NEET Biology Microbes As Biocontrol Agents Multiple Choice Question And Answers

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Biology MCQ For NEET With Answers Microbes As Biocontrol Agents

Question 1. The natural method of pest and pathogen control involving the use of viruses, bacteria, and other insects is called

  1. Biochemical control
  2. Biological gene control
  3. Biocontrol
  4. Chemical control

Answer: 3. Biocontrol

The natural method of pest and pathogen control involving the use of viruses, bacteria, and other insects is called biocontrol or biological control. For example, ladybird beetle feeds on aphids, while dragonflies prey upon mosquitoes.

Question 2. The biological control component is central to advanced agricultural production. Which of the following is used as a third-generation pesticide?

  1. Pathogens
  2. Pheromones
  3. Insect repellents
  4. Insect hormone analogs

Answer: 4. Insect hormone analogs

Professor Carroll M. Williams (1956) was probably the first to recognize the potential of applying insect hormones in pest control and in 1967 hailed them as ‘third-generation pesticides. The first generation is exemplified by an arsenate of lead and the second by ddt.

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Question 3. Ipm (integrated pest management) involves

  1. Biological control
  2. Pesticides
  3. Confusion technique
  4. Biofertilizers

Answer: 1. Biological control

According to IBM, biological control methods should be followed and the use of chemical pesticides should be minimized.

Biology MCQ For NEET With Answers

NEET Biology Microbes As Biocontrol Agents Multiple Choice Question And Answers

Question 4. Integrated pest management (IPM) discourages the excessive use of

  1. Biological methods
  2. Chemical pesticides
  3. Mechanical methods
  4. Variable cultural controls

Answer: 2. Chemical pesticides

  • Ipm discourages the excessive use of chemical pesticides. Sustainable pest management (spam) is otherwise known as integrated pest management (pm).
  • Ipm involves the use of different pest control methods, which are ecologically safe, for example, biological control methods, and better agricultural practices like crop rotation, sanitation, etc.

Question 5. A biocontrol agent to be a part of integrated pest management (ipm) should be

  1. Species-specific and symbiotic
  2. Free-living and broad spectrum
  3. Narrow spectrum and symbiotic
  4. Species-specific and inactive on

Answer: 4. Species-specific and inactive on

A biocontrol agent to be a part of an item should be species-specific and inactive on non-target organisms.

Question 6. The latest trend in plant disease control in Punjab

  1. Chemical control
  2. Biological control
  3. Good manure and fertilizer
  4. Breeding for disease resistance

Answer: 2. Biological control

Biological pest control is one of the suitable methods, i.e. Use of other organisms to kill the pests. Thus, the latest trend in plant disease control is biological control.

Question 7. Milkweed vine is being eradicated from citrus with the help of herbicide

  1. Phytophthora parthenium
  2. Phytophthora palmivora
  3. Pyrethrin
  4. 2, 4- D

Answer: 2. Phytophthora palmivora

The first bioherbicide developed in 1961 was a mycoherbicide derived from a fungus, phytophthora palmivora which controls the growth of milkweed vines in citrus orchards.

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Question 8. The free-living fungus Trichoderma can be used

  1. For killing insects
  2. As a biological control of plant diseases
  3. To control butterfly caterpillars
  4. For producing antibiotics

Answer: 2. As a biological control of plant diseases

Trichoderma is a free-living saprophytic fungus that most commonly lives on dead organic matter in the soil and rhizosphere. It acts as a biopesticide for the biological control of many soil-borne plant diseases.

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Question 9. Consider the following statements.

  1. Ladybirds and dragonflies are used to get rid of aphids and mosquitoes.
  2. The bacteria Bacillus thuringiensis (Bt) are used to control butterflies.
  3. Trichoderma sp. Is present in root ecosystems where they act against several plant pathogens.
  4. Rhizobium is a symbiotic bacterium that lives in the stem of legumes.

Which of the statements given above is correct?

  1. 1, 2 And 3
  2. 1, 3 And 4
  3. 2, 3 And 4
  4. 2 And 4

Answer: 1. 1, 2 And 3

  • All given statements are correct except statement iv. The incorrect statement can be corrected as
  • Rhizobium is a symbiotic bacterium that lives in the root nodules of legumes and fixes atmospheric nitrogen into organic compounds.

Question 10. Match the following columns

NEET Biology Microbes as Biocontrol Agents MCQs Question 10 Match the following columns.

