Comparison of the Application Methods of Varroa Control Strip and Oxalic Acid Solution on Infection Rate of Varroa Mite and Growth Population in Honey Bee Colony (Apis mellifera L.)

Introduction: The Varroa mite (Varroa destructor Anderson and Trueman) is one of the most important and destructive parasites of the honey bee (Apis mellifera L.), which causes irreparable damage to the beekeeping industry. The reduction of protein concentration and hemolymph volume depends on the number of mites feeding on the pupa. The mite is also a vector of some honey bee viruses such as Kashmir honey bee virus (KBV), Sac-brood virus (SBV), acute bee paralysis virus (ABPV), acute paralysis virus Israeli (IAPV) and Deformed wing virus (DWV). Using chemical drugs is the most common way to fight against ticks. Today, it is known that these drugs have not only created a kind of resistance in the mite, which accumulates in honey, beeswax, and other beehive products and enters the human food cycle besides reducing the quality and nutritional value of honey, but they also harm the human body.Materials and Methods: This research is aimed at controlling the Varroa mite population by comparing the effectiveness of fluvalinate chemical substance and paper towels impregnated with oxalic acid on the percentage of mites, the number of pupae, the number of total births, the amount of pollen and honey production in the form of a replication plan in time with three treatment and four repetitions were performed. The treatments included: a control group (no mite control), paper towels impregnated with oxalic acid and glycerin, and mite control tape containing fluvalinate. The study was conducted over three 26-day periods to assess the number of pupae, total births, and the amounts of pollen and honey production. Additionally, four 18-day periods were used to evaluate the percentage of aphid infestation. For assessment, two to three frames were initially selected where the pupae were either about to emerge or had just emerged from the cells. Then we shake the frame on a pan and pour a glass with a capacity of 300 bees from inside the pan into a plastic bottle that contains 100 cc or more of alcohol and immediately close the lid of the bottle. Then, the fallen mites were counted. Finally, the number of counted mites is divided by the number of bees to get the contamination percentage. Suppose there is no infestation in the colony. In that case, the mite should be given artificially along with the frame from the hive whose percentage of mite is known to the mite-free colony. Then, a sample was taken from the colony after a week for better mite distribution inside the colony.Results and discussion: The treatments were evaluated over three time periods, each separated by 26 days. The results showed no significant differences in mite counts among treatments across the periods. However, in the third period, the oxalic acid treatment had the highest percentage of mites, which was significantly different from the control (P < 0.05). There were no significant differences among treatments in terms of the number of pupae, total births, or honey production. However, these parameters did differ significantly across time periods (P < 0.05), with the highest values observed in the first period, followed by a decline in the subsequent periods. On August 17th and September 14th, the highest pollen reserves were observed; on July 22nd, the lowest pollen reserves were observed, significantly different (P<0.05). The oxalic acid strip may help to maintain sufficient acid concentration inside the colonies for a long time. In addition, combining glycerin with oxalic acid can help keep the drug longer in the hive and thus the mites (including those emerging from the brood cells). The significance of the difference between the treatments at different times is because the bee genotype, temperature changes, the amount of nectar, and the amount and composition of pollen are very important factors that affect the amount of pupa. The birth rate of fluvalinate anti-mite strip treatment compared to the control treatment led to a 9.7% decrease in the birth rate. One of the reasons for the difference in reproduction within the treatment in different periods can be pointed to the empty cells for the queen to lay eggs. Considering that the normal temperature range of the colony is 33 to 36 Celsius degrees and the outside temperature of the colony was 36 to 42 Celsius degrees in August, we can point to the role of heat stress in the birth rate.Conclusion: From this experiment, it can be concluded that natural mite killers such as oxalic acid can be a suitable substitute for chemical substances that do not negatively affect the amount of pupa, pollen and honey. Considering that the mite-repelling property of paper towels containing glycerine and acid oxalic has been increasing compared to fluvalinate tape. On the other hand, glycerin maintains the mite-repelling properties of paper towels for up to three months; so paper towels containing glycerin and acid oxalic can be used for severe mite killing if paper towel is kept in the honey bee hive.