Griselinia Borer

lespat, Jul 30, 6:50am
Have small piles of fine wood drillings around parts of the trunk and some away from trunk of maybe 4/5 trees as part of 2 boundary lines of hedging. Took sample to garden centre. They say it is borer and to spray inject Kiwicare No Borer into the holes. Problem is I can't find any obvious borer holes. The infected trees are also starting to lose foliage. Suggestions please.