Natural and Biological Controls of Shade Tree Insect Pests Whitney Cranshaw Colorado State University
Natural Controls Natural Enemies Abiotic (Weather) Controls Topographic Limitations
Temperature Extremes Heavy Rainfall Abiotic (Weather-related) Controls of Insects
N Natural Enemies Predators Parasitoids Pathogens
Characteristics of Insect Predators Immature stages actively hunt prey Several prey are consumed in the course of development Adults may or may not have similar food needs as immature form
Some Common Arthropod Predators Lady beetles Ground beetles Clerid beetles Lacewings Flower flies Robber flies Mantids Assassin bugs Predatory stink bugs Minute pirate bugs Predatory thrips Predatory mites All spiders
Most lady beetle adults are brightly colored
Photograph courtesy Jim Kalisch
The bad apple of the lady beetle clan
Adult Eggs Mexican bean beetle - a plant feeding lady beetle Larva Pupa
Adults Eggs Lady Beetle Life Stages Larva Pupae
Twospotted lady beetle with newly laid egg mass
Lady beetles with egg masses
Lady beetles lay masses of eggs near sources of food for their young
Lady beetle larvae at egg hatch
Lady beetle larvae Predators of small softbodied arthropods (aphids etc )
Some odd looking lady beetle larvae Woolly looking larvae that feed on scale insects Spider mite specialists are tiny
Lady beetle prepupae
Lady beetle pupae
Multicolored Asian lady beetle Convergent lady beetles
Adult lady beetles emerging from the pupa
Purchasing lady beetles?
Convergent lady beetle the lady beetle of commerce
Purchasing lady beetles?
Lady beetle releases are fun
Clerid Beetles Coleoptera: Cleridae
Clerid Beetles Adults feed on insects present on the bark Larvae feed on insects under the bark
Green Lacewings Neuroptera: Chrysopidae
Adult green lacewings sustain themselves on nectar and pollen
Green lacewing eggs are uniquely stalked
Green lacewing eggs often are laid in groups. Egg hatch has occurred in the lower picture.
Photographs courtesy of Brian Valentine
Right: Green lacewing larva eating leaf beetle larva Left: Green lacewing larva eating aphid
Green lacewing pupae, within cocoons
Green lacewing eggs are available from many suppliers that rear/distribute insects
Brown Lacewings Neuroptera: Hemerobiidae
Brown lacewing adults
Brown lacewing larvae
Flower (Syrphid) Flies
Syrphid flies are excellent mimics of bees and wasps Honey Bees Flower (Syrphid) Flies
Syrphid fly eggs are typically laid in an aphid colony
Photograph courtesy Brian Valentine
Flower fly larvae
Syrphid smear
Predatory Hemiptera Predatory stink bugs Assassin bugs Damsel bugs Minute pirate bugs Geocoris spp. seed bugs Daereocoris spp. plant bugs
Minute pirate bugs Hemiptera: Anthocoridae
Feeding on a thrips Feeding on a small caterpillar Nymph feeding on an aphid Adult feeding on spider mite eggs
Assassin Bugs Hemiptera: Reduviidae
An Assassin Bug - Zelus luridus Egg mass and nymph Adult Nymph feeding on wasp
Photograph by Jim Kalisch, University of Nebraska Wheel Bug (Arilus cristatus) Largest regional assassin bug
Ambush Bugs Phymata spp.
Clockwise from upper right: Ambush bug feeding on a sweat bee, fritillary butterfly, and honey bee.
Predatory Stink Bugs Hemiptera: Pentatomidae
Stink bugs with prey
Spiders Order Araneae
Some spiders use webbing to snare prey
Some spiders hunt prey without the aid of silk
Characteristics of Insect Parasitoids Larvae develop in, rarely on, their hosts One or more larvae develop in a single host They are invariably lethal to the host parasitoids Adults often have different food needs Nectar, honeydew Pollen Insect blood feeding may occur
Common Insect Parasitoids Parasitic Hymenoptera Braconid wasps Ichneumonid wasps Chalcid wasps Eulophid wasp Trichogrammatid wasps Parasitic Diptera Tachinid flies
Parasitic Wasps Ichneumonidae, Braconidae, Eulophidae, Trichogrammatidae, Encrytidae, Chalcidae and other families
Parasitic wasps sustain themselves on nectar and pollen
Some parasitic wasps Females possess an ovipositor ( stinger )
Photograph courtesy Brian Valentine
Parasitic Wasps Male (left) and Female (right)
Ectoparasitic wasp larvae on fall webworm caterpillar host
Parasitoid larvae emerging from caterpillar host
Parasitoid larvae (Cotesia glomeratus) emerging from cabbageworm host and spinning pupal cocoons
Cocoons of cabbageworm parasitoid
Some parasitoids pupate on the insect host. Left: Buck moth caterpillar Below: Tobacco hornworm
Giant Ichneumon Wasp, Parasitoid of the Pigeon Tremex Horntail
Pigeon Tremex and Giant Ichneumon Wasp Fact Sheet 5.604
Pigeon tremex a wood boring wasp of deciduous trees in decline
Giant ichneumon wasp the most spectacular natural enemy of the pigeon tremex
Ovipositor Sheaths
Egg parasitoids
Trichogramma wasps, a type of egg parasitoid
What s wrong with this picture?
Aphid parasitoids
Host evaluation Oviposition Photographs courtesy of Brian Valentine
Aphid Mummies Aphid showing early symptoms of parasitism
Parasitized psyllids (above) and European soft scale (below) Parasitized aphids (above) and oystershell scale (below)
Tachinid Flies
Tachinid fly eggs on tent caterpillar (above), squash bug nymphs (upper right), Japanese beetle