Good Bug? Bad Bug?

Biocontrol of Insects and Weeds

Dr. Meredith Shrader

Entomology Extension Agent Tri-River Area

Meredith.shrader@mesacounty.us 970.244.1834

Biological Controls

• Predators

• Parasitoids

• Pathogens

• Nematodes

Good Bugs

• Lady beetles

• Ground beetles

• Lacewings

• Flower flies

• Robber flies

• Mantids

• Assassin bugs

• Predatory stink bugs

• Minute pirate bugs

• Predatory thrips

• Predatory mites

• All spiders

Bad Bugs

• Aphids

• Caterpillars

• Squash Bugs

• Borers

• Beetles

• Earwigs

• Lygus

• Stinkbugs

• Fruit Flies

KNOWLEDGE IS HALF THE BATTLE!!!

GO JOE!!!!

Characteristics of Insect Predators

• Immature stages actively hunt prey

• Several prey are consumed

• Adults may or may not have similar food needs as

immature form

• Can only eat so many

• May not be able to see immediate

impact

Adults Eat the Same Thing As Young

Adults and Young Eat Different Food

Hover fly

larvae

Adults and Young Eat Different Food

Green lacewing eggs are available from many

suppliers that rear/distribute insects

Predatory Mites

Female two spotted spider mite and its eggs along with adult predatory

mite, Phytoseiulus persimilis. (Photo by Jack Kelly Clark)

Mites Attack

Order Mantodea Mantids

European mantid life stages

European mantid egg cases

Chinese Mantid

Tenodera sinensis

Egg cases of the Chinese mantid are

sold by some nurseries and in some

garden catalogs

Collect egg cases, but

keep outside to avoid

hatching

European mantid mating pair, 2:30 PM, Mon. Sept. 29, 2008.

European mantid male as lunch, 4:00 PM, Mon. Sept. 29, 2008.

Characteristics of Insect

Parasitoids • Larvae develop inside 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

Common Insect Parasitoids

• Parasitic Hymenoptera

– Braconid wasps

– Ichneumonid wasps

– Chalcid wasps

– Eulophid wasp

– Trichogrammatid wasps

• Parasitic Diptera

– Tachinid flies

Photographs courtesy of Brian

Valentine

Host evaluation

Oviposition

Tachinid fly eggs on

caterpillars and squash bugs

Photograph courtesy of David Shetlar

Photograph courtesy of Jim Kalisch

Cabbage looper supporting six developing

tachinid fly larvae

Tachinid fly pupae within killed cabbage

looper larva

Pathogens / Nematodes

• Fungi

• Bacteria

• Viruses

• Nematodes

Pathogens / Nematodes

Advantages

•Specificity

• No toxic residues

• Slower resistance?

• Compatible with pesticides

• Applied with pesticide technology

• Easily modified genetically

Disadvantages • Specificity

• Short shelf life and field persistence

• High population density optimal for spread

• Affected by weather

• Slow acting

• Cadaver residues contaminate produce

• Commercial development difficult

Pathogens / Nematodes

Some Important Fungi and Common Hosts

• Entomophthora muscae* - flies

• Erynia neoaphidis - aphids

• Beauveria bassiana - many insects

• Metarhizium anisopliae – many insects

• Coelomomyces spp. - mosquitoes, bugs

• Hirsutella thompsonii - mites

• Verticillium lecanii - aphids

• Nomurea rileyii - caterpillars

• Paeciliomyces fumosaroseus - bugs

Nematodes

• steinernema and heterorhabditis

• Peach Tree Borer

• White Grubs

• Caterpillars

• 10 Acres (500 mill)- $270.00

Crop(s) Targeted Pest Common Name Efficacious

Nematodes2

Artichokes Artichoke plume moth Sc

Vegetables Armyworm Sc, Sf, Sr

Turf Billbug Hb,Sc

Turf, vegetables Black cutworm Sc

Berries,

ornamentals Black vine weevil

Hb, Hd, Hm, Hmeg, Sc,

Sg

Fruit trees,

ornamentals Borer Hb, Sc, Sf

Home yard, turf Cat flea Sc

Pome fruit Codling moth Sc, Sf

Vegetables Corn earworm Sc, Sf, Sr

Vegetables Corn rootworm Hb, Sc

Cranberries Cranberry girdler Sc

Turf Crane fly Sc

Citrus, ornamentals Diaprepes root weevil Hb, Sr

Mushrooms Fungus gnat Sf, Hb

Grapes Grape root borer Hz, Hb

Vegetables,

ornamentals Leafminer Sc, Sf

Fruit trees Plum curculio Sr

Turf, ornamentals Scarab grub3 Hb, Sc, Sg, Ss, Hz

Ornamentals Shore fly Sc, Sf

Conserving and Enhancing Natural Enemies

• Don’t kill them – Limit use of broad spectrum insecticides

• Provide foods that the adults need – Often need nectar, pollen

– Good Bug Power Blend is a combination of yellow, red, crimson, rose, and

white clovers, grizzly alfalfa, white alyssum, nasturtium, white yarrow, carrot,

dill, daikon radish, and celery seeds.

• Provide foods that the immature stages need – Allow there to be some hosts, prey available

Some Plants Useful for Providing

Food for Adult Predators

• Umbelliferae/Apiaceae - (dill, fennel, etc.)

• Yarrow

• Many sedums

• Spurges*

• Alyssum

• Basket-of-gold

• Thyme, several herbs

What to Release??

• Inundate

– Acts like a spray

– No long term beneficial populations

– Fast results in pest population decline

• Inoculate

– Small amount released

– Biocontrol population increases, feeds

slowly on pest

– Residual population to control pest

What to Release and When

• Lots of biocontrol agents can be purchased online

• May be expensive

• Biocontrol may be specialized; egg vs larvae

• Release before pest population reaches damaging levels

Plan Ahead!!

USPS Tracking page should not

be a bookmark

• May take time to arrive or hatch

• Feed 1-3 weeks before pupation

• Adults may not eat target pest

• Initial release followed by additional releases 3-4 weeks later

Can’t make them stay where you released them

Two-Year-Old Effect

Your house!! Neighbors house!!

Plant Refugia Within Fields

Insects Don’t Move Far

*Research on beneficial insect movement

Movement??

-Planning

-Planting

-Flowering when

pest present

Can do in orchards,

gardens and large

acreage commercial

row crops

Cons to Refugia Planting

• Attracts ALL bugs, not just good ones

• Plants may move outside of planting area

• Water requirements increase

• Some seed maybe costly

• Variety of seeds needed to keep adult beneficial insects around- prolonged

flowering period

Weed Control – Palisade Insectary

Palisade Insectary

• Call to purchase

• Only for Colorado residents

• Can be in high demand

• Can be expensive

• Proper release for beneficial organisms

• May not give 100% control; puncturevine weevil

• May take several years; Tamarisk beetle

Alternatives To Conventional Herbicide • Burning

• Vinegar (20%)

• Hoeing

• Discing

• Mowing

• Manual hand removal

• Plant competition – Cover crop

Thank you