Common Garden and Lawn Pests

By Linda Ly

Garden pests can be more than just a nuisance for the home gardener. When not dealt with properly and swiftly, bugs in the garden can do actual – sometimes irreversible – damage to lawns and gardens. Ready to learn more about how to identify garden pests? Read on for everything there is to know about garden and lawn nuisances. We’ll even illustrate the different measures on how to deter them, using both physical methods and natural deterrents.

• Common Garden Bugs and Insects
• Common Lawn Pests

Common Garden Bugs and Insects

Though they may be common, that doesn’t mean they’re not wildly annoying (and sometimes very damaging). Find out what each of these little pests look like, are attracted to and best of all, how to rid your garden and yard of them!

Cutworms

Cutworms are moth larvae that like to hide under soil by day, only to feed on plants by night. They are usually out in the early evening or nights, and they can range in color from pink to greyish, depending on the species. They can be spotted, striped or solid and can grow up to 2 inches in length, but they generally like to curl up when resting. These detrimental pests are not discriminatory and will attack the first part of almost any plant they encounter. Most often, that is the stem of a young plant or seedling. As the attack generally results in the plant severing, the name “cutworm” makes perfect sense – they will cut the plant down.

Combat cutworms by hand-picking them or sprinkling ground up eggshells or coffee grounds around plants. You can also circle around the stems of plants with diatomaceous earth (not the kind sold for swimming pools). Diatomaceous earth is a natural powder that comes from ground fossils and kills critters as they cross over it.

Whiteflies

Whiteflies, as their name would imply, are tiny white flies that cluster on the underside of plant leaves in the garden. They are winged, soft-bodied and look similar to mealybugs or aphids. They can be as tiny as 1/12 of an inch and are triangular in shape. Unlike many other garden pests, whiteflies are active during the day. They suck juice from plants and leave behind a sticky substance called “honeydew.” If honeydew is left on plant leaves, it can cause fungal disease. Whiteflies like warm weather and ornamental plants. Common plants they’ll attack include tomatoes, sweet potatoes, eggplant and peppers, to name a few.

If you spot whiteflies in the garden, it is important to get rid of them as soon as possible. Start the process by blasting the undersides of leaves with the soft wash setting on a Front Control Watering Nozzle. Once the flies scatter, spray the leaves with insecticidal soap. Do this during the cooler part of the day, either early morning or after the sun sets, repeating up to three times. You can make your own deterrent with a homemade mixture of dishwashing liquid, water and lemon.

Thirps

Thirps are brownish or greenish, slender, very tiny insects with fringed wings. They wreak havoc on plants, essentially sucking the life out of them. If plants are becoming splotchy, pale or silvery and look discolored or twisted and scarred, thirps may be the culprits. They feed in large groups and are drawn to several different host plants, including squash, onions, carrots and beans, among other garden vegetables. They also feed on flowers like roses and gladiolus. They are attracted to light-colored blossoms and can spread viruses.

Controlling thirps is not all that difficult as long as you are vigilant and swift about it. Promptly removing cut yard debris is important so thirps don’t find an alternate host once the green plant they have been invading is cut down. Blue sticky traps can help control adult populations and a strong blast of water can knock them off plants. Insecticidal soaps and insecticides may be needed for extensive infestations.

Cabbage Looper

The cabbage looper is a moth that hosts on cruciferous vegetables like bok choy, broccoli and cabbage. But, while it does love the cruciferous vegetables, the larvae will use more than 150 other plants as hosts, too, making this pest a potential problem for nearly any yard or garden. Though not always hugely destructive in small numbers, these garden pests are known to be resistant to many types of insecticides, making them somewhat challenging to control. They will chew the undersides of leaves when young and will grow to chew larger holes across plants. They also bore into cabbage heads and leave slimy, wet fecal matter in their wake. Born white and a bit hairy, larvae quickly mature into green worms with white stripes on the side. They will arch their midsections into a “looping” motion as they crawl along plant leaves.

