked Questions

How Do You Eliminate Fungus Gnats In Potting Soil?

Make a solution of 4 parts of water and 1 part of hydrogen peroxide. Water your in-house tomato plants with this solution only when the potting soil is partially dry. This kills the larva and doesn’t harm the plant. There’ll be an effervescent sound once the peroxide solution contacts the soil.

Should You Repot Tomato Plant With Fungus Gnats?

You may need to repot your tomato plant to eliminate the gnat larvae. However, ensure you clean the potting container thoroughly and use a new and fresh potting mix.

Why Does Potting Soil Get Black Gnats?

Contamination of the potting soil from unclean potting containers and gardening tools causes black gnats to thrive in the potting soil. This way, the ground hides gnat eggs and larvae.

Final Word

The truth is, it’s hard to eradicate the black gnats on tomato plants completely. However, several preventive and control measures ensure your plants thrive. This way, you can harvest the biggest, juiciest round tomatoes ever!

Most importantly, your choice of control measures matters a lot. Ensure you choose methods that are harmless to your plants yet effective against the black fungus gnats. It would be best to settle on ways that don’t involve using chemicals.

Above all, take action now to prevent future infestation.