Answer: 2. A–3, b–4, c–2, d–1

Question 11. Microbe used for biocontrol of pest butterfly caterpillars is

  1. Saccharomyces cerevisiae
  2. Bacillus thuringiensis
  3. Streptococcus sp.
  4. Trichoderma sp.

Answer: 2. Bacillus thuringiensis

  • Biopesticides are biological agents that are used to control weeds, insects, and pathogens. The microorganisms used as biopesticides are viruses, bacteria, protozoan, fungi, and mites.
  • The spores of Bacillus thuringiensis bacterium produce an insecticidal cry protein that kills the larvae of insects upon ingesting them. Thus, bacillus thuringiensis is a biopesticide for butterfly caterpillars

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Question 12. Trichoderma harzianum has proved a useful microorganism for

  1. Bioremediation of contaminated soils
  2. Reclamation of wastelands
  3. Gene transfer in higher plants
  4. Biological control of soil-borne plant pathogens

Answer: 4. Biological control of soil-borne plant pathogens

  • Trichoderma harzianum is a useful microorganism for the biological control of soil-borne plant pathogens.
  • It is a fungus that is also used as a fungicide. It is used for foliar application, seed treatment, and soil treatment for suppression of various diseases causing fungal pathogens.

Question 13. The viruses which have been tested as insecticides against the serious pest of cotton Heliothis species are

  1. Cytoplasmic polyhedrosis virus
  2. Entomopoxvirus
  3. Nuclear polyhedrosis
  4. All of the above

Answer: 4. All of the above

  • Heliothis is a genus of moths, whose larvae are agricultural pests on crop species such as tobacco, cotton, soybean, and pigeon pea.
  • The viruses, which have been tested as insecticides against the serious pest of cotton Heliothis species are cytoplasmic polyhedrosis virus and entomopoxvirus, and nuclear
    polyhedrosis.

Question 14. Ecological suicide is forced on to rice moth Corcyra cephalonica by a compound extracted from

  1. Chrysanthemum
  2. Neem
  3. Eichhornia crassipes
  4. All of the above

Answer: 3. Eichhornia crassipes

  • Ecological suicide is forced on to rice moth, Corcyra cephalonica by a compound extracted from Eichhornia crassipes. The prothoracic gland of insects secretes molting hormones or ecdysone which is responsible for the molting, pupation, and maturation of insects.
  • This hormone can be used to bring the insect into developing conditions during unfavorable seasons, thus forcing them to commit ecological suicide. One such compound is isolated from Eichhornia crassipes, which has a similar mode of action.

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Question 15. Which of the following can be used as a biocontrol agent in the treatment of plant disease?

  1. Trichoderma
  2. Chlorella
  3. Anabaena
  4. Lactobacillus

Answer: 1. Trichoderma

Fungus Trichoderma is a biological control agent that is being used in the treatment of plant diseases.

Question 16. Which of the following statements regarding baculoviruses as biocontrol agents is/are correct?

  1. Baculoviruses are pathogens that attack insects and other arthropods.
  2. Most of these biocontrol agents belong to the genus– nucleopolyhedrovirus.
  3. They do not harm plants mammals, birds, fish, and other non-target insects.
  4. Baculoviruses are helpful in integrated pest management (ipm) programs, in which beneficial insects are conserved.

Choose the correct option.

  1. 1, 2 And 3
  2. 1, 2 And 4
  3. 2, 3 And 4
  4. 1, 2, 3 And 4

Answer: 4. 1, 2, 3 And 4

  • All given statements are correct. Baculovirus Heliothis (a group of viruses) are known to infect the larval stages of many harmful insects beetles, wasps, and ants.
  • A number of baculoviruses, which are used as biopesticides belong to the genus nucleopolyhedrovirus. These biological weapons are effective as potential biological control of harmful insects and are harmless to non-target organisms (plants, birds, mammals, non-target insects, etc).
  • Baculoviruses are helpful in integrated pest management (ipm) programs in which beneficial insects are conserved.

Question 17. One of the following is third-generation pesticides

  1. Chemosterilants
  2. Organochlorines
  3. Antifeedants
  4. Carbamates

Answer: 3. Antifeedants

Antifeedants are organic compounds produced by plants to inhibit attack by insects and grazing animals. So, they are third-generation pesticides.

