Basil Pests: 11 To Watch For (Plus Prevention & Treatment)

Basil is in high demand in both North America and worldwide for its ability to be easily grown. Its primary purpose is as a flavor-enhancing herb in cooking, but it can also be found in alternative forms such as teas, oils, and soaps.

One of the best aspects of the basil plant is that it isn’t nearly as susceptible to common pests as other garden-variety plants are. 

Additionally, because of its potent aroma, basil is often used as a form of organic pest control. 

Just planting basil near other plants drives away scores of harmful insects. However, basil is not completely pest resistant.

Read on below to discover the 11 main pests to watch for on your basil plants as well as prevention techniques and treatments that actually work.

1. Aphids

Aphids are one of the main pest issues for early spring and summer plants, including basil.

These pests target green shoots and fresh new growth, such as developing leaves and blooms.

Despite the fact that basil is one of the most pest-resistant herbs in the garden, aphids strike before the iconic aroma of the basil plants has developed for the year.

Symptoms and Damage Caused

The main sign of aphids attacking your basil is the little yellow discolorations they leave on the underside of leaves. Curly deformed leaves are another sign that aphids are working on your plant.

How To Treat

  • Blast with a direct water spray.
  • Use neem oil.
  • Various insecticides.

Tips for Prevention

  1. Watch for issues, and remove affected sections of the plant.
  2. Plant onions or chives nearby.
  3. Tackle the problem as soon as it arises.

2. Japanese Beetles

The Japanese beetle is one of the basil plant’s main natural enemies.

Every summer, normally in June, these beetles crawl up from their hiding places in the ground and begin to gorge themselves on the smelliest plants around.

Unfortunately for basil, it is practically guaranteed to be one of the plants hit the fastest and hardest.

Japanese beetles can devour a basil plant in a single attack, which usually happens during the morning to mid-afternoon hours (while it is bright but not very hot).

Symptoms and Damage Caused

The damage caused by Japanese beetles is easy to spot — they turn robust leaves into skeletons. Japanese beetles eat the soft fleshy parts of the leaves, leaving the veins and stems intact.

How To Treat

  • Spray with water and soap (to suffocate them).
  • Spray with oil (to suffocate them).
  • Various insecticides.

Tips for Prevention

  1. Try row covers.
  2. Use less water.
  3. Preemptive insecticide.

3. Slugs

There are few plants in the yard or garden that slugs won’t consider snacking on from time to time.

That said, they tend to stay away from smelly plants like mint, lemongrass, lavender, and yes, even basil.

However, because basil is so nutrient rich and doesn’t smell strong while it’s still young, the plants are often attacked by slugs.

Slugs prefer eating basil when it is nighttime or when the weather is overcast and cloudy for days on end (when plants are less scented due to less sun and heat).

Symptoms and Damage Caused

Shredded leaves, destroyed blooms, and missing sections of stalk near the base of the plant are the primary symptoms of slugs attacking your basil.

How To Treat

  • Keep a watchful eye on your plants.
  • Remove slugs one by one (by hand).
  • Apply nematodes to soil.
  • Use slug spray (and remove dead ones).

Tips for Prevention

  1. Make a sticky barrier to trap slugs.
  2. Make a rocky and salty barrier slugs won’t cross.
  3. Use copper tape to make a barrier.

4. Whiteflies

The strong odor of basil plants repels typical houseflies with ease; however, it does no such thing for the issue of whiteflies.

These nasty little pests are attracted to the scent of fresh new basil. 

That means they are likely to attack your plants early in the year and again when they start to produce new growth in the late summer or fall.

Symptoms and Damage Caused

Discoloration, curling, and yellowing of basil leaves are the main indicators that whiteflies are feeding on your plants.

How To Treat

  • Apply neem oil.
  • Use dish soap and water as a spray.
  • Use baking soda and vinegar with water as a spray.

Tips for Prevention

  1. Use fly traps (sticky yellow fly tape).
  2. Apply reflective mulch around the base of your plants.

5. Spider Mites

Spider mites are one of the most common pests that are attracted to aromatic herbs and flowering plants.

Unfortunately, basil is one of the spider mites’ very favorites.

If your basil plants are somewhere that receives plenty of bright sunlight all day long, they are even more likely to attract spider mites.

Symptoms and Damage Caused

Small white and yellow spots on the upper parts of your basil plants’ leaves are a clear sign that spider mites are at work on them.

How To Treat

  • Check plants closely and constantly.
  • Remove spider mites by hand.
  • Use rubbing alcohol and a rag.

Tips for Prevention

  1. Keep your garden/plants tidy.
  2. Regularly wipe plants down with water and a cloth.
  3. Apply preemptive insecticide.

6. Snails

Like slugs, snails are typically turned off by strong-smelling plants like basil, thyme, mint, and rosemary.

However, everything else about basil is quite attractive to them, specifically the abundance of fresh green growth, the consistently semi-moist soil, and the mulch that is around the stalks.

That means snails are just as likely to jump on your basil and have lunch as they would any other plant that requires heavy watering and mulching (such as peppers).

The good thing is that they are less likely to disturb your basil plants once they are mature and smelling strong.

