TRICHOGRAMMATIDS IN BIOLOGICAL CONTROL OF INSECT PESTS

1. TRICHOGRAMMATIDS IN BIOLOGICAL
CONTROL OF INSECT PESTS
Dr. Mandeep Rathee

2. INTRODUCTION
• At global platform, Trichogrammatidae are represented by 89 genera
and 840 species (Querino et al., 2010).
• In India, many species of Trichogramma and Trichogrammatoidea have
been used in applied/augmentative biological control programmes (Singh
and Jalali, 1994)
• In India, about 28 species of Trichogramma and about 8 species of
Trichogrammatoidea are known to occur naturally (Sithanantham, 2013)
• Trichogrammatids, commonly known stingless wasps (Hymenoptera:
Chalcidoidea: Trichogrammatidae), are tiny (0.2 to 1.5 mm)
endoparasitoids that parasitize the eggs of holometabolous orders mainly
Lepidoptera and of Coleoptera, Diptera, Hemiptera, Orthoptera and
Thysanoptera as well.
• Of these, the genus Trichogramma Westwood, with about 250 species
distributed across the world, is the most important one from the applied
point of view

3. • The first Trichogramma species was described by Charles V.
Riley in North America in 1871 as Trichogramma minutum
from eggs of the Viceroy butterfly, Limenitis archippus Cramer
(Riley, 1871; Smith and Smith, 1996).
• It was first mass reared in 1926 on eggs of Angoumois grain
moth, Sitotroga cerealella Olivier, later Flanders (1930) enabled
the large-scale multiplication of Trichogramma on the eggs of
S. cerealella.

4. Distinguishing features: Trichogramma and Trichogrammatoidea
Trichogramma Trichogrammatoidea
Vein track RS1 present in the forewings Vein track RS1 absent
Flagellum of male antenna
unsegmented with two slight
constrictions below
Flagellum of male antenna 5 segmented with
two funicular segments and a 3 segmented
club
Marginal fringe of setae on forewings
short, not more than one-fifth the
width of wing. Discal setae close,
arranged in distinct rows
Marginal fringe of setae distinctly much longer,
measuring one-fourth to three-fourth the
width of wing. Discal setae sparser and
arranged irregularly
Cilia on the hindwings are longer Cilia on the hindwings are shorter
Male genitalia with dorsal expansion
of gonobase of variable shape
Male genitalia without dorsal expansion of
gonobase

6. Domain Eukaryota
Kingdom Metazoa
Phylum Arthropoda
Subphylum Uniramia
Class Insecta
Order Hymenoptera
Suborder Apocrita
Superfamily Chalcidoidea
Family Trichogrammatidae
Genera Trichogramma & Trichogrammatoidea
Scientific classification of Trichogrammatids

7. Biology of Trichogrammatids
• Trichogramma, like other hymenopterans, are haplodiploid, where
males develop from haploid eggs, and females develop from diploid
eggs.
• The female wasp augers a hole through the egg chorion, oviposits its
egg (0.1 mm) within the host egg, and then feeds on yolk that exudes
from the hole.
• A female parasitoid has innate ability to differentiate previously
parasitised eggs, that help avoid super or multiple-parasitism under
field conditions.
• Large-sized females are known to parasitize more eggs than smaller
ones.
• Further, depending upon the size of the host egg, the number of eggs
laid per host egg may vary from 1 to 20 or more.
• Fecundity may vary from 20-200 eggs per female.

8. Mass rearing of Trichogrammatids
• The Trichogramma endoparasitoids, as biocontrol agents, can be
produced quickly and affordably relative to other parasitoids because
of (a) short life cycle (8-10 days from egg laying to adult emergence);
(b) high breeding potential (female can lay eggs for 7-8 actively days);
(c) high proportion of female offspring (60.0-90.0%); (d) adaptation to
the fictitious laboratory host for mass multiplication (Mansour, 2010).
• Most commonly used factitious hosts in India are rice moth,
Corcyra cephalonica Stainton, rice grain moth, S. cerealella, the flour
moth, Ephestia kuehniella Zeller (Nagaraja, 2013) and eri silkworm,
Samia cynthia ricini Donovan (Manisha et al., 2017; 2020).

9. Maa rearing of Trichogrammatids
• Sharma et al. (2016) standardized that the optimal number of
inoculative eggs for the rearing of C. cephalonica should be 0.20 cc per
box, each having 2.5 kg of milled sorghum for maximizing its
production competence.
• Recently, Manish et al. (2017; 2020) reported that eri silkworm, S.
cynthia ricini could be used as an alternate host to rice moth in
Trichogramma production, because eri silkworm as laboratory host
yields trichogrammatids with superior parasitization (76.3%), adult
emergence (9-18/egg), female emergence (86.6%) and adult longevity
(6 days) as compared to C. cephalonica (74.3%, 1/egg, 67.3% and 3
days, respectively).

10. Trichocard method of mass production of Trichogramma spp.
 Trichocards: White or coloured cards containing host eggs parasitized by
Trichogramma are known as trichocards
 Preferred laboratory host: C. cephalonica eggs
 Initially to prevent hatching, the collected eggs of C. cephalonica are treated
with UV radiations for 45 minutes
 Cards of size 15 x 12 cm are cut out of white sheets
 Later on, mechanical pre-punched is done is these cards to facilitate cutting
into small strips
 Gum Arabic (10%) coat is applied on the grids and the C. cephalonica eggs are
sprinkled uniformly using a tea strainer

11. Trichocard method of mass production of Trichogramma spp.
 To prepare sentinel Corcyra cards the eggs are glued on an area of 15 x 10 cm
leaving margin of 1 cm on both sides to staple these cards on the leaves or
other plant parts.
 Information pertaining to the manufacturer, parasitoid species, date of
parasitization and date of emergence are also labeled on the remaining space
 After air drying the cards under fan, the excess eggs are brushed away gently
 The unparasitized egg cards are then shifted into glass jars and exposed to
adult Trichogramma females in the ratio of 8:1 for 24 hours
 Within 3 or 4 days, the eggs on the trichocard get parasitized and turn back
 6-day-old trichocards are prepared for field release
 Each trichocard contains about 20,000 parasitized eggs

12. Trichocard method of mass production of Trichogramma spp.
 To delay the emergence of Trichogramma, these cards can be stored in
refrigerator at 5-10°C for 10-15 days
 Standards: 95±5 per cent egg parasitization, 90±5 per cent adult emergence,
and a sex ratio of 1: 1.5, female: male
 Different dosages are recommended for different insect-pests in particular
crops
 For laboratory mass production trichocards of green colour are most suitable
followed by white (Mehendale, 2009; Dileep, 2012; Mahal, 2021)
 These trichocards are available at the Biocontrol Lababoratory, Regional
Research Station, Karnal, CCSHAU, Hisar, Haryana and Department of
Entomology and Regional Stations, Abohar, Gurdaspur and Bathinda, PAU,
Ludhiana, Punjab.

