Recognizing and Working with Beneficial Insects How planting selections and pest management practices can impact populations of desirable insects
Whitney Cranshaw Colorado State University Plants can support populations of Plants may be contribute to incidence desirable insect species of pests that limit plant value Garden plantings can affect incidence of….
• Butterflies • Natural enemies • Hummingbird moths of insect pests • “Miller” moths • Nuisance invaders of • Honey bees buildings • “Double or Nothing” • Bumble bees species ……………. • Various solitary bees Insect Needs • Food for their young • Food for the adults • Shelter (some species) Insect Needs
Food for the young Larval Food Example: Painted Lady
Larval host plants are thistles, hollyhock, mallow, occasionally legumes and some other plants Insect Needs
Food for the adults Adult Food Example: Many predators of garden pests (biological controls) Insect Needs (for some species) Shelter Shelter Example: Nest cavities for leafcutter and mason bees Landscaping for Biological Control Agents Principles of Gardening for Natural Enemy/Bio-Control Insects • Learn to recognize them – and don’t kill them • Provide for food needs of adults • Provide for food needs of immature stages • Provide nest sites, if required Principles of Gardening for Natural Enemies of Insect Pests • Learn to recognize them – and don’t kill them • Provide for food needs of adults • Provide for food needs of immature stages • Provide nest sites, if required
Most lady beetle adults are brightly colored Pinkspotted lady beetle Coleomegilla maculata
A species that feeds mostly on eggs and larvae of beetles LeConte’s giant lady beetle Anatis lecontei
A species that feeds on aphids and mealybugs on trees Upper left: Coccidophilus, a scale predator Lower left: Olla sp., a grey colored lady beetle of forests Below: Chilochorus sp., a predator of various scales Adults
Eggs
Lady Beetle Life Stages
Pupae Lady beetle egg masses Lady beetles lay masses of eggs near sources of food for their young Lady beetle larvae Some odd looking lady beetle larvae
”Woolly” looking larvae that feed on scale insects
Spider mite specialists are tiny Principles of Gardening for Natural Enemies of Insect Pests • Learn to recognize them – and don’t kill them • Provide for food needs of adults • Provide for food needs of immature stages • Provide nest sites, if required Lady beetles (“Lady bugs”, “Lady birds”….) Lady beetle adults feed on nectar and pollen Green Lacewings Neuroptera: Chrysopidae Photograph courtesy of Brian Valentine Immature stages of green lacewings – ‘aphid lions’ feed on a wide variety of insects Most adult green lacewings maintain themselves on nectar and pollen Flower (Syrphid) Flies Flower fly larvae feed on aphids
Brian Valentine
Brian Valentine Ken Gray Insect Mimicry in Action! Syrphid flies are excellent mimics of bees and wasps Honey Bees
Flower (Syrphid) Flies
Flower/Syrphid Fly
Honey Bee Adult flower flies sustain themselves on nectar and pollen Adults of many predators use flowers (nectar, pollen) for sustenance Parasitoid wasps maintain themselves on nectar and pollen Tachinid fly adults sustain themselves on nectar and pollen
Larvae develop within and kill other insects Natural Enemies of Japanese Beetle for Potential Introduction into Colorado?
Istocheta aldrichi – tachinid fly parasitoid of Japanese beetle adults Istocheta aldrichii requires accessible nectar/pollen resources when the adults are active – late June-July Small, accessible flowers are most commonly used by natural enemies of garden pest insects Some plants useful for providing food for adult stages of insect natural enemies • Most Apiaceae - (dill, fennel, coriander, Ammi, Queen Anne’s lace, etc.) • Yarrow (some) • Many sedums • Spurges • Sweet alyssum • Basket-of-gold • Thyme, several herbs Two personal favorites for good natural enemy insect action Ammi (white cultivars)
Mooncarrot Principles of Gardening for Insect Natural Enemies • Learn to recognize them – and don’t kill them • Provide for food needs of adults • Provide for food needs of immature stages • Provide nest sites, if required Spirea aphids on my bridal wreath spirea shrub – A pest?? Bridal wreath spirea Rubber rabbitbrush
Perennial plants that consistently provide predator food sources in my garden Hunting Wasps Families Sphecidae, Crabronidae, Pompilidae Hunting Wasp Habits
• Mother (usually) prepares some nest cell for rearing young • Mother hunts specific prey, paralyzes it and returns it to the nest cell • Larvae of the hunting wasp consume the paralyze prey provided by the mother Ammophila wasp digging nest (left), carrying caterpillar prey (lower left), at nest entrance with prey (below) Bembix wasp digging while holding horse fly prey
Howard Ensign Evans Bicyrtes quadrifasciatus – a hunting wasp that nests in sandy soils
