This handy list of natural controls for common garden pests for organic gardeners interested in alternative solutions is from the new Mother Earth News Almanac. From aphids to weevils, see what you can do to reduce plant damage from these insects without causing harm to the environment.
If you want to garden organically, a great first step is to start a compost pile which provides a jump start on healthy soil.
Mother Earth News Almanac
I’m a bit of a sucker for almanacs. I tell myself I’ll just browse for a few minutes and end up pouring through tons of quirky and intriguing ideas.
The new Mother Earth News Almanac: A Guide Through the Seasons has a good mixture of facts, recipes, garden tips, folklore, homestead animal-raising tips, remedies, and DIY projects. In keeping with traditional almanac style, each item is fairly brief and to the point.
What’s Bugging Your Garden?
It wasn’t easy deciding what I wanted to share with you from the book but I settled on this very handy chart of organic pest controls since it’s something that you can bookmark and return to throughout your garden seasons.
When it comes to pest management, it often comes down to either removing the source that attracts the pest, encouraging a (non-invasive) predator, or hand-picking the pest.
The first step is to determine if there really is a problem and if it actually requires action at all.
I try to always consider the bigger picture first.
- What harm will come if I don’t do anything to the pests?
- Is the cost so great that I can justify the time, energy, and collateral damage to try and get rid of them?
- And, what further harm could my actions cause?
If our first responsibility is as stewards of the earth, it quickly narrows down the best course of action.
Organic Approaches to Pest Control
This excerpt from Mother Earth News Almanac is provided with permission from the publisher.
I do not have the expertise to vouch for these controls, and neither have I had to deal with very many of these pests in my garden, so this post is informational only.
A growing number of gardeners—tired of drenching their vegetable patches with chemical fertilizers and wide-spectrum, persistent pesticides—are turning to more organic methods of raising food.
SPECIAL NOTE: Pyrethrum, rotenone, and ryania are not chlorinated hydrocarbon, persistent pesticides. All three are derived from plants and none of the three presents the cumulative dangers to plants, animals, and people inherent in the broad-spectrum chemical insect control
Visual Index of Garden Pests
This chart provides drawings of the pests to help identify them visually.
Natural Pests, Signs of Injury to Plants, and Treatments or Remedies
Sometimes you can’t see the pest but you can see the damage they are doing. Between the images (above) and the symptoms (listed below), you should be able to figure out what’s bugging your plants. Suggested treatments or remedies are also listed.
Aphids or plant lice
Small, soft, pear-shaped, various colors, work in massed groups.
Injury: Suck juices, causing plants to wither and sometimes become blotched. Leaves may curl badly, yellow, and thicken.
Treatment: Ladybugs are very effective natural control…or spray the aphids with a strong stream of water, soapy water, rotenone or pyrethrum. Crush by hand. Prevent attacks by planting nasturtiums between rows of plants to be protected. Treatments is most effective if started at first signs of attack.
Blue or orange, 1/4″ long.
Injury: Feeds on foliage, attacks tender shoots and later gnaws the stalks.
Treatment: Pick stalks daily in season. Dust with rotenone to kill larvae in April and May. In fall, clean the garden and plow, with poultry following behind to eat larvae. Let hens have run of asparagus beds.
Twelve-spotted asparagus beetle
Larger than asparagus beetle and with 12 spots on wing covers.
Injury: Feeds almost exclusively on the berries.
Treatment: Same as above.
Small, chunky snouted beetle, rather square across the back and tapering into a wedge shape toward the front. Brownish gray or olive.
Injury: Attacks mature seeds in storage. Chews holes in pod and eats out interior of seeds.
Treatment: The easiest way to avoid this pest is by planting early or late so that adult beetles miss the plants’ blossoms. Cure seeds properly by pulling up plants with pods on them and placing them off the ground on stakes for six weeks or more. Obtain seed from a reputable dealer. If seed floats in water, don’t use it.
