COMPARATIVE RESISTANCE OF 4 HONEY-BEE (HYMENOPTERA, APIDAE) STOCKS TOINFESTATION BY ACARAPIS-WOODI (ACARI, TARSONEMIDAE)

The prevalence, mean intensity, and abundance of Acarapis woodi (Renni e) in 4 selected stocks of honey bees (Apis mellifera L.) were monitor ed under field conditions. The test stocks used were ARS-Y-C-1 (A. mel lifera carnica imported from Yugoslavia), Hastings (A. mellifera carni ca imported from northern Saskatchewan), F-1 hybrid between ARS-Y-C-1 and Hastings, and Louisiana stock available at the Baton Rouge laborat ory apiaries. Two trials were conducted. The Ist trial used 20 colonie s per stock and continued for 2 yr. The 2nd trial used 10 colonies per stock and was monitored For 1 yr. Results of both trials showed that ARS-Y-C-1 and F-1 hybrids consistently maintained approximately a 10% level of A. woodi infestation, which is below the level that causes ec onomic damage to host colonies. These stocks also had significantly lo wer mean intensities of mites than the Hastings and Louisiana bees. A. woodi was least abundant in the F-1 hybrid. Similar numbers of mites per bee were found in ARS-Y-C-1, Hastings and Louisiana stocks. These observations suggest that both ARS-Y-C-1 and F-1 hybrids are resistant to A. woodi.