Apiculture

Ectoparasitic Mites

In India, ectoparasitic mites Varroa destructor and Tropilaelaps clareae are causing severe damage to A. mellifera colonies. However, no damage in A. cerana colonies due to these mites has been reported.
Nature of damage:
i) Tropilaelaps clareae: This mite feeds only on bee brood. In case of severe infestation of this mite dead brood is thrown outside the hive by workers. The bee colonies may even abscond if control measures are not adopted. The diagnostic symptoms are:

• irregular brood pattern
• perforated brood capping
• dead or malformed wingless bees at the hive’s entrance
• fast running small brownish mites can also be seen on the infected brood frame.
ii) Varroa mite:







• This mite develops and reproduces in the sealed brood cells of honey bees (Fig. 16.6) feeding on haemolymph of bee pupa (Fig. 16.8). Parasitized individual may die or develop into deformed, weak individual incapable of normal functioning
• This mite has caused heavy losses to A. mellifera colonies throughout the world as it reproduces both on drone and worker brood of this species. Although the native host of this mite is A. cerana, yet it is causing no serious damage to it. On A. cerana this mite reproduces only on drone brood and is unable to complete life cycle on worker brood due to slightly shorter developmental period
• In India, there was no serious damage in A. mellifera colonies till 2004 due to this mite though reported in 1988 on this species from Himachal. Serious infestation in A. mellifera was recorded in Gurdaspur, Amritsar and Hoshiarpur districts of Punjab in 2004 for the first time and now seriously affecting this bee all over India
• Now it is well known that the mite earlier referred to as Varroa jacobsoni is in fact a species complex consisting of two species V. jacobsoni and V. destructor, each having several strains. Only two strains of V. destructor have become pest of A. mellifera
  
The symptoms of colony infestation with Varroa are:

• Spotty brood pattern (Fig. 16.6)
• Mite can be seen on adult bee’s body (16.7) as mature female mite attaches to young adult bee and also feed on haemolyph till further reproduction in the brood cell
• Dead brood and malformed adult bees are seen near/around hive entrance
• Colonies become weak and wounds inflicted by mites make the bees more susceptible to bacterial and viral diseases.
Methods of Varroa mite detection:

• Open about 50 sealed brood cells and remove pupae using forceps and count number of mites in each cell and pupa
• To examine mites on adult bees, take about 100 bees from a colony in a wide mouthed bottle and sprinkle about 15 gram of finely powdered sugar and shake the container after closing its mouth. Fine sugar particles will dislodge the mites as these stick to mite foot pads and disable them to grip the bee body surface. Take a white paper sheet and release the contents over it. The adult bees will fly away whereas mites can be seen in the collected sugar powder. Count the number of mites
• Natural mite drop in 24 hours is also taken as assessment tool for mite infestation but for this purpose screened bottom boards (with 8 mesh wire screen) with sticky paper need to be inserted in the bee hives. A drop of more than 30 mites in 24 hours is considered high infestation and requires treatment of bee colony.
Control:

i. Tropilaelaps clareae : Sulphur dusting on top bars @ 200mg/frame
ii. Varroa destructor: Formic acid fumigation @ 50ml/hive in sponge pads covered with perforated polythene bags. Level of mite infestation can be kept low by putting sugar (finely powdered sugar) @ 30g/frame and then sweeping sugar down between the frame spaces using a bee brush.