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Home , Biological pest control, Lysiphlebus testaceipes, Metaphycus, Wasp

Biological Control and Natural Enemies of Invertebrates Integrated Management for Home Gardeners and Landscape Professionals

Biological control is the beneficial ac- tion of parasites, , and preda- tors in managing pests and their dam- age. Biocontrol provided by these living organisms, collectively called “natural enemies,” is especially important for re- ducing the numbers of pest and (Figure 1). Use of natural enemies for biological control of rangeland and wildland (e.g., Klamath , St. Johnswort) is also effective. Plant pathogens, , and vertebrates also have many natural enemies, but Figure 1. Adult convergent lady Figure 2. Parasitic larvae feeding on . () visible through the sur- this biological control is often harder to face of their scale . recognize, less well understood, and/or more difficult to manage. Conservation, augmentation, and classical biological control are tactics for harnessing natu- ral enemies’ benefits.

TYPES OF NATURAL ENEMIES Parasites, pathogens, and predators are the primary groups used in biologi- cal control of insects and mites (Table 1). Most parasites and pathogens, and many predators, are highly specialized Figure 3. mummies and a para- Figure 4. Entomopathogenic nematodes and attack a limited number of closely sitic wasp ( testaceipes). emerging from a root they related pest species. Learn how to rec- killed. in addition to the host mortality caused ognize natural enemies by consulting by . phidae, and are other resources such as the Natural Enemies groups that parasitize insect pests. It’s Handbook and the Natural Enemies Although the term “parasite” is used important to note that these tiny to Gallery. here, true parasites (e.g., fleas and ticks) medium-sized are incapable of do not typically kill their hosts. Spe- stinging people. The most common Parasites cies useful in biological control, and parasitic are the typically hairy A parasite is an organism that lives and discussed here, kill their hosts; they are . Adult tachinids often re- feeds in or on a host (Figure 2). Insect more precisely called “.” semble house flies. Their larvae are parasites can develop on the inside or maggots that feed inside the host. outside of the host’s body. Often only Most parasitic insects are either flies the immature stage of the parasite (Order Diptera) or wasps (Order Hyme- Pathogens feeds on the host. However, adult fe- noptera). Parasitic wasps occur in over Natural enemy pathogens are micro- males of certain parasites (such as many three dozen families. For organisms including certain , wasps that attack scales and ) example, (a subfamily of fungi, nematodes, protozoa, and - feed on and kill their hosts (Figure ) attack aphids (Figure 3). es that can infect and kill the host (Fig- 8), providing an easily overlooked but parasitize insect ure 4). Populations of some aphids, cat- important source of biological control . , , Eulo- erpillars, mites, and other invertebrates

PEST NOTES Publication 74140

Statewide Integrated Pest Management Program December 2014 December 2014 Biological Control and Natural Enemies of Invertebrates

