INSECTS AT OR BELOW GROUND

Many insect, such as ants and termites live below ground in colonies, and many others, such as bubble bees and beetle larvae spend at least some of their lives underground.  Below we will discuss some of the insects and bugs you will find at ground level or below the ground.

Cutworms

Cutworm. Small caterpillar that is tan with brown spotted lines down its body.
Cutworm

Many surface-feeding caterpillars are known as cutworms and are often mistaken for grubs.  There names reflect their feeding habit, which is to chew plant stalks until they are cut through.

They feed on many garden plants with seedlings being their favorite.

Cutworms emerge at night curling themselves around plant stalks to feed.

During the day the cutworms hide under litter or an inch or so below ground.  And you will find them near the scene of the crime (the plant they will attack).

There are three types of cutworms that feed on:

  1. Plant roots
  2. Seedlings at ground level
  3. Buds above ground level

The adult cutworm is a nocturnal (night-flying) moth that ranges in color from grey to pink, green, brown, and black and can be up to about two inches long.  They can be solid, spotted or striped.

Some plants affected by cutworms include:

  • Beans
  • Cabbage
  • Corn
  • Lettuce
Controlling Cutworms
  1. Make plant collars.  Put a 4-inch piece of cardboard around the stem of your plants to stop the cutworm from reaching the stems.  Although this is time consuming, it works.  Another way to do this is by recycling toilet paper rolls.  Cut them in half, stand them up and add soil to plant your seeds in them.  When it is time to plant you can put the whole thing directly in the ground.
  2. Hand pick them off the plant.  Armed with a flashlight and gloves, go out in late evening or after dark and pick off cutworms and place in a bucket of soapy water.
  3. Recycle your coffee grounds and egg shells by placing them around your plants.
  4. Diatomaceous earth, a natural powder made from ground up fossils which kills insects when they walk over it.
  5. BT.  (Bacillus thuringiensis) is a natural way to kill cutworms.  Remember that this insecticide can harm butterflies, which is an important pollinator.
  6. Use preventive measures such as planting later in the spring, cutting off the cutworm food supply or clearing any debris and weeds from garden site, destroying their habitat.
  7. Beneficial insects and bugs such as fireflies, as well as many birds you may see in your garden are natural predators to cutworms.

Root Maggot (Delia radicum)

onion root maggot
Root Maggot

The Root Maggot, also known as the cabbage fly, root fly or turnip fly is a pest to many plants.  They are the larvae Of the cabbage root flies that lay their white eggs in the soil at the base of host plants.

There are several different species that target different host plants.  They are sometimes known as cabbage maggot, onion maggot, or root maggot.

The adult root maggot is about 1 cm long and is gray and nodescript, resembling a common housefly.  The larvae of the root maggot are white and about 1/4-inch long.

Onion maggots seek out anything in the onion family, including garlic and leeks: cabbage maggots look for any cabbage family plant including broccoli or turnips.

Both the onion and the cabbage root maggots are more common in the Northern half of the United States.

Maggots are most active during the cooler month of spring and fall.

Root maggots disfigure their host crops with their tunneling but can also create rot diseases such as black rot around their entry points.

Infested plants lack vigor, growth may be stunted, and are prone to wilting during the heat of the day.

Root maggots attack the roots of many other plants including:

  • Broccoli
  • Cabbage
  • Cauliflower
  • Carrots
  • Collards
  • Kale
  • Kohlrabi
  • Mustard
  • Onions
  • Radish
  • Rutabagas
  • Turnips
Controlling Root Maggots
  1. Spread diatomaceous earth around plants while they are seedlings.
  2. Floating row covers can be used over seedlings but need to be removed when plants begin to flower for pollination purposes.
  3. Nematodes added to the soil will kill the root maggots
  4. Pesticides can be used but need to be used early, before the maggots have penetrated the root of the plant, where it is difficult for the chemicals to reach the pests.  If using apply weekly during the first 8-10 weeks of spring.
  5. Crop rotation can help control root maggots.
  6. Clean up garden debris, weeds, and any dead vegetation.  Destroy any plants infested with root maggots and do not put them in the compost pile.
  7. Cutting back on the amount of organic material in your garden, especially manure based organic material can help.  This is because root maggot flies prefer to lay eggs in soil that is high in organic materials.

