Varroa Mites Fact Sheet

FACT Sheet FACTS-23 PPQ -- made available through the CAPS program May 21, 1993 Fact sheet for HONEY BEE (tracheal) MITE (with some comparisons to Varroa Mite, FACTS-13) ACARAPIS WOODI causes acarine disease of the honey bee, APIS MELLIFERA. The only other known host is another species of APIS, A. CERANA. The Honeybee Act of 1922 was enacted primarily to prevent importing infested bees into the U.S. The life span of infected bees is significantly shortened. The disease affects flight efficiency and causes a large number of crawling bees, unable to fly. Because they are unable to fly, large numbers of bees can be seen crawling on the ground near the hive. Diseased bees will often drop to the ground from the alighting board or while flying and may also gather in small clusters near the hive. The inability to fly contributes to losses of field bees and scarcity of food in the colony. In such cases, the colony population could dwindle and ultimately result in the death of the colony. Acarine disease could persist in a colony for years causing little damage, but combined with other diseases, unfavorable conditions, scarcity of pollen, an/or a poor foraging season, the disease significantly increases the mortality of colonies in winter. The mite has mouth parts adapted for piercing and sucking; the very tiny female infests the prothoraic tracheal system of the the honey bee. The life cycle of the mite is apparently completed in the bee trachea. The development time for female mites from the egg to the nymph and gravid female is about 14 days. The eggs are laid one at a time; each female lays 5-7 eggs. The egg stage lasts 3-6 days, then the six-legged larvae emerges. The larvae complete their development and then emerge from the spiracles to move on to other bees. When they encounter a young bee, enter the trachaea. Bees less than 9 days old are the most susceptible. The trachea of diseased bees is obstructed by mites in different stages of development, as well as by mite debris. Feeding by the mites damages the walls of the trachea which turn from their normal white color to black, from elastic and flexible to stiff and brittle. Discoloration and atrophy of the flight muscles may also occur, producing the symptomatic abnormal "dislocated" position of the wings of walking bees. Infested colonies do not develop normally and may exhibit symptoms of dysentery. Often these colonies show an excessive tendency to swarm. The female mite is distinguished from other ACARAPIS species by having a shallow indentation on the posterior margin of the coxal plate, and by the relatively short leg IV and anterior median apodeme. These characters and the presence in the bee trachea readily identify the species, and should prevent confusion with the external ACARAPIS mites, A. EXTERNIS and A. DORSALIS. A. WOODI was first reported in 1921 on the Isle of Wight, England. It is now known to be widely distributed around the world, found in several counties in Europe, Asia, Africa, and South America. In North America, infestations have been reported from Mexico in 1981, and in 1984 came to the U.S. There are no reported infestations as yet in Canada which has quarantined the shipment of bees into that country in a last-ditch effort to prevent its spread there. Acarapis Woodi was first discovered in the U.S. during a routine APHIS survey of bees (July 3, 1984) in the Rio Grande Valley. The apiary, belonging to Waylon Chandler Apiaries of Weslaco, Hidalgo Co., TX, was in an FACTS 23 page 2 isolated area directly on the riverbank. The APHIS laboratory in Brownsville, TX made the initial identification on July 5 and forwarded the samples to Beltsville, where confirmation was made July 6, 1984. Comments from TX summarize the current overall U.S. situation: The tracheal honey bee mite is widely distributed throughout U.S. Few, if any, apiaries in the U.S. are without a resident population (infestation) of tracheal mites. Beekeepers, and those who work with them, have come to understand how to effectively deal with this parasite in their particular area and operation. There are losses, but these are far more sporadic and far less common due to prophylatic/preventive annual treatment (menthol) in certain geographic areas and to the development of genetic tolerance or resistance in surviving honey bee stocks (also selective breeding for inherited resistance by most U.S. queen breeders). Varroa mites are a much more recent parasite problem and its U.S. distribution somewhat more restricted. However, it is generally recognized as a much more devastating (deadly) parasite problem. Fortunately it is more easily monitored in colonies - you can see this mite with the naked eye; which is not the