Slender, cylindrical insects 1/2 to 1″ long, gray, black or yellow with black stripes. Moves in colonies or swarms late in season.
Injury: Eat leaves.
Treatment: Handpick… but wear gloves because these little devils really will give you blisters. Believe it or not, swarms can be driven out with the sweeping motion of a branch or stick.
Yellow-white, up to 1/2″ long. Adult fly resembles housefly but is smaller and rests on ground until disturbed.
Injury: Tunnels into roots and stems, causing plant to wither and die. All season long.
Treatment: Find where maggots are working, pull dirt away, put heaping tablespoon of wood ashes around stem, replace dirt, firm plant and water. Put 4″ circle or square of tar paper around stem of plant to repel adult female fly and keep her from laying eggs.
Imported cabbage worm
Smooth, leaf-green, up to 1 1/2″ long. Larvae of white cabbage butterfly.
Injury: Eats leaves full of holes, often delaying growth and heading for several weeks.
Treatment: Handpick worms from undersides of leaves. Dust cabbage in the early morning with rye flour or powdered lime. Spray with a mixture of two tablespoons of table salt in one gallon of water or use rotenone or pyrethrum. Try companion plantings of tansy, tomatoes, sage, catnip, mint, hemp, rosemary, or nasturtium.
Same size as above but lighter green with white stripes. Humps its back as it crawls.
Injury: Same as above.
Treatment: Same control as above.
Larvae of the diamondback moth
Small, green worms.
Injury: Usually known to feed on undersides of leaves and not until the pests are numerous are the holes eaten clear through.
Treatment: Same as above.
Celery leaf tier
Greenish caterpillar up to 3/4″ long. Moths are brown with wings crossed by dark wavy lines.
Injury: Eat holes in leaves, and often fasten leaves together with webbing.
Treatment: Handpick the worms and discard leaves that appear damaged. Dust with ground tobacco, lime, pyrethrum, or sulfur and repeat after 30 minutes.
Colorado potato beetle (potato bug)
Larvae is brick-red, soft, humped. Adult is chunky, yellow with 10 black stripes on back. About 3/8″ long.
Injury: Both larvae and adults eat foliage.
Treatment: Handpick beetle or larvae. Use ladybugs, mulch, dust with rotenone, or spray with extracts from common or sweet basil. Companion plant with bush beans.
Brown, green, or pink larvae, up to 2″ long and striped.
Injury: Eat leaves and buds. On corn, feed on silk and kernels near the tip of an ear.
Treatment: Electric insect traps. For corn, after silks go limp and tips start to turn brown, apply five or six drops of mineral oil to the end of each ear. Or handpick. For other vegetables, use a dust of rotenone or ryania.
Plump, soft-bodied, dull-colored light to black, scantily covered with coarse bristles or hairs, 1 to 1 1/2″ long.
Injury: Feed at night, curl when exposed. Cut off plants even with the ground. Some cutworms burrow into the stalks or through heads and roots of vegetables.
Treatment: When you put out plant seedlings in the spring, place paper or tin can (with both ends cut out) collars around each little plant. Set the collars 2″ deep in the soil. Spread and cover crushed eggshell between and around plants. Handpick the worms and cultivate lightly. Encourage your garden’s toad population. Allow no grass to grow in the vegetable patch. Plow in spring and fall and let hogs and chickens root and pick through the freshly turned soil.
Reddish brown, up to 3/4″ long with forceps on tail end.
Injury: Eat plant parts (and some aphids and other sucking insects… making them partially -but only partially -beneficial).
Treatment: Feed at night. Trap earwigs under boards or in newspaper that has been rolled up and left in the garden overnight. Be sure to burn the paper daily.
Flea and leaf beetle
Many species, 1/16″ long, black, brown or striped. Leap like fleas.
Injury: Leaves first become blotched with minute white dots, then look like they’ve been shot through with holes.