 

Wire Worm

Found throughout the United States these worms are tough slender worms about 1 1/2-inches long with shiny skin and three pairs of legs just behind the head.

Wireworms have a yellowish, golden-brown shell and are the larvae of click beetles.

They live in the soil where they feed underground on stems, roots, seeds, and tubers of a wide variety of plants.  They are rarely a problem, but they are most likely to show up in large numbers in garden soil that was recently covered by sod.

Infected plants soon wilt and die.  If infestations are heavy, reseeding will most likely be necessary.

The larvae and the adult wireworm overwinter in the soil.  The female beetle emerges in early spring, mates and lays several hundred very tiny , pearly white, rounded eggs in the soil underground.

The eggs hatch in two to four weeks, and the larvae begin looking for food.  The larvae can live underground for 2-6 years, doing most of their damage in the spring.

There is one generation every 2 to 3 years with the years overlapping there is various stages of the wireworm each year.  With the larvae feeding underground for 2 to 3 years before reaching maturity their life cycle requires 1-6 years to complete.

Plants affected by Wireworm include:

  • Beets
  • Carrots
  • Corn
  • Onion
  • Potatoes
  • Sweet Potatoes
Controlling Wireworms
  1. Planting later in the season when the soil has warmed up some is recommended.  This is because the larvae prefer cool soils and dig deeper into the soil when the ground temperature rises.
  2. Tilling the soil in the spring and fall will expose the adult and the larvae to predators and weather.
  3. Birds will feed on the wireworms.  So, make your yard bird friendly by hanging bird houses and feeders throughout.
  4. Trap the wireworm with potatoes.  Cut one in half and put a stick in it.  Bury it about one inch in the soil.  Remove the traps in a few days and discard the wireworms.
  5. Apply beneficial nematodes into the soil when planting.  They attack and destroy any developing pests in the soil.
  6. Crop rotation can reduce many pest problems in the garden.
  7. Insecticides such as pyrethrin can be effective but should be used as a last resort.

 

Fire Ants (Solenopsis)

Fire ants on a 2 x 4 board. Approximately 25 to 30 ants on the board.
Fire Ants

These destructive ants, sometimes referred to as red ants, or ginger ants, can be found across the entire southern tier of the United States, including North Carolina, Southern Tennessee, Southern Arkansas, Texas, New Mexico, and Southern California.  They can also be found in mild winter areas of the Southwest and West Coast.  These insects can be found at or below ground.

The body of the mature adult fire ant is divided into three sections, their copper brown head, the thorax and the darker abdomen.  The worker ant can be black or reddish-brown and about 2 to 6 mm long.

Winged reproductive forms appear in the spring and early summer.  After mating the male dies and the female starts a new colony.  Her first eggs hatch in a week, and the resulting worker ants mature in less than a month.  A queen can live several years producing more than 1500 eggs per day.

These little creatures with their vicious stings are partial to uninterrupted sun and sandy soil, while they avoid shady, dark areas.  They make conical nests as large as 18 inches in diameter and 10 inches high and are commonly found in lawns, gardens, school yards, parks, roadsides and golf courses.  If disturbed they attack aggressively, stinging the intruder.

Unlike other ants, which bite and then spray acid on the wound, fire ants bite to get a grip then sting from the abdomen, injecting a toxic alkaloid venom called piperidine into its victim creating their vicious painful stings.  The sting has a similar sensation to what it feels like to be burned (hence the name fire ant) and can be deadly to some.

Fire Ants feed on:

  • Germinating seeds
  • Young shoots
  • Fruits
  • Saplings
  • Insects and bugs
  • Dead animals

Fire ants provide protection for aphids in order to obtain their sweet excrement (honeydew).

Controlling Fire Ants
Up close view of a worker fire ant. View of its face.
Worker Fire Ant
  1. The first method of control is to broadcast a fire ant bait over the entire area.  You may need to treat a couple of times a year during hot months.  This treatment usually destroys 80%-90% of fire ant infestations.
  2. The second method requires treating individual mounds with a liquid insecticide poured into the mound, making sure to use enough to kill the queen.
  3. You can also use Fire Ant Baits around each mound.  Be sure to put them around the mound and not on the mound.

