Pine resin midges (Diptera: Cecidomyiidae) in Monterey pine plantations: control decisions and perception of aesthetic injury

Two insecticides (dimethoate and fenpropathrin) applied monthly, every other month or every third month to plantation-grown Monterey pines, Pinus radiata D. Don, did not reduce the number of active feeding sites of a complex of pine resin midges during the 6-mo period when the insects were active. Trees that were wounded each month to simulate natural growth cracks were significantly more heavily infested than the insecticide-treated or untreated trees. A consumer preference study suggested that the aesthetic injury caused by the resin midges was not a factor in purchasing a choose-and-cut tree. Thus, although the insect damage was recognized by the producers, was difficult to reduce through applications of chemical insecticides, and was exacerbated by wounding, it may not be an economic problem during the short-term rotation of Christmas tree production because consumer choice is not adversely affected by injury caused by the insects