high humidity or dense pest popula- commissioner office in your county for tions. In addition to a naturally occur- aid in identification. ring disease outbreak (epizootic), some beneficial pathogens are commer- CONSERVATION: PROTECT cially available as biological or micro- YOUR NATURAL ENEMIES bial . These include Preserve existing natural enemies by thuringiensis or Bt, entomopathogenic choosing cultural, mechanical, or selec- nematodes, and granulosis . tive chemical controls that do not harm Additionally, some beneficial species. Remember, only by-products, such as avermectins and about 1% of all insects and mites are spinosyns are used in certain insecti- harmful. Most pests are attacked by cides; but applying these products is multiple species of natural enemies, and Figure 5. An adult assassin bug (Zelus not considered to be biological control. their conservation is the primary way to renardii) a bug. successfully use biological control. Judi- Predators cious (e.g., selective, timing) Predators kill and feed on several to use, control, and manipula- many individual prey during their tion are key conservation strategies. lifetimes. Many species of , , , and reptiles prey Pesticide Management extensively on insects. Predatory - Biological control’s importance often be- tles, flies, lacewings, true bugs (Order comes apparent when broad-spectrum, ), and wasps feed on various residual pesticides (those that persist pest insects or mites (Figures 5 and 6). for days or weeks) cause secondary pest Most feed entirely on insects. outbreaks or pest resurgence. An ex- Predatory mites that feed primarily on ample is the dramatic increase in pest spider mites include Amblyseius populations (flaring) that some- Figure 6. An alligatorlike green lace- Neoseiulus spp., spp., and the western times results after applying a carbamate wing larva eating a rose aphid. predatory mite, Galendromus occidentalis. (e.g., carbaryl or Sevin) or organophos- phate (malathion) to control wards their residues kill predators and RECOGNIZING NATURAL or other insects. parasites that migrate in after spraying ENEMIES (Figure 7). (e.g., dineto- furan, imidacloprid) and other system- Proper identification of pests, and dis- Eliminate or reduce the use of broad- ic that translocate (move) tinguishing pests from natural enemies, spectrum, persistent pesticides when- into blossoms can natural is essential for effective biological ever possible. Carbamates, organophos- enemies and that feed on control. Carefully observe the mites phates, and pyrethroids kill natural and . Even if beneficials and insects on your plants to help dis- enemies that are present at the time of spraying and for days or weeks after- survive an application, low levels of cern their activity. For example, some people may mistake syrphid larvae TOXICITY TO PARASITES for caterpillars. However, syrphid fly AND PREDATORS 1 larvae are found feeding on aphids and Direct Residual not chewing on the plant itself. If you find mites on your plants, observe them microbial () no no with a good hand lens. Predaceous botanicals (pyrethrins) yes/no2 no mites appear more active than plant- oil (horticultural), soap (potash soap) yes no feeding species. In comparison with microbial (spinosad) yes/no2 yes/no2 pest mites, predaceous mites are often 2 larger and do not occur in large groups. neonicotinoids (imidacloprid) yes/no yes carbamates (carbaryl), organophosphates yes yes Consult publications listed in the Refer- (malathion), pyrethroids (bifenthrin) ences to learn more about the specific 1. Direct contact toxicity is killing within several hours from spraying the beneficial or its pests and their natural enemies in habitat. Residual toxicity is killing or sublethal effects (such as reduced reproduction or ability to locate and kill pests) due to residues that persist. your gardens and landscapes. Take 2. Toxicity depends on the specific material and how it is applied and the species and life stage unfamiliar organisms you find to your of the natural enemy. local University of (UC) See the active ingredients database at www.ipm.ucanr.edu/PMG/menu.pesticides. Cooperative Extension office, UC Mas- php for more information about specific pesticides. ter Gardener Program, or agricultural Figure 7. Relative toxicity of insecticides to natural enemies.

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pesticide residues can interfere with such as Bacillus thuringiensis (Bt) that combined with the synergist piperonyl natural enemies’ reproduction and kills only caterpillars that consume butoxide. their ability to locate and kill pests. treated foliage. In situations where you wish to foster When pesticides are used, apply them For most other types of exposed-feed- biological control, use of nonpersistent in a selective manner. Treat only heav- ing insects, rely on contact insecticides pesticides can provide better long-term ily infested areas with “spot” applica- with little or no persistence, including control of the pest because they do less tions instead of entire plants. Choose azadirachtin, , narrow- harm to natural enemies that migrate insecticides that are more specific in range oil (horticultural oil), neem in after the application. To obtain the types of invertebrates they kill, oil, and pyrethrins, which are often adequate control, thoroughly wet the

