Well, after my first couple of applications of powdery Sevin, I got
relief for almost a week. Then, the JBs came back in swarms each time.
I finally decided to buy some concentrated Sevin liquid today (mainly
because I didn't like the idea of casting the power to the wind). I
sprayed liberally and saw an almost immediate effect (something I
never saw with Orthonex, Shiva's experience notwithstanding). It
really knocks them down right on the spot!

It says to do no more than 5 foliar applications per season, but they
should be gone for good in about 3 weeks, so I'm hoping that this will
do the trick.