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Microbial insecticides
- 1. Microbial insecticides SUBMITTED BY:RAMA JUMWAL M.SC.(BIOTECHNOLOGY) MAU20PBT010
- 2. Introduction Insects aremost abundant group of organisms on earth and they negatively affect humans in a variety of ways They cause massive crop damage They act as vectors of both animal and human diseases
- 3. Microbial insecticides Singlecell organisms such as bacteria,fungi,and protozoa and viruses have been mass produced and formulated for use in a manner similar to insecticides Microbial insecticides can be any organism microbially produced toxic substance
- 4. Drawbacks of chemicalinsecticides Targeted insect pest populations be increasingly resistant to treatment with many chemical insecticides Chemical insecticides were found to lack specificity ,consequently beneficial insects were being killed along with those that were considered to be pests Some times the natural enemies of the insect pest species were killed more efficiently than the target organisms
- 5. Types Bacteria Fungi Virus Protozoa
- 6. 1. Bacteria About90 species of bacteria is pathogenic to insect pests Bacillus thuringenesis-first discovered in 1902 Rod shaped Spore forming Genus bacillus Isolated from soil samples
- 7. Types Obligate :B.papillae, B.lentimorbus Facultative : B.cerens ,BT Potential : P.aerugonisa
- 8. Bacillus thuringenesis Itis a gram positive, spore forming aerobic bacteria Produces a toxin or crystal protein (BT toxin or CRY) that kills certain insects The commercial BT products are produced as dust, wettable powder and emulsifiable concentrates The BT toxin or CRY is produced when the bacteria sporulates
- 10. Mode of action To kill an insect pest B.thuringensis must be ingested as the contact of bacterium or the toxin with the surface of an insect has no effect on target organism After ingestion by larvae the crystal protein broken by midgut juice proteases under high pH into smaller toxic peptic molecules
- 12. 2. Fungi Morethan 750 species are known to infect insects Some attack insects through cuticle Spore attached to cuticle –germinates and penetrates into body wall ,spreads,colonize and sometimes produce toxins Beauveria Metarrhizium Verticilium lecanii
- 13. Mode of action Formation of an infection structure Penetration of cuticle Production of toxin
- 14. 3. Virus Insectspecific viruses can be highly effective natural controls of several caterpillar pests
- 15. Baculoviruses Rod shapedDNA virus Include NPV and GV Pathogenic to lepidoptera,hymenoptera and diptera Infection is done by ingestion of food
- 17. Mode of action The polyhedrin protein dissolves in the alkaline environment of the new host’s gut and the occluded virus is released This virus infects the gut epithelial cells and virus replication takes place Nonoccluded virus is then produced and budded from the infected gut cells
- 20. 4. Protozoa Singlecelled organisms Some of them parasitize and kill insects Not suited for short time Effective against grasshoppers, mosquitoes They reduce host reproduction or feeding rather than killing the pest
- 22. Advantages Non toxicand non pathogenic to organisms not closely related to target pest Often specific to single group or species of insect Residues present no hazards to other animals
- 23. References https://edurev.in/studytube/Microbial-Insecticides--PPT--Powerpoint- Presentati/cec48faf-466a-4f5f-a31c-1364a94d1521_p# https://www.powershow.com/viewht/58cd42- MWVmM/Microbial_Insecticides_powerpoint_ppt_presentation https://www.slideshare.net/suprabhasanil/microbial-insecticides-62299392 https://www.slideshare.net/IniyaLakshimi1/microbial-insecticides-133380671