History-methods-progress -advantages and limitations

1. STERILE INSECT TECHNIQUE
Presented by:
K.SANKARA RAO
13-503-003

2. INTRODUCTION
HISTORY AND DEVELOPMENT
CURRENT TARGETS
MASS REARING
INDUCTION OF STERILITY
FIELD RELEASE AND EVALUTION
ADVANTAGES AND LIMITATIONS
CONTENTS OF PRESENTATION(SIT)

3.  Insect pests contribute significantly to the high prevalence of undernourishment in
the world.
 New, innovative pest control tactics and strategies are therefore needed that are
both effective and not detrimental to the environment.
As part of the of environmentally-friendly control tactics, the sterile insect
technique (SIT) has proven to be a very effective tool pest management.
INTRODUCTION
Use where Insect pests for which effective and affordable alternative controls are
not available (Lance and McInnis,2005).

4. BIOLOGICAL
CONTROL
GENETIC
CONTROL
STERLIE INSECT
TECHNIQUE
LETHAL
MUTATIONS
STERILE INSECT TECHNIQUE

5. NORMAL
FEMALE
STERILE
MALE
UNFERTILISED EGGS
Continued sterile male releases ,the population decline
Ratio of sterile to normal male increases until no nomal male remain.
The population becomes extinct for lack of progeny
Sterile Insect Technique is the method of genetic control comes broadly
under biological control

6. Eradication of pest not merely suppression(Hendrichs et al., 2005)
(usually crop pests or human and animal pests)
Autocidal control
OBJECTIVE OF SIT
PRINCIPLE OF SIT

7. Sterile Insect Technique (SIT) was initiated by E.F. Knipling and R.C. Bushland in
the 1930s
They worked with the screwworm fly, a devastating pest of cattle in North America.
 Bushland initially researched chemical treatment of screwworm-infested wounds in
cattle
Knipling developed the theory of autocidal control – breaking the life cycle of the
pest itself.
The first successful use of SIT to control screwworm was on the island of Curaçao in
1953.
Development of the sterile insect technique

8. screwworm fly life cycle

9. FEMALE SCREWWORM MATES
ONLY ONCE IN HER LIFETIME
REASON BEHIND THE SUCCESS OF SIT

10. HYPOTHETICAL MODEL DEVELOPED BY KNIPLING
GENERATION
NATURAL
POPULATION
STERILE
INSECTS
RELEASED
S:F
MATINGS
INFERTILE
%PROGE
NY
NO.OF
FERTILRE
1 1000 2000 2:1 665.1 333
2 333 2000 6:1 85.7 47
3 47 2000 42:1 97.7 1
4 1 2000 2000:1 99.9 0

11. Sterile insects have a unique biological advantage that matches them very well to the
concept of eradication, i.e. their effectiveness increases as the pest population
declines in numbers: their action is inversely dependent on the density of the target
population (Dame, 1970).
USE OF SIT IN IPM

12.  In 1954, the technique was used to completely eradicate screwworms from the
176-square-mile (460 km2) island of Curaçao
 Screwworms were eliminated in a span of only seven weeks, saving the domestic
goat herds that were a source of meat and milk for the island people.
SUCCESSFUL ERADICATION OF SCREWWORM

13.  During the 1960s and 1970s, SIT was used to control the
screwworm population in the United States.
 The 1980s saw Mexico and Belizium eliminate their screw worm
problems through the use of SIT
 In 1991, Knipling and Bushland's technique halted a serious
outbreak in northern Africa.
Screw worm erdication……..

14. Success stories
 Screwworm fly (Cochliomyia hominivorax) eradicated from the United States,
Mexico, and Libya
 Mexican fruit fly (Anastrepha ludens) eradicated from most of northern Mexico.
 Tsetse fly eradicated from Zanzibar
 Medfly (Ceratitis capitata) from northern part of Chile and southern part of Peru and
southern part of Mexico.
Melon fly (Bactrocera cucurbitae, Coquillett) eradicated from, Japan
The sterile fly is an innovative solution to the problem of the African
trypanosomiasis

15. Anopheles sp.
Aedes sp
TARGET INSECTS

16. Medfly Ceratitis capitata

17. Painted Apple Moth Teia anartoides
Codling moth Cydia pomonella

18. Tsetse fly Glossina spp
Mexican fruit fly Anastrepha ludens

19. SL.NO COMMON NAME ENTOMOLOGICAL
NAME
REASON OF RELEASE
place
1.
Mosquito Anopheles sp. MALARIA vector AFRICA
2.
Mosquito Aedes sp. vectors for filariasis dengue
and yellow fever
AFRICA
3. Painted Apple Moth Teia anartoides Borer pest of apple
NEW ZEALAND
4. Codling moth Cydia pomonella BRITISH COLUMBIA,
CANADA
5. Tsetse fly Glossina spp sleeping sickness vector
6. Mexican fruit fly Anastrepha ludens USA
7. Medfly Ceratitis capitis
8. Queensland fruit fly Bactrocera tryoni AUSTRALIA
9. other
Bactrocera sp. ASIA
C
U
R
R
E
N
T
TARGETS

20. MASS REARING OF INSECTS
Research toward mass production must emphasize on
1.Food or rearing media
2.Techniques for extracting all stages from the media
3.Techniques to avoid crowding
4.Information on mating and oviposition behaviour
5.Rearing room islolation
6.Maximum automation