13. Field releases of Trichogramma spp.
• Sugarcane: One trichocard with 20,000 parasitized eggs is cut into 40 small
strips (5 x 0.75 cm), each having approximately 500 parasitized eggs. These
strips are later stapled on the underside of leaves at 16 spots/hectare in a
uniform manner.
• Organic rice: Two trichocards, one each of T. chilonis and T. japonicum are
into 40 small strips (5 x 1.5 cm), each having approximately 1000 parasitized
eggs. These strips are later stapled on the underside of leaves at 16
spots/hectare in a uniform manner.
• Maize: Two trichocards of T. chilonis are into 40 small strips (5 x 1.5 cm), each
having approximately 1000 parasitized eggs. These strips are later stapled on
the underside of central whorl of leaves at 16 spots/hectare in a uniform
manner (Shera et al., 2019).

14. Importance of Quality Components in Trichogramma
production and use
Bigler, 2000

15. History of classical biological control through exotic trichogrammatids introduced
into India
Natural enemy Source/year of
introduction
Pest/crop/status
release
Trichogramma
australicum
Girault
Taiwan, 1963;
Trinidad, West
Indies, 1981
Released and recovered from eggs of sugarcane
internode borer, Chilo sacchariphagus indicus
Kapur
Trichogramma
fasciatum
(Perkins)
Barbados, 1965 Released and recovered in sugarcane fields and
recovered from eggs of Chilo spp. and S.
excerptalis
Trichogramma
perkinsi Girault
Colombia, 1966 Introduced against borers of sugarcane, recovered
from eggs of Plassey borer, Chilo tumidicostalis
Hampson and stalk borer, C. auricilius
Trichogrammatoi
dea brasiliensis
(Ashmead)
Trichogramma
pretiosum Riley
South America via
California, USA,
1968 and 1982;
France, 2007
Released and recovered from sugarcane tissue
borers; Helicoverpa armigera Hubner on tomatoes
and cotton; pink bollworm, Pectinophora
gossypiella Saunders on cotton and okra
(Source: Sankaran,1974; Singh, 2004; NBAIR, 2021)

16. Natural enemy Source/year of
introduction
Pest/crop/status
release
Trichogramma
cacaeciae
Marchal
France, 1978 and
2007
Released and recovered from codling moth, Cydia
pomonella Linnaeus on apple
Trichogramma
japonicum
Ashmead
The Philippines,
1963;
Trinidad, West
Indies, 1979
Released and recovered from eggs of Gurdaspur
borer, Bissetia steniella (Hampson); sugarcane
shoot borer, C. infuscatellus and Scirpophaga spp.
in sugarcane fields
Trichogramma
embryophagum
(Hartig)
Rumania, 1978;
Germany, 1988;
France, 2007
Released and recovered from C. pomonella on
apple
Trichogrammatoi
dea bactrae
Nagaraja
Taiwan, 1992 Released and recovered from diamond back
moth, Plutella xylostella Linnaeus
Trichogramma
evanescens
Westwood
Colombia, 1966;
France, 2007
Released and recovered in sugarcane fields and
recovered from eggs of Chilo spp. and S.
excerptalis
(Source: Sankaran,1974; Singh, 2004; NBAIR, 2021)

17. Trichogrammatids maintained at NBAIR, Bangalore and recommendations in IPM
Natural
enemy
Source/year of
introduction
Pest/crop/status
release
T. chilonis Sugarcane borers: C. infuscatellus, C.
sacchariphagus indicus, C. auricilius & B. steniella
Cotton (non-Bt) bollworms:
H. armigera, Earias spp. & P. gossypiella (being
reported in Bt as well)
Maize stem borer: C. partellus
Diamond back moth: P. xylostella
Tomato fruit borer: H. armigera
50,000/ha on sugarcane and
vegetables; 1,00,000/ha on
maize and 1,50,000/ha on
cotton
T. japonicum Sugarcane:
Top shoot borer: S. excerptalis
Paddy:
Yellow stem borer: S. incertulas
50,000/ha
T. achaeae Cotton (non-Bt) bollworms 1,50,000/ha on cotton (non-Bt)
50,000/ha on vegetables
(Source: www.nbair.org; NBAIR, 2021)

18. Trichogrammatids maintained at NBAIR, Bangalore and recommendations in IPM
Natural
enemy
Source/year of
introduction
Pest/crop/status
release
T. pretiosum Tomato fruit borer: H. armigera 50,000/ha
T.
embryophagu
m
Apple codling moth: C. pomonella 2,000 adults per tree or
1,00,000/ha
T. brassicae Borers on cabbage and cauliflower:
Diamondback moth: P. xylostella Cabbage
butterfly: Pieris brassicae L.
1,00,000/ha
Tr. bactrae Borers on cabbage and cauliflower:
Diamondback moth, P. xylostella
2,50,000/ha
(Source: www.nbair.org; NBAIR, 2021)

19. Trichogrammatids used in augmentative biological
control in India
Trichogramma achaeae Nagaraja & Nagarkatti
Trichogramma pretiosum Riley
Trichogramma chilonis Ishii
Trichogramma chilotraeae Nagaraja & Nagarkatti
Trichogramma embryophagum Hartig
Trichogramma japonicum Ashmead
Trichogrammatoidea bactrae Nagaraja

20. Role of Trichogrammatids in biological control
of cotton insect pests
Common
Name
Sc. Name Order: Family
Spotted
bollworm
Earias vittella Fabricius (Lepidoptera: Noctuidae)
Spiny
bollworm
Earias insulana Boisduval (Lepidoptera: Noctuidae)
Pink
Bollworm
Pectinophora gossypiella
Saunders
(Lepidoptera: Gelechiidae)
American
Bollworm
Helicoverpa armigera Hubner (Lepidoptera: Noctuidae)
The major target insect pests

21. Trichocards
• Card containing parasitized host eggs (Corcyra cephalonica) safely packed
in packets indicating date of emergence of adult trichogrammatids
• Each Trichocard contain about 20,000 parasitized eggs
• 6 day-old trichocards are prepared for field release
• Different dosages are recommended for different insects pests in
particular crops

22. Precautions for field release
• Trichocard should be packed keeping parasitized surface on inner side
• Emergence date should be specified on cards
• Cut piece of trichocard should be stapled on inner side of leaf to avoid
direct sunlight
• Use safer pesticides either 15 days before or after trichogramma release

23. Parasitoids of Earias spp.

24. Parasitoids of Pectinophora gossypiella

25. • Bollworms have been the most serious pests of non-Bt cotton in India.
Among these bollworms viz., spiny bollworm, E. insulana, spotted
bollworm, E. vittella, American bollworm, H. armigera and pink
bollworm, P. gossypiella have posed greater threats to the production of
non-Bt cotton.
• Before the introduction of Bt cotton hybrids, inundative release of
parasitoids have been reported to play a significant role in suppressing
the bollworms.
• In early 1940’s, Cherian and Margabandhu (1943) recorded 60.0-100.0
per cent egg parasitism of E. vittella by Trichogramma spp. and 22.0
per cent decline in boll infestation at Coimbatore, Tamil Nadu.
• Dhumal and coworkers (1982) reported that 7 releases of T. pretiosum,
Apanteles angaleti Muesebeck and Chelonus blackburni Cameron at
10-day interval beginning from 45 days old crop reduced the bollworm
infestation by 55.5 per cent in cotton grown in Maharashtra.
• Inundative releases of T. pretiosum and C. blackburni at 7 to 10 days
interval parasitized 65.0-72.0 and 37.0-89.0 per cent population of
bollworms in Punjab and Haryana, respectively (Singh, 1985).