Treatment: Keep weeds down. Dust with mix of fine ashes and tobacco dust, pyrethrum, or rotenone.
Dull brown, gray, green, black, yellow, up to 2″ or more in length. Jump and have wings.
Injury: Eat vegetation and sometimes completely devour whole plants.
Treatment: Handpick and destroy, use as fish bait, or -like the Native Americans -fry or roast the pests and eat them. Spray rotenone on nonedible (such as potato) leaves. Rill in the fall at least 5″ deep.
Harlequin cabbage bug
One of the stink bugs. Black or dark blue with red or yellow spots. Shield shaped, up to 3/8″ long.
Injury: Suck sap from leaves causing wilt. Look for and destroy eggs (capsules with black stripes) on early blooming plants.
Treatment: Plant a trap crop of turnip, mustard, radish, or rape, and destroy the cabbage bugs that gather. If early arrivals are destroyed, later ones will not follow. Dust with sabadilla or pyrethrum when your cruciferous crop leaves look brown and scalded. Keep garden weeded.
About 1/2″ long, oval, metallic green and brown. Larvae is 1″ long, white with brown head.
Injury: Eat foliage. Larvae eat roots.
Treatment: Handpick or trap beetles. Spray them with rotenone. Treat soil once with milky spore disease to eliminate larvae. Interplant crops to be protected with garlic.
Wedge shaped, 1/2″ long, greenish or brown, active.
Injury: Suck the undersides of leaves and spread the virus disease yellows.
Treatment: Spray with pyrethrum or rotenone. Dust with sulfur. Plant lettuce in sheltered places near hedges or buildings.
Lygus bug or tarnished plant bug
Oval, flat, almost 1/4″ long, brownish, marked with yellow and black. When disturbed, hides behind stems.
Injury: Suck juices causing plants to wither and carries diseases from plant to plant.
Treatment: Hides in trash and weeds, so eliminate these from the garden in fall or spring. Dust with sabadilla or spray with pyrethrum.
Several species, look like 1/4″ long grubs without legs.
Injury: Flies deposit eggs on plants or in soil, maggots hatch and kill young plants by tunneling into seeds, roots, and stems. Cause decay of onion bulbs.
Treatment: Surround young plants with tar paper squares. Dust earth with ashes. Don’t plant onions in rows, scatter them throughout the garden.
Mexican bean beetle
Copperish brown, oval, with 16 spots on back. Larvae are orange to yellow, furry or spiny, up to 1/2″ long. Eggs are orange in clusters on leaves’ undersides.
Injury: Feed on pods and underside of leaves, skeletonizing them.
Treatment: Interplant beans with potatoes or marigolds. Plant early. Remove vines immediately after harvest and eliminate debris and dead plants. Spray under leaves with rotenone or pyrethrum.
Nematode or eelworm
Tiny worms, from 1/125″ long, white or colorless. Not an insect.
Injury: Damage roots and suck juices. Cause knots and swellings.
Treatment: Interplant with marigolds. Change location of garden, rotate crops. Plant resistant varieties, keep weeds down, add humus to the soil.
Not over 1/20″ long, active insects, brownish or yellowish with fringed wings. Jump like fleas.
Injury: Suck juices from plant, causing white splotches and brown tips on leaves, both upper and lower sides.
Treatment: Plants then wilt and bulbs rot. Destroy hibernating insects by plowing under or burning all grass and weeds near onion field in the spring. Plant White Persian, Sweet Spanish, and other resistant varieties. Drench plants with hose. Spray or dust with rotenone, pyrethrum, or nictotine.
Stout, chunky beetle about 1/2″ long, dark brown with black and white marks. Larvae are white with small brown head and about 1/2″ long.
Injury: Adults feed on blossoms of peas and lay eggs on young pods. Larvae burrow into the green seed.
