Acecap Systemic Tree Care Implants implants are 3/8" dia. and begin killing destructive insects and providing protection 2-4 days after application. Implants are EPA approved for use indoors where foliar sprays and soil systemics cannot be used. Not for use in fruit or nut trees or trees from which syrup is harvested and sold or consumed. Implants should be placed in 4" intervals around the DBH of the tree. Packet contains 10 cartridges for trees 3" in diameter or larger.