 

Earwig (Dermaptera)

Earwigs are found throughout the United States.  There are about 2000 species of Earwigs in 12 families that make up the order Dermaptera and more than 20 species are found in the United States.  They are one of the smallest orders of insects.

The Earwig commonly feeds on insects and plants causing damage to foliage, and flowers.  These insects are found at or below ground.

An earwig insect on a leaf.
Earwig

 

Earwigs     are hemimetabolous, which  means they undergo incomplete metamorphosis, developing through a series of 4 to 6 molts.  The developmental stages between molts are called instars.

Adult Earwigs are reddish-brown in color with sharp pincers on their abdomen and membranous wings folded underneath short, rarely used forewings.

The eggs are white or cream-colored and oval shaped.  Right before they hatch they become kidney shaped and brown.  The eggs are about 1 mm tall and 0.8 mm wide.

Feeding mostly on decaying organic matter, and other insects you can find them hiding in dark, damp places during the day.  Preferring these damp moist places this is where the female lays her eggs, and also where you can find them living.

If there is a high population of earwigs, they may feed on a variety of garden plants and insects including:

  • Beans
  • Corn
  • Celery
  • Dahlias
  • Marigolds
  • Squash
  • Potatoes
  • Tender young seedlings
  • Blossoms and ripening fruits
  • Slugs
  • Snails
Controlling Earwigs
  1. Prevent entry by sealing all cracks and crevices in out-buildings or houses with a silicon-based caulk, steel wool or a combination of both.
  2. Create a perimeter around your house that is free of any organic debris such as leaf piles, mulch piles, firewood piles, logs, or weeds.
  3. Insure proper water drainage around you home to prevent any moisture buildup that may attract earwigs.
  4. Diatomaceous earth can be used, causing the earwigs to dehydrate and die.  Follow directions on container and do not inhale!
  5. Roll up a newspaper, wet it well and tie it securely with string.  Put it in a place that you know the earwigs are and they will crawl into the newspaper, becoming trapped and you can dispose of them in the trash.
  6. Boric Acid can be used to kill earwigs.  It is a natural insecticide that kills earwigs on contact.  Sprinkle in area of infestation.

 

Nematodes

Nematodes are microscopic insects found at or below ground.  These microscopic round worms are multicellular insects with smooth, unsegmented bodies and they are found all over North America, although they appear to be a much bigger problem in the South.

Some nematodes are good for plants and the soil because they attack and kill pest insects, and feed on fungi, protozoans and even other nematodes.  These nematodes are considered beneficial to the plants and soil and can even be purchased commercially and released into the garden.  When purchasing nematodes, it is important to choose the right species because different kinds of nematodes are effective against different pests.

If you purchase Nematodes, remember they need moist, humid conditions and warm soil to do their job well.

Beneficial nematodes can combat a variety of pest insects at or below ground including:

  • Weevils
  • Clearwing borers
  • Cutworms
  • Sod Webworms
  • Chinch bugs
  • White grubs

Nematodes are not only insects at or below ground because not only do they affect plants and soil, they affect animals and humans as well.

Both types of Nematodes, have successfully adapted to almost every ecosystem: from marine, (salt water), fresh water, soils, from the polar regions to the tropics.  They have been found in such places as mountains, deserts, oceanic trenches, and even in gold mines well below the surface of the earth.

They represent 90% of all animals on the ocean floor.  A spade-full of soil can contain more than a million nematodes.

It has been said that if everything from our planet was removed except for nematodes, much of the topography of the Earth would be recognizable as a layer of nematodes.

So, keep in mind that although generally small and unnoticeable, they have an enormous impact on us and our world.

Pest nematodes feed on many garden plants including:

  • Beans
  • Carrots
  • Celery
  • Cherry
  • Tomatoes
  • Corn
  • Lettuce
  • Peppers
  • Tomatoes
  • Spinach

Symptoms of a plant infected with nematodes are stunted growth, and yellow foliage.  Also, they may wilt in hot dry weather, and can die if badly infested.