Symptoms and Damage Caused

Strange-looking holes at odd places on your plant’s stalks, and silvery trails on and around your plant are the main symptoms of a snail problem.

How To Treat

  • Watch plants closely (and remove snails by hand).
  • Apply salt.
  • Use insecticide.

Tips for Prevention

  1. Set up barriers with salt or sticky substances.
  2. Water the ground around your basil less often.
  3. Use snail baits or traps.

7. Cutworms & Other Caterpillars

Cutworms and caterpillars are both known species that enjoy munching on basil leaves and/or the stalks of basil plants, but caterpillars specifically eat the root systems of basil plants.

The good thing is that these pests are mainly only a threat during the early part of the year. 

The bad part is that they are one of the pests that is the most likely to stunt or kill your basil seedlings.

Symptoms and Damage Caused

Entire plants going missing, plants looking like they have been cut, or plants suddenly and severely wilting are all signs that cutworms are a problem. Furthermore, chewed-up leaves, munched-down blooms, and missing flowers are all common damage caused by caterpillars.

How To Treat

  • Sprinkle baking soda around the base of plants and on the bottom of the main .
  • Spray the leaves with insecticide.
  • Prune affected areas.
  • Pick off pests by hand when you notice them.

Tips for Prevention

  1. Apply a chemical barrier.
  2. Use a mesh border.
  3. Avoid growing other plants near your basil that cutworms or caterpillars are attracted to.

8. Flea Beetles

Flea beetles are attracted to a plethora of plants, including the weeds that are growing in and around your garden.

Being not so picky, once they devour one plant, they’ll move on to whatever else is closest. If that happens to be your basil, well, they’ll go to town munching on it just like they would on any other plant.

These pests typically target basil from late July all the way up until late September or early October.

Symptoms and Damage Caused

The biggest giveaway that you have a flea beetle issue is tiny little holes appearing in your basil leaves. Entire leaves missing or the leaves looking like someone went crazy on them with a hole-punch means you have a serious problem with flea beetles attacking your basil.

How To Treat

  • Sprinkle insecticidal dust on the leaves of the plant and around the base.
  • Apply spinosad or another insecticide spray.
  • Use a strong home remedy like vinegar, baking soda, and lemon juice spray.

Tips for Prevention

  1. Keep the garden nice and neat (including the compost pile).
  2. Apply some sort of row covering over your plants.
  3. Do regular weeding near your basil plants.

9. Grasshoppers

Grasshoppers are known for swooping in on an area and leaving crops completely devastated.

That is why even though grasshoppers are typically repelled by the pungent aroma of herbs like basil and thyme, they are still known for eating the plant from time to time.

When grasshoppers eat your basil, it is usually during the young phase before it is strong in scent. 

Otherwise, these pests normally only end up eating your basil when it is planted too close to the corn crop, wheat crop, or some other crop they are feasting on.

Symptoms and Damage Caused

Grasshoppers leave basil leaves looking like they went through a paper shredder or worse. Many times, grasshoppers eat basil leaves entirely. Other times, they avoid eating the veins and stems.

How To Treat

  • Use an insect growth regulator agent.
  • Apply an insecticide spray.

Tips for Prevention

  1. Use vinegar and lemon juice spray on your plants once per week or so.
  2. Sprinkle a mixture of cinnamon and cayenne pepper powder on your plants regularly.

10. Leafminers

The leafminer moth is another pest that isn’t as well known as aphids or spider mites but is every bit as much of a potential threat to your basil.

Normally attracted to fresh leaf growth on citrus trees, leafminers are also highly attracted to basil plants during their new and vigorous growth stages.

Leafminers are also attracted to certain smelly weeds that may draw them closer to your basil and cause them to take note of it (and make future lunch plans).

Symptoms and Damage Caused

Pale splotches and tunnel-like ridges appearing on your basil plant’s leaves are the most significant signs of the damage caused by leafminers.

How To Treat

  • Remove the pests by hand when you see them.
  • Apply DIY pesticide sprays.
  • Use insecticide on affected areas.

Tips for Prevention

  1. Removing small leafminers before they get bigger.
  2. Pulling weeds around your basil plants regularly.

11. Nematodes

Nematodes are a major source of pain for gardeners around the world.

They are attracted to basil root systems, more specifically the gaseous attractants produced by them as well as the host of micro-organisms living on and around the roots.

Unfortunately, nematodes are often considered one of the hardest pests to spot because you quite literally need a microscope to see them most of the time.

However, sometimes they are just big enough to see with the naked eye.

Symptoms and Damage Caused

Nematodes typically destroy basil, like most plants, from the ground up (literally). The first place to notice nematode damage is around the base of the plant and the root system. The main signs of a nematode problem are reduced productivity, wilting, and discoloration of leaves.

How To Treat

  • Remove the infected soil and literally bake it to approximately 140°F (either in the oven or in the sun).

Tips for Prevention

  1. Regular crop rotation.
  2. Blasting the soil with full sun for days.

Conclusion 

Aphids, slugs, and Japanese beetles are the biggest potential pests regularly causing issues for basil plants. That said, the other eight pests we discussed on our list are equally tangible threats to your basil plants. 

Hopefully, with all of the above information at your fingertips, you now feel confident in treating and controlling whatever is harassing your basil with confidence and success!