Stink bugs and leaffooted bugs are prey for this insect Top: Chlorochroa spp. stink bugs (nymphs) Middle: Rough stink bugs (nymphs) Bottom: Western conifer- seed bugs (nymphs)
Insect prey collected from nests of sand wasps at a Longmont playground Golden Digger Wasp – Predator of longhorned grasshoppers/katydids Pemphredon wasps nest in plant stems and hunt small insects Pemphredon wasps nest in plant stems and hunt small insects
Condominium Project for Pith Nesting Pempredon Wasps An excellent publication by the Xerces Society on improving habitat for natural enemies of insect pests Landscaping and Pollinators Bees Flies
Primary Groups of Flower Visitors and Pollinators
Butterflies and Moths Beetles Bees (946 CO species) • Rear young on nectar an pollen – Often seen carrying pollen on their body • Have a hairy body • Some produce wax • Capable of stinging – Social bees have painful sting – Solitary bees have mild sting Gardeners can help various species of bees by expanded use of high value flowering plants Honey Bee Apis mellifera Honey bees – and most bees – collect nectar as their primary energy source. Honey bees – and most bees – use pollen as their primary source for proteins, fats and most other nutrients
Pollen carried in pollen sac on hind legs Principles of Gardening for Bees
• Provision of high quality sources of nectar • Provision of high quality sources of pollen • Provision of nesting sites Principles of Gardening for Bees
• Provision of high quality sources of nectar • Provision of high quality sources of pollen • Provision of nesting sites Top Ornamental Plants Visited by Honey Bees in CO include: • Blue mist spirea • Aster novae-angliae • Cleome (bee plant) • Sedum spectabile • Agastache • Cotoneaster foeniculum • Allium tangitucum • Penstemon eatonii • Ocimum (basil) • Nepeta • Salvia • Linden Salvia nemorosum
Catmint
My top three ornamental plants for providing consistent sources of nectar and/or pollen New England Aster Principles of Gardening for Bees • Provision of high quality sources of nectar –Sources need to be available throughout the growing season! • Provision of high quality sources of pollen –Sources need to be available throughout the growing season! • Provision of nesting sites Perennial or winter annual brassicas Some important pollinator resource plants early in the season
Dandelion
Early flowering Prunus spp. Some early season, predominantly trees and shrubs can be very important early season pollen sources for honey bees
Salix spp. (willow)
Alnus spp. (alder)
Acer spp. (maple, boxelder) Several very early flowering bulbs in Iridaceae, Amaryllidaceae and Liliaceae were important early season pollen sources. Maples are an exceptionally important early season source of pollen Rubber Rabbitbrush Thymus coccineum Some plants heavily visited plants by honey bees late in the season
Blue Mist Spirea Monarda Lawns can be an important nectar/pollen resource site for many beneficial insects!
>50 total species collected Some discretion can be important when siting plants highly favored by honey bees To the left: Sedum spectabile
To the right: Caryopteris x candonensis
Bumble Bees Bombus species
FROM: Bumble Bee Life History
Providing nesting sites for bumble bees? Various plans exist to construct bumble bee nests Providing nesting sites for bumble bees? Bumble bee colonies are sold for the pollination of certain crops Some plants (e.g. the tomato) are dependent on buzz pollination Plants heavily visited by bumble bees include: • Echinacea • Echinops • Most Penstemons • Russian sage • Agastache • Hypericum rupestris frondosum • Campanula • Cleome • Caragana • Foxgloves Cultivar differences can be great, depending on features such as flower color
Highly favored by bumble bees – and painted lady butterflies
“Kudos Silver Blue” Cultivar differences can be great, depending on features such as flower color
Favored but less visited – Rosie Posie
Very little visitation – Kudo’s Gold
Little visited – Kudo’s Ambrosia The greatest number of kinds of bees are solitary bees Solitary Bee Life Stages Most solitary bees are ground nesters Some ground nesting bees nest in open sites of bare ground
Some ground nesting bees nest in a patch of soil near the base of a plant. Digger Bees Favorable digger bee nesting site Digger bee nesting site near Purgatoire River (Otero County)
Alkali bee nesting sites Andrenidae – Mining Bees Andrenid bee nest site Sweat Bees Halictid bee nest sites in backyard patio area Some ground nesting bees nest in open sites of bare ground
Some ground nesting bees nest in a patch of soil near the base of a plant. Very few – if any – will nest in a site that has a thick mulch layer Very few ground nesting solitary bees will be able to establish nests at sites with heavy mulch Quality pollinator habitat?
