question_answer

                                                                         

Why are baculoviruses used as the biological control agents? Mention their importance in organic farming.

Or

The biogas plant shown below is used in rural areas for the production of biogas.

(i) Observe the figure and label the different parts marked as A, B and C.

(ii) Explain the working of a biogas plant.

Answer:

Baculoviruses are used as biological control agents because they attack insects and other arthropods. They show species - specificity and narrow spectrum insecticidal activity. They do not show negative impact on plants, birds, mammals and non - target insects.

Importance in organic farming Baculoviruses are used in Integrated Pest Management (IPM) programme. These are important in organic farming or while dealing with ecologically sensitive areas in order to kill harmful insects and to conserve the beneficial ones.

Or

(i) The different parts of the biogas plant marked as A B and C are

A - Sludge tank                                       B - Gas holder                                        C - Digester

(ii) The biogas plant consists of a concrete tank (1 Q - 15 feet deep) in which the biowastes are collected and a slurry of dung is fed to make slurry equal amount of water and dung is mixed. A floating cover is placed over the slurry which keeps on rising as the gas is produced in the tank due to the microbial activity (methanogens like Methanobacterium).

Methanogens grow anaerobically on cellulose present in the cow dung producing large amount of methane\[(C{{H}_{4}})\], hydrogen \[({{H}_{2}}O)\] and carbon dioxide\[(C{{O}_{2}})\]. The biogas plant has an outlet which is connected to a pipe to supply biogas. The spent slurry is removed through another outlet and can be used as manure.