26. • Sekhon and Varma (1985) recorded 27.2 per cent parasitization of E. vittella
eggs by T. achaeae from Punjab. Inundative releases of the egg parasitoid @
2,00,000/ha at 10 days interval resulted in 55.7 per cent decline in the
bollworm incidence and the yields increased by 43.6 per cent (Brar et al.,
1991).
• In Punjab, Varma and Gill (1992) reported 20.0-45.0 per cent reduction in
boll infestation by releasing Trichogramma spp. @ 1,50,000/ha at 10-day
intervals in cotton crop.
• Comparatively higher parasitization of E. vittella eggs by Trichogramma
spp. (88.6%) was recorded in cotton + Senna occidentalis L. (Link) (3:1) by
Yadav and Jha (2002; 2003) as compared to sole cotton crop (10.9%), in
Gujarat.

27. • Inundative releases of T. chilonis remarkably reduced the incidence
of cotton bollworm H. armigera to the extent of 43.0 per cent in
Andhra Pradesh (Bhat et al., 2004).
• Kumar et al. (2009) reported 25.0 per cent natural parasitization of
H. armigera eggs from cotton fields at Hisar, Haryana.
• Recently, the Bt-resistant P. gossypiella has been reported from
North Zone of India including Haryana and Punjab (Kumar et al.,
2020), and the role of Trichogramma parasitoids becomes crucial to
manage this pest and avoid any forthcoming epidemic in coming
years.

28. Field trial with MITS of T. chilonis against
cotton bollworms in Coimbatore
Treatment Mean % parasitism Mean % damage
of fruiting bodies
Released plots 9.40 4.00
Control plots 0.00 10.50
CD at 5% 3.35 0.42
Anon. (2003)

29. Field trial with MITS of T. chilonis against
cotton bollworms in Anand, Gujarat
Treatments % Egg
parasitism
% Square
damage
% Boll
damage
Yield (q./ha.)
MITS 32.19 8.17 15.98 18.94
Local strain 28.25 8.23 16.32 18.05
GAU
practices
8.71 6.65 15.32 17.36
Control 15.70 15.67 26.67 12.50
S.Em ± 0.89 0.26 0.19 0.28
CD at 5% 3.10 0.90 0.65 1.00
Anon. (2003)

30. Field evaluation of pesticide tolerant strain of T. chilonis
on cotton in Ferozpur, Punjab
Treatments Incidence in
Fruiting
Bodies(%)
Incidence in
Green bolls
(%)
Parasitism % in
H. armigera eggs
Yield
(q./ha.)
PT strain 7.98
(16.31)
9.93
(18.34)
10.93
(19.28)
16.12
PAU strain 8.88
(17.29)
11.14
(19.46)
9.14
(17.57)
15.80
PAU spray
schedule
10.40
(18.79)
15.12
(22.83)
0.00
(0.00)
15.10
Control 50.87
(45.48)
43.20
(41.05)
1.20
(6.21)
2.48
CD(P=0.05) 2.33 3.00 1.20 0.71
Anon. (2004)
(Values in the parentheses are original values of arcsine transformation)

31. Parasitism of H. armigera eggs by Trichogramma
species in the laboratory
S. No. Trichogramma species Mean parasitism (%)
1 T. chilonis 66.7 ± 5.0 (55.2)a
2 T. brasiliense 50.1 ± 3.3 (45.2)b
3 T. pretiosum 76.7 ± 4.5 (61.6)a
CD (0.05) 13.1
Ballal and Singh, 2003

32. Effect of different release rates of Trichogramma
species on H. armigera parasitization in sunflower
Ballal and Singh, 2003

33. Role of Trichogrammatids in biolgical control of Sugarcane Borers
Common Name Sc. Name
Early Shoot Borer Chilo infuscatellus Snellen
Inter node Borer Chilo sacchariphagus indicus (Kapur)
Top Shoot Borer Scirpophaga excerptalis Walker
Stalk Borer Chilo auricilius Dudgeon
Root Borer Polyocha depressella Swinhoe
Gurdaspur Borer Bissetia steniella (Hampson)
Pink Borer Sesamia inferens Walker
Plassey borer Chilo tumidicostalis Hampson
The major target insect pests

34. • Borer complex on sugarcane in India include namely the early shoot borer (ESB), C.
infuscatellus; internode borer (INB), C. sacchariphagus indicus; top shoot borer
(TSB), S. excerptalis; stalk borer (STB), C. auricilius; root borer (RTB), Polyocha
depressella Swinhoe; pink stem borer (PSB), Sesamia inferens Walker; Gurdaspur
borer (GSB), B. steniella and Plassey borer (PLB), C. tumidicostalis (Kalra, 1979).
• It is quite difficult to control the larval stage of sugarcane borers as it remains hidden
in the cane leaves and the dense crop growth also hinder chemical application,
therefore, targeting the egg stage seems the best option to manage these devastating
pests. The egg parasitoids are key factors in minimizing the intensity of borer
infestation (Nagarkatti, 1980).
• The scope for using Trichogramma spp. as biological control agents for sugarcane
borers has been well documented (Sithanantham et al., 1982; David and
Easwaramoorthy, 1990; Srikanth et al., 2016; Srikanth, 2019) in India.

35. • In mid-sixties, Rao et al. (1966) reported that Trichogramma releases led to high levels
of parasitization (62.0-90.0%) in C. infuscatellus eggs in sugarcane fields at Mysore,
Karnataka.
• INB on sugarcane was observed to be heavily parasitized (7.0 to 55.0%) by T.
japonicum at Cuddalore, Tamil Nadu (Venugopal et al., 1968).
• Remarkable reduction in the dead heart appearance due to ESB (58.0%) and INB (
28.0%) was reported by Kamalakara Rao (1980) in Andhra Pradesh.
• The inundative releases of T. chilonis @ 50,000 per ha at 10-15-day intervals reduced
the incidence of C. auricilius to 12.6 per cent in the colonized areas (Varma et al.,
1991).
• Kalyanasundaram and coworkers (1992; 1993) demonstrated that 6 releases of T.
chilonis (@ 40,000/ha) at 15-day intervals significantly lowered the incidence of INB
from 12.6 to 2.9 per cent.

36. • Rajendran and Gopalan (1995) reported T. chilonis as the most efficient biocontrol
agent with 56.0 per cent reduction in the incidence of INB.
• Rachappa and Naik (2000) reported that 4 releases of T. chilonis @ 50,000/ha at
fortnightly intervals after 45 days of planting resulted in significantly higher mean
parasitism of C. infuscatellus eggs in sugarcane + coriander (30.5%) as compared to
sugarcane alone (21.2%).
• In Ludhiana district of Punjab, 6 releases of T. japonicum at 10-day intervals @
50,000/ha against S. excerptalis significantly reduced the incidence in parasitoid-
released plots (7.5%) compared to control plots (15.7%) (Anonymous, 2005).
• The release of Ludhiana strain of T. chilonis @ 50,000/ha at 10-day intervals from
April to June against ESB revealed almost similar incidence in parasitoid release field
(9.8%) and insecticide treated field (9.4%).
• Releases of T. chilonis @ 50,000/ha for 11-12 times in sugarcane from July to October
reduced STB incidence by 55.0-60.0 per cent.

