If you are starting the garden or you are a full-time gardener, garden pests are something you need to know.
All kinds of small invertebrates like hiding and feeding on your garden plants. Mostly, the presence of these creatures is beneficial for a balanced ecosystem of your garden. But when they are causing significant damage to plants, they are named Garden Pests.
In this article, we’ll take a look at 7 of the most destructive garden pests, their identification, the extent of damage they cause, their biological and organic control, and prevention tips.
Jump right in:
#1 Aphids
#2 Whiteflies
#3 Cabbage White Caterpillars
#4 Tomato Hornworm
#5 Stink Bugs
#6 Colorado Potato Beetle
#7 Japanese Beetle
Final Tips
#1 Aphids
Aphids are tiny creatures that feed on the juices of plants, causing them to wilt or produce fewer flowers. Aphids can be found almost in every garden. If you see clusters of tiny green, black or pink bugs hanging out together, they are aphids. These insects are wingless. However, as the population of aphids increases, some females develop wings and fly out to colonize other plants.
Usually, a pesticide-free garden can handle a lot of aphids with the help of beneficial insects. When major infestation is seen, only then consider other controls.
Identification of Aphids
- Aphids are small sap-sucking insects, about 1/8 inches (3 mm) long.
- Aphids vary in color from green, peach, brown, black, and sometimes colorless.
- These garden pests have a pair of antennae on the tip of the head region and short legs.
- Most aphid species have a pair of tubes emerging from their abdomen.
- Aphids have long slender sap-sucking mouthparts.
- Aphids mostly live on the undersides of the leaves or on the top part of the plant’s stems.
Plants Susceptible to Aphid Attack
There are many species of aphids and numerous possible host plants. Some plants appear to be more vulnerable than others, including nasturtiums, milkweed, tomatoes, peppers, cucumbers, lettuce, cabbage, squash, and strawberries.
The Damage Aphids Cause
Aphids feed in clusters on new plant growth or the undersides of leaves, resulting in curling, distorting, or discoloring of the stem. Well-established plants can tolerate the damage, but young growth may be stunted. Aphids excrete a sticky, glossy liquid called honeydew that discolors leaves and causes an unsightly black sooty mold to grow.
Live Biological Control of Aphids
Aphids are at the bottom of the food chain. A lot of predatory insects will feed on them.
The natural predators of aphids are aphidius wasp, ladybugs, lacewings, hoverfly larvae, assassin bugs, damsel bugs, big-eyed bugs, minute pirate bugs, parasitic wasps, spiders, praying mantis.
If you see aphid cream in color and motionless, do not remove it. It means that it was infected by an aphidius wasp. The wasp will hatch from this aphid and will further control the aphid population. [1]
Organic Control of Aphids
Use neem oil or garlic extract spray to remove aphids naturally.
Aphid Prevention Tips
- Remove. Keep monitoring your plants regularly and remove infested plant growths.
- Dislodge. Use a fine jet stream of water to blast the aphids off.
- Trap. Plant a variety of plants that will trap aphids, preventing the important crops from being damaged.
- Select plant varieties for your garden that can withstand pest damage.
Read more about aphids in our “Aphids – Identify and Control” article.
Also, watch this fun video about aphids, presented by TED-Ed.
#2 Whiteflies
Whiteflies are tiny insects that feed on the juices of plants and cause them to wilt or produce fewer flowers. They can’t survive extremely cold weather conditions. But due to their rapid reproduction, they are challenging to control in greenhouses. Some species are not harmful to host plants. Still, a few species, such as greenhouse whitefly, Silverleaf whitefly, can become problematic.
Identification of Whitefly
- Whiteflies are triangular-shaped small insects with a body length of approximately 1/20 inches (2 mm).
- Whiteflies are easily identified due to their white color.
- These garden pests are active during the day hours and disperse in swarms if you shake the plant.
- Whiteflies are mostly found on the lower surface of leaves.
- Like aphids, whiteflies have sucking mouthparts.
Plants Susceptible to Whiteflies Attack
Whiteflies can infest nearly any plant. However, their favorite hosts include ornamental flowers, citrus trees, sweet potatoes, okra, tomatoes, peppers, and eggplants.
The Damage Caused by Whiteflies
Whiteflies suck the sap from plants and introduce toxic saliva into the plant. They secrete honeydew that encourages sooty mold growth. Whiteflies cause yellowing, wilting, and drooping of leaves, with stunted growth.
