Field and greenhouse evaluation of rapeseed spray oil against spider mites, green peach aphid and pear psylla in Serbia

Biological efficacy of rapeseed spray oil against twospotted spider mite (Tetranychus urticae Koch) on cucumber, against European red mite [Panonychus ulmi (Koch)] on apple, green peach aphid (Myzus persicae Sulzer) on pepper and pear psylla [Cacopsylla pyri (L.)] was evaluated in seven field and three greenhouse trials at eight localities in Serbia during 2005-2008. The efficacy of rapeseed spray oil in controlling these pests was compared to the following insecticides and/or acaricides: abamectin, acetamiprid, bifenthrin, clofentezine, diflubenzuron, dimethoate, fenazaquin, mineral oil, combination of mineral oil and methidathion, pymetrozine and spirodiclofen. In two greenhouse trials against a T. urticae population on cucumber, the efficacy of rapeseed oil was 84.1% and 94.6%, 11 days after treatment (DAT). Applied as a late dormant oil against winter eggs of P. ulmi in two apple orchards at the BBCH 09 growth stage, rapeseed spray oil achieved 89.3% and 98.9% efficacy, 24 DAT. In a treatment against the summer population of P. ulmi, rapeseed oil showed 97.4% (7 DAT), 80.5% (14 DAT), 68.6% (21 DAT) and 67.7% (38 DAT) efficacy. Three field trials against M. persicae on pepper revealed high (> 96%, 7-14 DAT) efficacy of rapeseed spray oil; in a greenhouse trial, the oil achieved 86.9% efficacy 8 DAT. Applied at the BBCH 09 pear growth stage against eggs laid by winterform females of C. pyri, rapeseed oil showed a total efficacy of > 90% in both assessments. Such high and persistant efficacy primarily results from the fact that the number of newly deposited, white eggs was reduced to null, while the effect on nymphs was weaker. The importance of these results for biorational pest control of spider mites, green peach aphid and pear psyllid in Serbia is