Gardening can be bad enough dealing with pests like caterpillars that you can see on your plants, sometimes chewing holes into your leaves, sometimes climbing the stems, and sometimes eating your fruits and vegetables. But what about pests that can damage your plants before you even know they are there?
There are some pests that attack your plants from underground, attacking the root systems and sources of nutrients. Next thing you know, you've got sick or dying plants without even knowing what hit them!
What are some signs that your plants are under attack by invisible pests that are undermining all your hard work in the garden?
Here are some of those sneaky pests, and some signs of their presence you can be watching for.
Common Garden Pests that Attack Your Plants at Ground Level or Below:
1. Carrot Rust Flies (Psila rosae): Carrot rust flies are tiny black flies with orange heads and legs (larvae are tiny, beige-colored maggots). These pests are becoming increasingly notorious, prevalent, and problematic for gardeners and farmers.
After mating, female carrot rust flies lay eggs near several different vegetable crops, like carrots, celery, parsley, parsnips, and more. After hatching, the larvae tunnel through and feed on the vegetable roots, and throughout the season, the scarring damage grows worse.
2. Celery Leaftiers (Udea rubigalis): Celery leaftiers (also Greenhouse leaftiers, or Celery leaf tiers), are found across the United States. Celery leaftier larvae feed on celery, beets, spinach, beans, and other plants. They are called leaftiers because the larvae tie together leaves plants they are feeding on with silk they use to pupate. They can weaken your plants, and make them prone to other diseases.
These little grey moths (larvae are little pale green caterpillars) were once known to mainly infest greenhouses and nurseries, but in the last few years have become increasingly prevalent in gardens of all sorts. They have a relatively short life cycle (about six weeks on average).
3. Cutworms (Several species): Cutworms get their nicknames as the caterpillar/moth larvae that hide under leaf litter or garden soil during the day, then come out at night to feed on several of your plants (e.g., tomatoes, cabbage, broccoli, etc.). The larvae usually attack the lowest part of the plants they encounter (the stems or seedlings), which results in the plant being "cut" down. Wilted and/or severed seedlings and plant stems is a reliable sign of cutworm presence.
Identifying cutworms is difficult as there are several different species that are different colors. Cutworms vary in color from grey, to brown, to black, and others range from tan to pink to green. Some feature striped markings, others feature spots, and others blend extremely well into the soil. The adult moths are usually grey to brown in color. These pests usually won’t grow more than 2 inches in length, and when picked up, they will curl into a "C" shape.
4. Earwigs (Dermaptera): Earwigs are actually beneficial insects in a way, as they prey on aphids, mites, scales, and other garden pests. But they are also omnivores and will feast on your precious lettuce, potatoes, beets, corn, and roses. In gardens, they chew weird-shaped holes through plant leaves, buds, flower petals, and they also eat your seedlings.
These pests are found all across the U.S., and are usually brown to black in color, measuring 1/2" to 1" in length. They are easily identifiable with curved forceps/pincers extending from their back ends. No worries, they possess no venom, and they rarely, if ever, use their forceps to bite.
5. Fire Ants (Solenopsis): Fire ants not only sting and bite, they can be a headache in your garden. If their nests are built nearby, they will head over and feed on your okra and potatoes, and they may also feed on the seedlings of your watermelon, corn, and cucumbers. Fire ants are large (for ants), measuring up to about 1/2" in length, and a bright orange or red color.
If you regularly till your garden, you'll likely see fewer fire ants in your garden, as the tilling disturbs their habitats, forcing them to go elsewhere. But if left alone, they may create a colony close enough to your garden that they become a permanent nuisance.
6. Nematodes (Nematoda): Nematodes are unsegmented roundworms, different from earthworms and flatworms. They can be beneficial by aerating your garden's soil with their digging, but some nematodes are also parasites to the roots of your plants.
After parasitic nematodes attack the roots of your plants for a while, they will inhibit your plants' ability to intake water and nutrients from the soil. Left untreated, eventually, your plants will become sickly and wilted looking, and the soil itself can become affected into the next season.
7. Root Maggots (Several species ): There are several species of root maggots throughout the U.S. that infest gardens, and they are especially destructive to plants in their early stages of growth. They feed underground on root systems, and attack several kinds of vegetables, including carrots, turnips, onions, radish, and cabbage. Seriously infested roots become rotted (e.g., Black rot) and full of tunnels, which can attack your plants' health, stunt them, or simply kill them.
Adults are small (~1/5" in length) dark, grey flies that resemble small house flies. Their larvae are small, whitish/yellowish maggots with rounded hind ends, and they are often found embedded in plant roots.
8. Root Weevils (Otiorhynchus ovatus, others): Root weevils are the larvae of species of beetles. Adults hide around the crowns of plants in the day, and then feed nocturnally, mostly on plant foliage. These adult beetles cannot fly.
Larvae maggots feed on the roots of blackberry and raspberry plants, but can also feed on small rootlets and destroy the bark of larger roots. Soon after the larvae begin feeding, plants will wilt because the leaves are struggling to get moisture. Plants can die, if left untreated.
9. Slugs and Snails (Gastropoda): Snails and slugs are both part of the same class of animals, known as gastropods. One striking difference between snails and slugs is the fact that snails have shells, while slugs do not. Snails and slugs do quite a bit of burrowing under the ground, and primarily attack plants close to the ground, or just under the ground.
These pests prefer fresh foliage or flowers, and are mainly parasites of seedlings and herbaceous plants. They also feed on turfgrass seedlings and ripening fruits that grow close to the ground, like tomatoes and strawberries.
10. Wireworms (Elateridae): Wireworms live in the soil and are common in gardens across the U.S. They are typically whitish/yellowish in color, shiny, and measure up to 1-1/2" in length. They are sturdy creatures, and primarily feed on carrots, onions, beets, and potatoes along with other garden vegetables.
You can distinguish them from other kinds of worms because wireworms feature three pairs of legs just behind their heads. These worms are larvae that develop into click beetles. They can take from two to six years to mature into full adulthood, so yes, these are overwintering pests.
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