Rid your garden from cabbage loopers quickly once they’ve been detected. Left unattended to, they can become harmful to plants and vegetables, multiplying quickly as second generations hatch. Some gardeners opt to use pheromone traps a bit away from the garden to detect when moths are in the area. Once detected, a full-fledged prevention strategy can combat the invasion. Several herbs like dill, fennel, parsley and coriander will attract larvae-eating insects and creatures. Floating row covers can be very effective if done early enough, preventing migrating moths from landing or laying eggs in your garden. Another option is to spray the bacterium Bacillus thuringiensis or Bt-kurstaki, which is effective on all types of inchworms. You can also try an organic spray that contains the biological agent spinosad, which is proven effective.

Mexican Bean Beetle

Mexican bean beetles are a relative of the ladybug and they actually look very similar. These small yellow-orangish garden bugs will leave a trail of destruction not unlike that of a Japanese beetle all along the garden, and they are mostly attracted to bean plants. Mexican bean beetles lay small yellow clusters of eggs on the backs of leaves, and once they hatch, the larvae grow to be spiny and about ½ inch long. Adult beetles will become darker orange as they mature, and they typically have 12 black spots on their back. It’s easy to spot damage from a Mexican bean beetle. Lacey holes chewed through the leaves are a good indicator of their presence.

Control and rid plants of Mexican bean beetles by hand-picking beetles and the larvae once they appear. For preventative measures, planting marigolds and rosemary may help as both are effective deterrents.

Flea Beetle

Flea beetles are little jumping insects that can cause big damage in gardens. They appear early in the growing season and the larvae are small cream worms that grow to be about 1/10 of an inch at maturity. Adult flea beetles are dark brown or black with large back legs that allow them to jump. Flea beetles live underground and feed on tubers, roots and germinating seeds. They will also chew small holes in plants’ leaves. A large infestation can kill entire plants. They prey on numerous popular summer plants including eggplants, potatoes, cabbage, tomatoes, lettuce and corn, among others.

To deal with flea beetles, catch the problem before it starts. Row covers over seedlings are extremely effective, and beneficial nematodes, microscopic parasites, can destroy the larvae. Diatomaceous earth is also helpful, as it harms the beetle when it crawls over it.

Codling Moth

The codling moth targets apples and is one of the most destructive orchard pests around. In addition to apple orchards, the moths can also do extensive damage to walnuts, pears, stone fruits and crabapples. The creamy white or pink larvae have brown heads and tunnel through fruit, leaving mounds of fecal matter pushed back out through the hole they entered. The damage codling moths cause to fruit makes it unfit for human consumption.

Deal with codling moth infestations naturally by spraying nontoxic beneficial nematodes that will destroy them. Another option is to spray Bt-kurstaki (Bt) which is a natural microbe (protein) found in soil that is harmful to larvae.

Aphids

These tiny, soft-bodied, sap-sucking insects appear in colonies on distressed plants on the undersides of leaves. They usually show up as a result of overwatering, underwatering or poor growing conditions.

If you catch the infestation early, a simple, effective solution is to simply blast the aphids with the soft wash on a watering nozzle attached to the hose. This may need to be repeated daily until all signs of these annoying little garden friends have disappeared from the leaves of plants.

Caterpillars

Leaf-eating caterpillars, including hornworms and cabbage worms, can quickly decimate an entire vegetable garden and must be controlled while they’re young, before they prepare for the pupae stage.

For new plantings, lay floating row covers over the garden as a preventative measure. Floating row covers allow sunlight and water to reach the plants, but effectively keep caterpillars and other garden pests out. If you spot any caterpillars slinking along your plants, hand-pick and destroy them immediately.

Grasshoppers

Small, bright greenish or brownish jumping insects, a grasshopper infestation can seem like an endless barrage of never-ending garden pests. And that’s exactly what it is. Grasshoppers are constantly moving from areas with limited food into areas of plenty. This constant movement means that unfortunately there just isn’t really any “one-time cure.”

Consider grasshopper control a repeated exercise. Placing a netting or floating cover over garden rows can help reduce infestation in small areas. Larger gardens might require hand removal in the early morning hours, when grasshoppers tend to be less active. Allowing tall grasses to grow around a vegetable garden can serve as a catch-all for grasshoppers and reduce the number in actual growing spaces.

