EFFICACY OF 'I'EMPERA1URETRE'KIMENTSFOR lliSEcr DISINFESTATION OF DRIED FRUITS AND NUI'S

In order to determine the potential of various temperature treabnents for disinfesting dried fruits and nuts of postha1:vest insect pests, high temperature/exposure response cw:ves for navel oran;Jeworm eggs and pupae and Indiarnneal moth pupae were estimated. For navel oran;Jeworm eggs, 99% mortality was achieved after exposure to 490e for 14 minutes. For navel orange worm pupae, 99% mortalities were prc:duced after a 12 minute exposure to 490e. Indianrneal moth pupae were less heat tolerant, similar mortalities were obtained after 13 minutes at only 46oe. Freezing points for various stages of the Indianrneal moth and navel orangeworm were also determined. Pupae had the lowest freezing points for both species, with freezing points of -24oe for Indianrneal moth and -22oe for navel orangeworm. DiapausiJ:lg Indianrneal moth lcu:vae also had low freezing points, averaging -230e. The freezing points for non-diapausing lcu:vae were highest, -lSoe for Indianrneal moth and -10oe for laboratoryreared navel oran;Jeworm. Wild-type NOWlcu:vae had lower freezing points (-16oe) than laboratory-reared lcu:vae, but freezing points for wild-type pupae (-22°C) were similar to those for laboratory-reared pupae. Age effected the response of both ll1M and NOWeggs to sub-freezing temperatures. Eggs appear to be the most cold tolerant stage of both ll1M and NOW, and the ll1M is more tolerant than the NOO. studies on the effect of high temperatures on prc:duct quality showed that the taste of prunes and raisins are only slightly effected by exposure to sooe for 1 hour. Walnuts showed little change in taste for up to 9 months of storage, but an increase in rancidity was associated with heat treatments. Information on the engineering and economic aspects of both high and low temperature treabnents was gathered and an analysis begun.