The roots may develop small, round nodules on them and have taproots that develop many side roots.

Nematodes are spread through infected soil, water, tools, and plants.

If you think this is a problem in your garden, you should have your soil tested for verification.

Controlling Nematodes
  1. One group of carnivorous fungi, (nematophagous fungi) are predators of soil nematodes.
  2. Always clean and sanitize tools and containers.
  3. Water plants giving them the right amount.

 

Slugs and Snails

 A brownish-orange slug on grass blade.
Slug

These shelled creatures (Mollusks) are found throughout North America, particularly in moist, temperate climates.  You will find these insects at or below ground as well as on plants, shrubs and trees.

Since snails require calcium for their shells, they are more likely to be found in areas that are high in the mineral calcium.

Slugs are gray to black or brown and soft-bodied, often with a soft hump in their center, while snails have a hard calcium shell.

Adult or nearly mature slugs and snails overwinter in the soil and emerge in spring or early summer.  Both slugs and snails are hermaphrodites.  They contain both male and female reproductive organs, so they don’t need to mate.

They lay as many as 100 eggs at a time depositing them in soil cracks, underneath dead leaves, in mulch or anywhere it is cool, moist and protected.  Eggs develop and hatch in about 1-3 weeks with some needing up to 12 weeks under certain conditions.

Some species of snails and slugs can lay up to 500 eggs per year.  Once the eggs hatch, young mollusks stay close to the nest for a few days before they start searching for food.  The larvae become adults within 3 to 6 months.

Both the slug and the snail will feed on almost any plant, especially young tender transplants, leafy vegetables, and succulent plant parts.  Slugs and snails thrive in damp, shady spots and can often be found along foundations, under rocks or in well mulched gardens.

Slugs and snails leave irregularly shaped holes with clean edges in the leaves and leave behind a shiny slime trail.  They are active mostly at night and in wet weather.

Snail on tree branch.
Snail

They feed on a variety of plants including:

  • Artichokes
  • Strawberries
  • Tomatoes
  • Almost all garden vegetables
  • Ornamental flowers
  • Citrus trees and other fruit trees

Some plants believed to repel snails and slugs include:

  • Azaleas
  • Apricots
  • Basil
  • Beans
  • California poppies
  • Corn
  • Chard
  • Daffodils
  • Fennel
  • Fuchsias
  • Grapes
  • Ginger
  • Holly
  • Parsley
  • Peruvian lilies
  • Pumpkin
  • Plum
  • Rhododendrons
  • Rhubarb
  • Sage
  • Swedish Ivy
Controlling Slugs and Snails
  1. Keep garden area clean and clear of all debris, including weeds and firewood or lumber.
  2. Hand pick them.  The best time to do this is about two hours after sunset.
  3. A shallow pan of stale beer sunk into the soil can be used to attract pest, which fall in and drown.
  4. Diatomaceous earth creates a barrier that keeps them from reaching plants, flowers and trees.
  5. Boric Acid granules spread around plants can help to eliminate slugs and snails.
  6. Organic bait, containing iron phosphate scattered on lawns or in the soil around plants can reduce the number of pests.  This bait kills them soon after they eat it and will decompose in your garden and act as a fertilizer.
  7. Chickens love to eat slugs and snails.

 

Want to know more about the insects and bugs found in the garden.  Get the ultimate guide below.

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For a healthy beautiful garden learn how to tell which insects you want in the garden and which ones you don’t.  It’s a complete guide with over 30 different insects and bugs.  Find out how to spot, control, and destroy them.  Download the guide and receive weekly newsletter from Daisies-n-dollars.com.  Sign up and join us today and get this gardening guide FREE!

 

Concluding,

Insects at or below ground include cutworms, fire ants, maggots, earwigs, slugs, snails, and nematodes, as well as many others.  Although some nematodes are beneficial to the soil, many are considered pest insects.  For a healthy, thriving yard and garden use the steps above to rid your yard and garden of unwanted insects and bugs.

Happy Gardening,

jackie@daisies-n-dollars.com

 

INSECTS AT OR BELOW GROUND
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