Ovicidal activity of essential oils from five plants against two stored-product insects

The fumigant activity of essential oil vapours distilled from anise Pimpine lla anisum, cumin Cuminum cyminum, eucalyptus Eucalyptus camaldulensis, ore gano Origanum syriacum var. bevanii and rosemary Rosmarinus officinalis wer e tested against eggs of two stored-product insects, the confused flour bee tle, Tribolium confusum, and the Mediterranean flour moth, Ephestia kuelzni ella. The exposure to vapours of essential oils from anise and cumin result ed in 100% mortality of the eggs. Oregano achieved mortalities as high as 7 7 and 89% in T. confusum and E. kuehniella, respectively. The highest morta lities caused by essential oils of eucalyptus and rosemary were 45 and 65%, respectively. At a concentration of 98.5 mu l anise essential oil/l air, t he LT99 values were 60.9 and 253.0 h for E. kuehniella and T. confusum, res pectively. For the same concentration of the essential oil of cumin, the LT 99 value for E. kuehniella was 127.0 h. As the essential oils from other pl ants investigated were less active their estimated LT99 values were too far beyond the tested exposure range to be reliable. (C) 2000 Elsevier Science Ltd. All rights reserved.