Treatment: Heat seed for 5-6 hours at 120-130°F. Put livestock or poultry in the pea patch after harvesting. Plow deeply and remove any possible shelter. Dust with rotenone. Plant early.
Yellowish-white with brownish head, dark spots on young, up to 3/4″ long.
Injury: Feeds on flowers and leaf buds, often tunnels into flowers, terminal buds, vines and fruit.
Treatment: Handpick worms before they reach fruit, dust with rotenone or sabadilla. Plant earlier trap crops, like squash.
Small, yellowish-white, legless larvae, narrow at front with enlarged posterior.
Injury: Bores into seeds, sprouts, and stems underground, causing bean plants to wither and die.
Treatment: Regulate plant growth by planting in warm weather, not wet. If loss is great, replant. Handpick maggots by lifting plants from ground, removing maggots, and resettling plant.
Spotted cucumber beetle
Yellowish-green with 12 black spots on back, 1/4″ long.
Injury: Eats blossoms of cucurbits and leaves and pods of beans.
Treatment: Plant with radishes. Handpick. Trap under boards. Protect young plants with screen cages. Spray upper and lower sides of leaves with a handful of wood ashes and a handful of hydrated lime dissolved in two gallons of water.
One of the stink bugs. Brownish-black, mottled yellowish underneath. Flat and 1/2″-1/4″ long. Oval brown eggs, laid in clusters.
Injury: Suck juices causing wilt and death of plant. May transmit diseases.
Treatment: Crush eggs. Handpick using gloves. Trap under boards. Dust with mixed wood ashes and hydrated lime or with sabadilla. Dust or spray with tyania. Destroy old vines after harvest. Plant earlier hills of squash for traps. Grow radishes, nasturtiums, and marigolds nearby.
Squash vine borer
White grubs about 1″ long. Brown to black head and small brownish legs on forepart.
Injury: Bore into squash and pumpkin vines, eat holes in stems near base of runner. Can get into the fruits.
Treatment: Looks for piles of yellow sawdust-like-excrement that falls from holes in infested stems. Slit such stems open, remove or stab grubs, heap moist soil over vine to protect it and induce rooting. Plant summer squash trap crops as early as possible between rows of later, main crop. When trap plants are well infested, pull and burn them. Sprinkle black pepper around vines of main plant.
Striped cucumber beetle
Yellowish-green with three black stripes on back and about 1/4″ long. Larvae are white, slender, brownish at ends, and 1/2″ long.
Injury: Adults feed on leaves and spread bacterial wilt. Larvae bore into roots and feed on stems causing plants to wilt and die.
Treatment: Mulch heavily. Interplant with marigolds. Dust with soot or charcoal or spray upper and lower sides of leaves with a mixture of one handful of wood ashes, one handful of hydrated lime, and two gallons of water.
Smooth, green, diagonal lines on sides and prominent horn on the rear. Up to 4″ long.
Injury: Feed on foliage, eat all but skeletons of leaves and damages fruit.
Treatment: Handpick and destroy unless worms are covered with small white bodies (which are parasites that will kill the worms and move on to others).
Soft-bodied worm with brown head, curved, 1/2″ to 1″ long. Often June bug larvae.
Injury: Feed on roots and tubers, causing plants to wilt and die. Reduces yields and quality.
Treatment: Try to avoid planting in newly turned sod. Plow in both fall and spring. Keep garden free of grass and weeds. Kill exposed grubs.
The larvae of the click beetle. Up to 1 1/2″ long, light to dark brown or yellow with dark head and tail. Slender, clumsy, looks like a jointed wire.
Injury: Attack germinating seeds, roots, and tubers. Avoid planting in infested soil. Develop good drainage.
Treatment: Plow sod once a week for 4-6 weeks before planting. Enrich earth with humus and compost. Companion plant vegetables with alfalfa and Mexican marigolds. Treat infested plants with tobacco dust. Bury half a potato 4″ deep, dig up in a week; and destroy worms.
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