When a large group of similarly sized insects gather, move, and behave as a collective they become known as a swarm. Swarming insects aren't simply annoying pests that can descend on your yard or picnic like a dark cloud, in some cases their large numbers are dangerous and can cause massive amounts of damage. Here are some ways to identify the most common swarms you might encounter and how to handle them.

Lawn Gnats

Lawn gnat swarm above grass

These mosquito-like bugs tend to swarm above your lawn and garden. In large groups, they're called hordes or clouds, and they tend to prefer damp soils that are full of decaying materials. You may notice them more in the hottest days of summer, especially during storms. Unlike some of the other culprits on this list, gnats are more of a nuisance than a threat and in the right ratio they may actually help with pollination and move decomposition processes along. However, if you have a horde that you want gone one of the simplest things to do is remove that things that attract them.

Getting Rid of Lawn Gnats

This means physically clearing your yard of the damp or decaying vegetation they love so much and removing standing water sources. Use soaker hoses and use a timer to control when and how long you water to avoid creating more stagnant water sources moving forward. Mulch is also a haven for gnats, so while it’s tempting to pile it on to suppress weeds, try to keep your layer of mulch under three inches thick. If you're concerned that the cloud may have larval populations in your garden, biological controls such as Bti (Bacillus thuringiensis serotype israelensis) or simple nematodes can be added to remove those.

Whiteflies

Whiteflies eating a plant leaf

Whiteflies are small, winged bugs that resemble their close relatives, aphids. Though their diminutive size makes it tough to see them, there are so telltale signs. When whiteflies attack a plant, they suck the juices from its leaves causing yellowing and leaving behind a sticky substance called honeydew that weakens plants and stunts their growth. Ants tend to be attracted to the honeydew though, so you may notice them first. The adult whitefly also lays eggs on the underside of leaves, so you can check there for clues as well.

What to Do About Whiteflies

Ridding yourself of them is a two pronged effort that requires not only removing them but also keeping the whiteflies away. Begin with simple soap and water, spraying your plant with a hose to physically remove the aphids before following up with insecticidal soap. If you don't own any insecticidal soaps, spraying the plants leaves with a mixture of dishwashing liquid and rubbing alcohol is also effective. On a long term basis, ensure your garden is full of beneficial insects, such as ladybugs, spiders, and even hummingbirds. All are natural predators of the whitefly. There's even a species of parasitic mosquito that targets whiteflies specifically and will not sting humans. Physical alterations to your garden, such as adding an aluminum reflective mulch near your tomatoes, eggplants, and peppers, can also drive away future infestations.

Termites

Close up of termites eating tree bark

A swarm of termites won't necessarily impact your garden, but the mere sight of them around your property is a big red flag that these destructive insects may be staking a claim to your house and other wooden structures next. They tend to travel in large swarms and form colonies that can absolutely ruin your home.

Tackling Termites

The best way to deal with these guys is to not take any chances. Consider it a blessing in disguise that enough of a swarm strayed from the colony long enough to get your attention, and call an exterminator to ensure you get all the vermin wiped out from your home.

Fire Ants

Red ant biting a human finger

Fire ants don't swarm in the air but they can build colonies in your garden and lawn. Hopefully you'll spot their hills first, but if you happen to come into contact with one by surprise, you’ll feel their fiery sting on your skin, which typically leaves a big, red welt. The painful venom is also known to kill small animals and people who are allergic to it.

Getting Rid of Fire Ants

The first step is to identify the mound or mounds the colony is using, which shouldn't be hard since they're usually large and obvious. Clear the area of any pets or people before attempting to kill the ants as they will get aggressive and attack anything nearby that they perceive as a threat. Wear boots, gloves, and long pants to protect your skin as you approach the mound. While heavy, chemical poisons will get the job done, for the sake of preserving your garden, try using an environmentally friendly insecticide or even a mixture of water, vinegar, and baking soda. Carefully flush out the anthill with your mixture multiple times over the course of about a week, which will kill the queen. Baits or other methods can be used to kill or capture any stragglers that flee the dying colony.

In terms of keeping fire ants out of your garden on an ongoing basis, there are some simple additions you can bring into your yard. Fire ants tend to thrive in the sunlight, so consider planting some trees or shrubs to create a little shade. As an added bonus, these plants can improve the fertility of your soil and create natural compost which makes your yard less welcoming to ant colonies. Plants that are particularly fragrant like herbs can also drive away many vermin, ants included. Lastly, if you're so inclined, welcoming some natural predators like chickens or reptiles to your garden is a mutually beneficial way to make short work of invasive ants.

Wasps and Yellow Jackets

Group of wasps swarming around their nest

These swarming stingers will not only pursue you relentlessly if they see you as a threat, they’ll also keep stinging. They often build nests in trees, wooden greenhouses, or on the eaves of houses. Yellow jackets prefer building nests in the ground, while other wasps build them in overhangs that are out of the way.

Driving Out Wasps and Yellow Jackets

Since these swarms are so aggressive, it's best to use a subtle approach. Rather than engaging them directly, cut off their food source. This includes cleaning up any food that is lying around and removing any fruit that has fallen from nearby shrubs and trees. Similarly if you're going to try a commercial wasp and hornet spray, apply it in the evening when the insects tend to be less active. Placing traps baited with food in their hiding places can also be effective. Once the traps are full, place them in the freezer to kill them. Just like with the fire ants, cover any exposed skin for protection. If your swarm is especially aggressive don't mess around and call a professional.

General Tips

Regardless of the kind of swarming insect you're looking to wipe out, avoid using toxic chemicals in the garden. If you’re growing edibles, anything you apply to your plants in the garden may end up on the vegetable or fruit later on and eventually in your body. While it can be a lot of work at tough times like the middle of the summer, keep your garden free of debris as this is a huge attractant for swarms. Finally, consider letting nature do the heavy lifting for you by encouraging the presence of beneficial insects, which help keep pests at bay.