After resting dormant all winter in ground cover thatch, adult curculios (Conotrachelus aratus) become active in the spring as pecan shoot growth commences. When the first leaf on new pecan shoots is about one half expanded, female curculios start searching of locations to lay eggs.
Once the larvae hatches and begins to burrow into pecan shoot tissue, it is impossible to control this pest with an insecticide. In other words, once you see the damage it too late to take action this year. If your pecan grove has a history of curculio attack plan on controlling adults early next spring.
Hickory shoot curculio is one of those sporadic pecan pests that seem to appear out of nowhere and then a couple of years later disappear altogether. I've only seen a few curculio infestations that warrant chemical control. It seems that naturally occurring biological control agents usually keep this pest in check.