Butterfly houses
Soil well covered by mulch Other bees use aboveground cavities for nest sites Family Megachilidae Leafcutter, mason, carder bees Leafcutter bee working sweet pea flower. Note how the anthers become exposed as the bee pushes the flower while nectaring
Leafcutter bee collecting pollen All members of the family Megachilidae (leafcutter, mason, carder bees) carry pollen on the underside of the abdomen Leafcutter Bees Nest cells in pith of rose cane Pith Nesting by Leafcutter Bees
Photograph courtesy of David Shetlar, Ohio State University
Nest cells with pollen in stem of weed Leafcutter bee nest sites
Soft, rotting wood is often excavated for nest sites Leafcutter bee excavation in rotten garden timber Leafcutter bees cut fragments from the edges of leaves that are suitable for nest building Rose, lilac and Virginia creeper are among the plants most favored by leafcutter bees for nest materials Leafcutter bee carrying leaf fragment Leafcutter bee returning with leaf fragment Cut leaves are used for nest construction
All leaf fragments are oriented with the smooth side inwards For nest construction:
3-4 rectangular pieces, crimped for the base Oval pieces along the sides of the cell Leafcutter bees collect pollen and nectar, carry it to the nest site, and use it to fill a leaf-lined nest cell. For nest construction:
3-4 rectangular pieces, crimped for the base Oval pieces along the sides of the cell Nearly perfect circles used to cap the cell
Nesting sites for leafcutter bees Mason Bees (Osmia species) Predrilled wood for nesting by mason bees Nest cells produced by mason bees in hollowed plant stems
Nesting habitat may be limiting activity of many native bees (leafcutter bees, mason bees, carder bees, carpenter bees) A variety of hole sizes can be used to attract a variety of species
Too much of a good thing? Excellent publication on the subject of North American bees! An outstanding – and free – public- cation from Utah State University Excellent publication on how to improve habitat for native pollinators Key Question: How can insecticides be used in ways that conserve beneficial insects?
How can they be used selectively? Selectivity of Insecticides Can Derive from…..
• Differences in inherent toxicity of the insecticide to different insects – Selectivity of the effects of the insecticide • Persistence of the insecticide • Formulation of the pesticide • Time when the insecticide is applied • Where the insecticide is applied Systemic insecticides as a way to minimize exposure to beneficial insects? Whole tree sprays can result in whole tree exposure to beneficial insects present on the plant
Photograph courtesy fo David Cappaert Applying systemic insecticides to the soil of trees
Soil drench
Photograph courtesy of David Cappaert Soil injection Basal trunk spray with dinotefuran (Safari, Zylam) Whole tree sprays produce surface residues on all foliage. Natural enemies are killed. Natural controls are wasted.
Treatment area limited to bark of lower trunk. Impacts on natural enemies are minimized Systemic insecticides that are applied to a limited area can reduce exposure/risk from insecticides – but they are not perfect
Insecticides may move in significant amounts into nectar and/or pollen, exposing flower using species
Some predators of insects may take a drink from the plant and be exposed to the insecticide Pesticide that is Selective in the Time it is Applied
Applications made during the dormant season Astro (permethrin) label
Do not apply the insecticide to blooming crops or weeds while bees are actively visiting the treatment area Conserve (spinosad) label Toxic for 3 hours. Do not apply to plants that may be foraged by bees during this time period The Pollinator Box – Present on Some Insecticides of Highest Risk to Pollinators You see the pollinator box on some insecticides that are systemic in plants and can have effects that do not appear immediately upon exposure
Do not apply while bees are foraging. Do not apply to plants that are flowering. Insecticides and Pollinators: Bottom Line Always avoid applications to plants that bees are visiting – It is the law! Systemic Insecticides and Pollinators: Bottom Line? Avoid applications to plants that bees visit that are in bloom – or soon will be in bloom A key risk to pollinators when using insecticides on turfgrass
Application to flowering weeds Mowing before application >greatly< decreases hazard to pollinators! Pesticide that is Selective because of its Persistence of Activity
Pyrethrins
Insecticidal Soap Pesticide that is Selective because of the Formulation of the Pesticide Baits
vs.
Sprays
Dusts Pesticide that is Selective because it is Inherent Toxicity of the Pesticide
LD50: Lethal dose that will kill 50% of the test population Pyrethroids are highly toxic to bees
Treated flowers may kill flower visitors for a couple of days after application Acute Toxicity of Neonicotinoids to Adult Honey Bees (Oral LD50 – micrograms/bee)
• Acetamiprid 14.53 • Imidacloprid 0.005 • Dinotefuran 0.056 • Thiamethoxam 0.005 • Chlothianidin 0.0003 My favorite/”go to” publication on this subject Pollinator protection directions appear in label language.
Those that have highest hazard will have the “bee box” with strict use instructions to protect pollinators. Issue of unusual concern with Japanese beetle
Overlap of adult feeding on flowers – and use of those flowers by pollinators Acelepryn (chlorantraniliprole) – a diamide class insecticide
Two insecticides with particularly low hazard to bees, and no pollinator protection language on labels as a result beetleGONE! (Bacillus thuringiensis var. galleriae) – a microbial insecticide Environmental hazards statements Labeled for use on turfgrass and landscape ornamentals do include warnings for aquatic organisms.
