Use of Trichogramma chilonis as biological control

        Use of Trichogramma chilonis as biological control

         Author: Saad Ramzan, Muhammad Ahsin Ayub, Naeem Arshad Maan and Imran Ali  

        Ayub Agriculture Research Institute (AARI), Faisalabad.       

 Introduction

            Trichogramma chilonis is an egg parasitoid. Charles V. Riley give the description for the first time in 1871 about trichogramma species. It was found in North America. He observed tiny wasp emerging from the eggs of the viceroy butterfly as trichogramma minutum. Trichogramma have less than 10,000 neurons. This number of neurons is hundred time less than the next smallest insect. Size of adult is less than 1mm. Rearing of trichogramma have been started since 1900’s for biological. Trichogramma is from family Trichogrammatida and have more than 200 species worldwide. Trichogramma can attack more than 150 species of moths.  

Adult females use chemical and visual cues for host eggs finding e.g shape and color. Adult female use antennal drumming to determine if the eggs has previously been parasitized. Also adult female use antennal drumming to determine the size of egg and quality which than determine how many egg a female can lay in host egg.

Taxonomist use features of antennae and genitalia of male to distinguish between different species.

It is essential to use chemical control for pest control. But indiscriminate use and use of non selective insecticides greatly effect the biological control agent.

Trichogramma chilonis mass reared and released world wide every year on an estimated area of 80 million acres of agriculture lands and forest in 30 countries (Li, 1994; Olkowski and Zhang, 1990) . Hewa-Kapuge et al. (2003) perasitize the egg of at least seven insect order having more than 400 species Bao (1989) and chen,(1989). Hewa-Kapuge et al.,(2013); Desneux et al . (2007) describe the different insecticidal effects on Trichogramma species. Insecticides also effect the feeding behavior as repellent , inhibitor, or olfaction disruptor Desneux et al . (2007)

Sub lethal effects can extremely reduce the action of biological control agents Desneux et al. (2007). Insecticides have indirect effects on natural enemies of insect pest as it destroy habitat, and effect ovipostion, resting and mating sites Desneux et al. (2007). And direct effect include physiological and behavior changes Desneux et al. (2007)

Acigona steniellus (Hampson), Thilo partellus Swin, Chilo infuscatellus Snell, Agrotis ipsilon(Hfn.), Autogeapha nigrisigna (Wlk), Emmalocera depressella (Swin), Heliothis peltigera (D.S), Helicoverpa armigera, and Spodoptera litura Hb are the hosts of Trichogramma in Pakistan (Mohyuddin, 1989; Irshad, 2008). Species of Trichogramma found in Pakistan are Tichogramma austalicum Gir, T.chilonis Ishii and T.minutum (Mohyuudin, 1981; Irshad,2003).

Component of successful use of trichogramma

1. Most effective parasitoid species determination.
2. To maintain parasitoid quality, rearing procedures including semi field conditions and renewal of colony after six generations to maintain genetic vigor
3. Development of effective release and distribution methods for field application.

Facilities required for mass rearing of host and trichogramma

1. Room
2. Wooden or angle iron racks
3. Glass jars or rearing chambers
4. Electric aspirator
5. Oviposition jars
6. Grain (Wheat/maize)
7. Incubator
8. Refrigerator
9. Microscope
10. Hygrometer
11. Thermometer
12. Sieves
13. Coarse muslin cloth
14. Rubber bands
15. Plastic dishes
16. Scissor and brushes
17. Sitotroga eggs
18. Cards
19. Glass jars
20. Knife
21. Gum paste
22. Shipping labels

Rearing of host

• The most common use insect as host for Trichogramma is Sitotroga cerelella.
• Required temperature = 26⁰-27⁰
• Required humidity = 58-60 %.
• Sterilize the grains by heating.
• Put the grains in glass jar and spread eggs in it for larvae rearing and adult emergence.
• Collect adults from grain ware houses or from rearing glass jars.
• Kept them in oviposition jars for egg collection..
• Collect eggs after 24 hours from oviposition jars.

Trichogramma rearing protocol

• Required temperature = 25⁰-29⁰ C
• Required humidity = 58-62 %
• Production of Trichogramma in the laboratory is relatively simple if one has access to a continuous supply of acceptable host eggs.
• When sufficient host eggs are available on daily basis then rearing of Trichogramma can
• Spread gum uniformly on pieces of card and sprinkle eggs of Sitotroga on card
• Dry these card and place them into glass jar containing 24 hours of Trichogramma adult
• Remove card after 24 hours because they get parasitized and place fresh cards in it.
• Parasitized egg turn black after 4 days

Transportation of Trichogramma to field

Once freshly parasitized eggs having been removed from the oviposition jars can be shipped or mailed to other locations. The card wrapped with tissue papers are assembled in acrated polythene bags and pack in thermo pore cartons with ice for shipping. Deliver the cards as soon as possible to destination. During transportation cards should not exposed to direct sunlight, toxic fumes, high temperature and extreme conditions as the consignment could be damaged leading to mortality of the Trichogramma stages.

 Field release

• Cards should be placed to the opposite direction to the sun.
• staple the cards to the lower leafs.
• Distance between cards should be 8X8 meter

Pesticides safer to Trichogramma

1. Emamectin benzoate
2. Lufenuron
3. Triflumuron
4. Imidacloprid