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Biological control of pests reading answers

Updated on 13 December, 2022
Mrinal Mandal

Mrinal Mandal

Study Abroad Expert

Cracking IELTS is no easy feat. You need to practice, practice and practice to get the desired band scores. To help you with the reading test section, here is an IELTS reading passage sample, ‘Biological control of pests’, with answers and explanations.

Biological Control Of Pests – What’s, Why’s And How’s!

The reckless and continuous usage of synthetic materials and chemicals to manage and control pests poses numerous threats to human health and agricultural crops. It's quite a counter-productive method of reducing the pest population. It has caused ecological imbalances and led to the development of immensely lethal superbugs, a new offspring of chemically-resistant pests.

According to the Food and Agriculture Organizations (FAO), over 300 pests and insects have grown resistant to potent chemicals. This doesn't include 100s of other disease-spreading insects that have immunity against insecticides.

Another major disadvantage of employing insecticides is that it kills not only infectious pests but also impact non-targeted, beneficial organisms that naturally ensure pest control. It leads to what agroecologists and growers refer to as the treadmill syndrome. Owing to their genetic diversity and extraordinary breeding capabilities, many pests can now survive against synthetic chemicals and produce offspring with an in-built resistance against insecticides.

The travesty that is treadmill syndrome can be noticed in Central America. At the beginning of the 1940s, the farmers, hoping to enhance cotton yield, turned to pesticides and practised intensive chemical-based agriculture. They used insecticides around eight times during the middle of the 1940s. In another decade, that usage jumped to the number of 28 times. There was also the introduction of three brand-new chemical-resistant pest varieties.

By the middle of the 1960s, the condition became alarming as four brand-new pests came into existence. It inadvertently increased the usage of pesticides to the point that around 50% of crop production expenditures were solely due to the chemicals. In the 1970s, pesticide spraying was approximately 70 times every season since the intrusion of genetically powerful pests couldn't be contained.

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Even today, the market is dominated by several poorly-tested pesticides that could contribute to cancer, mutations, and other diseases, as noted by US environmental agencies. United States (US) National Resources Defense Council notably claimed that DDT was among the most sought-after dangerous chemicals.

When confronted with such adversity and the failure of pesticides, another ecologically conscious and effective strategy was birthed – biological control of pests. This involved the usage of specific natural enemies against the pest and insect population. This activity is on the rise and has limited potential to grow. One of the prime advantages of the biological control of pests includes the minimum detrimental impact on health and low expenditures. If done by experts, it's non-polluting, self-dispersing and safe.

One of the most agile and non-commercial research organizations working in the field of pest control via natural enemies is the Commonwealth Institute of Biological Control (CIBC), Bangalore. It has a global network of field stations and research laboratories and serves as both an importer and exporter of biological agents helpful to control pests worldwide.

CIBC controlled the harmful parthenium weed, which has wreaked havoc in the agricultural field across Australia and India, with the help of seed-feeding weevil. Similarly, the Regional Research Laboratory in Hyderabad, aided by CIBC, uses Argentinian weevil to destroy water hyacinth, which hinders crops and human health. Kaiser Jamil from RRL stated that the Argentinian weevil was not harmful to any plant, and the adult bugs could easily eradicate the dangerous weed in under a week. Additionally, the CIBC is trying to hone its technique of procreating parasites that devour the 'disapene scale' insects, which notoriously torment the fruit shrubs and trees in Indian and the US.

Several excellent examples in front of us depict the efficacy of biological control when used correctly. Let's look at them!

At the end of the 1960s, Sri Lanka's prospering coconut groves were attacked by the leaf-mining hispid. Singapore's larval parasite was imported for rescue. It helped bring the pests under control. Neodumetia sangawani, a native Indian predator, also aided in managing and controlling Rohdes grass-scale pests that plagued the forage grass around the US. In another case, Neochetina bruci, a Brazilian indigenous beetle, was used by the Kerala Agricultural University to eradicate the weed known as Salvinia molesta (also known as African Payal) from a 12-kilometre-long canal. Over 30,000 hectares of fields in Kerala that grow rice are still struggling with Salvinia molesta weed.

It indicates that using natural enemies under the control of humans can produce better and healthier results than pesticides. Whether the growers use conservation, classical biological management or augmentation – the three different kinds of biological control of pests – they are likely to see more satisfactory results.

