CLEARING BEES FROM HONEY SUPERS

CLEARING BEES FROM HONEY SUPERS Reprinted from Bee World 49 (2): 55-62 (1968) GENERAL PRINCIPLES The physical removal of honey supers from the hive usually presents no special problems except those of lifting, but it is highly desirable to get each super free of bees before moving it. Methods for doing this are classified as follows, and detailed in Table 1: sometimes one method may be used in conjunction with another: A. Mechanical: by shaking and brushing bees off the comb; B. Behavioural: making use of the bees behaviour pattern bee-escapes ; C. Chemical: using a substance that repels bees carbolic acid (C1); propionic anhydre (C2); benzaldehyde (C3); smoke could also come into this category; D. Physical: blowing the bees out by applying a stream of air. Table 1 METHODS OF CLEARING BEES FROM HONEY SUPERS Advantages Disadvantages Hazards General recommendation 1 2 3 4 A. SHAKE-AND-BRUSH single manipulation robbing remove all but last super bee-free supers time-consuming before the nectar flow ends reduces heavy lifting irritates bees B1 ESCAPE BOARD ON HIVE eliminates robbing requires two visits, with double robbing if equipment is not use bee-tight equipment lifting of supers beetight minimum disturbance drones, propolis or burr comb may clong exit cheack that all exits function correctly granulation of some honey if second visit delayed use screen-board with escapes opening to outside bees may not leave instal at dusk; remove honey 24 or 48 hours later bees may manage to return B2 ESCAPE BOARD ON STACK OF SUPERS colonies not disturbed a combs may melt second time robbing by insects seal all holes young bees remain robbing by humans move supers from hives at dusk C1 CARBOLIC ACID single rapid manipulations ineffective on cool cloudy days can cause severe skin burns not recommended danger of contaminating irritates bees remove queen excluder honey best results with shallow supers remove burr comb the day before C2 PROPIONIC ANHYDRIDE as effective as carbolic ineffective in cool weather stupefied bees must be brushed off C3 BENZALDEHYDE effective at lower temperatures D AIR BLOWER efficient at all temperatures robbing unlikely colony activities quickly resumed excessive vaporization stupefies bees Initial outlay higher than with other methods noisy skin contact to be avoided skin contact to be avoided some related compounds are poisonous stupefied bees must be brushed off in hot weather rotate fume board to increase air supply store board in sealed plastic bag away from light use smoke to start the bees moving use special fume board in hot weather: rotate fume board use empty shallow underneath insulate fume board idea useful use wide-spaced frames, or spread frames apart while blowing

Historically, smoking (C) is probably the oldest method, combined with shaking each comb removed from bees nest and knocking the bees off hand (A). The use of carbolic acid seems to have originated with Rev. G. RAYNER in England in 1968, and E.C. PORTER devised the first bee-escape (B) in the United States in 1891. A great search was made for good chemical repellents (C) in the past decade; propionic anhydride was introduced in 1961 and benzaldehyde in 1963. Interest has now swung back to a method avoiding the use of chemicals blowing the bees out. WHICH METHOD TO USE? No single method is best for everyone. The needs of the beekeepers with several thousand hives spread over a large area, and of those with a few hives in their back garden or beehouse, are quite different. Table 2 lists the methods likely to be suitable in different circumstances, and the methods which are best avoided, for reasons that will be clear from Table 1. METHODS SUITABLE FOR DIFFERENT CIRCUMSTANCES BEEKEEPING CONDITIONS: 1. What is to be removed? whole super (s), use B, C3, D some frames only, A* or C3 2. Super and super-frames deep, avoid C* shallow, use B, C3, D 3. Scale of operations large, use C3, D small, use A, B, C3 4. Apiary/extracting plant home/home, use B, C3, D out-apiary/central, avoid B out-apiary/home, avoid B out-apiary/mobile, use C3, D 5. Beekeeper professional, use C3, D amateur, use A, B, C3 6. Method of working alone, avoid B1 with a helper, use A, B, C*, D HONEY FLOW AND OTHER CONDITIONS: 7. Flow still on, use A, B, C*, D finished, avoid, A, B 8. Temperature hot, use A, C*, D cool, use A, C3, D 9. Sky clear or overcast sunshine, use A, B, C*, D cloudy, avoid C1, C2 LEGISLATION: 10. The minimum allowed content of certain chemicals in honey may preclude the use of C1. * Because of danger of contaminating the honey, reliance on carbolic acid (C1) and/or smoke is not recommended. Table 2 Fortunately, hive bodies or supers containing capped do not contain as many bees as do those with brood or open cells, and if it is cool many of the bees will be clustered in the brood chamber. Colonies vary in their behaviour during manipulations. Some are extremely nervous, pouring out over the edge and hanging on the outside of the hive body or worse still flying at and around the operator. Such colonies, like those whose bees sting without provocation, should be requeened. Apart from this, the most important and undesirable behaviour trait of bees when the beekeeper is harvesting honey is their readiness to rob. The partial closure of hive entrances (especially to protect small colonies or nuclei) will reduce the chance of serious robbing, as will careful behaviour on the part of the beekeeper. At the height of a nectar flow, discarded bits of comb or drips of honey in the apiary may receive little attention from the bees. But when nectar is scarce or non-existent, any source of food near the hives is likely to be discovered and exploited quickly. The consequent search for more food, by more and more bees, can then lead to serious robbing, and the whole apiary can be put into an uproar in a matter of minutes by the beekeeper s carelessness. If honey supers are to be cleared of bees while nectar is still available, it is best to do the work during the warmest part of the day while many bees are out foraging. If nectar flow has stopped, try to limit manipulations to cloudy days, or the latter part of the day when fewer bees are flying; chances of serious robbing are thus reduced. A. SHAKE-AND-BRUSH Many beekeepers with only a few hives to care for use this method, which requires only a minimum of apparatus and has the advantage of being finished in a single visit, even though it is time-consuming. The frames are lifted out one by one, most of the bees bumped off into the open hive by jerking the frame, and the remainder brushed off in front. Although bee-brushes and long whisk brooms are available from beesupply houses, a goose wing or even a single large primary feather is better. A few puffs of smoke are directed over the frames as the cover is removed; some beekeepers also smoke the entrance, but unless the brood chamber is to be examined this is best avoided. The operator works from one side or from the back of the hive, and as each frame is freed of bees, it is placed in an empty hive body made bee-tight at the bottom and with a bee-tight cover. From time to time additional smoke will be required. Some colonies produce burr comb between the tops and bottoms of the frames. This is trimmed off with a hive tool or narrow sharp-

