Classical Biological Control Pages 115137

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Classical Biological Control (Pages 115-137)
Read Chapters 8, 9 and 13 in Van Driesche and
Bellows Modern biological control began in 1873
with the shipment of the predaceous mite to
France for control of the grape
phylloxera. However, it was the cottony cushion
scale project in Californiaduring 1888-1890 that
really lodged the idea in the minds of many
growers and scientists alike. A few other key
projects extensively shaped modern biological
control We will examine key programs then move
into the processes of classical biological
control and current issues in the field.
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Classical Biological Control (Pages 115-137)
Cottony cushion scale in California (Pages
115-117) Cottony cushion scale Icerya purchasi
(Homoptera Margarodidae) Entered California
ca. 1868,probably on ornamental
acacias Serious pest of citrus by 1880 Growers
groups formed to address the problem
Cottony cushion scale
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Classical Biological Control (Pages 115-137)
Cottony cushion scale in California (Pages
115-117) Complex and nasty personal and
scientific battles raged as several control
efforts failed, e. g. fumigation with HCN. C. V.
Riley led USDA Division of Entomology and the
pro-biological control faction. January 1888
biological control gains support. Decided
cottony cushion scale was from Australia, but
could not use Division of Entomology funds for
foreign travel. Sent Albert Koebele to Australia
in August 1888, as part of a trade group
attending and International Exposition in
Melbourne to represent the State Department.
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Classical Biological Control (Pages 115-137)
Cottony cushion scale in California (Pages
115-117) Koebele collected three potential
agents. Two were shipped to California 12,000
Cryptochetum iceryae(Diptera Cryptochetidae)(Ri
leys preferred agent) 129 Rodolia
cardinalis,(Coleoptera Coccinellidae)the
vedalia beetle
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Classical Biological Control (Pages 115-137)
Cottony cushion scale in California (Pages
115-117) Both established Cryptochaetum
iceryae mainly in coastal areas, e. g. San
Francisco Rodolia cardinalis efforts focused in
Los Angeles County, tented trees, very
successful By June 1889 10,555 beetles
redistributed (plus 113,000 reared from later
shipments by fall) 1889 citrus harvest in LA
County was 2000 boxcars, up from 300 the
previous year. BC was set in the minds of
growers and entomologists.
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Classical Biological Control (Pages 115-137)
Cottony cushion scale in California (Pages
115-117) Another measure of success 1945 DDT
introduced to the citrus groves of southern
California. A terrible new pest emerged. It
was the cottony cushion scale. BC had been so
good that the sons/grandsons of the growers in
the 1880s had completely forgotten about the
cottonycushion scale. Modified spray regimes
allowed BC to re-establish.
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Classical Biological Control (Pages 115-137)
Gypsy moth project in northeastern US (Pages
117-118) Gypsy moth, Lymantria dispar,
introduced by Leopold Trouvelotto start a silk
industry Browntail moth, Nygmia phaeorrohoea,
accidentally introduced Browntail
moth Both were serious forest pests.
male
female
Gypsy moth
larva
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Classical Biological Control (Pages 115-137)

• Gypsy moth project in northeastern US (Pages
  117-118)
• L. O. Howard had succeeded Riley as Head of
  the Division of Entomology
• Initiated first BC super project for both
  moths The duration, the magnitude and the
  budget of the project were greater than
  previous endeavors