Table 1. Some Pests and Their Common Natural Enemies. Natural Enemies Pests Lacewings Lady Parasitic Parasitic Predatory Other Groups and Examples flies wasps mites aphids X X X entomopathogenic fungi, soldier beetles, syrphid fly larvae carpenterworm, clearwing X entomopathogenic nematodes larvae caterpillars (e.g., California X X X Bacillus thuringiensis, birds, entomo- oakworm) pathogenic fungi and viruses, preda- ceous bugs and wasps, spp. ( parasitic wasps), spiders

cottony cushion scale X X Cryptochaetum iceryae (parasitic fly), vedalia beetle elm leaf beetle X X Erynniopsis antennata (parasitic fly), Oomyzus (=Tetrastichus) spp. (parasitic wasps) eucalyptus longhorned borers X Avetianella longoi (egg parasitic wasp) eucalyptus redgum lerp psyllid X Psyllaephagus bliteus (parasitic wasp) giant X X X hispida, Encarsia noyesi, Entedononecremnus krauteri, and Idioporus affinis (parasitic wasp), syrphid fly larvae glassy-winged sharpshooter X X assassin bugs, Gonatocerus spp. (egg parasitic wasps), spiders lace bugs X X X assassin bugs and pirate bugs, spiders X X X destroyer lady beetle mosquitoes Bacillus thuringiensis spp. israelensis, mosquito-eating fish psyllids X X X pirate bugs scales X X X X Aphytis, Coccophagus, Encarsia, and Metaphycus spp. parasitic wasps slugs, snails X Rumina decollata (predatory snail), pre- daceous ground beetles, birds, snakes, toads, and other vertebrates spider mites X X X bigeyed bugs and minute pirate bugs, Feltiella spp. (predatory cecidomyiid fly larvae), sixspotted ,Stethorus picipes ( destroyer lady beetle) thrips X X X minute pirate bugs, predatory thrips , root or soil-dwelling X Steinernema carpocapsae and Heterorhab- ditis bacteriophora (entomopathogenic nematodes) whiteflies X X X bigeyed bugs and minute pirate bugs, Cales, Encarsia, and Eretmocerus spp. parasitic wasps, spiders ◆ 3 of 6 ◆ December 2014 Biological Control and Natural Enemies of Invertebrates

infested plant parts with spray begin- beneficials will do poorly unless flow- Releases are unlikely to provide satis- ning in spring when pests become ering and nectar-producing plants are factory in most situations. abundant. To provide sustained control, available to supplement their diet. To Some marketed natural enemies are repeated applications may be needed. retain predators and parasites, grow di- not effective. Many natural enemies are verse plant species well adapted to the generalist predators and are cannibal- For certain harder-to-control pests local conditions and that tolerate low istic and feed indiscriminately on pest where contact-only insecticides are populations of plant-feeding insects and beneficial species, thereby reduc- inadequate, other choices include and mites so that some food is always ing their effectiveness. spinosad, a fermentation product of a available. naturally occurring bacterium. This Only a few natural enemies can be insecticide persists about 1 week and it Other cultural controls that can help effectively augmented in gardens and natural enemies include reducing dust has translaminar activity (is absorbed landscapes. For example, entomopatho- and properly fertilizing and irrigat- short distances into plant tissue). Spi- genic nematodes can be applied to ing. Dust can interfere with natural nosad can be toxic to certain natural control certain tree-boring and - enemies and may cause outbreaks of enemies (e.g., predatory mites, Tricho- pests such as spider mites. Reduce dust feeding insects. Convergent lady bee- gramma wasps, and syrphid fly larvae) by planting ground covers and wind- tles () purchased and bees when sprayed and for about breaks and hosing off small plants that in bulk through mail order, stored in a 1−4 days afterwards; do not apply spi- become excessively covered with dust. refrigerator, and released in very large nosad to plants that are flowering. Avoid excess fertilization and irriga- numbers at intervals can temporarily tion, which can cause phloem-feeding control aphids; however, lady beetles Ant Control and pests, such as aphids, to reproduce purchased through retail outlets are Producers more rapidly than natural enemies can unlikely to be sufficient in numbers The Argentine ant and certain other ant provide control. and quality to provide control. species are considered pests primarily because they feed on honeydew pro- AUGMENTATION Successful augmentation generally duced by insects that suck phloem sap, When resident natural enemies are requires advanced planning, biological such as aphids, mealybugs, soft scales, insufficient, their populations can expertise, careful monitoring, optimal psyllids, and whiteflies. protect sometimes be increased (augmented) release timing, patience, and situations honeydew producers from predators through the purchase and release of where certain levels of pests and dam- and parasites that might otherwise con- commercially available beneficial spe- age can be tolerated. Situations where trol them. Ants sometimes move these cies. However, there has been relatively pests or damage are already abundant honeydew-producing insects from little research on releasing natural are not good opportunities for augmen- plant to plant (called “farming”). Where enemies in gardens and landscapes. tation. natural enemies are present, if ants are controlled, populations of many pests will gradually (over several generations of pests) be reduced as natural enemies become more abundant. Control meth- ods include cultivating soil around ant , encircling trunks with ant bar- riers of sticky material, and applying insecticide baits near plants. See Pest A. Egg B. Larva Notes: Ants for more information.

