Pyrenone, a pyrethrin (Bayer AG), was tested on coqui frog eggs. Egg clusters or clutches (at least 4 days old) were cleared of dead or infertile eggs and dissected into two masses; one half was treated and the other served as untreated control. A solution of Pyrenone (14 oz / 100 gal) was sprayed over the egg masses, which were observed until hatching. Nearly 92% of the eggs that were treated with Pyrenone hatched, compared to 97% among the untreated eggs.

For eggs at the ages tested (4-7 days after being laid), Pyrenone does not seem to provide effective control. Further testing on eggs at different ages, and of Pyrenone in combination with other treatments, are being planned.