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Classical Biological Control (Pages 115-137)
Gypsy moth in northeastern US (Pages
117-118) Project ran from 1905 to
1911 Involved 5 dedicated buildings 5
soon-to-be pre-eminent entomologists First
large-scale foreign exploration (Europe, Russia,
Japan) Imported 34 species of agents Released
1,881,818 individual agents 15 species
established (12 parasitoids, 3 predators)
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Classical Biological Control (Pages 115-137)
Gypsy moth in northeastern US (Pages
117-118) Gypsy moth, primary target Reduced,
but not controlled Browntail moth, secondary
target Got good control, now a minor pest The
project was not a great success in pest
management. So, why do we care about it?
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Classical Biological Control (Pages 115-137)
Gypsy moth in northeastern US (Pages
117-118) Other products of the program that make
it importantFive leaders of biological control
in first half of century Procedures-
identification of all taxa imported
quarantine procedures study biology of
taxa, avoid hyperparasites record
keepingTechniques- coldroom to synchronize host
and parasitoid sleeve cagesEcology-
enhanced knowledge of parasitoids, e. g. adult
food showed value of multiple
agents It set the scientific base for modern
biological control.
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Classical Biological Control (Pages 115-137)
Coconut moth in Fiji (Pages 118-119) The coconut
moth, Levuana iridescens entered Fiji about
1900serious pest of coconut 1924 Government
sought a solution(offered 5,000 pounds
sterling) Hired J. D. Tothill (from gypsy moth
project) W. Paine and T. H. C. Taylor to conduct
a BC program
Coconut mothadult and larva The adult is a
beautiful metallic lavender.
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Classical Biological Control (Pages 115-137)
Coconut moth in Fiji (Pages 118-119) Coconut
moth was thought to come from larger, nearby
island, Viti Levu (hence generic name
Levuana) Found almost no parasites attacking
moth on Viti Levu Sought moth in other areas,
failed to find it anywhere else Looked at
related mothsFound Cathartona catoxantha with
parasitoidsFirst shipment died en route (1924)
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Classical Biological Control (Pages 115-137)
Coconut moth in Fiji (Pages 118-119) 1925 Tried
importing parasites from Hawaii and other
locales Expanded search for
Cathartona catoxantha Found two parasitoids
near Kuala Lumpur Apanteles sp.
(Braconidae) Bessa remota (Tachinidae)
Shipped to 85 small palms with
20,000 moth larvae 315 B. remota
survived No braconids survived
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Classical Biological Control (Pages 115-137)

• Coconut moth in Fiji (Pages 118-119)
• B. remota proved easy to rear
• October 1925, escaped flies established
  around insectary (This would end your career
  today.)
• January 1926 15,000 flies released
• Found throughout Fiji by July 1926
• Controlled pest within a year

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Classical Biological Control (Pages 115-137)
Coconut moth in Fiji (Pages 118-119) This
project was regarded as a complete success, the
economic base of Fiji was stabilized The project
was also noteworthy because First use of a
parasite of one species to control another
species (new association) First (and
possibly still worst) non-target impact in an
entomophagous program- B. remota appears to
have exterminated a native moth
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Classical Biological Control (Pages 115-137)
Modern Biological Control Programs (Pages
119-137) The eight steps of modern entomophagous
projects are structured on the bases of what was
learned in these early programs 1.
Planning 2. Exploration 3. Shipment 4.
Quarantine 5. Rearing 6.
Colonization 7. Establishment 8.
Evaluation
Sounds easy enough,but reality intrudes
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Classical Biological Control (Pages 115-137)

• 1. Planning (Pages 120 and 121)
• Recognize pest as new must know the local fauna
• Identify the pest need adult, need literature,
  need skill, need help
• Determine if pest is native or introduced use
  literature, catalogues, taxonomic papers
• Determine origin of species museums, earliest
  reports, related species
• Assess knowledge of natural enemies of the
  pest/relatives taxonomic and predator-prey
  catalogues
• Assess feasibility of biological control type of
  damage, economic tolerances, control
  options, history of success with related pests
  and agents

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Classical Biological Control (Pages 115-137)

• 1. Planning (Pages 120 and 121)
• Survey indigenous natural enemies might they
  give adequate control, find open niches
• Consider impacts on beneficial insects in the
  system
• See if program is underway with CSIRO, etc.
• Plan the exploration make contacts know local
  laws/requirements, e. g. guides required?,
  can you take pictures? arrange all necessary
  permits consider equipment needed for
  collecting and shipping
• Ensure receiving laboratory is ready
• Synchronize exploration with preparations in
  quarantine

