Biocontrol agents & biofertilisersजैव नियंत्रण कारक व जैव उर्वरक
Class 12 Biology · Chapter 8 · interactive diagram
Parts and their functions
- Ladybird beetle (लेडीबर्ड भृंग) — Red-and-black beetle; a natural predator used to get rid of aphids.
- Dragonflies (व्याध पतंग (ड्रैगनफ्लाई)) — Natural predators useful to get rid of mosquitoes.
- Bacillus thuringiensis (Bt) (बैसिलस थुरिंजिएंसिस (Bt)) — Microbial biocontrol agent for butterfly caterpillars. Dried spores (sachets) are mixed with water and sprayed on plants like brassicas and fruit trees; in the larva's gut the toxin is released and the larva is killed. Other insects are unharmed. Bt toxin genes are also put into plants (Bt cotton).
- Trichoderma (ट्राइकोडर्मा) — Free-living fungi very common in root ecosystems; effective biocontrol agents of several plant pathogens.
- Baculoviruses (Nucleopolyhedrovirus) (बैक्यूलोवायरस (न्यूक्लियोपॉलीहीड्रोवायरस)) — Viruses that attack insects and other arthropods. Species-specific, narrow-spectrum insecticides with no harm to plants, mammals, birds, fish or non-target insects — good for IPM.
- Rhizobium (राइजोबियम) — Forms nodules on roots of leguminous plants (symbiosis) and fixes atmospheric nitrogen into organic forms the plant uses.
- Azospirillum & Azotobacter (एजोस्पाइरिलम व एजोटोबैक्टर) — Bacteria that fix atmospheric nitrogen while free-living in the soil, enriching soil nitrogen.
- Mycorrhiza (Glomus) (कवकमूल (ग्लोमस)) — Fungus–root symbiosis. The fungus absorbs phosphorus from soil and passes it to the plant; also gives resistance to root-borne pathogens, tolerance to salinity and drought, and better growth.
- Cyanobacteria (blue-green algae) (सायनोबैक्टीरिया (नील-हरित शैवाल)) — Autotrophic microbes; many fix atmospheric nitrogen (Anabaena, Nostoc, Oscillatoria). Important biofertiliser in paddy fields; also add organic matter to soil.
Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake