The deterrent effect of limonene enentiomers and limonene derivative: ( + )-(1S,4S,6S)-4-(1-methylethenyl)-9-oxabicyclo[ 4.3.0]nonan-8-one, on Myzus persicae was investigated. Only S-enantiomers of limonene and its derivative showed feeding deterrent properties. S-limonene inhibited phloem sap ingestion and reduced the number of phloem sap ingestion phases during aphid stylet penetration of plant tissues. Aphids spent twice less time on leaves painted with ( + )-1S,4S,6S-4-(1-methylethenyl)-9-oxabicyclo[ 4.3.0]nonan-8-one than on control and S-limonene-treated leaves and the probes were shorter than 2 minutes on these leaves. Our studies confirmed that the chiral centre configuration of the lactones was important in expression of feeding deterrent activity.

The aim of the work was to study the feeding deterrent activity ofprecocenes, their synthetic analogues, and some related compunds to storage pests: Sitophi/us granarius L., Tribolium con/usum Duv., Trogoderma granarium Ev., and aphids: Myzuspersicae (Sulz.). Among all tested compounds precocenes I and 11 exhibited the best feeding deterrent activity against all tested insects. 4-Chromanols ( 16, 17 and I 8), alcohols 19, 20 and 3-chromanone (15) showed high deterrence towards the larvae of T con/usum. The best antifeedant activity towards the adults of both T confusum and S granarius was observed for substituted phenols with methoxy group at benzene ring. The biological tests carried out on aphids showed that the presence ofmethoxy group in the molecule was a crucial structural factor for the appearance of antifeedant activity against these insects.