This field is still under heavy research and development but shows incredible promise!

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Questions 1-4

Pick the correct answer: A, B, C, or D.

State the letter in boxes 1-4 on your answer sheet.

1.  The use of pesticides has contributed to

A) Different ecological classifications by agroecologists.

B) The aversion to environmental disasters around the world.

C) Ecological imbalance around the world.

D) Increase of ecologies that farmers can utilize.

2.  The Food and Agriculture Organisation has counted more than 300 agricultural pests which

A) No longer respond to most pesticides in use

B) Spread diseases in a wide range of crops.

C) Are easy to control through the use of pesticides.

D) Are used as a replacement for insecticides under the bio-control practice.

3.  Cotton farmers in Central America began to use pesticides

A) As a response to reduced varieties of new pests.

B) To ensure better cotton production.

C) Due to the government's intensive advertising campaign.

D) Due to the noticeable changes in weather and climate.

4.  By the mid-1960s, cotton farmers in Central America found that pesticides

A) We're leading to a 50% increase in new and harmful pests.

B) Were harming 50% of the crops that required protection.

C) Were eradicating 50% of pests infesting the crops.

D) Were leading to 50% more expenditures on crop production.

Questions 5-6

Are the following statements in accordance with the writer's claims in Reading Passage 2?

Write your answers in boxes 5-6 on your answer sheet,

if it's a

YES, i.e., you agree that the statement is on the lines of the writer's intent

No, i.e., if you believe that the statement does not match the author's view

NOT GIVEN, i.e., if there is not enough context given in the passage to support the statement

5.  Disease-spreading pests respond more quickly to pesticides than agricultural pests do.

6.  Several pests are now born with innate immunity to some pesticides.

7.  Synthetic chemicals are used under the biological control of pests to try to rewire the genetics of the pests' offspring.

8.  Bio-control is not dangerous under specific circumstances

Questions 9-13

You must complete the following sentences with correct words, choosing from option A-I below.

State the correct letter from A-I in boxes 9-13 on your answer paper.

A. Forage grass

B. Parthenium weed

C.  Rice fields

D. Brazilian beetles

E.  Coconut groves

F.  Grass-scale pests

G. Fruit trees

H. Larval parasites

I.   Water hyacinth

9.  Disapene scale insects feed on:

10.  Neodumetia sangawani ate: 

11.  Salvinia molesta plagues:

12.  An Argentinian weevil may be successful in wiping out:

13.  Leaf-mining hispides blighted:

Question numberAnswerExplanation

According to the biological control of pests reading answer IELTS sample, the answer is in line 3, first paragraph, where the author mentions how pesticides have been counter-productive and have caused ecological imbalances around the world.


As per the reading passage ‘biological control of pests,' you can locate the answer on lines 1-2, second paragraph, where the author talks explicitly about FAO and their notable study of 300 pests that have grown immunity against the most-used pesticides.


You will find the answer to this question in lines 1-3, paragraph 4, of the biological control of pests reading answers IELTS sample. The passage clearly states that farmers in Central America turned to chemical-intensive options and pesticides to ensure better crop yield of cotton.


The reading sample of the IELTS sample about the biological control of pests answers this question neatly in lines 2-3, paragraph 5. It clearly states that the usage of pesticides accounted for 50% of expenditures in crop production.

5.Not Given

This statement cannot be found conclusively anywhere in the biological control of pests reading answer IELTS sample.


You can find this answer clearly stated in lines 4-5 of paragraph 3 in the reading sample of IELTS, ‘biological control of pests.’


Nowhere in the reading sample of IELTS, ‘biological control of pests,’ will you find any mention of using synthetic chemicals as part of the biological control of pests.


You can find the answer mentioned in lines 5-6 of paragraph seventh in the reading sample of IELTS, ‘biological control of pests.’


You can find the answer in the reading sample of IELTS, ‘biological control of pests,’ one the last line of paragraph ninth.


This answer can be found on line 4 of paragraph 11 in the reading sample of IELTS, ‘biological control of pests.’


The answer is given on lines 7-8 of paragraph 11 in the reading sample of IELTS, ‘biological control of pests.’


The answer is on lines 3-4 of paragraph ninth given in the reading sample of IELTS, ‘biological control of pests.’


The answer is stated on line 1 of paragraph 11th of the reading sample of IELTS, ‘biological control of pests.’

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