case for tracheal mites. Varroa mite distribution is rapidly becoming on a par with tracheal mite which in the last 24 months has almost become universal through-out the U.S. The mite is still of great concern to the U.S. beekeeping industry, being very costly to the bee industry when combining both colony losses and control/ prevention costs. The ultimate solution will be genetic resistance in honey bee stocks. Comments from other States give some typical local situations: The Tracheal Mite is the number one problem for beekeepers in AL. It is the #1 cause for colony loss in the State. It was a serious problem in winter of 1990-1991 and 1991-1992. The winter of 1992-1993 it was still #1 problem but not as bad as previous years. In FL, the mite is passing into an uncertain status since it is difficut to detect, and few control methods are available. In Indiana apiaries, the use of the annual treatment (menthol) mentioned above is not possible at the right time of the year due to the lack of volitility of this agent at low temperatures. This has caused the loss of 60-100% of honey bees in apiaries across the State as of May, 1993. Tracheal mite was introduced in 1984 into NY and is now considered to be widespread in the State and the U.S. Tracheal mite caused high mortality during 1987-1989, but the honey bee has managed to build up a tolerance to this mite. Since it is difficult to detect and widespread, survey efforts are no longer being conducted in NY. However, colonies suspected of being infested are sampled during routine bee inspections and sent to the Beltsville Diagnostic Lab for confirmation. In PA tracheal mites are established throughout the State; therefore, distribution data is of little interest. PA is no longer doing systematic survey for tracheal mites. But, since it is a serious pest, diagnostic surveys have continued to be done at the request of beekeepers. In the fall of 1992 apiaries in 24 WI counties were surveyed for varroa mite and honey bee tracheal mite. In 21 counties there was at least one beeyard infested with both mites. In 3 additional counties, beeyards were infested with tracheal mite only. In all surveyed colonies, 84% had at least one trachael mite infestation, 94% had at least one varroa mite infestation. Beekeepers are very concerned about both mites with hive losses up to 50% for the spring of 1993. How much of this damage is due to mites is unknown. REFERENCES The above information was taken directly from the PNKTO article cited below and from the comments from all the States who cooperated so well in sending in information about the current status of the pest in their area. PESTS NOT KNOWN TO OCCUR IN THE UNITED STATES OR OF LIMITED DISTRIBUTION, NO. 17: HONEY BEE MITE Prepared by M. Delfinado-Baker and H. Shimanuki, USDA, Plant Protection Institute, Bioenvironmental Bee Laboratory, Bldg. 476, Barc-east, Beltsville, MD 20705 Many thanks to: Hachiro Shimanuki who helped write the original PNKTO article and sent further information about the mite's first record in the U.S.; Wheeler Foshee AL SSC/ADP and Dr. Eric Benson, Entomologist, Auburn University; Tracey Austin FL ADP and Tom Sanford, Extension Apiculturist, University of Florida; Wayne Buhler at Purdue University in Indiana who also informed about the Canadian attempt to keep the mite out relating to export certification; Jan Knodel NY SSC/ADP and Bob Mungari, Director, of NY State Department of Ag & Markets; Randy Tressler PA ADP and James Steinhauer; Leslie A. Hunter TX ADP-Extension Assistant and Dr. John Thomas, Department of Entomology -Texas A&M University; Annette Phibbs, WI State Apierist, Wi Dept. of Agriculture, ARM Division. Bill Wilson who has done research on the mites; would be a good resource for further information. Honey Bee Research Laboratory, USDA/ARS, 2413 E. Hwy. 83 Weslaco, TX 78596 (210)969-4870 USDA/APHIS/PPQ RECORD SUMMARY 05/20/93 15:27 There are a total of 4814 records in NAPIS entered 1984-1993 which give the reported distribution and survey effort for this pest. It is evident that some of the records discussed above have not been recorded in NAPIS. </td></tr></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr><td> <table style="width: 100%;display:none" cellpadding="0"> <tr> <td style="text-align: left" valign="bottom"> <a href="http://www.cannonvalleynursery.com/"> <img border="0" src="_borders/flower.gif" width="64" height="64">Wildflower Seed For Sale</a></td> <td style="text-align: right" valign="bottom"> <a href="http://www.welchproperty.com/nature/landforsale.htm"> Wilderness Land For Sale<img src="images/wilderness.gif" width="52" height="64" style="border-style: solid; border-width: 0"></a></td> </tr> </table> </td></tr></table></body> </html>