Live Biological Control of Whiteflies
Live biological control is the most effective in controlling whiteflies. DO NOT USE Chemical pesticides. They will kill beneficial garden insects and may damage your plants.
Introduce predator insects to your garden, such as green lacewings, ladybirds, big-eyed bugs, damsel bugs, and minute pirate bugs.
Organic Control of Whiteflies
Use neem oil or citrus oil to remove whiteflies naturally. You can also use insecticidal soap to remove the whitefly infestations.
Whiteflies Prevention Tips
- Avoid. Make sure to inspect plants for any whitefly infestations before you buy them.
- Remove infected plant parts regularly.
- Dislodge. Use a fine jet stream of water to blast the whitefly off.
- Trap. Place a variety of plants that will attract whiteflies to protect the vital crops from harm.
- Select plant varieties for your garden that can withstand pest damage.
Read more about whiteflies in our “Whiteflies – Identify and Control” article.
#3 Cabbage White Caterpillars
These are also known as cabbage whites, small cabbage whites, white butterflies, or cabbage butterflies in different world regions. These caterpillars have three to five generations per year and can form large destructive populations.
Identification of Cabbage White Caterpillars
- The average length is about 1 inch (2.5 cm), but they can grow up to 2 inches (5 cm) when fully grown.
- The small white butterfly is identified by its white color and two black dots on its wings. It lays hundreds of eggs after mating on the leaves of host plants. These eggs are hatched into velvety green caterpillars.
- The large white butterfly is also white in color. It has a black band on the tip of its forewings. It lays eggs in clusters of 20, and these eggs hatch into black and yellow hairy caterpillars.
Plants Susceptible to Cabbage White Caterpillar Attack
All types of Brassica like cabbages, swede, turnips, cauliflower, and brussels sprouts. Nasturtiums and rapeseeds also get attacked by these pests.
The Damage Cabbage White Caterpillar Cause
These caterpillars are common pests that can cause significant damage to their host plant by overeating foliage. The larger holes in the leaves of brassica crop and nasturtiums indicate the presence of these caterpillars. These insects make tunnels through the hearts of cabbage. But it is easy to spot them. Just look for droppings on the leaves. If you see the droppings, that means the caterpillars are on the leaves above.
Live Biological Control of Cabbage White Caterpillar
Introduce predator insects to your garden, such as assassin bugs, damsel bugs, green lacewings, and hoverflies. These beneficial insects attack only very young caterpillars. Sometimes they even destroy the caterpillar eggs.
The parasitic wasps and tachinid flies are the most efficient beneficial insects in controlling cabbage white caterpillars.
Organic Control of Cabbage White Caterpillar
Use citrus oils and botanical oils against cabbage white caterpillars. It will act as a repellent, so you don’t need to use chemical pesticides.
Cabbage White Caterpillar Prevention Tips
- Examine your garden regularly, especially before cabbage starts to develop hearts.
- Pick the caterpillars and egg clusters by hand and dispose of them into the bucket with soapy water.
- Protect your plants with floating row cover to keep butterflies from laying eggs.
- Attract predator birds such as house sparrows, goldfinch, and skylark into your garden by hanging bird feeders and nests.
- Grow sacrificial plants such as nasturtiums to trap the caterpillars.
- Plant varieties that are less susceptible to cabbage white caterpillar attacks.
- Sprinkle the host plant with cornmeal or rye flour. If cabbage white caterpillars eat it, they will bloat and die.
Read more about cabbage white caterpillars in our “Cabbage White Caterpillar – Identification and Control” article.
#4 Tomato Hornworms
The tomato hornworms are also known as the five spotted hawkmoths. Tomato hornworms are caterpillars that will do significant damage to tomato plants. Controlling them as soon as you see one is essential for the health and production of your plants.
Identification of Tomato Hornworm
Tomato Hornworm
- Most tomato hornworms have a horn protruding from the back of their bodies.
- Tomato hornworms are green in color, with white diagonal lines running down their sides.
- Tomato hornworms can grow to 4 inches (10 cm) in length, which they will reach after eating leaves from your plants for several weeks.
- The larvae are usually found on the undersides of leaves, but they can eat the stem also.