37. • The reduction in damage was 54.2 per cent over chemical control and 56.1 per cent
over untreated control at Ludhiana.
• The cost-benefit analysis of T. chilonis releases in sugarcane for internode borer
biocontrol showed that the benefit cost ratio exceeds 1:10, both for 6 releases and for
24 releases, which lend support to the scope for maximization of impact without
sacrificing the attractiveness of the profit margin (Kaur and Brar, 2008).
• More than 50.0 per cent reduction in the incidence of C. infuscatellus was reported
by Singh et al. (2007) with 9 releases of high temperature tolerant PDBC strain of T.
chilonis (52.7%) and Ludhiana strain (50.5%) @ 50,000 parasitoids/ha.
• The mean parasitization of the ESB by temperature tolerant strain of T. chilonis
(31.7%) and Ludhiana strain (31.1%) was significantly higher than the untreated
control (4.9%) and chemical control (4.6%) as reported by Virk et al. (2008).
• Geetha (2010) found that releases of T. chilonis at 12.5 cc/ha resulted in the highest
reduction of INB incidence (29.9%) and maximum yield (25.9%).

38. • Yalawar et al. (2010) reported that T. chilonis resulted in 39.7-54.9 per cent
reduction in INB incidence in sugarcane at Bhadra, Karnataka.
• Padmasri and Sudhrani (2014) reported that average intensity of INB damage
decreased to 70.70 and 53.87 per cent, and mean damage decreased to 64.9 and 49.6
per cent in 2011 and 2012, respectively, by releasing T. chilonis at 15-day intervals
during mid-July to mid-October.
• Visalakshi et al. (2016) obtained marked reduction in the incidence of ESB (89.7%)
and INB (18.8%) along with enhanced cane yields (14.43 tonnes/ha) by releasing T.
chilonis @ 50,000/ha, four times at 7-10-day intervals and twice after the node
formation.

39. • Further investigations by Visalakshi and Bhavani (2020) with 6 releases of T.
chilonis @ 75,000/ha/release, reported much lower incidence of ESB and INB (6.5
and 2.3%; 3.9 and 5.8%) whereas untreated control recorded the highest
incidence of ESB and INB (10.9 and 15.9%; 5.1 and 18.2%) during 2015 and
2016, respectively. Moreover, the highest per cent field recovery was recorded in
T. chilonis release @ 75,000/ha/release, during monsoon period (68.6 and 20.0%)
as compared to pre monsoon period (12.1 and 9.3%) of 2015 and 2016,
respectively.
• Augmentative studies carried out by Sharma et al. (2020) in the sugarcane
growing districts of Punjab over a period of 5 years (2015-2019) revealed that 8
releases each of T. chilonis and T. japonicum @ 50,000/ha at 10-day intervals
resulted in a lower incidence of C. infuscatellus (2.9%) and S. excerptalis (3.9%)
than the untreated control (8.5%).

40. PAU recommendations for trichogramma use
Crop Target pest Sc. Name Trichogramma species No. of
release
Dose
(No./ha)
Initiation
(DAS)
Sugarcane Early shoot borer Chilo infuscatellus
Snellen
Trichogramma chilonis Ishii 8 at 10 DI
from mid-
April to end-
June
50,000 45
Top shoot borer Scirpophaga
excerptalis Walker
Trichogramma japonicum
Ashmead
8 at 10 DI
from mid-
April to end-
June
50,000 60
Stalk borer Chilo auricilius
Dudgeon
T. chilonis 10-12 at 10 DI
from July to
October
50,000 90
Organic Rice Yellow stem borer,
Rice leaf folder
Scirpophaga
incertulas Walker
Cnaphalocrocis
medinalis
(Guenee)
T. chilonis
T. japonicum
5-6 at 7 DI
starting from
30 days after
transplanting
1,00,000 30
Maize Maize stem borer Chilo partellus
Swinhoe
T. chilonis 2 releases on
10
and 17 days
old crop
1,00,000 10
DI= Days interval, DAS= Days after sowing
(Aggarwal et al., 2013; Shera et al., 2019; Mahal, 2021)

41. Field evaluation of T. chilonis (Temp. Tolerant Strain) against
Chilo infuscatellus of sugarcane in Nawanshahar, Punjab
Treatments Incidence
(%)
Reduction
over
control (%)
Parasitism
(%)
Yield
(q/ha)
CBR
TTS 6.4a 52.9 31.04b 771.7a 1:8.60
Local strain 6.6a 51.5 27.68b 759.5b 1:6.99
Chemical
control
6.2a 54.4 0.00a 762.3ab 1:3.98
Control 13.6b - 0.00a 706.4c -
C.V.(%) 8.78 - 9.67 9.87 -
Anon. (2006)

42. Role of Trichogrammatids in biolgical control of pests of cereal crops
Common Name Sc. Name Crop (s)
Yellow Stem Borer (YSB) Scirpophaga incertulas Walker Paddy
White stem borer Scirpophaga innotata Walker Paddy
Leaf Folder Cnaphalocrocis medinalis
(Guenee)
Paddy
Pink stem borer Sesamia inferens Walker Paddy
Shoot Fly Atherigona soccata (Rondani) Maize and
Sorghum
Maize Stem Borer Chilo partellus Swinhoe Maize and
Sorghum
Fall armyworm Spodoptera frugiperda (J.E.
Smith)
Maize and
Sorghum
The major target insect pests

43. PADDY
• In paddy, the yellow stem borer (YSB), S. incertulas and the rice leaf folder (RLF),
C. medinalis are of major economic concern and trichogrammatids namely T.
japonicum and T. chilonis predominantly parasitize these pests under field
conditions (Sharma et al., 2020).
• The other stem borers namely white stem borer, Scirpophaga innotata Walker and
pink stem borer, S. inferens are found to occur frequently.
• T. japonicum is preferred over T. chilonis for the pests which have their egg masses
are layered or covered with hairs, for instance, S. incertulas.
• Inundative releases of T. japonicum resulted in significant decrease in leaf damage
(3.7-59.0%) due to RLF (Bentur et al., 1994).
• The releases of T. japonicum proved much effective in controlling S. incertulas
compared to endosulfan application in Maharashtra (Shirke and Bade, 1997).
• Gururaj et al. (2001) installed pheromone traps @ 20/ha and released T. chilonis @
1,00,000/ha (3-5 releases) and recorded significantly lesser YSB and leaf folder
damage resulting in a significant increase (38.0-45.0%) in grain yields over farmers’
practice.

