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Biocontrol
Solutions for Greenhouses and Nurseries PO Box 1555, Ventura, CA 93002 800-248-2847 *
805-643-5407 * fax 805-643-6267 questions
bugnet@rinconvitova.com orders
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Biological control with
beneficial insects makes dollars and sense. Costs of sprays, scheduling sprays
when people are not present, managing residue and resistance problems, etc. can
all be avoided. A savings of 50 to 75 percent in pest control costs is often
reported in the first two years of transition to predominantly biological
control. Plants live longer when not weakened by chemicals. Public and worker
liability risks, even insurance costs, may be reduced. As if this were not
enough, there are also valuable public relations benefits from using this
"green," environmentally friendly alternative to chemical pest
control.
GREENHOUSES AND
NURSERIES, CHALLENGING ENVIRONMENTS
Greenhouse and nursery
production frequently requires perfect-looking plants, flowers and fruit. Other
challenges, related to the density and often the diversity of plants, and the
constant movement of plants in and out, represent a unique horticultural
environment, requiring unique pest control solutions. At Rincon-Vitova, we are
prepared to help you every step of the way.
It is important to
correctly identify pest species needing control, so as to select appropriate
beneficial insect species for your beneficial bug army. If you are unable to
make your own pest identifications with help from local extension agents,
universities, pest control advisors, Rincon-Vitova provides identification
services.
Greenhouse environments
differ from outdoor environments in often filtering out some of the ultraviolet
light that protects plants. Excessive nitrogen fertilization, another common
fact of greenhouse production, also contributes to indoor plants growing up
soft, and attractive to pests. When pests invade soft, weakly defended plants,
the principles of invasion ecology take effect. The pests, freed of natural
enemies, multiply rapidly on suitable host plants, quickly reaching pest
status. Beneficial insect releases help restore the checks and balances found
in natural ecosystems. The beneficial insects (all natural, none genetically
engineered) supplied by Rincon-Vitova Insectaries establish a natural
predator-prey cycle, putting the brakes on runaway pest population growth. In
this new equilibrium, pest populations are kept at tolerably low levels by
their natural enemies. Pest eradication is not a goal, as a few pests always
need to be present as food for the beneficials, which might otherwise starve
and have to be reintroduced.
GETTING STARTED
Initially, it may be
necessary to knock down runaway pest populations to levels that small populations
of newly-introduced beneficials can easily mop up. Use the least-toxic,
low-residual spray materials available, e.g. insecticidal soaps, botanicals
like neem, microbials, and highly refined horticultural "summer"
oils.
Chemical residues last
longer in greenhouses than outdoors, as intense sunlight is necessary for rapid
degradation of most pesticides. Thus, chemicals with little residual effect
under outdoor open field conditions, may persist many weeks longer than
expected in greenhouses. Diazinon and some pyrethroids may even be translocated
from roots to plant leaves, and persist for months. Landscape and plantscape
buyers who use biological control have problems carrying out their programs
with nursery plant material containing residues. To minimize the possibility of
poisoning beneficials with pesticide residues, it is best to wait at least one
month after application of hard pesticides before beginning beneficial insect
releases.
Chemical residues are
particularly detrimental to Rincon-Vitova's parasites, e.g. Aphytis melinus,
which attacks scale insects, Leptomastix dactylopli, which attacks citrus
mealybug, and Encarsia formosa, which attacks greenhouse whitefly. Hence, keep
pesticides off leaf surfaces in at least part of the greenhouse or nursery
ecosystem. For example, an isolated corner where pests are not out of control
can be used as a beneficial insect refuge (safe haven).
One of our most popular
strategies is initially releasing large numbers of beneficials to colonize the
greenhouse or nursery, and following up with a number of smaller releases to
ensure long-term establishment of pest natural enemies.
MAINTAINING BIOLOGICAL
CONTROL
Maintaining biological
control in greenhouses and nurseries is an on-going process involving
conservation of natural enemies and careful monitoring. Conservation of natural
enemies is facilitated by phasing out hard pesticides interfering with
biological control, as well by periodic maintenance releases of beneficials.