Five Spotted Hawkmoth
- The adult five spotted hawkmoths are grayish-brown in color with narrow front wings.
- The abdomen usually has five, but it can also be six pairs of yellow spots.
- The forewing is a dark brown and gray color.
Plants Susceptible to Tomato Hornworm Attack
As the name indicates, these caterpillars feed on tomato plants. They also feed on potatoes, peppers, tobacco, and all other plants belonging to the nightshade family.
The Damage Tomato Hornworm Cause
Tomato hornworms eat voraciously, stripping leaves off plants and even devouring entire stems. Due to their camouflage, tomato hornworms are less noticeable while feeding. These large-sized hornworms can even destroy the whole fruit.
Live Biological Control of Tomato Hornworm
Attract assassin bugs and parasitic wasps to your garden.
If you see a hornworm with white cocoons attached to its back (picture below), do not remove it. These are cocoons of a beneficial parasitic wasp. They will hatch and control the hornworm population further.
Organic Control of Tomato Hornworm
Organic products that contain spinosad will control the tomato hornworm population. There are not many other organic products that can prevent or destroy tomato hornworms.
Tomato Hornworm Prevention Tips
- Plant marigold, dill, and basil near tomato plants to deter tomato hornworms.
- Pick off the tomato hornworms with your hands. Dispose of them in soapy water.
- Remove part of the plant that has hornworm on it. Do this only if you do not want to touch the caterpillar.
- Attract birds to your garden, and they will pick out the juicy tomato hornworms.
- Tilling the soil is also effective in killing the overwintering larvae of the tomato hornworms.
Read more about tomato hornworms in our “Tomato Hornworm – Identification and Control” article.
#5 Stink Bugs
The stink bugs are commonly known as brown marmorated stink bugs (BMSB). These bugs are notorious for destroying fruits and vegetables. Stink bugs have a mouthpiece that can be used to suck juices from plants. To deter their predators, they also release a stinky odor when threatened. This is the reason they are named stink bugs.
Identification of Stink Bugs
- Adult bugs are 5/8 inch (1.6cm) long.
- Stink bugs have a shield shape or triangle on their backs.
- The color varies depending on the stink bug species, but typically they are green, dark brown, or greenish-brown.
- They have alternate light-colored bands on antennae.
- They have a dark pattern of bands on the outer edge of the abdomen.
Plants Susceptible to Stink Bug Attack
Stink bugs are not picky. They feed on most fruit trees and many vegetables. Some crops that stink bugs will feast on include apples, cherries, apricots, grapes, peaches, tomatoes, peppers, beans, and many more.
The Damage Stink Bugs Cause
A stink bugs invasion can cause a lot of damage. These garden pests pierce the plant tissue and suck plant juices. Stunning of the plant, discoloration, dimpling, and corking of fruit are all signs of a stink bug attack.
Live Biological Control of Stink Bugs
Attract parasitic wasps, praying mantis, and spiders to your garden.
Install bird feeders to encourage bird visits as they are natural predators of these garden pests. In addition, install a garden pond to attract frogs. They will also eat stink bugs.
Organic control of Stink Bugs
Insecticides are not effective in controlling stink bugs. They develop resistance against certain insecticidal chemicals.
Spray horticultural oil or insecticidal soap directly on stink bugs. Also, neem oil works most of the time to get rid of these insects.
Pro Tip: Stink bugs look very similar to one of the beneficial insects called spined soldier bugs. Do not remove them from your garden! The picture below compares both insects. The most significant visual difference between the two insects is their shield shape. Stink bugs have an oval shield on their backs, while spined soldier bugs have a spiky shield.
Stink Bugs Prevention tips
- Pick stink bugs up and throw them into a bucket with soapy water.
- Sow trap plants to keep the stink bugs away from your main crops.
- Trap stink bugs by using pheromone traps.
Read more about stink bugs in our “Stink Bug – Identification and Control” article.
#6 Colorado Potato Beetle
Colorado Potato Beetles are one of the most notorious garden pests. Colorado potato beetles are usually found on plants from the nightshade family. The female Colorado beetles lay eggs on the undersides of leaves, which hatch into larvae that feed voraciously on foliage before pupating.
Identification of Colorado Potato Beetles
- Colorado potato beetle adults are black and orange striped, oval-shaped, and about 3/8 inch (10 mm) in length.
