.. rst-class:: bee-header Varroa Management ----------------- .. qa:: How has Varroa destructor changed beekeeping? Once Varroa destructor shifted hosts from `Apis cerana` to `Apis mellifera`, beekeeping changed forever. This parasitic mite has transformed honey bee management into a constant battle against a highly destructive pest. Prior to Varroa, colonies could often survive with minimal intervention. Today, however, beekeepers must regularly monitor and actively manage mite populations in order to keep colonies alive and productive. Varroa infestations have led to significantly higher colony losses, with many beekeepers losing large percentages of their hives each year, especially over winter. Even surviving colonies are often weakened, resulting in reduced honey production and poorer pollination performance. In addition to direct damage, varroa mites spread viruses, particularly Deformed Wing Virus (DWV), which further accelerates colony decline. As a result, modern beekeeping now requires regular mite monitoring, timely treatments, and integrated pest management strategies. Without consistent varroa control, most honey bee colonies will not survive. .. qa:: How many mite species are there and how many are harmful to honey bees? There are 40 different mite species in which three are harmful to honey bees. At this time only 2 are found in the US: * Tracheal mites, `Acarapis woodi` * Varroa mites `Varroa destructor` * `Tropilaelaps` (found only in Asia) .. qa:: What are the 2 syndromes that have been linked to honey bee mites? Parasitic mite syndrome Colony Collapse disorder .. qa:: What is parasitic mite syndrome? Parasitic Mite Syndrome (PMS) is a condition in which a honey bee colony gradually deteriorates, ultimately dwindling and dying. Although no single pathogen has been identified as the direct cause of the brood symptoms associated with PMS, varroa mites are consistently present in affected colonies. Colonies that initially appear healthy and productive may suddenly experience a sharp decline in their adult bee population. After collapse, these colonies often still contain ample stores of pollen and honey, but have very few adult bees. The remaining brood is typically spotty and appears unhealthy, reflecting the overall decline in colony health. .. qa:: What are the symptoms of Parasitic Mite Syndrome? * Nibbled or perforated cell cappings. * Chewed pupae Dead pupae * Visible `Varroa` * Adults with deformed wings * Spotty brood pattern (shotgun brood) * Supercedure cells Neglected or absent brood .. qa:: How does Parasitic mite syndrome (PMS) differ from Colony Collapse Disorder (CCD)? In Parasitic Mite Syndrome (PMS), some adult bees, either alive or dead, are typically still present in the colony. These colonies often survive through the winter but collapse in early spring, with adult bees dying while still clustered. In contrast, Colony Collapse Disorder (CCD) is characterized by the sudden disappearance of adult bees, leaving behind brood and food stores. These colonies usually die in the fall or early spring and appear largely devoid of adult bees. In both PMS and CCD, brood and stored honey remain in the hive, indicating that starvation is not the primary cause of colony death. .. qa:: Where did `Varroa destructor` come from? Southeast Asia. Varroa’s original host is `Apis ceranae`, the Eastern or Asian honey bee, and causes little to no damage to colonies. .. qa:: Why is `Varroa destructor` damaging to the European honey bee? `Varroa destructor` reproduces within the brood cells of honey bees, where it feeds on developing pupae. The mites consume the fat body tissue of the bee, which reduces pupal weight and suppresses the immune system. As a result, affected bees often emerge weaker, have shortened lifespans, and are more susceptible to disease. In addition to this direct damage, Varroa acts as vectors of several viruses, most notably Deformed Wing Virus (DWV), further compromising the health and survival of the colony. .. qa:: Describe the life history of the female `Varroa destructor`. The life history of the female `Varroa destructor` begins when a mated female, known as a foundress, enters a honey bee larval cell just before it is capped. She hides in the larval food at the bottom of the cell until capping occurs. Once the cell is sealed, she climbs onto the developing prepupa to avoid being trapped in the silk cocoon spun by the bee. After the cell is capped, the foundress begins reproduction. Her first egg develops into a male, followed by several female eggs. The foundress creates a feeding site by piercing the pupa’s exoskeleton, allowing both herself and her offspring to feed on the bee’s fat body. Reproductive success depends on the type of host cell. In worker brood cells, the foundress typically produces one to two mature daughters. In drone brood cells, which have a longer developmental period, she can produce up to five mature daughters. .. qa:: What happens to the