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Question 18. The antifeedant compound is extracted from

  1. Sesbania rostrata
  2. Trifolium repens
  3. Azadirachta indica
  4. None of the above

Answer: 3. Azadirachta indica

Azadirachtin from indian neem tree azadirachta indica, is a most versatile antifeedant

Question 19. Thuriocide is released by

  1. Bacillus thuringiensis
  2. Virus
  3. Fungi
  4. Protozoan

Answer: 1. Bacillus thuringiensis

Thuriocide is a toxin produced by the bacterium, bacillus thuringiensis. Thus, it is of bactericidal origin. It is first used as a bioinsecticide on a commercial scale in the world, as it is highly effective against disease-causing insects like flies, moths, mosquitoes, etc. If consumed by mistake, it acts as a stomach poison.

Question 20. The cultivation of cotton has been much in the news. The prefix bt refers to

  1. ‘Barium-treated’ cotton seeds
  2. ‘Bigger thread’ variety of cotton with better tensile strength
  3. ‘Biotechnology’ process using restriction enzymes and ligases
  4. An endotoxin gene carried by bacillus thuringiensis

Answer: 4. An endotoxin gene carried by Bacillus thuringiensis

In Bt cotton, bt means carrying an endotoxin gene from Bacillus thuringiensis. Specific Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into several crop plants such as cotton, and corn. The toxin is coded by a gene named cry.

21. Which bacterium was first used as biopesticide on a commercial scale in the world?

  1. Bacillus thuringiensis
  2. Escherichia coli
  3. Pseudomonas aeruginosa
  4. Agrobacterium tumefaciens

Answer: 1. Bacillus thuringiensis

Thuriocide is a toxin produced by the bacterium, bacillus thuringiensis. Thus, it is of bactericidal origin. It is first used as a bioinsecticide on a commercial scale in the world, as it is highly effective against disease-causing insects like flies, moths, mosquitoes, etc. If consumed by mistake, it acts as a stomach poison.

Question 22. Cry I endotoxins obtained from Bacillus thuringiensis are effective against

  1. Mosquitoes
  2. Flies
  3. Nematodes
  4. Bollworms

Answer: 4. Bollworms

Cry I endotoxin obtained from Bacillus thuringiensis is effective against bollworms. A bollworm is a common term for any larva of a moth that attacks the fruiting bodies of certain crops, especially cotton.

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Question 23. Bioherbicides and bioinsecticides

  1. Are non-persistent, non-toxic, and biodegradable
  2. Maintain the biodiversity and stability of the ecosystem
  3. Decrease the chances of environmental pollution and degradation
  4. All of the above

Answer: 4. All of the above

Bioherbicides and bioinsecticides are biocontrol agents that exhibit high pest specificity and biodegradability. Thus, they are non-persistent in the environment and do not cause environmental pollution. Due to their host specificity, they maintain biodiversity and ecological stability.

Question 24. The first bioherbicide developed in 1981 was based on

  1. Phytophthora palmivora
  2. Phytophthora infestans
  3. Bacillus thuringiensis
  4. Azadirachta indica

Answer: 1. Phytophthora palmivora

The first bioherbicide was developed in 1981. It is a mycoherbicide, based on the fungus, phytophthora palmivora, which controls the growth of milkweed vines in citrus orchards.

Question 25. Devine and College are two trade names in agriculture. They are used as

  1. Bioinsecticides
  2. Natural insecticides
  3. Biofungicides
  4. Bioherbicides

Answer: 4. Bioherbicides

  • Devine is the first bioherbicide registered in the united states and is used for controlling milkweed vines. College is another bioherbicide made from Colletotrichum gloeosporioides.
  • the anthracnose-causing fungal pathogen and is used to control aeschynomene Virginia in rice and soybean crops. So, they are used as bioherbicides.

Question 26. Most recent insecticides in India are

  1. Chlorinated hydrocarbons
  2. Organophosphorus compounds
  3. Carbamates
  4. Pyrethroids

Answer: 4. Pyrethroids

Pyrethroids are the most recent insecticides in India. These are called ‘third generation insecticides’, for example, deltamethrin. Chlorinated hydrocarbons are first-generation insecticides. Carbamate and organophosphorus are second-generation insecticides.

Question 27. Pyrethrin is obtained from

  1. Azadirachta indica
  2. Rosa indica
  3. Poa indica
  4. Chrysanthemum

Answer: 4. Chrysanthemum

Pyrethrins are a class of organic compounds normally derived from chrysanthemum cinerariifolium. They have potent insecticidal activity by targeting the nervous systems of insects. Pyrethrins are less toxic pesticides from a human health standpoint.

