^ She is 100% correct, though I didnt know sweet potatoes were in that. Its possible though

.
Fun Fact of the day, Potatoes, Tomatoes and Egg Plants all contain Nicotine. Potatoes it is more is in the actual plant then the vegetable, where as with Tomatoes and Egg Plant, are high in Nicotine content. The plants themselves all contain nicotine as does all of the nightshade family (Tobacco plant is nightshade).
Nicotine is an insecticide as in its pure form is poisonous. To a serious extent, a drop of pure nicotine on your skin will equal death, that looks a lot like a heart attack.
Horn worms are strangely immune to Nicotine's effects in small doses much like humans, too much can still kill them however. This is why Horn worms fed tomato are toxic it is the nicotine in there system.
So for that record, If any of you are Vapers like me

, be especially careful vaping around your cham and feeder insects.
Cool article about the Nic in plants

.
http://abouttesting.testcountry.com/2010/06/6-common-food-with-nicotine-content.html
Another tip, Be careful with pesticides. Most "Organic Pesticides" Contain nicotine, as in small amounts the human body can take it( new studys are even suggesting it has some positive effects (not smoking obviously due to tar, but pure nicotine). However for bugs and chams the slightest amount could be fatal.