Everything you need to know about bio-pesticides. Some of the most frequently asked exam questions are as follows:-
Q.1. What are the bio-pesticides?
Ans: The bio-pesticides have been defined as either microbial themselves or products derived from microbial, plants and other biological entities.
Q.2. Name 5 categories of bio-pesticides.
Ans: These are microbial pesticides, entomopathogenic nematodes, baculoviruses, plant derived pesticides and insect pheromones.
Q.3. How do insect pheromones work as bio-pesticides?
Ans: The insect pheromones can be used as bio-pesticides by using as mating disruption agents in orchards and vineyards.
Q.4. What are Bt-Engineered crops?
Ans: These are transgenic crops expressing Bacillus thuringiensis (Bt) insect protein toxins, for the control of lepidopteran pests.
Q.5. Give an example of a recently introduced commercial bio-fungicide.
Ans: The AQ 10® which has been developed from the fungus Ampelomyces quisqualis, is a recent introduction as a control against PMD (powdery mildew) of fruit primarily grapes.
Q.6. Give an example of joint action of bio-fungicides.
Ans: The joint action or possibly synergy increases the utility of bio-fungicides as was demonstrated by combining a nonpathogenic strain of fungus Fusarium oxysporum with a strain of bacterium Pseudomonas fluorescents to control the Fusarium wilts. History
Q.7. How and in which country was the fungal insecticide Beauveria bassisana produced?
Ans: This fungal insecticide was developed in China more than 10 years ago by harvesting a vast amount of vigrous mycelium from fermentation (liquid stage) and transferring into semisolid media (solid stage) consisting of bran, sugar, agar and minerals. The final product contained 1.8 x 1011 spores/g. Many village manufacturers adopted this procedure to produce Beauveria bassiana for control of pine caterpillar and corn borer.
Q.8. Give the mode of action of bacterium Burkholderia cepacia (= Pseudomonas cepacia) as a biological control agent.
Ans: It produces antifungal compounds such as sideropnores and chlorinated phenylpyrrole antibiotics as well as hydrolytic enzyme β-1, 3 – glucanase.
Q.9. What are spinosyns?
Ans: During the course of fermentation screening programme extracts from fermentation broth of soil sample collected in 1982 on a Caribbean island were found to be active on mosquito larvae. The microorganism involved was identified as an actinomycete belonging to a less common genus Saccharopolyspora. The microorganism Saccharopolyspora spinosa was identified as a new species. It produced a new unique macrolides (molecules containing macrocyclic lactone, originally referred to as A 83543 factors) but now called spinosyns.
Q.10. What are crystal proteins of Bt?
Ans: The crystal proteins are protoxins which require proteolytical conversion into smaller toxic peptides in the migut of insects. The insecticidal protein crystals are also called 5-endotoxins. It is believed that toxins cause osmotic imbalance by creating pores in the cell membrane of the midgut epithelium of susceptible insects.
Q.11. Name a transgenic tree with 8 (delta) endotoxin of Bt.
Ans: Populus deltoides plants were transformed using A. tumefaciens LBA 4404 strains containing a gene from Bt and two of the three plants regenerated successfully integrated the Bt gene.
Q.12. Which are the Baculovirus types? Give their general properties.
Ans: The Baculoviruses compose a single family Baculoviridae which possesses two genera of occluded viruses Nucleopolyhedronvirus called as nuclear polyhedrosis viruses (NPVs) and Granulovirus called as granulosis virus (GV). The occluded viruses have been so named because after formation in infected cells the mature virus particles or virions are occluded within a protein matrix forming paracrystalline bodies which are generically referred to as either inclusion or occlusion bodies. The occlusion bodies of NPVs are referred to commonly as polyhedrad because these are typically polyhedral in shape.