Papaya Leaf Infection

There are several Papaya plants in the lower greenhouse that are constantly blooming.  They have to be trimmed back every few months as the quickly reach the top glass.  They've produced fruit several times but nothing in the last few months.

The leaves have been intentionally infected with a pathogen.  This could be treated but the pest is being studied on campus.  It doesn't seem to be very harmful to the plant.  Leaf loss seems typical and growth rate is fast.  It does however leave interesting variegated leaves.