They do not have any pollinator warning statements Non-selective pesticides can destroy natural enemies of insect/mite pests Pest Resurgence following application of pesticide
Pesticide knocks down pest, but also whacks the natural enemies. The pest population rebounds. Two plant pests with common track records of resurgence from inappropriate insecticide use
Scale insects Spider mites Secondary pests – Trading one kind of pest for another when certain pesticides are used Use of mountain pine beetle insecticides over time….
…may lead to outbreaks of pine needle scale. Pyriproxifen Mimics juvenile hormone. Target pests: Scale insects, whiteflies, aphids (suppression)
Special Colorado Niche: A selective insecticide for use on scale insects
Excellent against neonicotinoid-resistant European elm scale Use of many pesticides can aggravate (‘flare’) problems with spider mites Minute pirate bug Most insecticides will kill predators of spider mites. If they are ineffective against spider mites, then populations often increase.
Predatory mites Predatory thrips Use of many pesticides can aggravate (‘flare’) problems with spider mites
Pesticides that only act on spider mites –Floramite (bifenazate) –TetraSan (extoxazole) –Hexygon (hexythiazox) Recognizing and Working with Beneficial Insects How planting selections and pest management practices can impact populations of desirable insects
Questions?? This presentation will be posted at the Colorado Insect Information web site
• Housed at Department of Bioagricultural Sciences and Pest Management –Search “BSPM CSU” • Click on “Entomology” • “Insect Information” –Extension presentations are posted at bottom of page as pdf files Top of the Insect Information Website
Bottom of the Website page
Pesticide that is Selective because it is Inherent Toxicity of the Pesticide
LD50: Lethal dose that will kill 50% of the test population Acute Toxicity of Neonicotinoids to Adult Honey Bees (Oral LD50 – micrograms/bee)
• Acetamiprid 14.53 • Imidacloprid 0.005 • Dinotefuran 0.056 • Thiamethoxam 0.005 • Chlothianidin 0.0003 Spider Mite Control Products • Least disruptive of natural enemies –Floramite (bifenazate) –TetraSan (extoxazole) –Hexygon (hexythiazox) Pesticide that is Selective in the Mode of Entry
Bacillus thuringiensis example Selectivity of Insecticides Can Derive from….. • Differences in inherent toxicity of the insecticide to different insects • Persistence of the insecticide • Time when the insecticide is applied • Where the insecticide is applied • Formulation of the pesticide Chlorantraniliprole for White Grubs
• Trade Names: Acelepryn, GrubEx • Anthranilic diamide insecticide – Limited systemic activity –Very low hazard to bees • Relatively slow acting • Provides control for months
Optimal time for application: Early period of egg hatch – typically mid-late June through midJuly Chlorantraniliprole is an insecticide in the anthranilic diamide class Ryania speciosa
Botanical source that lead to development of the anthranilic diamides
Powdered stems are the source of the insecticide ryania.
Active ingredient: ryanodine Anthranilic Diamides
• Based on chemistry of active compounds in ryania (ryanodines) – Effects ryanodine receptors associated with insect muscle • Some systemic activity in plants • Extremely low toxicity to mammals (Category IV) • Recently registered products: – chlorantraniliprole (Acelepryn) – cyantraniliprole (Ference – turfgrass label only) Anthranilic Diamides
• Based on chemistry of active compounds in ryania (ryanodines) – Effects ryanodine receptors associated with insect muscle • Some systemic activity in plants • Very low toxicity to mammals (Category IV) • Recently registered products: – chlorantraniliprole (Acelepryn) – cyantraniliprole (Ference – turfgrass label only) Chlorantraniliprole for White Grubs
• Trade Names: Acelepryn, GrubEx • Anthranilic diamide insecticide – Limited systemic activity –Very low hazard to bees • Relatively slow acting • Provides control for months Optimal time for application: Early period of egg hatch – typically mid-late June through midJuly Overlap of adult feeding on flowers – and use of those flowers by pollinators
Never apply persistent insecticides to plants that are in flower and attractive to pollinators!! Chemical Controls Most Effective for Control of Japanese Beetle Adults • Most pyrethroids (e.g., cyfluthrin, permethrin, bifenthrin) • Carbaryl • Imidacloprid • Acetamiprid – Ortho Rose and Flower Killer • Chlorantraniliprole – Acelepryn Pollinator hazard warning statement regarding use of Tristar 8.5 SL (acetamiprid)
This type of warning statement allows use of this product on a plant in flower only during times of day when pollinators are not visiting the plant Classification of Insecticides Broad Spectrum or Selective Activity? Pesticides can be selective due to Mode of Entry
Soaps, Oils – Must be applied on body of target pest, no persistence
Bacillus thuringiensis – Must be ingested, short persistence