Biological Insect Controls: Predator Insects, Parasites and Pathogens.
Biological controls is defined as the restraining influence of parasites, predator insects, and pathogens on populations of insect pests.
The tremendous benefits of natural or biological control of harmful insects is not difficult to understand. Theoretically one pair of aphids in the spring, become the progenitors of several billion progeny which would completely cover the earth if all lived. To wit comes this poem:
Great bugs have little bugs on their back to bite' em,
And little bugs have lesser bugs and so on infinitum,
And the great bugs themselves in turn have greater bugs to go;
While these again have greater still and greater still, and so on.
Predatory insects, mites, and mollusks are the meat eaters of the garden. They are generally larger than their prey and equipped with sturdy mouth parts adapted to the feeding habits. Some are built to tear and chew the prey into manageable swallows; others have piercing mouth parts through which they suck the life out of victims.
Parasitic insects reproduce at the expense of other insects by planting their eggs in or on any stage of the host, from egg to adult. Victims typically are insects that have a complex (four-stage) metamorphosis. While some parasites use a number of species as hosts, many are host-specific, and this characteristic explains why they are generally considered more effective than predators in controlling a given pest problem.
Microbial controls are an attractive alternative to chemical pesticides. These insect pathogens include -- bacteria, viruses, fungi, and nematodes. Microbial controls are host-specific, which means they don't harm non-targeted organisms which happen to come into contact with the spray, dust, or bait. Concentration of spores of insect-infesting bacteria are available as dusts, wettable powders, and stabilized suspensions.
Readily available controls:
|
Name |
Type |
Control for: |
|
Green Lacewings |
predator |
Aphids, Mealybugs, Whiteflies, immature scales & the eggs of Mites, Thrips, Spider mites. |
|
Ladybugs |
predator |
Aphids, Colorado potato bettles. |
|
Chilocorus nigritus |
predator |
Scale insects, Red scale |
|
Cryptolaemus |
predator |
Mealybugs |
|
Spined Soldier Bugs |
predator |
Mexican bean beetle, brocolli worm, cabbage looper, cabbageworm |
|
Pedio wasps |
predator |
Mexican Bean Beetle |
|
Praying Mantis |
predator |
Most any insect. |
|
Mite Predators Phytoseuilus persimilis (greenhouse use) Amblyseius californicus (in home use) Phytoseiulus longpipes (hot houses) |
predator |
Common red two-spotted spider mite |
|
Encarsia Formosa |
parasite |
Whiteflies |
|
Trioxys pallidus |
parasite |
Walnut aphid |
|
Parasitic Nematodes |
parasite |
The larval and grub stages of: Whitegrub, Japanese Beetle, Northern Masked & European Chafer, Oriental Beetle, June Beetle, Billbug, Cutworms, Armyworms, BlackVine Weevils, Strawberry Root Weevils, Fungus Gnats, Mole Crickets, & Carrot Weevils, fly maggots, black vine weevils. |
|
Trichogramma wasps |
parasite |
Cabbageworm, tomato hornworm, Corn earworm, codling moth, Cutworm, Armyworm, Webworm, Cabbage looper, Corn borer, moth & butterfly eggs |
|
Avermectin |
pathogen |
Fire ants |
|
Clandoscan |
pathogen |
Rootknot nematodes |
|
Nosema locustae |
pathogen |
Grasshoppers |
|
Gall-trol |
pathogen |
Combats crown gall disease |
|
Bacillus poilliae (Milky spore) |
pathogen |
Grubs of the Japanese beetles, Rose chafer, Oriental beetle, May & June beetles |
|
Bacillus thuringiensis (BT) BT/san diego BT/israelensis BT/kurstake bait BT/berliner-kurstake |
pathogen |
Colorado potato beetles Mosquito larvae, black fly European corn borers Cabbage looper, cabbageworm, diamondback moth, tomato horn-worm, tomato fruitworm, grape leaf roller, & gypsy moth |
|
Entomorphthora exitialis |
fungi |
Spotted alfalfa aphid |
|
Beauveria bassiana |
fungi |
Colorado potato beetle, European corn borer |
|
Hirsutella thompsonii |
fungi |
Citrus rust mites |
|
Spicaria rileyi |
fungi |
Corn earworm, tomato fruitworm, cotton bollworm |
