Benefits and Limitations of Predators as an Alternatives of Chemical Pesticides 

According to State of Queensland (2017), followings are the benefits and limitations of predators;

a. Benefits

• They often attack different life stages of the pest, and even different pest species and act as alternatives of chemical pesticide for pest control.
• Many predators are also able to supplement their diet by feeding on alternative food sources, such as nectar, pollen and fungi.
• They are often voracious feeders and more robust than parasites.

b. Limitations

• They usually require higher populations of their prey to work effectively and once they have ‘cleaned them up’ may disappear from the scene.
• It is often difficult to show the impact of predators due to the difficulty in isolating their action among a complex of natural control factors in field situations.
• Need to set up an appropriate home for the predator – nesting habitat etc. not too common in corn fields.
• If the predator is too good, it consumes up all the pest and then migrates out- must be alternate prey.
• Need to have handy a good taxonomist who knows how to id the pest and appropriate predator.
• Introduction of foreign predators has lead to problems as they move out into natural systems and outcompete similar native species. They themselves have been known to become pests eventually.

Some Beneficial Predators

According to Washington State University Extension, there are about 25 families of insects that contain predatory species, and virtually all of the more than 100 families of spiders are predatory. Other arachnids like harvestmen (daddy-long-legs) and mites also contain many families which are predatory

1. Lady Bird Beetle:

Mostly lady bird beetle attack on aphids, whiteflies, scales, mites, mealybugs and other soft-bodied insects.

2. Lacewings:

It predates mostly on aphids, spider mites, whiteflies thrips, leafhoppers, scales, mealybugs, psyllids, small caterpillars and insect eggs. Green lacewing larvae feed on insect pests. Both larvae and adult brown lacewings feed on pests. Green lacewings are commercially available.

3. Syrphid (Hover) fly larvae:

It predates on aphids, scales, thrips and other small soft-bodied insects.

4. Praying mantids:

It prey on any insects including aphids, flies, beetles. Feeds on pests as well as beneficials. Mantids grasp their prey with spined front legs and hold them while they eat. moths, crickets, and grasshopper.

5. Minute pirate bug:

Aphids, spider mites, thrips, psyllids, whiteflies and small caterpillars.

6. Aphid midge:

It prey on aphids.

7. Big eyed bug:

It feeds on flea beetles, mites, insect eggs, small caterpillars, other bugs

8. Predatory mites:

It prey on spider mites, thrips, fungus gnat larvae

9. Parasitic wasps:

It is the predator of aphids, caterpillars, whiteflies

10. Ground Beetles:

Prey on cutworms, ants, maggots, earthworms, slugs, and other beetles.

11. Predatory Midges:

Prey on mites and aphids.

12. Robber Flies:

It is the predator flies, wasps, grasshoppers, leafhoppers, beetles, and butterflies.

13. Predatory Thrips:

Prey on mites, aphids, small caterpillars, and other thrips.

14. Spiders:

They consume aphids, flea beetle, red pumpkin beetle, leaf hoppers and many more.

15. Assassin Bug:

It sucks the fluid from its preys like caterpillar and other many insects.

16. Tiger beetle:

 Tiger beetle feed on rice ear head bug (rice gundi bug)