try lightly brushing the spadix. Or just put beetles in the flowers (in nature, beetles are attracted to the flowers at night, because the tip of the spadix actually makes heat, sometimes raising the temperature of the tip of the spadix to 98oF. the beetles stay in the flowers overnight and mate, brushing up against the spadix in the process.)

hope this helps,

Chris

In nature the beetles are all members of the genus Cyclocephala. Although there are beetles in north America that are also members of that genus none are natural pollinators of Philodendron species. Nature has a unique method of pollinating Philodendron in the wild and it can be very tricky to do without a great deal of study and observation. One of the best people in the U.S. that does artificial pollination is LariAnn Garner who often posts on this forum.

The link below written by aroid expert Julius Boos will give you a basic foundation and explains how nature does it and how you can do it yourself. But you will first need to collect pollen from an inflorescence and store it until the next spadix is at female anthesis. Philodendron uniquely divide the female, sterile male, and male flowers in order to prevent self pollination.

Here is a link that might be useful: Natural and Artificial pollination by Julius Boos