You work hard to keep your garden looking its best and producing as much as it can. A lush garden naturally attracts other creatures interested in the bounty. You can live in harmony with most of them if you just take a few basic steps.
'''Integrated pest management''', or IPM, refers to a four-step program for managing pests. This approach is not as aggressive as the typical, "Kill all the critters," kind of plan. It does not use pesticides unless they are deemed absolutely necessary. (Since weed and fungus controls are dealt with in separate buying guides, this guide mainly deals with insect and other invertebrate animal pests.)
* '''Action Thresholds''' -- the set point at which pest control action must be taken. Generally, this is the point when pests become an economic threat.
* '''Monitor and Identify''' -- organisms are identified so that proper action can be taken. Not all pests require pesticide. This step determines the necessity and type of treatment.
* '''Prevention''' -- steps taken to manage crops and lawns so that the likelihood of infestation is decreased.
* '''Control''' -- when action is necessary, the first step is using pest controls with the least harmful chemicals. Solutions are altered and chosen based on efficacy.
For more information on this process, read this guide from the U.S. Environmental Protection Agency.
One way to limit insect damage is to have a diversity of plants, especially in vegetable gardens. When you plant crops in monoculture, you risk enormous "boom" periods for the insect community. If you plant a wide variety of species instead, and intermix them with each other, the risks of massive insect damage are reduced. You can also consider adding a few vertebrate predators to your garden: chickens! Chickens will eat many insects while patrolling your veggie patch; just don't leave them in there for too long, because their droppings contain a lot of nitrogen and can hurt your plants in large doses. (Also, free eggs!)
Use of insecticides should be strictly limited, especially near the home. Insecticides are very dangerous and will usually kill beneficial insects along with the target -- this "collateral damage" can come back to haunt you, since a lack of natural predators will allow even larger populations of pests to return to your area.
Every insect has a role to play in the ecosystem, but as far as your garden is concerned there are "good" insects and "bad" insects. The "bad" insects are the ones that damage your plants, while the "good" ones are the superheroes that defend and help your plants. Insects, along with your vigilance, are your first and best line of defense against other insects. Keep them around by restricting your pesticide use; you wouldn't spray Metropolis with kryptonite and then ask Superman to save the day, would you?
Fortunately, you can purchase some insect patrollers from a number of gardening sources. Not all are available, however, so for some species you'll just have to hope that you have a strong local population.
** '''Ladybugs''' are one of the best known insect predators.
*** Both adults and larvae feed on aphids, thrips, tree lice and various other larvae.
** '''Lacewings''' are beautiful, pale-green insects that eat many pests.
*** Eat acids, thrips, lice.
** '''Soldier beetles'''
*** Adults eat nectar and pollen, but the larvae are predatory on caterpillars and several destructive beetles.
*** Adults eat nectar and pollen, but larvae eat other flies, small caterpillars and mites.
*** Larvae eat mosquito larvae, and adults eat mosquitos.
** '''Praying mantis'''
*** Mantids are ambush predators that will eat just about anything -- including each other.
** '''Ground beetles'''
*** Eat ground-dwelling pests like cutworms, maggots of many other beetles, snails and slugs.
** '''Assassin bugs'''
*** Large bugs that can also bite people.
*** Eat just about anything, including mosquitos, flies, caterpillars, and beetles.
* '''Parasites''' -- these critters lay their eggs on live insects. The hatched parasite slowly devours its host.
** '''Tachinid flies''' -- eat moths, bean beetles, potato beetles, grasshoppers, caterpillars and cutworms.
** '''Trichogramma wasps''' -- worms, borers, webworms, leafworms, cutworms.
** '''Chalcid wasps''' -- aphids, whitefly, scale insects.
** Bees and butterflies spread pollen from plant to plant, an important part of the life cycle of many plants.
** Some butterfly larvae may eat your plants but bees are only beneficial to your garden.
Organic Pest Control
Fortunately, there are many effective ways to control insect pests that have a minimal impact on the ecosystem.
* '''Beneficial Insects'''
** As discussed above, many are for sale as adults, eggs, larvae or a combination.
** Follow the instructions for rearing and releasing your insects for best results.
** There are many nematode species which prey upon insect pest larvae. You can order a preparation of nematodes in a liquid that can be sprayed on your lawn or garden.
** The nematodes will attack the larvae of many beetles and some nematodes will go after slugs. They are species-specific and will only reduce the population of the pest species.
** In addition, many will remain in the soil for years, possibly even decades.
* '''''Bacillus thuringiensis ''''''''(Bt)'''
** Bt is a species of bacteria that kills insects in the larval stage.
** They have to eat it, so you need to spray it directly on your plants.
** Host-specific -- once you know what kind of pest you have, you can choose the strain of Bt that suits your needs.
* '''Milky Spore'''
** Milky spore is a species of bacteria that attacks Japanese beetle larvae (which have no natural predators in this country).
** Can persist in the soil for years.
* '''Botanical Extracts'''
** Plant and seed extracts that are sprayed on plant.
** Repel or kill insect invaders.
*** Extracted from the tropical neem tree -- insecticide, miticide, fungicide.
*** Extracted from chyrsanthemums -- insecticide.
*** Don't confuse this will pyrethoids, which are more potent, synthetic versions used only by commercial farms.
* '''Horticultural Oil'''
** Petroleum-based oils that kill both fungi and insects.
** Can irritate human skin.
* '''Diatomaceous Earth'''
** Exoskeletons of dead marine creatures called diatoms, which are like algae with a hard silica shell.
** Harmless to most creatures, but extremely dangerous to soft-bodied animals like slugs.
** The sharp edges of the diatoms rip the underside of the animal and kill it.
** Just be careful not to breathe this in while applying it.
* '''Insecticidal Soap'''
** Different from your ordinary soap -- don't use skin soap on your plants!
** A mixture of soap, oil and water that kills soft-bodied insects.
* '''Kaolin Spray'''
** Kaolin clogs up the ends of the insect so they can't eat or lay eggs.
** Needs to be reapplied after heavy rain.
Should You Use Insecticides?
* '''Prevention is the most important step. '''
** Make sure your plants are healthy, well-watered, and well-fed. Healthy plants are less susceptible to infestation.
** Remove any pests you see with a hose or by hand.
** Eliminate standing water, a favorite breeding ground for mosquitos.
** Attract beneficial insects with flowers that they like.
** Use physical barriers such as netting.
** Start with mechanical and biological controls.
** Try releasing beneficial insects or spraying nematodes.
** Attract other predators, such as birds and toads, by providing appropriate shelter and water.
** If you have an insect problem, there are many organic farming solutions that are widely available and used by many gardeners.
* '''When all other methods have failed, some controlled use of insecticides may be appropriate. '''
** Remember, most insecticides are also extremely dangerous to humans and other mammals.Many are also used as nerve gas. Use them very carefully, take appropriate precautions, and protect yourself, your family and your pets.