Title: Classical Biological Control Pages 115137
1Classical 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.
2Classical 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
3Classical 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.
4Classical 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
5Classical 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.
6Classical 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.
7Classical 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
8Classical 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
9Classical 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)
10Classical 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?
11Classical 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.
12Classical 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.
13Classical 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)
14Classical 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
15Classical 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
16Classical 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
17Classical 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
18Classical 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
19Classical 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
20Classical 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
21Classical 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
22Classical 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.
23Classical 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
24Classical 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
25Classical 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
26Classical 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
27Classical 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?
28Classical 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
29Classical 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
30Classical 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
31Classical 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
32Classical 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)
33Classical 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)
34Classical 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
35Classical 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.
36Classical 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
37Classical 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
38Classical 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
39Classical 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)
40Classical 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.
41Classical 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.
42Classical 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
43Classical 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
44Classical 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
45Classical 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
46Classical 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)
47Classical 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
48Classical 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).
49Classical 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
50Classical 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
51Classical 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
52Classical 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.
53Classical 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.
54Classical 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.
55Classical 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
56Classical 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
57Classical 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.
58Classical 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.
59Classical 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?