Synthetic pyrethroids are pesticides recommended for use in apple orchards to control leaf miners, insects whose larvae feed on the...
GMAT Critical Reasoning : (CR) Questions
Synthetic pyrethroids are pesticides recommended for use in apple orchards to control leaf miners, insects whose larvae feed on the leaves of apple trees. Synthetic pyrethroids also kill predators of spider mites, however. Thus these pesticides do more overall harm than good in an apple orchard.
Which of the following, if true, most strengthens the argument above?
Passage Analysis:
| Text from Passage | Analysis |
| Synthetic pyrethroids are pesticides recommended for use in apple orchards to control leaf miners, insects whose larvae feed on the leaves of apple trees. |
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| Synthetic pyrethroids also kill predators of spider mites, however. |
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| Thus these pesticides do more overall harm than good in an apple orchard. |
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Argument Flow:
The argument starts by explaining what synthetic pyrethroids do (kill leaf miners), then reveals an unintended consequence (they also kill spider mite predators), and concludes that this makes them harmful overall.
Main Conclusion:
Synthetic pyrethroids do more overall harm than good in apple orchards.
Logical Structure:
The argument relies on the idea that killing spider mite predators creates enough negative consequences to outweigh the benefit of killing leaf miners. However, we don't actually see evidence that spider mites cause more damage than leaf miners, which is a gap in the reasoning.
Prethinking:
Question type:
Strengthen - We need to find information that makes us more confident that synthetic pyrethroids do more harm than good in apple orchards
Precision of Claims
The argument makes a comparative claim about overall harm vs. good. The key is that killing spider mite predators somehow creates more damage than the benefit of killing leaf miners.
Strategy
To strengthen this argument, we need information that shows the negative consequences of killing spider mite predators outweigh the benefits of controlling leaf miners. We should look for scenarios that either make the spider mite problem worse or make the leaf miner benefit smaller.
This choice states that spider mites are beneficial to apple trees. Wait - this would actually weaken the argument, not strengthen it. If spider mites help apple trees, then killing their predators wouldn't be harmful at all. In fact, we'd want more spider mites around! This contradicts the author's reasoning that killing spider mite predators causes harm.
This says predators in apple orchards do more harm than good. This is too vague and doesn't help our specific argument. We're only concerned with predators of spider mites, not all predators. Plus, even if this were true, it might actually weaken the argument by suggesting that killing predators (including spider mite predators) is a good thing.
This focuses on consumer behavior regarding pesticide-treated apples. While this could be seen as a negative consequence of using pesticides, it doesn't directly address the core logical gap in the argument about whether killing spider mite predators creates more problems than killing leaf miners solves. It's an economic consideration rather than a pest management one.
This is exactly what we need! If spider mites are more serious pests than leaf miners, then the harm caused by letting spider mites proliferate (because we killed their predators) would outweigh the benefit of controlling the less serious leaf miners. This directly supports the conclusion that the pesticides do more overall harm than good in the orchard ecosystem.
This tells us that leaf miners are sometimes parasitized by other insects. This might suggest there are natural ways to control leaf miners without pesticides, but it doesn't address the core comparison between the harm from spider mites versus the benefit from controlling leaf miners. It's not directly relevant to strengthening the main argument.