44. • Multi-locational evaluation of three releases of T. japonicum and T. chilonis @ 50,000
and 1,00,000/ha, respectively at weekly intervals starting from 20 days after
transplanting (DAT) resulted in significant reduction in YSB and RLF incidence,
increase in parasitization of both the species and higher yields in parasitoid released
plots compared to insecticide schedule and Bt sprayed plots (PDBC, 2000-2001).
• An IPM strategy involving 2-4 releases of T. japonicum provided effective
management of both YSB and RLF and proved superior to farmers’ practices in
western UP, which mainly comprised of intensive chemical control (Grag et al.,
2002).
• Khan and Kumar (2005) also found inundative release of Trichogramma spp. @
1,00,000/ha superior over the lower doses in reducing the incidence of YSB in paddy.
Release of T. japonicum @ 1,00,000/ha + azadirachtin 1.0 per cent against YSB
reduced the dead hearts and white ear by 12.2 to 91.0 and 72.4 to 92.8 per cent,
respectively over insecticide application in paddy at Palakkad, Kerala.

45. • T. chilonis alone @ 1,00,000/ha reduced the RLF damage by 41.6-98.6 per cent and
increased the yields by 25.7 and 45.1 per cent over conventional insecticide
application (Karthikeyan et al., 2007).
• Single release of T. japonicum @ 50,000 /ha not only resulted in nearly similar stem
borer incidence (11.5% dead hearts) as observed in control (Phorate 10G @ 10
kg/ha) (10.7% dead hearts) but also reduced the cost of protection by 7.4 times
(Bhushan et al., 2012).
• Nayak (2013) reported that combined application of Carbofuran 3G @ 1 kg a.i./ha +
T. chilonis (@ 1, 00,000/ha, released thrice) + pheromone traps (with 5 mg lure @ 20
lures/ha) resulted in significantly lesser damage (2.7%) by C. medinalis in paddy as
compared to farmers’ practice (5.4%) (Monocrotophos @ 0.5 kg a.i/ha).
• Reuolin and Soundarajan (2017) assessed up to 38.1 per cent natural parasitization
of YSB egg masses by T. japonicum at Paddy Breeding Station, Coimbatore, Tamil
Nadu.

46. • Six releases of T. japonicum each @ 1,00,000/ha at weekly intervals starting from 7th
DAT (Tripathi et al., 2017) significantly declined the dead heart formation due to
YSB (17.9 to 12.2 at 30 DAT) and folded leaves due to RLF (36.7 to 23.4 at 60 DAT)
in paddy at Seppa, Arunachal Pradesh.
• Sangha et al. (2018) concluded that 6 augmentative releases of T. chilonis and T.
japonicum each @ 1,00,000/ha resulted in 61.5, 58.1 and 62.5 per cent mean
reduction of dead heart, white ear appearance and RLF damage, respectively in the
release fields over untreated control.
• Four releases of T. chilonis @ 1,50,000 parasitized eggs/ha reduced the RLF damage
by 63.3 per cent over untreated control in paddy crop at Kangra, Himachal Pradesh
(Chhavi et al., 2019).
• In organic basmati paddy, Sharma et al. (2020) recorded 5.9 and 4.1 per cent
parasitization of S. incertulas eggs by T. chilonis and T. japonicum as compared to
conventional rice (1.7 and 1.1%, respectively) sown at Patiala, Punjab.

47. • YSB was reported to be parasitized by T. japonicum (7.1 to 23.1%) in Rabi
sown paddy at Tiruchirappalli, Tamil Nadu by Sharmitha et al. (2020).
• As per Murali-Baskaran et al. (2021), four split releases of T. japonicum @
50,000 wasps/ha/release at weekly intervals from 30th DAT of paddy resulted
in maximum reduction in dead heart (52.8%) and white ear formation
(66.1%) by YSB over untreated control in Chhattisgarh plain of central
India.

48. MAIZE
• Amongst various insect pests infesting the maize crop, the alien invasive fall
armyworm (FAW), Spodoptera frugiperda (J.E. Smith) and the renowned maize stem
borer, C. partellus are the most serious pests of maize.
• Studies on the extent of yield losses in maize by Chatterji et al. (1969) and Panwar
(2005) revealed 26.7 to 80.4 per cent losses due to C. partellus in different agro-
climatic regions of India.
• Dhaliwal (2016) reported losses to the tune of 8.6-16.3 per cent due to C. partellus in
Kharif maize in Punjab.
• Rawat et al. (1994) found that inundative releases of T. chilonis effectively
suppressed C. partellus in maize crop in Himachal Pradesh.
• Singh and Jalali (1994) reported that inundative releases of T. chilonis at 20,000/acre
at 10-15 days interval reduced the incidence of C. partellus to 9.7 and 5.3 per cent in
the colonized areas compared to 21.7 and 19.8 per cent in no-release areas during
1992 and 1993, respectively.

49. • Jalali and Singh (2003) found that out of four species of trichogrammatids, T.
chilonis parasitized 77.9 per cent of C. partellus eggs compared to other species
(38.1-55.7%) in maize crop sown under net house conditions.
• Kanta et al. (2008) revealed that single release of T. chilonis @ 100,000/ha on 13-day-
old maize crop proved very effective with 65.0% egg parasitization in C. partellus.
• Number of plants infested by C. partellus in IPM field with T. chilonis as one
component did not exceed 4.0 per cent, whereas 3-fold infestation (12.0%) was seen
in farmer’s field (Chaudhary et al., 2012).
• T. chilonis gave a higher parasitization of 43.9 per cent against C. partellus when
released @ 50,000/ha twice during the brood of the pest at weekly interval in maize
crop (Halagatti, 2012).

50. • Aggarwal and Jindal (2013) reported significantly higher parasitization of C.
partellus (31.8%) by single release of T. chilonis @ 1,00,000 adults/ha as compared to
farmers’ practice (two sprays of deltamethrin 2.8 EC @ 200 ml/ha on 15 and 30
days after germination) (2.3%) and untreated control (7.6%) during two years of
studies (2011 and 2012) at Hoshiarpur, Punjab.
• T. chilonis application @ 1,50,000/ha at 25 DAS as a component of BIPM against C.
partellus in maize resulted in significantly less damage (19.9%) as compared to
control (29.7%) at Sabarkantha, Gujarat (Patel et al., 2015).
• Vijaykumar and Jalali (2015) also reported 43.9 per cent parasitism of C. partellus
eggs by T. chilonis.
• Aziz and Gaherwal (2017) reported significant parasitism of C. partellus eggs by T.
chilonis during 2015 (59.0-75.0%) and 2016 (51.0-77.0%) at Indore, Madhya
Pradesh.

51. • Kumar et al. (2017) advocated that two releases of T. chilonis @ 1,25,000 and
1,50,000 parasitoids/ha resulted in 66.0 and 67.0 per cent reduction in dead heart
appearance, respectively over untreated control.
• A remarkable reduction in the mean incidence C. partellus (56.4%) and increase in
maize yield (13.6%) over untreated control was reported by Shera et al. (2017) by
single release of T. chilonis @ 1,00,000/ha in different districts of Punjab.
• Behera and Mishra (2020) revealed that the combination of T. chilonis @ 1,50,000
parasitized eggs + 1,500 Cotesia flavipes Cameron pupae/ha resulted in egg
parasitization (80.4%) and larval parasitization (46.5%) of maize stem borer with
maximum grain yield (52.5 q/ha) in Kharif maize in Odisha.
• Kaur et al. (2020) recorded 5.6 per cent parasitization of C. partellus eggs by T.
chilonis in Kharif maize sown at IARI, New Delhi. Twin inundative releases of T.
chilonis @ 1,25,000/ha at 7 and 14 days after germination of Kharif maize resulted
in maximum parasitization of C. partellus eggs (62.4%) and grain yield (63.20 q/ha)
at Karnal, Haryana.

