One of the biggest challenges in beekeeping is managing pests and diseases that can threaten the health of your hive. Early detection and prompt treatment are crucial for maintaining a thriving colony. This chapter will cover the most common problems faced by beekeepers in Ireland, how to identify them, and the various treatment options available. Understanding how to manage these challenges is key to keeping your bees healthy and ensuring a productive hive.
1. Varroa Mites
Varroa mites (Varroa destructor) are small external parasites that feed on the haemolymph of honeybees, weakening them and spreading deadly viruses, such as Deformed Wing Virus (DWV). Varroa mites are one of the most damaging pests in modern beekeeping, and if left untreated, they can lead to the collapse of a colony. Managing Varroa mites is one of the top priorities for beekeepers in Ireland and across the world.
- Identification:
- Small reddish-brown mites visible on adult bees, particularly on the underside of the abdomen or thorax.
- Mites can also be seen in brood cells, especially drone cells, where they reproduce.
- Affected bees may have deformed wings or reduced ability to fly, often linked to DWV infections caused by the mites.
- Control Methods:
- Chemical Treatments: Common chemical treatments include oxalic acid, formic acid, and thymol. These treatments differ in their application and effectiveness depending on the time of year and the level of infestation. For instance, oxalic acid dribble or vapour is often used during the broodless period in winter, while formic acid treatments can be used when there is active brood. Always follow local regulations and product guidelines when using chemical treatments to avoid harming the bees or contaminating honey.
- Biological Methods: Integrated Pest Management (IPM) strategies are becoming increasingly popular as they aim to control mites while minimising chemical use. This includes using screened bottom boards to allow mites to fall out of the hive, removing drone brood (since mites prefer to reproduce in drone cells), and introducing hygienic bee strains that are bred to remove mite-infested brood. Some beekeepers also dust their bees with powdered sugar to encourage grooming, which can help dislodge the mites.
2. Nosema
Nosema is a microsporidian parasite that affects the digestive system of honeybees, leading to dysentery and weakened colonies. Two species of Nosema are commonly found in bees: Nosema apis and Nosema ceranae, with the latter being more prevalent in recent years. Nosema can cause significant colony losses if not properly managed, particularly during the spring when colonies are building up.
- Identification:
- Brown streaks of faeces on the outside of the hive or on the frames inside.
- Slow population growth, especially in spring, when the bees should be building up their numbers.
- Bees may appear sluggish, unable to fly, or disoriented.
- Control Methods:
- Ventilation: Ensuring proper hive ventilation is critical for controlling moisture levels, as Nosema thrives in damp environments. Keep the hive well-ventilated, especially during winter when moisture build-up can be a problem.
- Fumagillin: This chemical treatment was once widely used to control Nosema, but its use has become more restricted due to concerns about its environmental impact and the risk of residues in honey. In some regions, it is no longer recommended, so it’s important to consult local guidelines.
- Preventative Practices: Maintaining a healthy colony through good nutrition, regular hive inspections, and proactive management can help reduce the impact of Nosema. In particular, ensuring that bees have access to clean, fresh water and good forage can strengthen their immune systems.
3. American Foulbrood (AFB)
American Foulbrood (AFB) is one of the most serious bacterial diseases affecting honeybee larvae. It is caused by the bacterium Paenibacillus larvae and is highly contagious. Once an infection takes hold, it is extremely difficult to eradicate, often necessitating the destruction of the infected colony to prevent the disease from spreading. AFB spores can survive for years, making prevention and early detection crucial.
- Identification:
- Sunken, dark, perforated cappings on brood cells.
- A distinct foul smell emanating from the hive, often compared to rotting meat.
- The “rope test”: Insert a matchstick or toothpick into a cell containing dead larvae and pull it out slowly. If the larval remains stretch like a rope, this is a strong indication of AFB.
- Control Methods:
- Burning the Hive: Unfortunately, once a hive is confirmed to have AFB, the most effective way to prevent the disease from spreading is to burn the hive, including the frames, comb, and any affected equipment. This is a devastating step but is often necessary to protect other colonies and prevent further outbreaks.
- Irradiation: In some countries, irradiation is used to sterilise beekeeping equipment after an AFB infection, effectively killing the spores without the need for burning. However, this option may not be readily available in all regions.
Prevention through regular inspections and strict hygiene practices is the best defence against AFB. Beekeepers should also avoid moving equipment between hives and be cautious about accepting second-hand equipment unless it has been properly sterilised.
4. Wax Moths
Wax moths, including the Greater Wax Moth (Galleria mellonella) and the Lesser Wax Moth (Achroia grisella), are opportunistic pests that lay their eggs in weak or abandoned colonies. The larvae feed on beeswax, pollen, and other materials inside the hive, tunnelling through the comb and causing extensive damage. While healthy colonies can usually fend off wax moth infestations, weaker hives are particularly vulnerable.
- Identification:
- Webbing and tunnels in the comb, particularly in stored comb or weakened hives.
- Damage to wooden frames, hive boxes, or other equipment.
- Presence of small, greyish larvae crawling through the comb.
- Control Methods:
- Maintain Strong Colonies: The best defence against wax moths is a strong, healthy colony. Wax moths are far less likely to infest a hive with an active, well-maintained population of bees.
- Freezing: If you need to store comb for any period, freezing it for at least 48 hours will kill any moth eggs or larvae present. This is an effective method for preventing wax moth infestations in stored equipment.
- Traps: In weaker colonies or stored equipment, moth traps or insecticide strips can be used to control the population of wax moths. However, these should only be used in stored or inactive hives to avoid harming the bees.
5. Small Hive Beetles
Small hive beetles (Aethina tumida) are an invasive species that feed on pollen, brood, and honey. While they are more common in warmer climates, their presence is being increasingly noted in temperate regions like Ireland. Small hive beetles can cause significant damage to the hive by contaminating honey and causing it to ferment.
- Identification:
- Adult beetles, which are small, black, and can be seen scurrying inside the hive or hiding in crevices.
- Larvae feeding on honey and pollen, causing a slimy appearance and foul smell in the hive.
- Control Methods:
- Trapping: Beetle traps can be placed inside the hive to capture adult beetles. These traps use oil or diatomaceous earth to immobilise the beetles, preventing them from reproducing and reducing their numbers within the hive.
- Ground Treatment: Since small hive beetle larvae pupate in the soil, treating the ground around the hive with beneficial nematodes or approved chemicals can help reduce infestations by killing the larvae before they mature into adult beetles.
Managing pests and diseases is a critical aspect of beekeeping, and staying vigilant is key to keeping your hives healthy. Early detection, good hygiene, and proactive treatment strategies can help prevent small problems from turning into serious threats. By understanding the common pests and diseases that affect honeybees in Ireland, you’ll be better equipped to protect your colony and ensure its long-term survival.