- Colorado potato beetles have a dark brown head with irregular black spots.
- Colorado potato beetles have a hard shell covering their wings.
- Colorado potato beetle wings are stripped in white, black, and brown colors.
- The larvae are reddish grubs with black heads.
Plants Colorado Potato Beetles Attack
Colorado beetles are most destructive to plants from the nightshade family, such as tomatoes, potatoes, peppers, and eggplants.
The Damage Colorado Potato Beetles Cause
Larvae and adults feed on leaves skeletonizing the host plant very rapidly.
Live Biological Control of Colorado Potato Beetles
Attract Assassin bugs, parasitic wasps, ground beetles, praying mantis, spiders, lacewings, praying mantis, tachinid flies, and damsel bugs.
Organic control of Colorado Potato Beetles
To control the Colorado potato beetles, you can use neem oil, citrus oil, botanical oil, spinosad, and pyrethrins.
Colorado Potato Beetles Prevention tips
- Inspect plants before bringing them into your yard or garden.
- Remove these garden pests and throw them into the bucket with soapy water.
- Knock colorado potato beetles off and crush them.
- Plant varieties that are resistant to the Colorado potato beetles.
- Cover your crops with floating row cover.
Read more about Colorado potato beetles in our “Colorado Potato Beetle – Identify and Control” article.
#7 Japanese Beetle
The Japanese beetle is a common garden pest. The beetles are attracted to areas with lush vegetation. They tend to reproduce quickly, which can lead to big problems in the garden. Japanese beetle adults look very similar to other scarabs, including June bugs and chafers bugs.
Identification of Japanese Beetles
- Japanese beetles have a metallic green head and thorax.
- Japanese beetles have copper-colored wing covers.
- These garden pests are about 1/2 inch (12 mm) long.
- Japanese beetles have a hard shell covering their wings.
- When Japanese beetles sense danger, they tuck in their legs and drop down from the plant.
- Japanese beetles larvae are C-shaped grub, greyish white with a brown head.
Plants Japanese Beetles Attack
Japanese Beetle grubs feed on grass roots and many other ornamental plants.
Adult Japanese beetles feed on many different varieties of fruits, vegetables, and ornamentals. Common once are plum trees, cherry trees, apple trees, rhubarb, raspberries, blackberries, grapes, asparagus, corn silk, and roses.
The Damage Japanese Beetles Cause
Japanese Beetle grubs can cause turfgrass to thin out.
Japanese Beetles mate and feed in groups. These garden pests feed on the leaves of their host plant, skeletonizing them in a matter of days. They will also eat flower buds and petals. When Japanese beetles eat, they release pheromones, attracting more beetles to the area.
Live Biological Control of Japanese Beetles
Parasitic wasps and beneficial nematodes are great for controlling the Japanese beetle population.
Organic control of Japanese Beetles
To control Japanese beetle grubs, use milky spore.
To control adult Japanese beetle, use neem oil or pyrethrins.
Japanese Beetles Prevention tips
- Reduce your lawn watering. Japanese beetle eggs and grubs require moisture to thrive.
- Remove these garden pests by hand and throw them into the bucket with soapy water.
- Knock Japanese beetles off the plants and crush them.
- Avoid commercial beetle traps. They will lure in more than they will trap.
Read more about Japanese beetles in our “Japanese Beetle – Identification and Control” article.
Final Tips
Live biological control is the most effective in controlling garden pests. DO NOT USE chemical pesticides. They will kill beneficial garden insects and may damage your plants.
Not all insects are pests. Using the inorganic solution for killing insects may disturb the ecosystem in your garden by destroying beneficial insects. That’s why organic control is highly recommended to keep the pests away without damaging the nearby environment.
Here’s a recipe for the best organic homemade spray that can deter common pests:
- Take a whole garlic bulb,
- 4-inch piece of raw turmeric,
- 15 ml neem oil, or neem extract.
- Crush garlic and raw turmeric and add all the 3 ingredients to 1 liter of water.
- Boil the mixture for 10 minutes to infuse the ingredients.
- Sift and pour the mixture into a spray bottle.
- Spray onto plants after every 7 days for effective results.
- It will keep the caterpillars, whiteflies, aphids, and other garden pests away from plants.
What To Do Next
Check out and learn from our other garden Problems articles.
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