52. • Recently reported from Karnataka, the fall armyworm, S. frugiperda
(Sharanabasappa et al., 2018) is emerging as the most destructive pest of maize in
India (Suby et al., 2020).
• Within no time, T. chilonis has emerged as a major natural enemy (Shylesha et al.,
2018) with egg parasitization of 25.6 per cent (Navik et al., 2019) and 15.8-23.9 per
cent (Navik et al., 2021), therefore must be utilized to suppress this pest in newly
invaded areas.
• An IPM strategy implemented by Varshney et al. (2021), comprising installation of
FAW pheromone traps, four releases of T. pretiosum @ 50,000/ha, two sprays of
neem oil (0.3%), and one spray of each Bacillus thuringiensis Berliner isolate
(NBAIR-BT25) and Metarhizium anisopliae (Metschn.) Sorokin (NBAIR Ma-35)
strain resulted in 76.0 and 71.6 per cent reduction in egg mass; 80.0 and 74.4 per
cent reduction in larval population at 60 days after treatment during Rabi and
Kharif season, respectively.
Fall armyworm, Spodoptera frugiperda (J.E. Smith)

53. Role of Trichogrammatids in biolgical control of pests of vegetable crops
Common Name Sc. Name Crop (s)
Pod borer H. armigera Tomato, potato, okra
Spotted boll worm E. vittella Tomato
Tomato pinworm Tuta absoluta (Meyrick) Tomato
Tobacco caterpillar Spodoptera litura Cabbage/cauliflower
Diamond back moth Plutella xylostella L. Cabbage/cauliflower
Til hawk moth Acherontia styx Westwood Brinjal
Cut worm Agrotis ipsilon (Hufnagel) Tomato
Brinjal shoot and fruit
borer
Leucinodes orbonalis Guenee Brinjal

54. Exotic egg parasitoids utilized for the control of pests
of vegetable crops
Krishnamoorthy et al.,, 2013

55. Species of egg parasitoids being utilized for the control of
insect-pests of vegetable crops
Krishnamoorthy et al.,
2013

56. BRINJAL
• The sphingid hawk moth, Acherontia styx Westwood and the fruit and shoot borer
(FSB), Leucinodes orbonalis Guenee are the major insect-pests of brinjal crop
targeted by the wasps of Trichogrammatidae family.
• Seminal report on T. australicum parasitizing (79.0 to 93.0%) the eggs of A. styx in
brinjal fields at Rajendranagar, Andhra Pradesh was put forth by Rao et al. (1980).
• In another similar study, Krishnamoorthy et al. (1999) reported 80.0 per cent
parasitization of A. styx eggs laid on brinjal crop by T. chilonis at Bangalore.
• Only 28.0 per cent fruit damage was recorded by Sasikala et al. (1999) due to L.
orbonalis in T. japonicum released plots as against 52.5 per cent in control.
• The damage by FSB was 19.0 per cent in brinjal when egg parasitoid was released
@ 2,50,000 adults/ha and further declined to 10.0 per cent when the rate of release
was doubled (Krishnamoorthy and Mani, 1999).

57. • Niranjana and Sridhar (2015) reported 91.9 and 41.5 per cent parasitization of L.
orbonalis eggs by T. pretiosum on Kharif and Rabi sown brinjal crop, respectively at
Coimbatore, Tamil Nadu.
• Shanmugam et al. (2015) reported that BIPM strategy involving release of multiple
insecticide tolerant T. chilonis @ 1,25,000/ha at weekly intervals from 30 days after
planting resulted in minimum fruit damage (8.0-1.4%) by L. orbonalis in brinjal and
maximum yield (135 t/ha) of Kharif sown crop at Dharmapuri, Tamil Nadu.
• Vivekananthanathan (2015) reported higher parasitization of L. orbonalis eggs on
brinjal crop by releasing T. pretiosum (92.0%) and T. embryophagum (90.0%).
• Out of six species of trichogrammatids recorded parasitizing L. orbonalis eggs on
brinjal at Bangalore (Murali et al., 2017), T. chilonis (37.5%) and Tr. bactrae (21.4%)
were the most prominent ones.

58. • Application of T. chilonis and T. pretiosum + sex pheromone traps @ 20/ha from the
onset of flowering up to 60 days with the release of trichocards at 10 days interval in
brinjal fields resulted in significant reduction in FSB incidence (up to 80.0%) at
Coimbatore, Erode and Tirupur districts of Tamil Nadu (Saravanan and Sridharan,
2017).
• Minimum shoot damage (11.9 and 12.6%), fruit damage (11.7 and 9.8%) and
maximum parasitization of L. orbonalis eggs (47.6 and 47.1%) was reported by
Singh et al. (2019) through 6 and 8 releases, respectively of T. chilonis @ 1,50,000/ ha
at 10 days interval starting from 15 DAT in brinjal crop at Udaipur, Rajasthan.
CABBAGE AND CAULIFLOWER
• Among the lepidopteran pest infesting cabbage and cauliflower, diamond back moth
(DBM) (P. xylostella), cutworm (Spodoptera litura Fabricius), and cabbage butterfly
(P. brassicae) are more pronounced in different geographical areas in India

59. • Srivastava and Kushwaha (1995) reported 31.8 per cent parasitization of S. litura
eggs by T. chilonis in cauliflower crop sown at Udaipur, Rajasthan.
• T. chilonis was observed to parasitize the DBM eggs; 42.0 per cent on cabbage and
4.0 per cent on cauliflower (Yadav et al., 2001).
• A total of 2,50,000 adults of Tr. bactrae released @ 40,000-50,000/week/ha, reduced
the DBM infestation by 30.0 per cent in cabbage (Krishnamoorthy, 2002).
• Halagatti (2012) obtained 45.3 per cent parasitization P. xylostella in cabbage by two
releases of the arrhenotokous form of T. pretiosum @ 50,000/ha at weekly intervals.
• Releases of the egg parasitoid, Tr. bactrae + foliar spray of indoxacarb resulted in
maximum reduction (99.3%) of P. xylostella in cabbage over control followed by
indoxacarb spray (98.9%) at Bangalore (Chaubey and Murthy, 2017).
• Three releases of T. brassicae @ 1,00,000 adults/ha under BIPM in cauliflower
targeted against P. brassicae reduced the incidence and increased the yield (Lalitha
et al., 2015).

