Take the 2-minute tour ×
Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It's 100% free, no registration required.

Bt corn is genetically modified to kill borers, but "regulations require farmers to plant conventional varieties as well, which is intended to stop the borers becoming resistant." -Source

How do susceptible organisms prevent parasites from overcoming host resistance?

share|improve this question
add comment

1 Answer 1

In an environment where all plants are resistant to certain parasites, a rare breed which has a mechanism against this resistance has free play - lots of food and no competition. However, in plants which do not have the resistance, this rare parasite breed may be at a disadvantage compared to parasites who do not have the mechanism against that resistance (even if only because they do not waste energy on a defensive mechanism they don't need).

By mixing resistant and unresistant plants, it is probably possible to maintain high enough a competition of parasites without that defensive mechanism to prevent the ones with the mechanism from developing. It's natural selection at work :)

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.