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Classical Biological Control (Pages 115-137)

• 2. Exploration (Pages 121 and 122)
• Sample regions where pest is native increases
  chances of finding natural enemies be aware of
  biotypes, sample numerous areas
• If native range unknown seek areas where pest
  reported for longer periods, more chance
  natural enemies there too
• Locate native habitat(s) crop may originate in
  pests native range, but also sample natural
  habitats, the greater diversity may support
  additional species of agents

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Classical Biological Control (Pages 115-137)

• 2. Exploration (Pages 121 and 122)
• Maximize genetic diversity of agents
  imported genetic diversity determines the
  potential of the agent population
• search as many habitats as possible, e. g.
  near ocean and in the interior prioritize
  areas similar to intended release site, (see
  walnut aphid project, page 132) search areas of
  high and low pest density, may find different
  agents with different traits, e. g.
  searching multiple trips to sample during
  different seasons may yield different agents

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Classical Biological Control (Pages 115-137)
2. Exploration (Pages 121 and 122) E. Sample
using many techniques will likely yield
different natural enemies sweep net good for
adult Coccinellidae, but lose host associations
with parasitoids and may injure wasps hand
picking mummies is better for parasitoids if
host mummy rare or not distinctive, host exposure
may be the best approach host exposure also
addresses biotype question, if you have pests
from the target area minimize plant material
sent to quarantine, but this is difficult with
scales, endophytophagous pests, etc.
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Classical Biological Control (Pages 115-137)
2. Exploration (Pages 121 and 122) F. Prepare
to ship natural enemies ship a
resting/non-feeding stage (eggs or pupae) if
possible, need less care in transit be very
careful with moisture, supply limited water in
a sponge accessible through a mesh be careful
with temperature, insulate the package, keep
cool, not cold, ice not touching inner
container supply food, if needed protect from
bouncing, give a cushioning substrate in the
inner container, e. g. strips of paper ship
in double-walled container (protection
insulation) send as much material as you
can tell the quarantine lab what is coming and
when
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Classical Biological Control (Pages 115-137)

• 3. Shipment (Page 123)
• Ship specimens in adequate container double-walle
  d, etc., as described previously
• Ship specimens by fastest means
  possible overnight express services, air
  freight, military flights, diplomatic pouch
• Track the fate of the shipment if it worked do
  it again, otherwise try alternatives

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Classical Biological Control (Pages 115-137)

• 4. Quarantine (Pages 123 124)
• The quarantine room double doors, with insect
  traps between double windows, outer
  reinforced self-contained laboratory (fewer
  trips in and out) autoclave all material that
  leaves the room positive pressure ventilation
  with filters for outflow
• Open all packages in secure settings use a
  sleeve cage inside the quarantine room
• Hold all exotic organisms nothing leaves alive,
  until authorized to do so

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Classical Biological Control (Pages 115-137)

• 4. Quarantine (Pages 123 124)
• Identify all taxa send material to
  authorities save voucher specimens of all taxa
• Study the biology of all taxa verify if it
  attacks the target pest, not an accidental
  inclusion if a parasitoid, ensure it is a
  primary parasioid discover adult food
  requirements, etc.
• Screen out hyperparasitoids, pathogens keep
  vouchers of these too
• Rear clean material for transfer to insectary

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Classical Biological Control (Pages 115-137)

• 5. Rearing (Page 124)
• Mass rearing in the insectary increase numbers
  for release keep several colonies to protect
  against pathogens, etc. improve rearing
  system maintain vigor of colony fluctuate
  temperature and photoperiod in prolonged
  rearings can eliminate diapause
  response change behavior, e. g. mating
  time reduce mobility
• Question Combine populations of the same
  species or keep them separate?