60. • Again, Lalitha and coworkers (2017) reported that exposure of P. xylostella eggs to
two species, Tr. bactrae and T. brassicae resulted in total parasitization and adult
emergence varying from 29.2 to 62.8 per cent and 66.9 to 96.1 per cent, respectively
in cabbage fields. Navik and coworkers (2019) reported 7.7 per cent natural
parasitization of P. xylostella eggs by T. chilonis on cabbage crop from Karnataka.
OKRA
• Okra shoot and fruit borer, E. vittella and okra fruit borer, H. armigera are the two
major lepidopteran pests of okra. ICAR has validated 4 to 5 releases of the egg
parasitoid, T. chilonis @ 1,00,000 / ha at weekly interval to manage these pests on
okra (Sardana et al., 2017).
• In late seventies, 8.0 per cent parasitization of H. armigera eggs on okra by T.
chilonis was reported by Thontadarya et al. (1978) from Karnataka. Fortnightly
releases of T. chilonis against H. armigera and E. vittella on okra significantly
reduced the pest damage and produced higher fruit yield (20.3 tonnes) as against
13.1 tonnes in control (Raja et al., 1998).

61. • Biointensive IPM studies by Thanavendan and Jeyarani (2009) with 3 releases of T.
chilonis @ 50,000 adults/ha + C. blackburni @ 1000 adults/ha + B. brevicornis
(Wesmael) @1000 adults/ha and T. chilonis alone @ 1,00,000 adults/ha resulted in
significant reduction in E. vittella (40.0 and 25.4%) and H. armigera (41.3 and
30.6%), respectively on okra crop sown at Coimbatore, Tamil Nadu.
• Gracy et al. (2011) for the first time reported parasitization of E. vittella by T.
chilotraeae on okra from Varanasi, India.
POTATO
• In potato crop, T. chilonis showed 64.0 per cent parasitization against L. orbonalis.
Moreover, inundative releases of T. chilonis @ 3,00,000/ha and 2,50,000/ha in five
installments recorded less shoot infestation of 25.8 and 22.9 per cent, respectively
(Hanapur and Nandihalli, 2003). While, a lower release rate of 1,00,000 parasitized
eggs/ha at 15-day intervals ensured remarkable parasitization (74.2%) (Kumar et
al., 2003). A. ipsilon eggs were reported to be parasitized by T. chilonis in potato
fields from Assam (Badal et al., 2006).

62. TOMATO
• Trichogrammatids are key players in the management of two most threatening
insect-pests of tomato crop i.e., tomato fruit borer, H. armigera and the invasive
alien tomato pinworm, Tuta absoluta (Meyrick).
• In 1970, T. chilonis and T. achaeae were recorded parasitizing H. armigera eggs (2.0-
80.0%) on tomato at Anand, Gujarat (Manjunath et al., 1970).
• T. pretiosum released @ 50,000 adults/ha at 7-10-day interval parasitized 27.8-93.4
per cent H. armigera eggs in tomato fields at Solan, Himachal Pradesh (Gupta and
Babu, 1998).
• Biological control studies by Singh et al. (2003) involving 5 releases of T. pretiosum at
50,000/ha/week against H. armigera in tomato crop resulted in effective
parasitization (43.2%). For the suppression of H. armigera in tomato, Halagatti
(2012) advocated two releases of the arrhenotokous form of T. pretiosum @
50,000/ha at weekly intervals with 49.3 per cent parasitization.

63. • Multiple insecticide resistant T. chilonis strain utilized by Jalali et al. (2016)
responded with 50.8 per cent egg parasitization in H. armigera on tomato crop
during winter and 39.0 per cent in summer, whereas, the susceptible strain was
unable to parasitize.
• The eggs of H. armigera collected from tomato fields were found parasitized by T.
achaeae while, eggs of T. absoluta were parasitized by T. achaeae and Tr. bactrae
collected from both Maddur and Kanakapura, Karnataka (Navik et al., 2017).
• Further, Navik and coworkers (2019) reported 16.2, 36.2 and 50.0 per cent natural
parasitization of H. armigera eggs by T. chilonis on tomato crop from Karnataka,
Telangana and Odisha, respectively.
• While, natural parasitization by T. achaeae was 28.5 and 13.6 from Karnataka and
Kerala, respectively. Tr. bactrae was recorded parasitizing T. absoluta eggs (5.3 to
8.8%) on tomato crop (Navik et al., 2019).

64. • Further, Navik and coworkers (2019) reported 16.2, 36.2 and 50.0 per cent natural
parasitization of H. armigera eggs by T. chilonis on tomato crop from Karnataka,
Telangana and Odisha, respectively. While, natural parasitization by T. achaeae was
28.5 and 13.6 from Karnataka and Kerala, respectively. Tr. bactrae was recorded
parasitizing T. absoluta eggs (5.3 to 8.8%) on tomato crop (Navik et al., 2019).
• Among the egg parasitoids evaluated by Sridhar et al. (2019), T. pretiosum released
@ 50,000/ha for five weeks was found promising with 48.0 per cent parasitization of
T. absoluta eggs on tomato crop followed by T. chilonis (41.0%) and Tr. bactrae
(38.0%) released at the same rate.

65. Role of Trichogrammatids in biolgical control
of pests of Fruit crops
Common Name Sc. Name Crop (s)
Codling Moth Cydia pomonella L. Apple, pear, peach, plum
Lemon Butterfly Papilio demoleus L. Citrus
Fruit Sucking Moths Eudocima materna
Linnaeus
Citrus and pomegranate
Anar Butterfly Deudorix Isocrates
Fabricius
Pomogranate
Ber Fruit Borer Meridarchis scyrodes
Meyrick
Ber
The major target insect pests

66. • Major lepidopteran insect-pests of the horticultural crops that are efficiently
parasitized by Trichogramma spp. include the codling moth (C. pomonella) in stone
fruits, lemon butterfly (Papilio demoleus Linnaeus) in citrus fruits, fruit sucking
moth (Eudocima materna Linnaeus) in citrus and pomegranate, anar butterfly
(Deudorix isocrates Fabricius) in pomegranate, and fruit borer (Meridarchis scyrodes
Meyrick) in ber.
• Trichogramma species namely, T. embryophagum, T. evanescens and T. pretiosum
have been reported to parasitize C. pomonella eggs on apple in India (Kaushik and
Arora, 1998). Releases of T. embryophagum @ 2,000 adults/tree at 7-day intervals
effectively suppressed the codling moth (Singh, 2000).
• Twin releases of T. embryophagum @ 4,000 adults/tree resulted in 35.0-45.0 per cent
reduction in fruit damage by C. pomonella in Himachal Pradesh (Anonymous, 2011).

67. • Releases of T. embryophagum @ 2,000 to 5,000 adults/tree resulted in 10.9 to 22.4 per
cent parasitization of C. pomonella eggs (Lalitha et al., 2015).
• In India, the C. pomonella threatens the production of pome fruits in cold region of
Ladakh, Jammu and Kashmir, and is a declared quarantine pest, hence strict
embargo is implemented on the transportation of apples outside Ladakh.
• To manage this pest twin application of T. embryophagum and T. cacoaciae adults @
2500-5000/tree is recommended during both the generations of this pest (Mohi-ud-
Din and Ahmad, 2018).
• High natural parasitization (75.9%) in the eggs Papilio spp. by T. chilonis on citrus
plants was reported by Krishnamoorthy and Singh (1986).
• Gaikwad et al. (2011) during surveys of natural enemies found T. chilonis as the sole
efficient egg parasitoid of the Papilio polytes polytes Linnaeus at Kolhapur,
Maharashtra.

