Muhammad Nazar, Ahmed Ali
Department of Agronomy, University of Agriculture Faisalabad
Corresponding author/ email: [email protected]
Biological Control of Insects:Trichogramma spp.
Biological Control: Biological control is the method in which we use parasites and predators (living organisms) to control insect pests.There are many kinds of living entities employed for Biological control but Trichogramma spp. have been found most suitable.
Trichogramma is one of around 80 genera from the family Trichogrammatidae, with over 200 species worldwide. Trichogramma spp. is an egg parasite of most of lepidoptrous. It is used to control American worm and pink boll worm in cotton and other crops by damaging their eggs. It is also used against top and stem borers of sugar cane. Trichogramma spp. is reared on the eggs of sitotroga cerealella.
Rearing of Trichogramma spp. in Lab:
- In first step wheat is boiled for 6 minutes or sterilized in an oven for killing of germs, mites and fungi.
- Then the wheat is dried in the room to avoid contamination.
- Then about 1.5 kg wheat is placed in plastic jar.
- Then the cards having eggs of Sitotroga cerealella are inserted in this jar containing wheat.
- Temperature is kept about 26-27 and R.H 70%.
- After 25-30 days when the population of Sitotroga cerealella sufficiently increases in wheat jar,these are shifted into a glass jar, leaving behind some Sitotroga cerealella for further population.
- The mouth of glass jar is covered by a thin cloth.Where they mate and females lay eggs.
- One gram of eggs contains 40,000 eggs.
- Now the Sitotroga cerealella eggs are sticked on a card of 2 inch sq. area.
- Now these cards are placed in the jars having Trichogramma spp. adults for parasitization.
- The color of Sitotroga cerealella eggs is white but after 2 days due to parasitization color becomes red, 3rd day dark red, 4th day blackish and 5th day full black in color and 6th day hatching of Trichogramma spp. eggs occur.
- The 5th days old black eggs of Sitotroga cerealella are stored at 7 to 8 Co for about 90 days.
Method of using Trichogramma spp. Cards:
Attach the cards on the lower side of leaf with stapler in the field ,at the top 1/3rd portion of the plants and card should be attached on the north side to avoid direct hitting of sun light. Hatching may occur within 2 to 3 days at 35°C. The females survive for 6 days. Female parasitization rate is maximum on 1st day and maximum eggs are parasitized in 48 hrs.
Fertilization rate of Trichogramma spp.
- 1st day fertilizer rate 60-100%
- 2ndday fertilizer rate 30-40%
- 3rdday fertilizer rate 15-20%
- 4thday fertilizer rate 10%
- 5th day fertilizer rate rest
- 6th day fertilizer rate Die
About 3000 eggs are parasitized during life time.
Time of application of cards:
When the eggs of harmful insects and top or stem borers of sugarcane are present in field, then six cards/ acres are recommended and it will be repeated after 7 days. If pest pressure is more then 10-12 cards are recommended and repeat it twice in a week.
Availabilty of Trichogramma spp. Cards:
- Siddique Bukhari Farm 15Rs. /card
- NARC Lab. 15Rs. /card
- Shakar Ganj Sugar Mill Jhang 15Rs. /card
- Shadaman Lahore 25Rs. /card
Transportation of cards:
In remote areas these cards are transported by keeping them inside the water cooler having ice in it. The card should not touch the ice but should be hung in the cooler.
Conclusion: Biological method is an efficient and economical way to handle the insect pest problem in our crops.It reduces the environmental pollution by lessening the use of chemical sprays.It also avoids resistance built up in insects due to intense use of chemicals.Therefore, we have to create its awareness among farmer society.