Efficacy of some plant extracts againstvarroa destructorand their sideeffect on honeybee colonies

Abstract EN

The present investigation was carried out in the apiary of Faculty of Environmental Agricultural Sciences, Arish University, North Sinai Governorate, Egypt, during 2018/2019 season to study the effect of some plant extractsi.

e.

thyme (ThymusvulgarisL.

)family Lamiaceae, castor (Ricinuscommunis L.

)family Euphorbiaceae, common horehound (Marrubium vulgare L.

) family Lamiaceaeand yellow nutsedge (Cyperusesculentus L.

) family Cyperaceaeat different concentrations and added to sucrose syrupwhich offered to honeybee colonies on the progress of Varroamite and brood rearing activity of the test colonies.

The bees were sprayedwitha solution of 100 mg (dry weight) plant extract diluted in 10 ml sugar syrup.

Numbers of dead fallen mites and bees were recorded daily.

Results revealed that theextracts of thyme (Thymus vulgarisL.

) and castor (Ricinus communis L.

)were lethal for the mite, whereas the other plant extract showed low effect.

High concentrations ofT.

vulgarisand R.

communis (20% ) were effective against both mite and bees.

Thus, the most promising extract, with minimal insecticidal and maximaml acaricidal activities were fromT.

vulgarisand R.

communis.