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Question 28. Which among the following is a mycoherbicide?

  1. Beauveria bassiana
  2. Bacillus thuringiensis
  3. Xanthomonas sp.
  4. Alternaria crassa

Answer: 4. Alternaria crassa

A mycoherbicide is a herbicide based on a fungus, Alternaria crassa. As a biological agent, these ‘mycoherbicides act by producing toxic compounds that dissolve the cell walls of targeted plants.

29. Which weed has been eradicated by biological control?

  1. Parthenium
  2. Cactus
  3. Eichhornia
  4. Chrysanthemum

Answer: 2. Cactus

Cactus has been eradicated by the method of biological control. It was done by introducing the cochineal insect, cactoblastis cactorum. The insect is a type of moth that exceptionally feeds on the cactus plant.

30. Biological control of weeds is carried out by

  1. Insects that feed on weeds and not the crop
  2. Use of pathogen microbes that cause disease only in weeds
  3. Both (1) and (2)
  4. Use of chemical pesticides

Answer: 3. Both (1) and (2)

Biological weed control involves the use of living organisms such as insects, nematodes, bacteria, or fungi to reduce weed populations. These organisms feed upon or cause diseases in weeds only and do not affect other crops.

Question 31. Confusion technique involves

  1. Laying traps containing pheromones
  2. Confusing insects by releasing sterile males
  3. Spreading pheromone containing hydrophobic papers
  4. Introducing pheromones at juvenile

Answer: 3. Spreading pheromone containing hydrophobic papers

  • ‘Confusion technique’ involves the use of pheromones or sex attractants. In this technique, hydrophobic paper having pheromones is placed over the crop area, due to which characteristic smell is spread over.
  • The whole field and thus males are unable to locate the females. This technique helps to prevent the mating of pests and thus check their population.

Question 32. Fruitflies have been controlled by

  1. Sterilization
  2. Pheromonal compounds as synthetic methyl eugenol
  3. Cultural control
  4. All of the above

Answer: 2. Pheromonal compounds as synthetic methyl eugenol

  • A large number of pheromones have been identified and their usefulness as bait or an attractant to collect a large number of insects to be killed or herded away from the opposite sex has been proved.
  • Some of these compounds are phenols, which attract the grass grubs and others like synthetic methyl eugenol have practically been used for controlling fruit flies.

Question 33. Which bioherbicide was first used?

  1. Mycoherbicide
  2. Molluscoherbicide
  3. Nematoherbicide
  4. Insecticide

Answer: 1. Mycoherbicide

The first bioherbicide was developed in 1981. It is a mycoherbicide, based on the fungus, phytophthora palmivora, which controls the growth of milkweed vines in citrus orchards.

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Question 34. Agrobacterium radiobacter strain 

  1. Fungal pesticide
  2. Microbial pesticide
  3. Mycoherbicide
  4. Viral pesticide

Answer: 2. Microbial pesticide

Agrobacterium radiobacter strain k1026 is a microbial pesticide that can be used to treat germinating seeds or roots and stems of certain stone fruit (such as cherries and plums), nut trees, and ornamentals to protect them from crown gall disease.

Question 35. Which of the following statements is/are correct?

  1. Herbicides kill plants mostly by blocking photosystem-ii and occasionally phloem transport
  2. Insecticides kill insects mostly through impairment of nerve conduction and sometimes through respiratory arrest
  3. Both (1) and (2)
  4. None of the above

Answer: 3. Both (1) and (2)

  • Herbicides kill weeds and unwanted plants in cultivated land. They kill plants mostly by blocking photosystem-ii and occasionally phloem transport.
  • Insecticides are those chemicals that destroy or kill insects mostly through impairment of nerve conduction and sometimes through respiratory arrest. Thus, the option is correct.

Question 36. Allethrin is a commonly used

  1. Fertiliser
  2. Herbicide
  3. Growth hormone
  4. Insecticide

Answer: 4. Insecticide

The allethrins are a group of related synthetic compounds used as insecticides. Allethrin was the first pyrethroid. They are commonly used in ultra-low volume sprays for outdoor mosquito control, including many household insecticides such as raid as well as mosquito coils.

Question 37. Which of the following is bioinsecticide?

  1. Ladybirds beetle
  2. Dragonflies
  3. Bees
  4. Both (1) and (2)

Answer: 4. Both (1) and (2)

Ladybird beetles control aphids, whereas dragonflies control mosquitoes. Bees have no role as bioinsecticides.

