2. Integrated Approach for Resistance
Management of Pink bollworm in
Transgenic Cotton
MUHAMMAD SHAHID
Ph.D Entomology
Supervisor: Prof. Dr. Shafqat Saeed
Department of Entomology
Muhammad Nawaz Shareef University
of Agriculture, Multan
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3. COTTON (Gossypium hirsutum)
๏ Cotton - White Gold
๏ Pakistan
๏Important Cash Crop
๏Backbone of Textile Industry
๏5.2% of the value added in Agriculture
๏About 1.0% of GDP
(Economic Survey of Pakistan, 2016-17)
๏ World
๏45% fiber need is from cotton
๏10% edible oil is from cotton
๏ Losses
๏4.5 million bales losses (Tahir, 2016)
๏The fiber yield reduced by 17-26%
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4. ECONOMIC IMPORTANCE OF COTTON
๏ Cash crop in more than 80 countries.
๏ Grown for clothes purposes.
๏ Seed crushed for edible oil.
๏ Cotton Lint
๏ Cotton Seed
๏ Cotton Seed Cake
๏ Cotton Stem
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5. COTTON
Gossypium hirsutum
Gossypium arborium
Kharif Crop
Tropical & Sub-
Tropical
Desi Cotton.. Mid
March-Mid May
American Cotton
Mid May- Mid June
C3 Plant, Family:
Malvaceae
In-determinate Type
of growth,
Epigeal Mode of
Germination
Deep Rooted,
Optimum pH 5.2-
7.0
Sympodial and
Monopodial
Drill Method,
7+1rauni Irrigation
Seed Cotton &
Cotton Seed
Oftenly Cross-
Pollination
5-6 Kg/Acre,
10-12 Kg/Acre
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7. IMPORTANT INSECTS PESTS OF COTTON
Sucking Pests Bollworms Cotton Stainer Cotton Defoliator
Whitefly American Bollworm Red Cotton Bug Shoot Weevil
Jassid Dusky Cotton Bug Stem Weevil
Aphid Spotted Bollworm Spodoptera leaf
Worm
Mealy Bug
Thrips
Pink
Bollworm
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8. PINK BOLLWORM
Pectinophora gossypiella (Saunders)
Family: Gelechiidae
Order: Lepidoptera
Status:
One of the most destructive pests of cotton
Distribution:
Worldwide especially in the USA, Africa, Australia and Asia
including Pakistan and India
Food Plants:
๏ P. gossypiella was found to prefer okra over cotton towards
the end of the season when the cotton boll surface was hard
(Khidr et al., 1990)
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searchP&q=Pectinophora
+gossypiella
9. DESCRIPTION OF STAGES
Adult:
๏ Dark brown
๏ Fore wings have blackish spots
๏ Hind wings are deeply fringed
๏ 8-9 mm across the spread wings
Eggs:
Oval, White and turns brown later
Larva:
๏ White when newly emerged and turns pink later on. Full grown
larva is 8-10 mm in length
Pupa:
๏ Yellowish brown
๏ Pupation takes place in the ground
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10. LIFE HISTORY
Active period: March-October
Inactive Period: Nov-Feb
Period of maximum activity or damage: July to Sep-Oct
No. of generations: 4-6
Life Cycle: 3-4 weeks
๏ Under optimal conditions, the entire life cycle is completed in 25-
35 days
(Green and Lyon, 1989).
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bm=isch&sa=1&ei=faA6WrnSGoj
OgAbsk7mgBw&q=pectinophora+
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ophora+gossypiella+life&gs 10
11. MODE OF DAMAGE
๏ Only caterpillars cause damage
๏ Larva enter the flower buds
๏ Later on enter into the bolls
๏ Two seeds join together to form a โ Double Seedsโ
๏ Cause shedding of squares, flowers and then bolls
๏ Worst attack from 15th August to first week of
October
๏ Rosette Flowers
๏ Damaged bools fall-off pre-maturely
๏ Poor quality Lint
๏ Lower ginning percentage
๏ Lower oil extraction
๏ Inferior spinning quality
๏ ETL: 5% damage of bolls
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iw=1366&bih=639&tbm=isch&sa=1&ei=uJ86
Wp_XAsifgAacwpawDQ&q=pectinophora+go
ssypiella+damage+symptoms&oq=pectinoph
ora+gossypiella+damage+symptoms&gs
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12. RESISTANCE TO Bt VARIETIES
๏ Transgenic crops commercialized since 1996.
๏ Bacillus thuringiensis (Bt) toxin decrease dependence on
synthetic insecticides in cotton (Wu et al., 2008)
๏ Bt toxins disrupts the midgut membranes
(Morin et al., 2003)
๏ Cry1A family is the most commonly used Bt toxins
๏ Especially Cry1Ac in transgenic Bt cotton
๏ Cry1Ab in transgenic Bt corn
(Tabashnik et al., 2003)
๏ Effectiveness would be decreased by evolution of resistance
by insect pests
(Ferre and Van Rie, 2002; Tabashnik et al., 2013)
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13. ๏ Most of the resistance reported cases belong to Cry1A family
(Tabashnik et al., 2014)
๏ Insect pests developed resistance to Bt crops by different
mechanisms (Tabashnik, 2001)
๏ The resistance is delay by understanding the molecular and genetic
basis of resistance in the insect pests
(Ferre and Van Rie, 2002)
๏ Pink bollworm evolved resistance to Cry1Ac in Bt cotton.