Where possible, screening should be used to keep natural enemies in, and new
pests out. Newly introduced plants should be checked for pests, and, if
necessary, disinfested (e.g. with dips or sprays of soaps, oil, neem or other
"soft" pesticides) before introduction to the nursery.
Rincon-Vitova Insectaries
tries to make transitions from chemically-managed to biologically-managed
ecosystems as smooth as possible by continually collecting new strains of
beneficials from heavily sprayed ecosystems Though we do not specifically test
natural enemies for ability to withstand chemical sprays, we believe that some
of our insects, particularly green lacewings, great all-around predators, have
been successful in transition situations due in part to this hardiness and
ability to withstand some chemical residues.
Careful monitoring of
pest and beneficial insect populations by a pest control advisor should be part
of a biological pest control program. The most effective methods are visual
observation, pheromone traps, sticky cards and beating trays. A vacuum sampling
device is useful in many situations. Even when it seems that everything is
under control, continued vigilance is needed to guard against entry of new
pests. Expect the unexpected.
A map of the nursery,
with the different plant species and varieties identified, can be very useful.
Awareness of changing conditions of neighboring plants and weeds, especially
near the greenhouse, can help a manager anticipate intruding pests and
beneficials. Plant species vary in hospitability to beneficial insects; some
plants produce poisons that pests use to protect themselves. Knowing the
correct identity of a problem plant and the surrounding environment can help us
work with you in developing alternative strategies.
Researchers are
developing methods for growing even more beneficial insect species to control
an ever wider range of pest problems. Customers on accounts are informed
through periodic mailings of new beneficial species, some of which are so
scarce that only very small quantities can initially be provided for
inoculation. In addition, where demand is sufficient, we can on special request
collect or obtain rarer natural enemies not normally available commercially.
Technical bulletins are
available for all the beneficials that we sell. A quality control specialist
works to insure that the best possible product is sent out. Nevertheless,
sometimes shipments of fragile insects can arrive injured or otherwise not meet
expectations. As we stand behind all product shipped, please feel free to
contact us should you ever feel that there is a problem or that a replacement
may be necessary.
BENEFICIAL ORGANISMS FOR
GREENHOUSES AND NURSERIES
These descriptions and
guidelines for use are compiled from research, experienced pest control
advisors and producers of beneficials. New information is regularly
forthcoming. Check package inserts and Technical Bulletins. Use may vary
between outdoor and greenhouse settings and interiors. Monitoring by
experienced pest control advisors is necessary. Some organisms are only available
seasonally or by advance commitment.
PREDATORS
APHIDOLETES APHIDOMYZA
(APHID MIDGES)
This predator is effective against over 60 species of aphids, including green peach aphid. The midges are very successful in greenhouses where they collect under the leaves in dark areas. They are also used in gardens, nurseries and street trees, but do not do well in fields. Egg laying is heaviest in heavy aphid infestations and may be increased by spraying a honey and water solution on the leaves. The bright orange-yellow larvae inject a toxin into aphids and suck out the fluids. When daylight is less than 16 hours and temperatures drop in autumn, they may go into diapause, but will reappear in successive seasons up to four years later. This low light will affect the larva when it goes into its pupa stage. But if you are using Aphidoletes to clean up a few aphids, you wont be getting much reproduction. Now we can boldly encourage greenhouse operators to use Aphidoletes to suppress aphids year round. Also the low light diapause will be overridden by temperatures of 78° F (24° C) or higher. So Aphidoletes can be used in warmer greenhouses even with short day length and low light.Control of aphids is generally more effective when insecticidal soap sprays are avoided. Soap harms biological controls and disperses aphids so predators have more difficulty getting to them.
Recent guidelines call
for 500 to 3000 cocoons per acre weekly depending on the infestation. A minimum
of two releases of 250 cocoons per season are needed in about 500 square feet
of greenhouse, depending on how rapidly and thoroughly control is sought.