Habitat Manipulation

Plant a variety of species that at different times to provide natural en- emies with nectar, pollen, and shelter D. Adult C. throughout the growing season. The adult stage of many insects with preda- Figure 8. In many cases, only the immature stage of a parasite feeds on the host, as ceous larvae (such as green lacewings illustrated here with a species that attacks aphids. A. An adult parasite lays an egg and syrphid flies) and many adult inside a live aphid. B. The egg hatches into a parasite larva that grows as it feeds parasites feed only on pollen and nec- on the aphid’s insides. C. After killing the aphid, the parasite pupates. tar. Even if pests are abundant for the D. The wasp chews a hole and emerges from the dead aphid, then flies off to find predaceous and parasitic stages, many and parasitize other aphids.

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CLASSICAL BIOLOGICAL ill-advised or illegal importations are Natural Enemies Gallery: CONTROL OR not part of biological control. http://www.ipm.ucanr.edu/PMG/NE/ IMPORTATION index.html. Negative impacts have occurred from Classical biological control, also called poorly conceived, quasi-biological importation, is primarily used against Narrated presentation on biological control importations of predaceous exotic pests that have inadvertently control (24 minutes): vertebrates like , mongooses, and been introduced from elsewhere. Many http://stream.ucanr.org/ certain fish, often conducted by nonsci- organisms that are not pests in their entists. To avoid these problems, bio- biocontrol_final/index.htm. native habitat become unusually abun- logical control researchers follow gov- dant after colonizing new locations ernment quarantine regulations and More biological control resources: without their natural controls. Re- work mostly with host-specific natural searchers go to the pest’s native habitat, www.ipm.ucanr.edu/PMG/menu.bio- enemies that pose low risks and can study and collect the natural enemies control.html. provide great benefits. As a pest comes that kill the pest there, then ship prom- ising natural enemies back for testing under biological control, population and possible release. Many insects and densities decline for both the pest and some weeds that were widespread the biological control agent because pests in California are now partially or host-specific natural enemies cannot completely controlled by introduced prey or reproduce on other species. natural enemies, except where these natural enemies are disrupted, such as REFERENCES by pesticide applications or honeydew- Dreistadt, S.H., M.L. Flint, and J.K. seeking ants. Clark. 2004. Pests of Landscape Trees and Shrubs: An Integrated Pest Management By law, natural enemy importation Guide. 2nd ed. Oakland: Univ. Calif. must be done only by qualified scien- Agric. Nat. Res. Publ. 3359. tists with government permits. Natural enemies are held and studied in an Flint, M.L. and S.H. Dreistadt. 1998. approved quarantine facility to prevent Natural Enemies Handbook: The Illustrated their escape until research confirms Guide to . Oakland: that the natural enemy will have mini- Univ. Calif. Div. Agric. Nat. Res. Publ. mal negative impact in the new country 3386. of release. , M.K. and D.-H. Choe. 2012. Pest It is important for landscape managers Notes: Ants. Oakland: Univ. Calif. to recognize imported natural enemies Agric. Nat. Res. Publ. 7411. Available and conserve them whenever possible. on l i ne at w w w.ipm.uca n r.edu/PMG/ Because classical biological control can PESTNOTES/pn7411.html. provide long-term benefits over a large area and is conducted by agencies and IMPORTANT LINKS institutions funded through taxes, pub- Quick Tip Beneficial Predators: lic support is critical to the continued http://www.ipm.ucanr.edu/QT/ success of classical biological control. beneficialpredatorscard.html.