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Classical Biological Control (Pages 115-137)

• 6. Colonization (Pages 124 125)
• Release as soon as safe and possible reduce
  risks of inbreeding, selecting insectary strain
• Select a safe site be sure disturbance is
  unlikely, e. g. protected public or
  private lane, private land ownership can
  change be sure land manager is informed select
  inconspicuous areas, especially if using cages
• Timing of releases seasonal- as early as
  appropriate stage of host is available, gives
  agents time to search, reproduce diurnally-
  early morning or evening, less harsh, agents
  less likely to disperse immediately weather- try
  to avoid temperature extremes, high wind

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Classical Biological Control (Pages 115-137)
6. Colonization (Pages 124 125) D. Release as
many individuals as you can larger releases more
likely to succeed withstands mortality,
facilitates mate finding release mated females,
if possible multiple release sites beneficial,
agent may not establish at all release sites
balancing larger releases vs more sites for
some agents there are guidelines on how many
you should release sometimes it is more art
than science
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Classical Biological Control (Pages 115-137)
6. Colonization (Pages 124 125) E. Choose a
suitable release method open field release-
natural, reduces predation risks, but agents
may disperse too quickly, release mated
females caged release- confines agents, mating
more likely, easier to find evidence of
establishment, but increases risk of predation,
some agents will cling to the cage, cage
effects limited cage release- cage agents for a
few hours or days, then remove cage, balances
the benefits and drawbacks described above,
often the preferred method
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Classical Biological Control (Pages 115-137)

• 7. Assessment of establishment (Pages 125 126)
• Confirm establishment can be difficult, agent
  population low avoid destructive sampling, look
  for adults, frass, mummies, etc. look within
  the year of release more importantly, look the
  following year keep trying, it may take years to
  recover an agent
• Look at multiple sites as noted earlier, an
  agent may establish at some, but not all sites

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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
126-130) Evaluation of BC programs began in the
1940s.Three main motivations Not all programs
were successful. Why? Pressure from
pro-pesticide groups to prove BC
works Interesting observations, e. g.
competitive displacement (see Oriental fruit
fly in Hawaii, pages 131 132)
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Classical Biological Control (Pages 115-137)

• 8. Evaluation of biological control (Pages
  126-130)
• Oriental fruit fly in Hawaii (Pages 131 132)
• Oriental fruit fly displaced Mediterranean fruit
  flyoviposition habit, larvae intrinsically
  superior
• 1948 Biosteres longicaudatus (Braconidae), 10
  parasitism
• B. vandenboschi, 40 parasitism
• B. oophilus, 65 parasitism (B.
  longicaudatus and B. vandenboschi 0.14)

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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
126-130) Oriental fruit fly in Hawaii (Pages 131
132) Sequential displacement due competitive
superiority B. longicaudatus parasitizes
late-instar host larvae,hosts dispersed, thus
low rate of attack B. vandenboschi parasitizes
early-instar host larvae, easier access to
hosts, intrinsically superior B. oophilus
parasitizes host eggs,easy access to aggregated
hosts, intrinsically superior,preoccupies the
niche
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
126-130) All these factors contributed to the
motivation to develop valid means of evaluating
the effectiveness of biological control
agents/programs. Multiple methods were
developed. Each has advantages in specific
applications. None is perfect.
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Classical Biological Control (Pages 115-137)

• 8. Evaluation of biological control (Pages
  126-130)
• Introduction/Addition/Before and After Studies
• Exclusion Studies Exclusion cages Insecticidal
  check/Insecticidal exclusion Hand removal Ant
  interference/Biological check
• Inclusion/Addition Studies Inclusion cages Prey
  enrichment

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Classical Biological Control (Pages 115-137)

• 8. Evaluation of biological control (Pages
  126-127)
• Introduction/Addition/Before and After Studies
• Theoretically simple, compare pest density
  before and after agent(s) establishedBut,Pre
  release studies were rareTiming is
  criticalOther factors could influence pest
  density, so needed numerous, large samples

