Hello,

Salicylic acid, a closely related enzyme to  acetylsalicylic acid found in aspirin, has been studied in plants for some time. 

The studies I reviewed were conducted by universities or the USDA and the salicylic acid was dissolved in water, at very specific doses, and sprayed on the leaves or were used to water the plants. Some doses were toxic and caused yellowing leaves.

This statement is from Cornell University---

"Salicylic acid, the chemical compound found naturally in most plants (as well as in the most-used medication, aspirin), is a plant hormone produced at elevated levels in response to attack by microbial pathogens. According to a report on the Web today in the Proceedings of the National Academy of Sciences (PNAS Early Edition, week of Dec. 7, 2003) by BTI's Dhirendra Kumar and Daniel F. Klessig, the aspirin-like hormone is perceived by the SABP2 protein and a message is transmitted, via a lipid-based signal, to activate the plant's defense arsenal."

This article, from the University of Arizona, is a brief discussion on the history of the research and aspirin use in the garden--- https://cals.arizona.edu/yavapai/anr/hort/byg/archive/plantimmunesystems.html

And this article refers directly to the USDA  study on tomatoes---

http://www.growingproduce.com/vegetables/study-pretreating-plants-with-aspirin-like-compound-may-hel...

As the Detroit News article states, in small doses you may see some benefit. You may want to conduct your own experiment and leave at least one third of your  tomatoes untreated, or as a backup, if you get an adverse response.