male `Varroa destructor`? Male mite mates with 1 or 2 sisters then dies. .. qa:: In the IPM strategy, there are several options for controlling varroa. Describe each one. a. Cultural control is a method is geared towards reducing pest reproduction within the colony. i. Increasing distances between colonies reduces the transfer of mites/diseases as well as drifting and robbing. Distinctively mark all colonies to reduce drifting. ii. Brood break – reduces the number of brood cells for the foundress mite to enter and reproduce. This method in combination with a chemical treatment such as oxalic acid, can greatly reduce Varroa populations in a colony. Caging the queen stops egg laying and eventually leads to a brood free period. Varroa need brood to complete their life cycle, so brood free time interferes with their life cycle and leads to decreased or absent Varroa in the colony. iii. Mite resistant stock - Minnesota hygienic, VSH, Russian and ankle or mite biters iv. Small cell – a method that gained popularity in the early 2000’s but to date has failed as an effective method for controlling varroa. b. Mechanical is a non-chemical control which helps to reduce mite populations by colony manipulations. i. Screened bottom boards - mites naturally fall through the screen and outside and are unable to attach to bees since they are underneath the hive. ii. Drone brood trapping – by placing a drone brood frame (green), allowing the queen to lay and once capped the frame is removed along with any mites that have parasitized the cells. Because Varroa prefers drone brood, removal of capped drone brood can remove a significant population of mites (up to 60%) iii. Hyperthermia – colonies are heated to fatal temperatures for Varroa but not the bees. c. Biological control involves the use of living organisms to reduce varroa mite populations. Several agents have been investigated, including entomopathogenic fungi, which have shown some promise in experimental settings. However, despite these encouraging results, no biological control agents have yet been successfully developed and brought to market for widespread use. d. Chemical control involves the use of organic or synthetic compounds to reduce varroa mite populations. These treatments are generally divided into “soft” (organic) and “hard” (synthetic) acaricides. Synthetic acaricides typically act on a single target site within the mite, which makes them effective but also increases the likelihood that mites will develop resistance over time. In contrast, soft acaricides have multiple modes of action and affect several target sites, making it much more difficult for mites to develop resistance. i. Synthetic acaricides include amitraz (Apivar), fluvalinate (Apistan) and coumaphos (Checkmite). ii. Organic acaricides include the essential oil, thymol (Api Lif Var, Apiguard), and organic acids, oxalic acid (Api-Bioxal) and formic acid (Formic Pro). e. For testing purposes, it would be good idea for the student to know how each method is applied to a colony, and when is the best time to apply. For example, using thymol or formic acid products during the spring and fall months in Georgia due to the compounds being detrimental to bees and brood during months with higher temperatures. .. qa:: Out of the chemical control methods mentioned, which can be used when human consumable honey is on the colony? The only one is oxalic acid. It naturally occurs in honey so it can be used while honey supers are on a hive. .. qa:: When should you treat for Varroa? Most sources recommend treating colonies when mite counts reach 2-3%. However, if the mite count is above 1% in late fall, the Honey Bee Health Coalition recommends treatment. Because of the pervasiveness and the ease with which a colony can be infected, many authorities recommend treating on a more regular proactive schedule. In Georgia that could mean treating 3-4 times a year and additionally, if needed. Treat all colonies in the bee yard simultaneously. .. qa:: Name several methods used to sample Varroa levels in a colony. * Capping scratcher- uncap drone brood and look for mites * Alcohol wash * Ether roll (quick start aerosol for automobile engines) * Sugar shake * Sticky board Soapy water .. qa:: Out of the above methods for sampling Varroa, which is the most accurate and used exclusively during experimental research? Alcohol wash .. qa:: When is the best time to use oxalic acid? Oxalic acid only works on phoretic mites. It does not penetrate the wax cappings where most of the mites are living. The most effective time to apply OA is when there is little to no brood in a colony. Broodless times occur during the winter months, after a colony swarms, after a colony has been re-queened or split or when the beekeeper creates a brood break. Mites during these times are living on the adult bees and are exposed to OA. .. qa:: What is an advantage of formic acid? Penetrates the wax cappings and kills mites in the brood cells.