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Classical Biological Control (Pages 115-137)

• 8. Evaluation of biological control (Pages
  126-127)
• Introduction/Addition/Before and After Studies
• Results can be qualitative, e. g. pictures

Before and after pictures of Hypericum
(Klamath/goatweed) control
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Classical Biological Control (Pages 115-137)

• 8. Evaluation of biological control (Pages
  126-127)
• Introduction/Addition/Before and After Studies
• Results can be quantitative winter moth
  study 10-years, numerous sites, labor intensive

Monitored adult female mothsin sticky traps,
larvae in pan traps as they fell to pupate,
Cyzenis was dissected from trapped larvae, both
parasitoids were monitored emergence
traps.(See page 136)
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Classical Biological Control (Pages 115-137)

• 8. Evaluation of biological control (Pages
  126-127)
• Introduction/Addition/Before and After Studies
• Winter moth project trackedspread of two,
  dominant agentsincreases in agent
  populationsdeclines in winter moth
  populationsdeclines in agent populations

Ten-year population trendsfor the winter moth,
O. brumata, and two parasitoids.
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
127-129) B. Exclusion Techniques- Exclusion
cages simple cage some pest populations to
exclude agents compare pest populations and
damage with and without agent(s)
impact Problems cage effects- temperature, RH,
light Therefore, include a sham cage
treatment, still not ideal.
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
127-129) B. Exclusion Techniques- Insecticidal
check simple (cassava mealybug project, page
137) spray some pest populations with sublethal
doses or selective insecticide kill agents,
not pests compare pest population densities,
damage with and without agents
present Problems may not have selective
insecticide insecticide could affect
insect behavior, e. g. increase emigration
insecticide could alter pest
reproduction, e. g. increase oviposition, skew
sex ratio insecticide could be
phytotoxic
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
127-129) B. Exclusion Techniques- Insecticidal
check Cassava mealybug project (Page 137)
Comparison of insecticidal check and exclusion
cage evaluations of biological control of the
cassava mealybug
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
127-129) B. Exclusion Techniques- Hand
removal simple hand pick agents from some pest
populations compare pest population densities,
damage with and without agents present avoid
cage and insecticide problems Problems labor
intensive not all agents easily found
and removed Not widely used
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
127-129) B. Exclusion Techniques- Ant
interference can be simple if pest produces
honeydew that attracts ants, exclude ants from
some pest populations so they do not interfere
with agents compare pest population densities,
damage with and without agents present avoid
cage and insecticide problems Problems need
large, non-intertwined plants ants not
100 effective
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
127-129) C. Inclusion Techniques- Inclusion
cages simple confine agents on some pest
populations, not all allows testing several
agent densities compare pest population
densities, damage with and without agents
present Problems best in areas without agent
populations cage effects (sham cages
for control)
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Pages
127-129) C. Inclusion Techniques- Prey
enrichment simple add pests to some plants, not
all allows testing several pest densities
expose plants and pests to natural agent
densities compare pest population densities,
damage with and without agents
present Problems best in areas where pest now
rare how do you distribute pests on the
plants? do pests stay where you put
them? how do you distribute the enriched
plants? Not widely used
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Classical Biological Control (Pages 115-137)
8. Evaluation of biological control (Page
130) As noted earlier, evaluation studies have
been uncommon. Time and money are
limitedGrowers priorities are on problem
solving, not researchScientists prefer familiar
track to quicker publications (Russian wheat
aphid project) However, some studies have moved
well beyond basic evaluation to include
extensive taxonomic, biological and ecological
information, e. g. Bob Lucks studies of the
California red scale (see pages 133 134).
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Classical Biological Control (Pages 115-137)
California red scale (Pages 133
134) Aonidiella aurantii (Maskell) (Homoptera
Diaspididae)Serious pest, kills young citrus
trees Introduced to California ca.
1870 Largely displaced related yellow scale, A.
citri, a minor pest
California red scale Yellow scale color
refers to body, under the wax shield
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Classical Biological Control (Pages 115-137)
California red scale (Pages 133 134) Taxonomic
confusion on scales hampers biological control
Body color was unreliable in scale
taxonomySome early parasitoid shipments were
actually from red yellow scales (A. citri),
useless on red scale (A. aurantii) Stable
taxonomic characters discerned in early
1900s Allowed workers to identify the target
pest
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Classical Biological Control (Pages 115-137)
California red scale (Pages 133 134) Aphytis
chrysomphali (Hymenoptera Aphelinidae) Ectoparas
ite of California red scale Accidentally
introduced ca. 1900 Established only near the
coast Did not give good control
Aphytis sp. parasitizinga diaspidid scale
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Classical Biological Control (Pages 115-137)
California red scale (Pages 133 134) Taxonomic
confusion on Aphytis hampers biological
control All Aphytis parasites found were thought
to be A. chrysomphali until reliable taxonomic
characters found in 1940s. Thus, many shipments
of parasitoids were never made. But, now
workers could recognize additional species of
Aphytis.
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Classical Biological Control (Pages 115-137)