21. Mediterranean fruit fly mass-rearing facility in El Pino,
Guatemala
Heat treatment of eggs Racks of cages with adult flies Larval rearing trays
Attention need at rearing:
Selection of artificial diet
Waste disposal
Biosecurity in a pest free area

22. Mass production of sterile insects across the globe
source:Marc J.B. Vreysen*, Alan S. Robinson(2010)

23. Commonly using method
Both sexes are irradiated ,sterilized and released but sterile females have
no desired effect on outcome, because species vary in the dose of radiation
Pupal stage appropriate stage for irradiation(Holometaba)
Lastal nymphal instar (Hemimetabola)
Sources : x-rays
Gama-rays
IRRADIARTION
Mode of action:
Radiation induces dominant lethal mutations in normal sperm
and in sperm carrying unbalanced chromosomes at equal
frequency and in an exponential
manner. (Franz,2000)

24. Ionising radiation also causes mutations in somatic cells
This impacts on the overall quality of the insect after radiation
expressed as the development of abnormalities,a reduction in
lifespan, flight ability, mating propensity, etc. (Bakri et al., 2005).
Sensitivity levels of insects to ionising radiation are affected by the level of oxygen
present during irradiation (Economopoulos, 1977; Fisher, 1997)
.
IRRADIARTION cont…….

25. Sterilizing effects of x-rays on insects had been observed as early
as 1916 with cigarette beetle results infertile eggs
After 10 years effect on drosophila also observed by generation of
mutations lead discovery of x-ray impact on screw worm pupae by
Bushland.
Mutations a s a result of complex injury in the sperm.
In 1950 screw worm pupae were irradiated at a dose of 2500 R
X-rays

26. After world war –(2 ) isotopes availabity helps in use of gama radiation
Commonly used sources are cobalt- 60 and Cesium-137
Availability of cobalt-60 sources was an important factor.
Effect as same as x rays but decrease the longevity of males
GAMA RAYS:

27. PROCEDURE
Scientific name Common name stage Sterilising dose(rads)
Musa domestica House fly 2-3 days pupal 3000
Cochliomyia homnivorax Screwworm fly 5 days pupae
1day adult
2500
Drosophila melanogaster Fruit fly Adult males 5000-7000
Culex quinquefasciatus House mosquito pupae 11000-12000
Apis mellifera Italian honeybee Adults 7700
Sitophilus oryzae Rice weevil 7-days adults 7500-11000
Tribolium confusum Confused flour
beetle
Old pupae 4000

28. Chemosterilants divided into 4 basic groups
1)Alkylating reagents- Largest class -ex: Aholate,Aphomate,Aphoxide
2)Phosphorous amides
3)Traizines
4)Antimetabolites ex:5-Fluorouracil,2-Thiouracil
cause multiple dominant lethal mutations or severely injured genetic material in sperm or
egg
TEPA-House fly control(1962)
Aholate-cotton boll weevil.
Recently Diflubenzuron using as chemosterilant in adult diet along with gama radiation
CHEMOSTERILISATION
Mode of action

29. Techniques for release
1.Aeril release-using aircrafts
2.Ground release
If the release is delayed ,survival can be increased by chilling treatment
All-terrain vehicle (ATV)

30. EVALUATION OF SIT PROGRAMME
1.Male fly sterility checking at laboratory
2.Performance of sterile insects in field.

31. Conditions for effective SIT
•An effective and reasonably economic method of mass rearing of the
target insect.
• The released insect must disperse rapidly through the wild
population.
• Sterilization must not affect sexual competitiveness
• Females preferably mate only once.
• It must be possible to overwhelm the native population with sterile
insects (ratio of sterile to fertile fertile males of at least 10:1,
preferably higher)

32. 1. The most target-specific
2. Non-disruptive method
3. It uses no chemicals,leaves no residues
4. Species specific
5. Does not release exotic agents into environments
6. Does not even introduce new genetic material into existing populations
7. improve the quality and quantity of fruit production while reducing
pesticide use and promoting ipm
ADVANTAGES:

33.  Costs of production [the major drawback]
 Must provide reliable sterilization
 Must have reliable supply of sterile insects
Regional cooperation
 Released insects must be competitive with wild Insects for
mating
 Lab rearing quality control issues
Sterilization quality control issues
Sterile insects should not inflict direct damage
Re-invasion of sterility zone
LIMITATIONS WITH SIT

34.  Use of juvenile hormone including methoprene and
fenoxycarb and protein diets in mass-rearing.
 Use of genetic sexing strains(GSS)
Conditions for effective SIT…..
The introduction of the filter rearing system (FRS) into GSS mass rearing

35. Ionising radiation and area-wide management of insect pests to promote sustainable agriculture. A review
-Marc J.B. Vreysen*, Alan S. Robinson
Mass rearing history and irradiation affect mating performance of the male fruit fly, Anastrepha obliqua
-Juan Rull*, Nery Encarnación, and Andrea Birke
Sterile Insect Technique for Suppressing and Eradicating Insect Population: 55 Years and
Counting-
-E. S. Krafsur
Genetic sexing strains in medfly, Ceratitis capitata, sterile insect technique programmes
- A.S. Robinson
References