1.   But as more and more farmers grew coca instead of food, coca leaf prices fell and the cost of food they had to buy soared.

2.   But they concede that they cannot be sure how solid their success will prove unless the coca leaf price comes down or the prices of legal commodities revive soon.

3.   The strategy succeeded in collapsing coca prices, destroying coca labs, and disrupting transportation routes.

4.   U.S. and Peruvian officials say the steep increase in coca prices is a result of several developments.

5.   Officials say the increase also may be related to rising coca prices in Peru, which are luring peasant farmers back to a crop many stopped growing years ago.

6.   The recent jump in coca prices is likely to undermine government efforts to persuade peasants to substitute less lucrative crops for coca.