Pollen reserves

Todd and Bishop (11) determined that 1 lb (0. 45 kg) of pollen will maintain about 4, 540 bees; and with some 200, 000 bees reared by a colony a year, 44 lb (20 kg) of pollen would be consumed during a year. Perhaps more than 50 lb (22. 7 kg) of pollen are consumed by a strong colony to support its brood-rearing. Most of this is consumed during the summer, but a reserve of pollen stored as bee bread is also necessary to support brood rearing during the winter (1).

Most colonies will be broodless during November and December but will begin some brood-rearing about the end of December, regardless of outside temperatures. This is a normal condition throughout North America. Strong colonies with adequate pollen reserves in the combs may replace their fall population with young bees by the time new pollen is available in the spring (2). The amount of reserve pollen required in the fall depends on the abundance and time of bloom of the early spring sources of pollen. Where spring sources are not adequate or bloom occurs later than March, pollen supplement will need to be fed to bridge the shortage.

Adequate pollen reserves year round will insure healthy, strong populations of bees. This is most essential for the overwintering colony. Brood-rearing, made possible by adequate pollen, also results in a greater consumption of honey stores. Beekeepers should always be aware of the cache of honey in the colonies and never allow colony reserves to become dangerously light. When pollen supplement is fed in early spring before much flight is possible for foraging, the colonies must draw upon the honey remaining in the combs from the previous fall. Most of the 90-lb (40. 8 kg) reserve of honey left in the colony in October is consumed during early spring brood-rearing before settled, warm weather returns. During March and April most so-called winter loss occurs from starvation.

Entrances

For every 10 lb (4. 5 kg) of honey that a colony consumes, about 1 gal (3. 8 1) of water is produced. This water escapes from the overwintering colony as vapor. Provision should be made for the escape of this moisture-laden air, or ice may form on the cover above the cluster and drip over the bees during thawing. Some frost formation on the cover is not objectionable, but excess frost or ice is not good. A top entrance for the overwintering colony will allow the moist air to escape, as well as provide a ready flight entrance during thawing when cleansing flights are possible. Most practical is a 1- or 3/4-in (2.5-or 1.9-cm) diameter auger hole provided in the top hive body just below the front hand hold.

All hive bodies used as year-round brood chambers should have their auger-hole entrances corked shut except for the top box during the winter. When snow is deep, the bottom boxes may be below the snow line and an entrance to the top box will allow winter flight.

The lower combs are normally not occupied by bees during the winter, making an attractive nesting site for mice that can severely damage brood combs if they can gain entrance. The lower entrance should be screened or reduced to the smallest possible opening to exclude mice. Entrance cleats are commonly made with a small, 3/8 by 3/4-in (0.7- by 1.9-cm), opening for winter use.

Disease

Nosema disease is the most serious disease for the overwintering colony. The prolonged confinement and reduced brood emergence during winter enhances the opportunity for buildup of nosema (9). Unchecked, nosema disease seriously weakens colonies and may lead to their loss in late winter or early spring. Fumidil B 3, fed in sirup in late fall, is an excellent management practice to suppress nosema buildup during winter. A gallon (3.8 1) of heavy sugar sirup containing 3 100 mg of fumagillin fed to the colony at the close of brood-rearing will be stored in the area where the last brood emerged and is the first food used by the colony at the onset of winter. This suppresses nosema disease development and prevents more serious development of the disease that may occur without such treatment (8).

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A thorough check for brood diseases and colony condition should be made early in the fall as soon as the honey crop has been removed. Preventive drugs such as Terramycin or sodium sulfathiazole should be used for any colonies exposed to brood diseases. Three or four gorging applications at 4- to 5-day intervals with about 1 pt (0. 5 1) of heavy sugar sirup containing 1/2 to 1 g of sodium sulfathiazole per gallon (3.8 1) or 3.3 g of Terramycin (TM25) per gallon of sirup can be used. Dust treatments may be used as an alternative.

Brood diseases should be controlled in colonies well in advance of the overwintering period. Diseased colonies are a serious hazard to all colonies in the apiary. They are often weaker than normal, become candidates for nosema buildup, and as a result may become seriously weakened or die by late winter or early spring. If undetected at that time, stronger colonies may overpower them and rob honey, thus transmitting brood diseases throughout the apiary.