Care and Distribution::
Aphid midge cocoons are disguised in a coating of moist vermiculite in which
they are shipped. Adults emerge over three days, usually starting on arrival.
When adults appear inside the lid, distribute contents in moist soil or root
media in the shade under plants. If cocoons are left in dry areas exposed to
sun, midges will not emerge.
CHRYSOPERLA (GREEN
LACEWING)
Lacewing larvae attack
many common pests including aphids, mealybugs, mites, whitefly and scale
insects. Adult females lay 10 to 30 eggs per day. Both longtailed mealybug and
sweet potato whitefly suppression have been demonstrated with regular release
in greenhouses. Lacewing can reduce or control aphids in ornamentals. The more
widely lacewing larvae are distributed, the better the control. Releases will
generally colonize in a supportive habitat.
Lacewing releases should
start when pest levels are low, then every one to four weeks as needed.
Quantifies depend on the degree of infestation, presence of other biological
controls, and other factors. A guideline is 5,000 to 50,000 per acre per season
or 1,000 per 2,500 square feet of planted area. When the plant canopy is touching,
distribute squares or tapes every third to tenth plant, alternating plants with
each release.
Care and Distribution:
Lacewing arriving as eggs should be incubated in a warm place (approximately
80º F and not near a direct heat source or in an oven). The tiny larvae start
crawling 1 to 4 days after arrival, depending on the age of the eggs and the
temperature. Hatching happens sooner at 80º to 90º F and can be delayed by
holding at around 60ºF. If air is dry, put a damp sponge or cotton in a larger
paper bag with the lacewing container. Do not wrap in plastic.
Loose Lacewing Eggs: Eggs
are usually shipped in a carrier of rice hulls with food, but can be shipped as
straight eggs with or without food. Rice hulls provide surface area for larvae
to crawl on before release. A paper cone funnel is convenient for distributing
larvae in the mixture on plant infestations.
Lacewing Cards: One card
has 2,500, 5,000 or 10,000 eggs and is perforated for division into 30-1 inch
squares. The squares, yielding approximately 100 and 200 larvae respectively,
can be fixed among leaves or branches. When larvae are crawling on the 6 inch
long by 3/4 inch wide tapes, peel off the paper on the ends and stick the ends
together around branches.
Lacewing Larvae in
Verticel Honeycomb Units: To distribute larvae from honeycomb units, peel back
the covering little by little and tap larvae onto plants or lift them out and
place them with a small brush. Each of the 500 cells contains a larva with a 1
to 2-day food supply. One larvae per plant is a guideline for a mild
infestation. Larvae pupate in about 12 days at which time a second release may
be needed.
CRYPTOLAEMUS MONTROUZIERI
(MEALYBUG PREDATORS)
This lady beetle attacks
many species of mealybugs. It will also feed on aphids and immature scale
insects when mealybugs are in low numbers. It may sometimes be less effective
against longtailed mealybug being a high density feeder, but will reproduce
when mealybug are present Both adult and larval stages are predatory, but don't
mistake "crypt" larvae for mealy-bugs since both have a white, waxy
coating. Two releases of approximately 1 beetle per square foot of planted area
or 2 to 5 per infested plant is a guideline when mealybug populations are
small. Subsequent monthly releases may be needed.
Care and Distribution: Do
not refrigerate these tropical beetles! "Crypts" are shipped as
adults ready for release by sprinkling on infestation sites.
DELPHASTUS PUSILLUS
(WHITEFLY PREDATOR)
These tiny, black beetles
can eat several hundred whitefly per day, supplementing activity of whitefly
parasites where pest densities are high. Spider mites are a probable alternate
host. They provide good eventual control, since each generation is 50 to 100
times greater in number than the previous one.
Care and Distribution:
Delphastus are shipped as adults for immediate release. Use is still
experimental, but guidelines for greenhouses start at 50 beetles per 2,000 to
5,000 sq. ft. when used as an inoculation.
HIPPODAMIA CONVERGENS
(Convergent lady beetle)
This general predator
feeds on aphids, mites and a variety of other soft-bodied insects. Their yellow
eggs are laid in clusters. Larvae consume pests for about 16 days before
pupating. Pupae remain on upper leaf surfaces for about a week until adults
emerge.
