Here's why:
The author of the essay begins with a topic sentence--which is good--but he/she does not indicate where the borrowed information or evidence begins. This can be tricky when using a summary or paraphrase of what another author has said because 1) there are no quotation marks, and; 2) you've put it in your own words; as a result, it could end up sounding like you. Here is one way that the author could make it clear.
There are many examples of how highly productive corporations have been poor global citizens. The Landers Corporation was made famous by several decades of successful research and development that led to the creation of many innovative products. However, this came at a cost because of the byproducts of some of their more covert development leading some to speculate that they knowingly poisoned the environment and people surrounding their operations in third-world countries (Spy 133).
There are many examples of how highly productive corporations have been poor global citizens. For example, Ima Spy, Professor of Business Ethics at Dalhousie University concludes that the Landers Corporation was made famous by several decades of successful research and development that led to the creation of many innovative products. However, this came at a cost because of the byproducts of some of their more covert development leading some to speculate that they knowingly poisoned the environment and people surrounding their operations in third-world countries (133).
By simply inserting an introductory phrase that identifies the source before the summary or paraphrase and by putting the page reference at the end, it is clear where the borrowed ideas begin and end. Notice, as well, that since the author is identified, then you do not need to include the author's last name in the citation, just the page number. The only exception would be if you were using more than one source from the same author. Then you would need to indicate this in the introductory phrase, for example:
Ima Spy, Professor of Business Ethics at Dalhousie Univeristy, in Corporations Behaving Badly concludes that...
This also gives you the opportunity to mention the qualifications of the expert you are quoting, thus, adding more credibility to both the source and your own argument.