Well, I'm sure this won't help you but...I've been going in August and I've never found the need to use it--I bring it just in case though. But in general, I don't recall having any bug trouble during my visits.
The past couple days I have been to Disney have been odd......I went on saturday night and was bothered by bugs. I got bit on the knee by a horsefly I think and my knee has swollen up.....there were an aful amount of bugs we had problems with that night. I dunno if it was just me......
One May trip, I was eaten by mosquitoes. Last year, I did not get a single bite. Maybe you should bring some just in case; seems hit and miss for those buggars!!!!
I just got back yesterday. Tiny black bugs got me. I felt one on my arm. It felt like he was gouging me. I also had a few bites on my legs. I think a light application of bug repellent should do. I wish I'd brought some.