Am I understanding this correctly?

Question

This is from a GRE test.

"Modern agricultural practices have been extremely successful in increasing the productivity of major food crops, yet despite heavy use of pesticides, considerable losses to diseases and insect pests are sustained each year."

Please let me know if I understand this correctly. Here is what I got from the passage:

1.The productivity of major food crops has been successfully increased due to new agricultural practices.

2.The use of pesticides doesn't reduce losses to diseases and pests, which implies that pesticides are not effective in increasing the productivity of food crops.

3.The passage is trying to say that modern agricultural practices are useful, except the use of pesticides.

Thank you.

Answer 1

(1) is certainly true. For (2) and (3), it could be said that the article implies that using pesticides is not as effective as we think in preventing losses of crop due to disease and pests. Pesticides have nothing to due with productivity, unless the text explicitly links losses due to disease and pests back to productivity (which it does not). The article does not say that pesticides are not useful, but that they are no as useful as they could be.