We are headed to Bahia Drake in a few short weeks. How bad is are ticks and chiggers (and other noxious insects) in this area? I have had problems with said insects in Central Panama so I wonder if they are bad on the Osa also?
Thanks.

Ticks can be horrific or non-existent depending on the recent weather and other conditions that you'd have to find a tropical entomologist to comment on. I've seen both.
In general chiggers are more of a problem in open areas/pastures and not in primary lowland tropical rainforest. While there is plenty of pasture on the Osa if you're in Corcovado you won't find much chigger habitat.
Chemical warfare (DEET and sulfa) can be helpful but certainly not 100% effective and you certainly want to examine all of your cracks crevices and hairlines after every day of hiking. Not sure what kind of ticks you're used to but some of the tropical varieties are very small (1mm or less) so look very carefully.