These trials indicate that several experimental materials would be very effective on peach twig borers. It is also apparent that dormant sprays provide an excellent means for reducing peach twig borer populations, and at a time of year when spraying results in probably the least ecological disruption. Dormant sprays in other trials have also proved effective for control of San Jose scale, and overwintering mite and aphid eggs.

J. H. Black is Farm Advisor, Kern County. R & L Farms, McFarland, and the C & R Ranch, Clovis, provided facilities; and W. Newhouse and R. Hines provided assistance in these trials.

With the exception of Diazinon, none of the materials included in the trials described here are registered—or recommended—at this time for use on peach twig borer during the dormant period.