This document provides information on rearing the parasitoid wasp Trichogramma spp. for use in biological control of insect pests. It discusses that Trichogramma are egg parasitoids commonly used against pests like corn borers. The main steps of rearing include collecting founder populations, selecting and storing host eggs, mass production, and release. Common host eggs used for rearing include rice moths, Angoumois grain moths, and oak silkworms. Precise methods are outlined for rearing the hosts and exposing their eggs to Trichogramma for parasitization. Guidelines are also provided for storing parasitized eggs and releasing the parasitoid wasps.

1. Syed Muhammad Ali Zahid
Department of Entomology
University College of Agriculture
University of Sargodha
alizahid686@gmail.com

2. Rearing of Trichogramma spp.

3. Introduction
 Parasitoid wasps of genus Trichogramma (Hymenoptera:
Trichogrammatidae) includes several species that are frequently
used as biological control agents worldwide
 Trichogramma spp. are egg parasitoids which lay their eggs inside
the eggs of insect pests
 Host of this parasitoid are the eggs of Sugarcane borers, Cut
worms (Agrotis spp.), Cotton bollworms and Maize stem borer
(Chilo pertellus).
 In 1960s to 1970s, nearly 700,000 ha of Chinese corn fields were
treated with Trichogramma totally. Farmers were involved in
rearing and releasing of Trichogramma.

4. Trichogramma species used for insect pests control
There are many identified species of Trichogramma and following are commonly reared
species
1. Trichogramma chilonis
2. Trichogramma dendrolimi
3. Trichogramma ostriniae

5. Rearing Of Trichogramma spp.
Several steps used for rearing :
1. Collection of Trichogramma from field as founder
population, propagation and conservation
2. Selection of host eggs and their storage
3. Exposure of Trichogramma to host eggs on large quantity
4. Mass production for Augmentation releases

6. Host used for Trichogramma rearing
1. Rice moth (Corcyra cephalonica)
2. Angoumois grain moth (Sitotroga cerealella)
3. Oak silkworm (Antheraea pernyi)

7. Steps in Rice moth production:
1. Sorghum/pearl millet/maize grain, free from insecticides,
are coarsely milled and broken into 4-5 pieces in a milling
machine.
2. The broken grains are heat sterilized at1000C for 1 hour to
eliminate the residual population of stored product insect.
3. 2 kg of broken grain are then transferred to plastic Corcyra
cages along with 5gm yeast(regulate larval growth).
4. After mixing the ingredients, Corcyra eggs are sprinkled
on top of the mixture.

8. Rearing of Trichogramma
1. In the plastic boxes population of female Corcyra moths
become high, egg cards are places in rearing boxes.
2. The cards of 15 X 7.5 cm size are used.
3. Name of the laboratory, releasing instructions, date of
preparation of card and expected date of parasitoid emergence
are printed on the backside of the cards.
4. Dilute Acacia gum is used for pasting the eggs.
5. Females lay eggs on these cards
6. These cards are then transfer to the Trichogramma chambers,
where mated females of Trichogramma are present.

9. Rearing…….
1. The egg pasted on the cards are sterilized by exposing the
cards under 30 Watt UV tube at a distance of 35 cm from
the source for 10 minutes.
2. The eggs on cards are exposed to adult Trichogramma for
24 hours at 28+20C in transparent plastic container.
3. Parasitized eggs start turning black on the 3rd day after
parasitization
4. Life cycle of Trichogramma is completed in 7-8 days
5. The eggs when turned black can be stored in the
refrigerator or can be transported for field releases.
6. The emergence of adults generally takes places after 3-6
days after blacking of the eggs.

11. Trichogramma wasps emerging from a Giant Swallowtail
butterfly egg.
A Giant Swallowtail butterfly egg is cut open with a razor,
revealing Trichogramma Wasp larvae inside.

12. Release of Trichogramma
 Inoculative and Inundative augmentative approaches are
applied for the release of Trichogramma.
 For inoculative control Trichogramma are released at a
rate of 7500-15,000 per ha with 10 days interval.
 For inundative control, total number of Trichogramma
wasps released range from 150,000–300,000 per ha,
according to field conditions, ecology and pest
infestation

13. Precautions For Releasing Trichogramma
1. Emergence date should be specified on the cards to
guide the user.
2. The cards should be stapled on the inner side of the
leaves to avoid direct sunlight.
3. The cards should be stapled in morning hours and just
before emergence to avoid predation.
4. Avoid application of insecticides in the field where
Trichogramma are released.
5. If need arises uses selective/safer insecticides.
6. Ensure that insecticides are used 15 days after or before
Trichogramma release.

15.  Parasitized egg cards showing blackening of eggs can be stored in a refrigerator at
12-150C for 10-15 days
 UV sterilized Corcyra eggs can be stored in the lower chamber of the refrigerator up to 5
days can be used for parasitization.
 The best stage for storage is pupal stage.
 During the storage the quality of emerging adults is affected.
 Prolonged storage beyond 15 day would impair emergence as well as longevity and
fecundity of the resulting progeny.

16. References
 All China Corn Borer Research Group, 1988. Studies on the identification of the dominant corn borer species
in China. Acta Phytophyl. Sin. 15, 145–152.
 Cao, J.L., Sun, H.J., 2002. Control effect analysis for Asian corn borer by releasing Trichogramma dendrolimi.
Rain Fed Crops 22, 116.
 Chen, H.Y., Wang, S.Y., Chen, C.F., 2000. Quality control of Trichogramma ostriniae (Hymenoptera:
Trichogrammatidae) mass reared with rice moth, Corcyra cephalonica eggs. Nat. Enemies Insect. 22, 145–1150.
 Cheng, W.Y., Hung, T.H., 1996. Rearing density for Corcyra cephalonica Stainton. Report of the Taiwan Sugar
Research Institute 153, 39–58.
 Wang, Z.Y., Wu, Y., He, K.L., Bai, S.X., 2007. Impact of transgenic Bacillus thuringiensis Bt maize pollen on
longevity and fecundity of Trichogramma ostriniae Chen et Pang (Hymenoptera: Trichogrammatidae) in
laboratory condition. Bull. Insectol. 60, 49–55.
 Wu, L., He, N.P., Hou, D.W., 2001. Studies on controlling effect of Trichogramma chilonis to corn borer. J. Jilin
Agric. Sci. 26, 35–37.
 Xia, J.Y., 2010. Advance the integrated innovation and industralized extension of green control techniques for
corn borer in China. China Plant Protect. 30, 5–8.

17. THANK YOU