Soft+Acaricides+(GAZ)


 * Soft Acaricides - a viable alternative in the control of //Varroa destructor //? **

Like hard acaricides, soft acaricides are pesticides used to control //Varroa // populations and treat hives that have succumb to infestation. Unlike the fat-soluble, synthetic hard acaricides, soft acaricides are predominately composed of water-soluble organic acids and naturally occurring essential oils such as formic acid, oxalic acid, lactic acid, thymol and wintergreen oil (Rosenkranz et al. 2008, 108). They are usually applied as fumigants, sprays, trickling a liquid over the combs or through the use of diffusers within hives.

These natural acaricides are advantageous as they have very low risk of accumulation of residues within bee products, making them an attractive alternative for some beekeepers. Most of them also happen to be natural ingredients of honey and therefore, pose even less of a risk of contaminating the honey and beeswax (Bogdanov 2006, 9). As both international and national food regulations become more and more stringent there has been an increase in the use of soft acaricides for these reasons.

However they do have associated disadvantages. Examples of these are that both lactic and oxalic acid based acaricides can only be applied under broodless conditions, i.e. brood combs must be blocked from contact or fully removed for these to be utilised (Emsen and Dodologlu 2009, 1007). While oxalic acid does not harm the adult bees, it does affect the development and size of the brood combs. Since the majority of the //Varroa’s //lifecycle happens to be spent developing within these brood cells, the timing of the application of oxalic acid based acaricides is crucial. Some soft acaricides are also affected by evaporation pressure, meaning that climatic conditions, coupled with intra-hive conditions can greatly affect the efficacy of some compounds. Generally as a result of these reasons, the effects from some organic acaricides are often highly variable and less effective than some synthetically produced alternatives (Rosenkranz et al. 2008, 111).

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[|Oxalic Acid Treatment being applied to a Varroa infested hive]