Question 38. Ladybird beetle is a predator of

  1. Moths
  2. Beetles
  3. Bacteria
  4. Aphids

Answer: 4. Aphids

There are many species of ladybird beetles, also referred to as ladybeetles or ladybugs. Ladybird beetle is a predator of aphids, spiders, mites, scale insects, white flies, leaf beetle larvae, some insect eggs, and small caterpillars.

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Question 39. Meliantiol and galanin bioinsecticides have been extracted from

  1. Chrysanthemum cinerariifolium
  2. Derris elliptica
  3. Azadirachta indica
  4. Eichhornia

Answer: 3. Azadirachta indica

The neem (Azadirachta indica) is one of the best sources of the most useful natural insecticides. Natural insecticides, for example. Azadirachtin, mediation, salanin, etc., Are extracted from neem. These are very effective as insecticides as well as insect repellents and antifeedants.

Question 40. The biocontrol of larvae of mosquitoes is done by

  1. Ladybird beetles
  2. Gambusia fish
  3. Eichhornia
  4. Azolla

Answer: 2. Gambusia fish

Effective biocontrol agents include predatory fish that feed on mosquito larvae such as mosquito fish, gambusia affinis, and some cyprinids, carps, and minnows.

41. Biopesticides are

  1. The chemicals which are used to destroy pests
  2. The living organism or their products which are used for pest control
  3. The organism which destroys crops
  4. None of the above

Answer: 2. The living organism or their products that are used for pest control

Biopesticides are less harmful than conventional pesticides. They are biological control agents which are used to control weeds and pests. They are of two types, i.e. Bioherbicides, and bioinsecticides.

Question 42. A fungal pesticide, beauvericin bassiana is used to kill

  1. Whiteflies and mites
  2. Larvae of Aedes
  3. Larvae of mosquitoes
  4. Cacti

Answer: 1. White flies and mites

Beauveria bassiana can be used as a biological insecticide to control a number of pests such as termites, white flies, and many other insects.

Question 43. A viral pesticide used against gypsy moths is

  1. Npv
  2. Nosema locustae
  3. Fusarium
  4. Beauveria bassiana

Answer: 1. NPV

Npv, i.e. Nucleopolyhedrovirus is a baculovirus that is a viral pesticide used against gypsy moths, aphids, and beetles.

Question 44. Which of the following is not a correctly matched pair?

  1. Azadirachtin–neem
  2. Nicotine–tobacco
  3. Pyrethrum–datura
  4. Rotenone–derris elliptical

Answer: 3. Pyrethrum–datura

Matched pair and can be corrected as pyrethrum is obtained from chrysanthemum. Rest options are correctly matched pairs.

Question 45. In the USA, the return of brown pelican is the result of banning the use of which pesticide?

  1. 2, 4-D
  2. Ddt
  3. Bordeaux mixture
  4. Malathion

Answer: 2. Ddt

  • There has been a decline in the number of ospreys and bald eagles along the eastern coast of the united states due to DDT pesticide contamination. Ddt reaches these birds through biomagnification.
  • It makes their eggs non-viable, as the disturbed calcium metabolism in these birds causes the formation of eggs with fragile shells. So, brown pelican populations recovered after the banning of most uses of ddt.

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Question 46. Consider the following statements.

  1. Biocontrol refers to the use of biological methods for controlling plant diseases and pests.
  2. The use of biocontrol measures greatly reduces our dependence on toxic chemicals and pesticides.

Choose the correct option.

  1. Statement 1 is correct, but 2 is incorrect
  2. Statement 1 is incorrect, but 2 is correct
  3. Both statements 1 and 2 are correct
  4. Both statements 1 and 2 are incorrect

Answer: 3. Both statements 1 and 2 are correct

Question 47. Consider the following statements about bt.

  1. The bacteria Bacillus thuringiensis (Bt) is used to control butterfly caterpillars.
  2. Fresh spores of bt are mixed with water and sprayed on plants such as brassica and fruit trees.
  3. Insect larvae after eating, but spores are killed by the toxin released in their gut.
  4. Bt toxin genes have been introduced into animals to prey on pests.

Choose the option containing the correct statements.

  1. 1, 2 And 3
  2. 1, 3 And 4
  3. 2, 3 And 4
  4. 1, 2, 3 And 4

Answer: 1. 1, 2 And 3

All given statements are correct except iv. Thus, the option is correct. Bt toxin genes have been introduced into plants so as to kill insect pests. Thus, an option is correct.

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