Download K - Natural Enemies - Charleville Gardens

Natural Enemies
Horticultural Allies
Natural Enemies
• Organisms that –
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kill
decrease the reproductive potential
or otherwise reduce the numbers
of another organism
• Can limit pest damage
Natural Enemies
• Reduce pest populations through
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predation
parasitism
herbivory
competition
antibiosis
Predation
• Predators –
– attack, kill and feed on several or many other
individuals
• Specialized predators –
– feed on a single species or a few closely
related species
• Generalized predators –
– feed on a variety of similar organisms
Predators
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Coleoptera – beetles
Hemiptera – true bugs
Diptera – flies
Neuroptera – lacewings
Hymenoptera – wasps
Arachnida – spiders
Vertebrates – birds, reptiles, coyotes,
etc.
Predators
• Predatory mites – family Phytoseiidae
– controls pest mites and other insects
• Mites, collembola, flatworms, protozoa
and some nematodes control pest
nematodes
• Giant amoebae, various soilborne animals
are pathogens to fungi and bacteria
Predators
• Birds, bats and fish prey on various
insects and other pests
• Raptors, cats and coyotes prey on various
pest birds, rodents and other vertebrates
Parasitism
• Parasites –
– feed in or on a larger host
– prolonged and specialized relationships with
hosts
– typically parasitize only one host individual in
their lifetime
Parasites
• Disease producing bacteria, fungi,
protozoa, viruses and some nematodes
• May attack invertebrates (insects and
nematodes), weeds, pathogens and
vertebrates
Parasites
• May weaken hosts without killing it
• Those that significantly weaken or kill the
host are important natural enemies in
biological control
Parasites
• Pathogens –
– parasitic microorganisms
– impair normal activities of host tissue or cells
– includes: bacteria, fungi, protozoa and viruses
• Important controls of insects, nematodes,
mites, weeds, and other pathogens
Parasites
• Parasitoid –
– insect that parasitizes and kills other
invertebrates
– parasitic in immature stage
– kills hosts as they enter maturity
– adults are free-living
– adults about same size as hosts
• Can include – Hymenoptera and Diptera
Parasite vs. Parasitoid
• Parasites derives food from host
organisms without killing the host
• Parasitoids end up killing the host before
the parasite matures
Internal vs. External Parasites
• Endoparasite – internal
– develops inside of the host
Internal vs. External Parasites
• Ectoparasite – external
– develops while attached to the outside of the
host
Herbivory
• Herbivores –
– animals that feed on plants
– important natural enemies of weeds
– specialized herbivores selectively feed on one
or several closely related weed species
– some limit production by feeding on flowers or
seed
Competition
• Competition –
– two or more organisms strive for the same
limited resources – i.e. food, water, shelter or
light
• Can limit some weeds
• Limited use as a biological control
Antibiosis
• Antibiosis –
– substances secreted by organisms inhibiting
vital activities of other organisms
• May be useful in controlling some plant
pathogens
• Few current applications
Common Natural Enemies
• Nematode-trapping fungi
Common Natural Enemies
• Predatory nematodes
• Not particularly useful
in disturbed soils
Common Natural Enemies
• Decollate snails control . . .
– European brown garden snails
– citrus thrips – feeds on pupae in soil
– can feed on seedlings
Common Natural Enemies
• Predatory mites
– occurs in several families
– tend to pear-shaped, longer-legged and shinier
than pest mites
– more active than plant-feeding mites
– feeds on plant-feeding mites, insect eggs,
immatures – crawler stages of scale, thrips
and whitefly nymphs
– translucent, bright white, red, yellow, green
Common Natural Enemies
Common Natural Enemies
• Parasitoid wasps control . . .
– various Homopterans including: aphids,
whitefly, scale, psyllids, mealybugs, and a host
of other pests . . .
– as well as various
Lepidopterans
Common Natural Enemies
• Lacewings (Order Neuroptera)
– larvae are predaceous
– not adults from all species are
– feeds on aphids, whiteflies, mealybugs,
caterpillars, mites, psyllids, insect eggs, and
other insects
Common Natural Enemies
• Green Lacewing
(Chrysopidae)
Common Natural Enemies
• Brown Lacewing (Hemerobiidae)
Common Natural Enemies
• Lady Beetles (Coccinellidae)
– over 500 species in America
– most are predaceous as larvae and adults
– many are prey-specific including various
insects and mites
Common Natural Enemies
Common Natural Enemies
Common Natural Enemies
Common Natural Enemies
• Assassin bugs (Reduviidae)
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over 160 species in North America
all are predaceous
some attack mammals
Feeds on a range of insect pests
Common Natural Enemies
• Damsel bugs (Nabidae)
– predaceous on mites, aphids, caterpillars,
leafhoppers, etc.
– resembles small Reduviidae
– long front appendages
Common Natural Enemies
• Syrphid flies (Syrphidae)
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AKA hover flies, flower flies
larvae are predaceous
adults often resemble honey bees
feeds on aphids and other soft-bodied insects
Common Natural Enemies
• Mantids
(Mantidae)
– praying mantids or
praying mantises
– predaceous
– elongated thorax
– long, grasping
forelegs
– opportunistic and
cannibalistic