(Zhang et al., 2012)
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14. Management Strategies
Early Season Management Mid Season Management Late Season Management
๏Natural Enemies
๏Planting Date
๏ Natural Enemies ๏ Natural Enemies
๏Host Plant Resistance
(transgenic cotton)
๏ Host Plant Resistance
(Transgenic Cotton)
๏ Plant Phenology
๏Mating Disruption ๏ Mating Disruption Host Plant Resistance
(Transgenic Cotton)
๏ Augmentative Biocontrol ๏ Augmentative Biocontrol ๏ Augmentative Biocontrol
๏ Chemical Control
๏Resistance Management
๏Sterile Insect Release
๏Chemical Control ๏Resistance Management
๏Crop rotation
๏Irrigation Timing (stimulate
emergence)
๏Resistance Management
๏Sterile Insect Release ๏Defoliation
๏Sterile Insect Release
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15. Resistance Management Strategies
Refuge Strategy:
๏ Itโs a primary strategy for delaying pest resistance to Bt crops.
๏ This strategy allowed the susceptible insects mating with resistant
insects, which led to reduce the resistance allele in the pest
population and led to delay the resistance.
(Hutchison et al., 2010; Tabashnik and Gould, 2012).
๏ The refuge strategy is most commonly used to delay resistance in
Bt crops.
(Jin et al., 2015; Shelton et al., 2000; Tabashnik et al., 2008).
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17. Pyramided plants:
๏ Pyramided plants delivering two or more Bt toxins targeting one
pest.
๏ Nowadays, pyramided plants have been broadly used to delay the
development of insect-resistance
(Carriere et al., 2015; Jin et al., 2015; Moar and Anilkumar,
2007; Tabashnik et al., 2015; Zhao et al., 2002, 2003)
๏ Pyramided Bt crops are expected to become even more dominant
in the future
(Brevault et al., 2013)
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18. Modified Bt toxin:
๏ Modified toxins, Cry1AbMod and Cry1AcMod killed
P. gossypiella that had cadherin deletion mutations
๏ These toxins could be valuable for delaying or countering
pest resistance to Cry1A toxins
(Soberon et al., 2007).
Release of Sterile Insects:
๏ Release of sterile insect method successfully used in different
insect pests (Gould and Schliekelman, 2004; Krafsur, 1998)
๏ The application of this technique to suppress pests resistant to
transgenic crops was first reported by Tabashnik by
using computer stimulation study in 2010
๏ The resistance of pink bollworm in Bt cotton was suppressed by
release of sterile insects
(Tabashnik et al., 2010)
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19. Natural enemies:
๏ The preservation of natural enemies could delay resistance
development in Bt crops.
๏ These study exhibited that natural enemies could delay the
resistance to Bt plants and have significant effects on integrated pest
management (IPM) in Bt crops.
๏ Trichogramma chilonis destroy its eggs
๏ Larvae are parasitized by Apanteles sp. and Bracon sp.
๏ Chrysoperla carnia
(Liu et al., 2014)
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20. Seed mixtures:
๏ Seed mixtures strategy is also used to delay resistance to Bt crops,
planting seed mixtures yielding random disseminations of non-Bt
corn plants and pyramided Bt plants within fields, were effective
only on pests with little inherent susceptibility to Bt toxins.
(Carriere et al., 2016)
๏ Different study reported that the seed mixtures strategies had low
efficiency in delaying resistance in pests with movable larvae and
inherently low susceptibility to Bt toxins.
(Brevault et al., 2015)
๏ Thus, seed mixture strategies might be suitable for delaying
resistance when used with other strategies.
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21. Pheromone Traps:
๏ Gossyplure-baited traps have proved to be highly effective
(Beasley et al., 1985)
๏ The numbers of male moths caught 3ยฑ4 days prior to the first
squaring of cotton are positively correlated to the lower infestations
during the first fruiting cycle.
(Beasley et al., 1985).
๏ Careful monitoring of pheromone traps
๏ Early-season lower the infestations can provide useful information
for estimating the extent and magnitude of the moth population that
will subsequently oviposit and produce economic infestations of
larvae in bolls.
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22. Planting date:
๏ Approximately 95% of PBW moths emerge from overwintering
during mid-March through to mid-June
(Slosser and Watson, 1972; Bariola, 1978).
๏ Delayed planting can prolong the period of suicidal emergence, but
may not be practical in all areas
(Adkisson et al., 1962; Henneberry et al., 1982)
๏ However, it may be a useful management tool in areas where good
plant stands can be established later in the season
๏ Uniform planting dates must be accepted by all growers in a
management area to avoid variability in the plant phenology and
different stages of cotton fruiting development.
(Henneberry et al., 1982)
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23. NON-CHEMICAL CONTROL
๏ Destruction of off-season cotton-sprouts
๏ Destruction of alternate host plant
๏ Grazing of goats and sheep on un-wanted bolls.
๏ Deep ploughing to bury the affected bolls.
๏ Trichogramma chilonis destroy its eggs
๏ Larvae are parasitized by Apanteles sp. , Bracon sp. and Chelonus
sp.
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24. Reduction of Pink Bollworm
๏ Bt cotton must be grown
๏ These genes produce proteins that are toxic to most leaf and fruit
feeding caterpillars after ingestion
๏ Bollgardยฎ cotton varieties were introduced in 1996 and contain
only one gene (Cry1Ac)
๏ Since then varieties containing multiple genes to control these
caterpillars are now available
๏ Bollgardยฎ II contains two genes(Cry 1Ac and Cry 2Ab)
๏ Bt cotton is very effective against the PBW and it has been a key
component of PBW eradication programs.
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25. Conclusion
๏ Bt cotton cultivation
๏ Area wide management
๏ To follow these management strategies
๏ Natural enemies should be preserved
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