Care and Distribution:
Lady beetles are shipped as adults and should be released in the evening near
food sources. If release is delayed a clay or two, they can be refrigerated.
Pre-release care can include spraying bag or cotton wick with water and or
prespraying release spot with a 5% sugar solution. A rule of thumb for releases
is 1 lady beetle per sq. ft.
HYPOASPIS MILES
(=Geolaelaps sp.)
(FUNGUS GNAT PREDATOR)
Root-feeding fungus gnats
can be controlled by this brown mite that feeds on small soil-dwelling insects,
including thrips larvae. The mites produce a new generation every week and are
easy to establish. They are used at a rate of 1/4 teaspoon of mixture per 2
plants or 1-2 liters per 1,000 sq. ft. One early introduction is enough for the
season.
Care and Distribution:
Distribute immediately or, if holding overnight, keep in a cool room (50º to
60º F). The adult mites are mixed in sawdust and can be shaken out in shady
moist soil or media.
RHYZOBIUS LOPHANTHAE
(=Lindorus lophanthae)
SCALE DESTROYER
This small black lady
beetle with orange head and thorax is an effective scale predator occurring in
southern US and occasionally available commercially. Adults and larvae feed
only on scale insects, both hard and soft, and will eat mealybug larvae; the
beetle larvae do not like soft scale with excessive honeydew. Release
approximately 1 beetle per 1-2 sq. ft
Care and Distribution:
These hardy adult beetles are released immediately.
AMBLYSEIUS CUCUMERIS
(THRIPS PREDATOR)
This predatory mite
attacks the immature stages of the western flower thrips and onion thrips.
Control is not generally apparent until 2 or 3 months after releases begin.
Distribute 1 to 10 predators per square foot per week depending on plant size
and foliage density; experimentation is encouraged. Releases should start when
thrips populations are low (less than 10% of leaves with adult thrips or 25% of
leaves with larvae).
Care and Distribution:
Adult thrips predator mites are shipped loose in bran or packaged in sachets
with all life stages, called controlled release system (CRS) bags, for hanging
on plants where sprinkled bran may be less effective. Distribution should be
thorough and heaviest during hot, dry months.
ORIUS
(Minute Pirate Bug)
These small black and
white bugs are naturally occurring in many crops and are predacious as adults
and immatures. They prey on thrips, mites, scale pests, whitefly, lepidopterous
eggs, psyllids, aphids, etc. Nymphs are yellow, amber or brownish. Only the
white circular caps of the eggs are visible in plant tissue. Beneficial members
of the Anthocoridae family are less harmed by insecticides than other
beneficials. Day length of a t least 13 hours and presence of host are needed
for reproduction. Quantities used range from 5,000 to 30,000 per acre.
Care and Distribution:
Adults are packaged in buckwheat hulls. Release as soon as possible after
delivery in spring when pest levels are low.
PHYTOSEIULUS SPP. &
NEOSEIULUS SPP.
(PREDATORY MITES)
There are several
commercially available species of predatory mites that attack the two-spotted
spider mite. Predatory mites should be introduced at the first sign of spider
mite damage, reintroduced two weeks later, and then at regular intervals until
a balance is reached between pest and predator mites and damage is stopped.
Distribute from 05 to 3 per sq. ft. depending on foliage density and how hairy
the leaves are, 2 predators per damaged leaf or 2 per plant if plants are
small.
Phytoseiulus persimilis
is preferred in greenhouses and fields, favoring mild humid conditions up to
80º F. Galandromis (=Metaseiulus) occidentalis fares better when temperatures
exceed 90º F. Neoseiulus (=Amblyseius) californicus can be very successful in
greenhouses when pest mite populations are low. It thrives in a minimum of 60%
relative humidity and can tolerate temperatures up to 90º F. Combinations of
species can be used in settings with varied micro-climates. Good control of a
moderate spider mite infestation should be achieved within 4 to 6 week, though
persistent pesticide residues delay establishment.