• California red scale (Pages 133 134)
• Aphytis lingnanensis was found in China during
  1948.
• A. lingnanensis offered better control along the
  coast, largely displacing A. chrysomphali
• But, it did not move inland, into the main citrus
  growing areas
• Comperiella bifasciata and Encarsia perniciosi
  (Aphelinidae)also introduced during 1948.

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Classical Biological Control (Pages 115-137)

• California red scale (Pages 133 134)
• Aphytis melinus was found in India during 1957.
• A. melinus offered much better control along the
  coast, largely displacing A. chrysomphali
• More importantly, it moved inland to the main
  citrus areas.
• This is the system Bob Luck studied.
• His findings are interesting and important.

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Classical Biological Control (Pages 115-137)
Aphytis chrysomphali preferentially attacks late
third-instar nymphs Aphytis lingnanensis prefere
ntially attacks early third-instar
nymphs,pre-occupying the niche (intrinsic
superiority) Aphytis melinus attacks
second-instar nymphs,pre-occupying the
niche Thus, the sequence of displacements along
the coast. But, A. melinus is also more tolerant
of high temperatures, thus its success inland
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Classical Biological Control (Pages 115-137)
California red scale (Pages 133 134) Similar
events seen with endoparasites Comperiella and
Encarsia Comperiella bifasciata is more heat
tolerant and occurs inland Encarsia perniciosi
occurs along the coast
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Classical Biological Control (Pages 115-137)
Recent Trends (Pages 134 135) During the 1980s
the number of biological control workers
increased. This allowed an increase in
quarantine facilities,relieving pressure on what
had been a serious bottleneck.It also allowed
states and other agencies to initiate biological
control programs.This contributed to the shift
in funding patterns mentionedearlier in the
semester.It permitted more projects to be
conducted.
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Classical Biological Control (Pages 115-137)
Recent Trends (Pages 134 135) Entomophagous
biological control programs were recognized as
not being ecologically benign.Hawaiian
butterfly eggs attacked by introduced
parasitoids.Coccinella septempunctata
displacing native Coccinella spp. Stopped
importation of Eriopus connexa, but Harmonia
axyridis is already hereImpacts on native
aphids? Compare to Coccinella undecimpunctata
in New Zealand few native aphids, few native
aphidophages, many exotic aphid pests.
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Classical Biological Control (Pages 115-137)
Recent Trends (Pages 134 135) Concerns led to
re-evaluating our multiple agent
lotteryapproach (see Myers. 1989. Environ.
Ent. 18 541-547)She contends most successes
attributable to one agent,this is not
universally accepted. APHIS is working on
protocols to reduce the risks of non-target
impacts in entomophagous programs, but this is
difficult.It is impractical to parallel BC of
weeds host specificity testing,there are just
too many species of insects.So, how safe is
safe enough?