life cycle and economic importance of Bracon hebetor

2. Bracon Hebetor

3. Introduction
Bracon hebeter is a minute Braconidae wasp that is a internal parasite to caterpillar
stage of Plodia interpunctella, the indian meal moth, in the late larval stage of
Mediterranean flour moth and the almond moth and many others.

4. Life cycle & Biology
• At 30 degree C , the life cycle of the wasp is about 10 to 13 days from initial
parasitism to final emergence of the adult.
• The adult female parasite lives about 23 days during which it produce about
100eggs.

5. Eggs
• It deposits 1 to 8 eggs in individual paralyzed late instar moth larvae.
• Freshly laid eggs were creamy white in color and become translucent later
• The deposited eggs were spindle shaped curved and loosely attached to the
surface of the host body 0.6mm long.
• Hatch in 1-2 days

6. Larvae
• Larvae were creamy white in color.
• Lives inside the host body.
• The length of larvae is 0.4mm.
• The larval duration is 2-4 days.

7. Pupae
• Pupation takes place outside the host body within a white cocoon.
• The mature pupae are dark brown and exarate type
• Length of pupal cocoon is 3.3 to 4.1 mm.
• The pupal duration is 4 to 6 days.

8. Adult
• The color variation is yellowish brown to dark brown or black.
• The body length of female is larger than male.
• The length of male and female adult varied from 2-3mm and 3-4mm
respectively.
• Male has large antennae.

9. Hosts
• The Lepidoptera species are founded as host
1. Indian meal moth
2. Mediterranean flour moth
3. Almond moth
4. Rice moth
5. Wax moth
6. Angoumois grain moth
7. Corn earworm
8. Tobacco budworm

10. Mode of action
• Bracon hebetor larva releases an enzyme in gut of caterpillar which destroys
the blood protiens and body fluid of that larva.

11. Economic Importance
• It is the biological control of a large number of moth larvae of stored grain
and crops insect pests

12. Why Need to rear?
Crop production in the present era is dependent upon integrated
plant protection measures to combat natural pests and diseases.
These measures also include the integration of chemical insecticides
with natural biocontrol agents (entomophagous insects) for the
suppression of insect pest populations.

13. Mostly, the chemical insecticides are not produced in developing countries and are
imported for formulations, though accompanied by safety data sheet but still needs
recertication of certain toxicities in local environments besides being efficacious against
pests and diseases. The natural enemies of insect pests, also known as biological control
agents, include predators, parasitoids, and pathogens. Bracon hebetor, primarily
recognized as an ectoparasitoid of the larvae of many Pyralid pest-species attacking
stored grain; is considered to have a potential for the biological control of many other
Lepidopteran pests of various crops, because it is highly aggressive. It occurs naturally,
throughout the world. There is a growing evidence that B. hebetor can also be an
important bio-control agent of Helicoverpa armigera. It is used in Turkmenistan, on
cotton, and to a lesser extent in Uzbekistan, where they rely more on Trichogramma
pintoi.

14. Mass rearing of Bracon hebetor
The field collected adults of the parasitoid are reared on a large scale, by using the larvae of the greater
wax moth, Galleria mellonella (L.) as host, at 29 ± 1 °C, 65 ± 5% R.H and. A number of 2 to 3 larvae of
the 3rd or 4th instars of G. mellonella, are placed in the glass vial, with a fertilized female of the parasitoid,
B. hebetor . The female was provided with a cotton swab, soaked in 20 % honey solution, for feeding
the parasitoid. After 24 hours, the females are shifted to the other vials, with new larvae of the host, G.
mellonella and honey-soaked cotton swab. This process can be continued upto the end of the life of the
female parasitoid. The parasitized larvae of the host, G. mellonella, are incubated, under the optimum
conditions of 29 ± 1 °C temperature and 65 ± 10 % of the relative humidity.

15. Rearing of wax moth
Life cycle:
Eggs : 10.2 days
Larva : 32.9 days
5-7 Instars
Pupal : 8.2 days
Temprature required : 32 to 34 C
Relative humidity : 60 – 70 %
Love Darkness

16. Feed
Wheat flour : 130g
Brain : 130g
Milk powder : 130g
Maize flour : 97.5g
Wax powder : 26g
Honey : 195ml
Glycrine 195ml