Most farmers attempting to control slugs and snails turn to baited slug poison, or molluscicide, which usually consists of a bran pellet containing either methiocarb or metaldehyde. Both chemicals are neurotoxins that disrupt that part of the brain charged with making the mouth move in a coordinated fashion—the "central pattern generator"—as the slug feeds. Thus, both neurotoxins, while somewhat effective, interfere with the slugs' feeding behavior and limit their ingestion of the poison, increasing the probability that some will stop feeding before receiving a lethal dose. Moreover, slugs are not the only consumers of these poisons: methiocarb may be toxic to a variety of species, including varieties of worms, carabid beetles, and fish.
Researchers are experimenting with an alternative compound based on aluminum, which may solve these problems, but this may well have a limited future as we learn more about the hazards of aluminum in the environment. For example, some researchers suggest that acid rain kills trees by mobilizing aluminum in the soil, while others have noted that the human disease Alzheimer's is more prevalent in areas where levels of aluminum in the soil are high. With farmers losing as much as 20 percent of their crops to slugs and snails even after treatment with currently available molluscicides, there is considerable incentive for researchers to come up with better and environmentally safer solutions.
The passage suggests that methiocarb and metaldehyde would be more effective as slug poisons if it were true that they
disrupt the slug's digestive processes rather than its reproductive functions
reduce the slug's ability to taste food
begin to affect the feeding behavior of a slug only after it has ingested a lethal dose
reach the central pattern generator more quickly
accumulate only in the central pattern generator rather than throughout the brain
题目的意思其实让我们找出这两者的劣势，然后反过来就是答案了。定位在“Thus, both neurotoxins, while somewhat effective, interfere with the slugs' feeding behavior and limit their ingestion of the poison, increasing the probability that some will stop feeding before receiving a lethal dose.”这两者的问题是鼻涕虫在吃到致命的剂量之前就被影响了饮食表现。所以，如果可以在致命剂量之后才影响饮食表现就可改进。
D选项：达到“central pattern generator”更快。这个选项说反了，如果更快的达到“central pattern generator”，鼻涕虫饮食表现受到的影响也就更快。
E选项：只在“central pattern generator”中累积而不是大脑中。不论在哪里累积，只要不能减缓影响饮食表现的时间，就无法让这两者的效果更大。