Is Biological Control “Safe”? Quick Tip Common Garden Spiders: A great benefit of biological control is http://www.ipm.ucanr.edu/QT/ its relative safety for human health commongardenspiderscard.html. and the environment, compared to widespread use of broad-spectrum Quick Tip Lady Beetles: pesticides. Most negative impacts from http://www.ipm.ucanr.edu/QT/ exotic species have been caused by ladybeetlescard.html. undesirable organisms contaminating imported goods, by travelers carry- Quick Tip Parasites of Insect Pests: ing in pest-infested fruit, and from http://www.ipm.ucanr.edu/QT/ introduced ornamentals that escape parasitesinsectcard.html. cultivation and become weeds. These

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AUTHORS: S. H. Dreistadt, UC Statewide To simplify information, trade names of products IPM Program, Davis. have been used. No endorsement of named products is intended, nor is criticism implied of similar products that are not mentioned. TECHNICAL EDITOR: K. Windbiel-Rojas This material is partially based upon work EDITOR: K. Beverlin supported by the Extension Service, U.S. Department of , under special project Section 3(d), ILLUSTRATIONS: Figs. 1, 3–6. J. K. Clark; Integrated Pest Management. Fig 2. A. Kapranas; Fig 8. D. Kidd. Produced by: Statewide Integrated Pest Management Program This and other Pest Notes are available at University of California www.ipm.ucanr.edu. 2801 Second St. Davis, CA 95618-7774 For more information, contact the University of California Cooperative Extension office in your county. See your telephone directory for addresses and phone numbers, or visit http://ucanr.edu/ County_Offices/. University of California scientists and other qualified professionals have anonymously peer reviewed this publication for technical accuracy. The ANR Associate Editor for Pest Management managed this process. WARNING ON THE USE OF CHEMICALS Pesticides are poisonous. Always read and carefully follow all precautions and safety recommendations given on the container label. Store all chemicals in the original, labeled containers in a locked cabinet or shed, away from food or feeds, and out of the reach of children, unauthorized persons, , and . Pesticides applied in your home and landscape can move and contaminate creeks, rivers, and oceans. Confine chemicals to the property being treated. Avoid drift onto neighboring properties, especially gardens containing fruits or vegetables ready to be picked. Do not place containers containing pesticide in the trash or pour pesticides down the sink or toilet. Either use the pesticide according to the label, or take unwanted pesticides to a Household Hazardous Waste Collection site. Contact your county agricultural commissioner for additional information on safe container disposal and for the location of the Household Hazardous Waste Collection site nearest you. Dispose of empty containers by following label directions. Never reuse or burn the containers or dispose of them in such a manner that they may contaminate water supplies or natural waterways.

ANR NONDISCRIMINATION AND AFFIRMATIVE ACTION POLICY STATEMENT It is the policy of the University of California (UC) and the UC Division of Agriculture & Natural Resources not to engage in discrimination against or harassment of any person in any of its programs or activities (Complete nondiscrimination policy statement can be found at http://ucanr.edu/ sites/anrstaff/files/183099.pdf). Inquiries regarding ANR’s nondiscrimination policies may be directed to Linda Marie Manton, Affirmative Action Contact, University of California, Agriculture and Natural Resources, 2801 Second Street, Davis, CA 95618, (530) 750-1318.

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