摘要：In honeybee colonies, insufficient struggle against diseases and parasites or the use of wrong drugs at wrong time which reduce the productivity of colonies significantly. Additionally, these kinds of wrong applications can also threaten the human health because of chemical residues. Varroa destructor, which affects negatively the colony productivity, is the most important external parasite of the honeybees (Apis mellifera L.). Therefore, beekeepers have to use many different synthetic miticides for reducing or preventing the V. destructor damages. This study was carried out to determine the possible effects of ocalic acid treatment in different seasons on V. destructor population in honeybee colonies. Ten of total twenty honebee colonies had similar in-festetion levels which were used for treatment group and ten colonies were also used as the control group. Average efficacies of oxalic acid treatment in different seasons on Varroa population in honeybee colonies in early spring (in March), summer (in June) and late autumn (in October) were found to be 80.22%, 69.72% and 84.61%, respectively (P<0.01). These results showed that oxalic acid treatment in late autumn and early spring against varroa in honeybees were about 21% and 15% more effective than summer, respectively.