Care and Distribution:
Distribute predatory mites immediately or, if holding overnight, keep in a cool
room (around 50º to 60º F). Mites are shipped in the adult stage in vermiculite
or bran for sprinkling on infested foliage. They will adhere better to leaves
covered with morning dew or misted.
PREDATORY NEMATODES
Substrains of the
Steinernamatidae and Heterorabiditae nematode families are predators that
attack insects, insect pupae and insect larvae in places that are constantly
moist. Among more than 250 susceptible insect pests are cutworms, white grubs,
thrips, fungus gnats and other root zone pests. The nematode enters the host
and kills it within 24 to 48 hours, then reproduces within and searches for new
hosts thus providing long-term control. One million are enough for 2,000 to
3,000 sq. ft. and 1 or 2 applications per year are usually enough.
Care and Distribution:
Nematodes are best applied in the evening, directly into the soil or growing media,
after mixing them in water. In larger areas, a sprayer is helpful. They are
perishable, but can be stored temporarily in the refrigerator.
PARASITES
APHIDIUS MATRICARIAE
(APHID PARASITE) This parasite of green peach aphid can be released early in the
spring. Developed in greenhouses and interiors to supplement programs using
Aphidoletes aphidomyza. Increasingly cost-effective programs are becoming
available.
Aphytis melinus (Red
scale parasite) California red, Aonidiella amantii, and oleander (ivy) scale,
Aspidiotus neroli, are among a number of species attacked by Aphytis melinus.
It does not parasitize all red scale pests. The tiny yellow wasp lays her eggs
on the soft body under the waxy shell of young scales. Programs depend on
number and age of scale pests present.
Care and Distribution: Do
not refrigerate! Release immediately, preferably in the morning.
DIGLYPHUS ISAEA
(LEAFMINER PARASITE) This ichneumon wasp is a natural enemy of 18 species of
leafminer, especially in greenhouses and warmer climates. It attacks its host
in the tunnel and lays one or more eggs on or near it. The egg develops in the
tunnel and turns into a new wasp which uses the dead larva as food. A
biological program should also include trapping and use of IGR sprays or horticultural
oils.
Care and Distribution:
One parasite for every 10 new mines per developed plant per week should begin
during the first 6 weeks of an infestation, or 500 to 1,000 per acre.
Monitoring of leaves for emerging parasites will show if parasitism is high
enough (at least 90 %) to suppress leafminers.
LEPTOMASTIX DACTYLOPII
(CITRUS MEALYBUG
PARASITE)
This tiny, delicate wasp
parasitizes the common citrus mealybug as a valuable part of their control. It
is capable of finding the last mealybug. Though it prefers a sunny, warm, humid
environment, it has been used successfully in areas of low humidity. Hosing
plants with soap and water followed by a release of Cryptolaemus will reduce
heavy populations giving a subsequent release of the parasites a head start.
Good control should be achieved in 2 to 3 months. Under ideal environmental
conditions, distribute 2 per square yard or 5 per infested plant, usually once
or twice a year. Uneven commercial availability.
Care and Distribution: Do
not refrigerate or hold in hot or humid condition. Release immediately.
ENCARSIA FORMOSA
(GREENHOUSE WHITEFLY
PARASITE)
Tiny parasitic wasps, no
bigger than a pencil point, lay their eggs inside 3rd and 4th instar larval
stages of whitefly found on the underside of leaves. Parasitized whitefly
larvae turn black which provides a way of assessing the success of the
introduction. Works best in temperatures over 70º F (ideally 80º F), relative
humidity below 70 % and high light levels (greater than 650 footcandles). Control
is not immediate, especially where chemical residues exist. Initial
introductions can be integrated with spot-vacuuming or spot-treatment.