68. • Natural parasitization ranging from 11.8 to 15.3 per cent of P. demoleus eggs by T.
chilonis was recorded on citrus host plants by Bhapkar et al. (2015) at Akola,
Maharashtra.
• Honnaya and Gawande (2018) reported 60.0-65.0 per cent parasitization of P.
demoleus in 24, 48 and 72-hours old eggs by gravid females of T. chilonis.
• Up to 48.0-86.0 per cent Deudorix epijarbas (Moore) eggs on pomegranate were
found parasitized by T. chilonis in Himachal Pradesh (Rawat and Pawar, 1991).
• T. chilonis was found parasitizing 33.0-93.0 per cent of D. epijarbas eggs at Kullu
(Thakur et al., 1991).
• Four releases of T. chilonis @ 2,50,000/ha at 10 days interval resulted in 50.0 per
cent parasitization of the pomegranate fruit borer, D. isocrates in Tamil Nadu
(Karuppuchamy et al., 2001). Nagaraja and Gupta (2007) for the first time reported
a new species, Trichogramma mani sp. nov., as an egg parasitoid of D. isocrates from
Bangalore.

69. • Eggs of the fruit piercing moth, E. materna, were found parasitized by T. chilonis
with a mean parasitization of 21.4±27.4 and 50.4±34.1 per cent during 1998 and
1999, respectively at Bangalore (Bhumannavar and Viraktamath, 2001).
• In laboratory investigation, 72.0 to 89.0 per cent parasitization of T. chilonis on the
eggs of E. materna was also recorded by Magar et al. (2017).
• Trichogramma sp. was also found parasitizing the eggs of the common baron,
Euthalia aconthea garuda Moore (30.7%) on mango at Kanakapura and Attur,
Karnataka (Navik et al., 2017; 2019).

70. Role of Trichogrammatids in biolgical control
of pests of pulse crops
Common Name Sc. Name Crop (s)
Pod borer Helicoverpa armigera
Hubner
Chickpea, pigeon pea,
soyabean, pea, black
gram, lucerne
Tobacco caterpillar Spodoptera litura Fab. Chickpea
Bihar hairy
caterpillar
Spilosoma obliqua
Walker
Soyabean, lucerne, black
gram
Pigeon pea pod borer Maruca vitrata
Fabricius
Pigeon pea
Soybean pod borer Cydia ptychora
(Meyrick)
Soybean
The major target insect pests

71. • Major insect-pests of pulses and other legume crops that are efficiently parasitized by
Trichogramma spp. include the chickpea pod borer (H. armigera), tobacco caterpillar
(S. litura), Bihar hairy caterpillar (Spilosoma obliqua Walker), pigeon pea pod borer
(Maruca vitrata Fabricius) and soybean pod borer [Cydia ptychora (Meyrick)].
• Releases of T. chilonis against H. armigera eggs @ 2,50,000/ha per week in lucerne
fields for 7 weeks resulted in a mean parasitization of 44.0 per cent as compared to the
control plots (31.0%) (Patel, 1975).
• T. chilonis was described as a successful biological control agent against S.
litura on soyabean crop (Joshi et al., 1980)
• Excessive parasitization of H. armigera eggs on lucerne crop (84.2-98.2%) by T.
chilonis was recorded by Yadav et al. (1985). Laxman (1986) reported 34.8 per cent
parasitization of H. armigera eggs on chickpea by releasing T. achaeae @ 2,50,000/ha,
but at lower release rate of 2,00,000/ha only 28.7 per cent parasitization was realized.

72. • Balasubramanian et al. (1989) recorded heavy parasitization of chickpea pod borer
(62.0%) by T. pretiosum.
• Tandon and Bakthavatsalam (2003) recorded 1.3-8.3 per cent parasitization of H.
armigera eggs by T. chilonis on different pigeon pea genotypes.
• Patel and Yadav (2017) reported 20.0 to 48.1 per cent parasitization of M. vitrata eggs
on pigeon pea grown at Pantnagar.
• Amarnath (2000) recorded 9.9 per cent parasitization of soybean pod borer, Cydia
ptychora (Meyrick) eggs of by T. chilonis.
• Patil (2002) reported that two releases of T. chilonis @ 2,50,000/ha resulted in
significant decrease in pod damage (36.9%) by soyabean pod borer, C. ptychora over
no release treatment (44.6%).

73. Effect of different release rates of Trichogramma
species on H. armigera parasitization in red gram
Ballal and Singh, 2003

74. • T. chilonis was also recorded on the coconut black headed
caterpillar Opisina arenosella Walker (Nirula, 1956)
• On castor, Trichogramma chilonis Ishii and Trichogramma
achaeae Nagaraja & Nagarkatti parasitized the eggs of
Achaea janata by up to 100 % (Patel and Yadav, 1979)
• Rao et al. (1980) observed Trichogrammatoidea bactrae
Nagaraja parasitizing 9.1-14 % eggs of A. janata on castor
crop in Kanataka
Role of Trichogrammatids in biolgical control of
other plantation crop pests

75. Effect of different release rates of Trichogrammatid
species on H. armigera parasitization in sunflower
Ballal and Singh, 2003

76. Constraints in Success of Trichogrammatids
• Adoption has been slow because of:
 Variable levels of pest control in the field
 Incompatibility with different pesticidal formulations
 Insufficient supply of the natural enemies to the farmers by government
institutions
 Unavailability of trichocards in the market attributed to short shelf life

77. Ecological constraints in maintaining released Trichogramma
 Parasitism represents replaceable mortality because of competition with
predators for eggs
 Wasp mortality caused by egg predators and hyperparasitoids
 Potential density-dependent predation of young larvae
 Difficulty in maintaining field populations of Trichogramma spp.

78. Future Prospects for Trichogrammatids
 Ensuring selection of the most suitable species or biotype for augmentative use
 Understand and quantify the relationship between numbers of parasites
released and their impact on the pest population
 Developing pest management systems that eliminate or limit insecticide
interference with natural enemies
 Development of efficient methods of Trichogramma rearing, commercial
production
 Determining the optimal size of the release area
 Defining environmental parameters and specifications for storage, shipment
and field release
 Development of multi-resistant strains

79. Conclusion
Trichogrammatids are the supreme egg parasitoids of a number of
lepidopteron insect pests infesting cotton, paddy, sugarcane, maize, vegetable,
horticultural and agroforestry crops. Trichogrammatids, undeniably, are amenable
in mass production and their ability to kill the pests at the egg stage, thus eliminates
the damaging larval stages from the scenario along with saving insecticide
expenditure which would otherwise have been an economic burden on the farmers’
pockets. Trichogrammatids offer an eco-friendly, low-cost and more effective plant
protection option in comparison to insecticides. BIPM approach and development
of multi-resistant and tolerant strains are bright sides of exploiting
trichogrammatids in coming future to save crops from insect pests. Leading
government institutes involved in R&D like ICAR-NBAIR, ICAR-NCIPM and
SAUs need to frame policies and set up quality infrastructure to accelerate the mass
production, ensure the quality control and facilitating the supply of these biocontrol
agents to benefit the farthest sitting farmer.