USE OF CONIFER VOLATILES TO REDUCE INJURY CAUSED BY CARROT PSYLLID, TRIOZA-APICALIS, FORSTER (HOMOPTERA, PSYLLOIDEA)

The feeding and oviposition of the carrot psyllid, Trioza apicalis, we re reduced by the application of fresh spruce and pine sawdust along t he seedling rows in carrot fields. Turpentine and separate monoterpene hydrocarbons, mixed into old sawdust and/or placed in polyethylene tu bes, were also effective. At a dose of 0.5 liter/m, fresh sawdust redu ced the damage to 18% of the plants, compared to 100% damage in untrea ted plants. The sawdust materials were spread on the soil surface at f our- or seven-day intervals during the oviposition period. The tubes w ere placed along the carrot rows before the oviposition started. Turpe ntine and separate monoterpene hydrocarbons afforded a protective effe ct of the same order of magnitude as that obtained from fresh sawdust. The volatile profiles of the spruce and pine sawdust as well as of th e turpentine used were determined.