Encarsia prefers to
attack 2-week-old whitefly, so plans are best made for an initial series of 4
releases every 10-14 days to assure that the 3rd and 4th instar stages are
present during at least 1 of the releases. Repeat this series if necessary,
usually once or twice a year. Guidelines are at least 1 parasite per 10 potted
plants or 1 per 10 square feet of planted area when there are less than 1
whitefly per 20 plants. Increase numbers up to 2 to 5 parasites per plant for
larger plants, such as poinsettias, and for plants with hairy leaves or
honeydew on them. If adult whiteflies exceed 10 per leaf, spot-spray new growth
of infested plants with insecticidal soap or horticultural grade petroleum oil.
Care and Distribution:
Shipping time and temperature affect how soon Encarsia parasites emerge from
the black parasitized GHWF scale glued on cards. If emergence has not begun,
cards can usually be stored up to 3 days at 40º to 50ºF, however, number
emerging decreases with increased storage time and colder temperatures. Hang
cards when emergence begins.
TRICHOGRAMMA SPECIES
(MOTH EGG PARASITES)
These tiny wasps lay their
eggs inside (or sometimes feed on) the eggs of over 200 species of moths that
cause damage as caterpillars. The progeny of the first release emerge after 8
to 10 days ready to attack more pest eggs. An increasing rate of parasitism
with each generation has been documented. Among the species currently available
commercially, T. pretiosum is usually used in fields, flats, shrubs and vines
and T. platneri for orchards on the West Coast.
Trichogramma parasitize
only freshly deposited moth eggs, so the ideal time to release is when the
moths are flying. For prevention or for control of low to medium infestations,
generally one square of 4,000 parasitized eggs is used for each 4,000 square
feet. In young tree and shrub plantings, start at 50,000 or 12 squares per
acre. Depending on the biology of the target host, releases are often planned
weekly or biweekly for 3 to 6 consecutive weeks, timed as close as possible to
moth flights. Don't miss making a release during egg-laying of the first
generation of moths. Pheromone traps and degree-day calculations can help in
planning the schedule.
Care and Distribution:
Trichogramma are shipped in the form of parasitized moth eggs, usually glued to
a perforated card. There are 125,000 eggs on a card and each card can be broken
into 30 one-inch squares with approximately 4,000 eggs per square. The wasps
will emerge in 2 to 5 days, depending on the holding temperature, which should
ideally be 80º F. Holding temperature can be manipulated to speed up or slow
down emergence. Squares are usually held during the incubation period
individually in paper cups or other container from which swarming, mated female
wasps can be released.
REFERENCES
1. Hussey, N.W. & N. Scopes editors.
1985. Biological Pest Control: The Glasshouse Experience. Inexpensive book from
Cornell University Press about biologies of important indoor pests and their
natural enemies with information not readily available elsewhere.
3. Bio-Integral Resource Center (BIRC).
1991. Least-Toxic Pest Management: Greenhouses & Indoor Plants. Collection
of 10 articles from BIRC's Common Sense Pest Control Quarterly and IPM
Practitioner publications, a wealth of information on indoor pest problems.
Many techniques described are used at the San Francisco Conservatory of Flowers
in Golden Gate Park. $16. Much of BIRC's information is contained in Taunton
Press' Common-Sense Pest Control a 715 page book available from BIRC (P.O. Box
7414, Berkeley, CA 94707).
4. Croft, Brian A. 1990. Arthropod
Biological Control Agents and Pesticides. 723 page book, published by John
Wiley & Sons (NY), is an essential reference where pesticide selection
decisions are being weighed against disruption of biological control. Charts
help in making recommendations.
5. Costello, R. A.,et al. 1992. Integrated
Control of Greenhouse Pests. 19-page how-to booklet. Request free (limited
availability) Extension systems Branch, British Columbia, Ministry of
Agriculture, Fisheries and Food, 808 Douglas Street, Victoria, B.C. VSW 211 or
call 604-387-3498. Or order copy from Rincon-Vitova.
Other
Rincon-Vitova Publications:
Biological
Control Solutions for Interior Plantscapes
Safe
Ways to Control Landscape Pests
Bulletins
about other crop systems and about each organism.
© 1996, 2006
Rincon-Vitova Insectaries, Inc. Reproduction all or part requires permission.