Earwigs

Earwig damage closely resembles the damage caused by slugs, snails, caterpillars and other garden bugs, so to make a definite garden pest identification, inspect plants at night when earwigs are actively feeding. These little buggers are attracted to light, so they’re easy to spot. The dark brown slender insects are small and winged with pincers that come out of their backsides.

During the day, earwigs hide in dark, cool, moist areas, so be sure to remove any garden debris that has accumulated outside garden areas and around the home perimeter – this will help eliminate earwigs as they won’t have that cool, dark place to hide during the daytime. Sprinkle a fine layer of garden pest control diatomaceous earth along areas where earwigs tend to travel. Reapply after heavy irrigation or rainfall.

Japanese Beetle Grub

One of the most common yard problems gardeners regularly face is the threat of Japanese beetle grubs. Grubs are small white larvae that become problematic for entire yards, as they turn into ravenous devourers of every rose in the garden once they hit adulthood. As if the brown patches on lawns and rose damage aren’t enough, grubs are also a favorite food of moles, birds and other creatures. These pests will tear up lawns to feed on Japanese beetle grubs.

Treatment options vary from region to region, so consult with local extension agents or a knowledgeable garden center employee about what might be most effective. If treating your lawn with an organic pesticide, something like the Gilmour Foamaster Cleaning Sprayer is best for application. Fully adjustable with dosage ratios, it hooks right up to the hose to operate on water pressure.

Snails and Slugs

Snails and slugs can cause extreme damage to a number of garden plants and vegetables. New and young plants are of particular risk, as they are most vulnerable to the damage these pests cause. Leaving behind a trail of holes in leaves, snail and slug damage can mimic that of other insects. To know if damage is really being caused by slugs and snails, use a tried and true beer trap.

Who knew you could bait destructive slugs and snails with a little beer? Turns out, these slimy little garden-lovers are highly attracted to the yeast in beer. To bait them, set up a beer trap by placing a shallow pan filled with beer near any areas with evidence of slug and snail damage. At night, they’ll stretch for the beer, fall in and drown. Remove perished slugs and snails each day, and replenish the beer trap every few days. Water early in the morning so the heat of the day dries the moisture, making the garden less desirable during the evening hours when slugs and snails are most active.

Common Lawn Pests

Insects aren’t the only pests to worry about in your yard or garden. Rodents and four-legged friends can cause quite the problems, too.

Mice

Mice tunnel underground, leaving annoying entrance and exit holes that can be an eyesore across the yard. Once underground, they pull and gnaw at roots from below.

To rid your yard of these unwanted little rodents, be sure to keep on top of yard maintenance, pulling weeds and maintaining long grasses. Unkempt foliage provides perfect hiding spots, so keeping areas tidy eliminates the chance of mice making themselves at home, and worse, multiplying. If you know a mice problem is a reality, set baited traps and cover any burrow openings that are visible.

Moles

Moles can be hard to find, and they can be even harder to get rid of once you do see them. The tricky thing about moles is they generally stay underground, unless they surface to look for a mate. They burrow deep underground tunnels that are well-known to contribute to the destruction of lawns and gardens. Sometimes, the only actual sign you may see of a mole is the kicked-up dirt that builds little mounds running the entire length of their tunnel. These mounds can crisscross all over the yard and can reach up to 8” higher than the surface of the ground. Moles can transmit rabies, but it is more likely they’ll spread fleas, ticks and parasites.

Getting rid of moles can be difficult but reducing ground moisture with proper drainage can make your yard less appealing, as they need moist, easy-to-dig soil to tunnel. Another tactic is to install barriers like wire mesh, cages or gravel that’s buried in a trench and covered with ample dirt. Barriers need to be quite deep – at least to 30 inches – to be effective.

Racoons, Possums, and Skunks

If nocturnal critters are your main garden pest concern, the best defense is a good offense. Take action to prevent four-legged friends from coming in to the garden in the first place. Protect plants by installing plastic, wire or wooden garden fencing, hardware cloth or mesh around the perimeter of garden beds. This barrier method prevents animals like raccoons, possums and skunks from digging up soil (often searching for grubs), while still allowing for watering, fertilizing and harvesting plants.

Successful garden pest control requires diligence and thoughtfulness. But when enough time and attention is dedicated to a pest-free yard, the reward is a gorgeous garden that flourishes and is healthy, season after season.