edged scoop, and dropped into a container kept at hand for the purpose; it should not be thrown on the ground. Success with the shake-and-brush method depends on the least possible disturbance of the bees, by calm and smooth manipulation, and by keeping frames and hive parts covered. Manipulating cloths are especially useful; they are used two a hive or box, one being rolled back (parallel to the frames), as the other is rolled forward, so that only one frame need be exposed at one time. Another helpful device is a sprayer that can be used to reduce the number of flying bees by creating a fine mist above an open hive or at its entrance. B. CLEARER OR ESCAPE-BOARD This is commonly a standard inner cover or crown board with one or more holes into which beeescapes are fitted. The super with capped honey is lifted up and replaced above this board; a bee-tight cover is put on top of the super. Various types of bee-escape can be purchased; they have light springs so arranged that bees can leave the super to reach the brood nest below, but cannot re-enter the super. Ideally, most or all of the bees will have left within 24 or 48 hours, and the super can then be removed without any bees. One way of speeding up the movement of the bees is to provide escapes to the outside (e.g., at two opposite corners of the board) as well as to the brood chamber below. If, by mischance, the honey super is not bee-tight, it will probably be robbed out before the beekeeper goes to remove it. The clearing operation may also fail because a drone gets stuck in the escape, or the bees fasten the springs tight with propolis. (Propolized escapes can be cleaned by boiling for a few minutes in washing soda sodium carborate). The moving parts of a bee-escape are delicate and vulnerable, so escape-boards without moving parts have an obvious advantage. They can be effective, and are surprisingly little used. In one type, a screen-board is provided with extra deep rims and a cross-piece of wood over the centre, through which several holes are bored. Underneath a bent strip of zinc or a length of plastic tubing forms a tunnel from each hole with egress below. Especially if the tunnel exists are near the corners of the board, bees do not re-enter them. Instead of inserting the escape-board under the super (s) on each hive, supers to be cleared can be stacked on one escape-board and covered with a second, put on upside-down, so that the bees can leave from both top and bottom of the stack and fly back to their own colonies. The stack must be bee-tight. Very young bees will remain, and must be shaken off in front of a hive. C1. CARBOLIC ACID The use of carbolic acid was widely adopted in the 1930 s especially in North America and Australia. It is still in extensive use, and therefore described here, but is not recommended, for reasons given later. An acid or carbolic board consists of a frame with the same cross-section as the hive, and a rim 3 to 5 cm (1 to 2 inches) deep. A wire screen is placed over the frame then one or more layers of absorbent cloth, and finally black metal or roofing paper, which forms the outside surface, used uppermost. A clothes-sprinkler cap on a bottle containing a 20 to 50 per cent solution of pure carbolic acid is used to sprinkle the cloth until it is damp. The board is placed on top of the hive for 3 to 5 minutes. Heat from the sun is absorbed by the black cover, vaporizes the acid, and drives the bees down. The acid-board is then placed on the next hive, and the first super of honey removed and stacked on a bee-tight cover on top. With six or more boards, one man can move along a row of hives and take off 100-200 supers of honey in rapid succession. Like all repellents, carbolic acid is more successful with shallow than with deep supers, and works best if there is no queen excluder. On dull cloudy days carbolic acid does not evaporate readily, and at temperatures below 24 O C (75 O F) it may not work at all. For many years the acid-board was a valued piece of equipment to professional beekeepers in warm climates; it enabled them to remove their honey crop during one visit to each apiary, whereas two were needed when escape-boards were used. The risk to the operator was recognized from the start; bad burns can result from contact with the skin and one drop of acid splashed into the eye could cause blindness. Before the 1930 s use had been made of a cloth dipped in dilute carbolic acid and wrung out by hand, placed over the top of the super. But, with acid concentrations safe to handle in this way, the method is not very effective. The possible risk to the consumer from honey contaminated with carbolic acid was much discussed around 1960 in the U.S.A. The acid is carcinogen and honey could by condemned by the Food and Drug Administration on the grounds of even a minute carbolic acid content. The use of carbolic acid is now widely disapproved, but is still in common use, especially in hot countries such as Australia, where it is both familiar and effective.

C2. PROPIONIC ANHYDRIDE As a result of the alarm in the U.S.A., the Department of Agriculture there set out to find a suitable replacement for carbolic acid, and in August 1961 publicized propionic anhydride as a promising repellent when used with a special fume chamber that incorporated bellows. Beekeepers have found the ordinary acid-board or slightly deeper version equally satisfactory with propionic anhydride. The original recommendation was two tablespoonfuls (14 cc) of a fresh mixture of equal parts of propionic anhydride (technical grade) and water. This is sprinkled on the absorbent layer (fume pad) that forms the underside of the board, and should yield enough vapour to repel the bees an overdose stupefies them so that they must be brushed off the combs. It was latter recommended that the anhydride be used without the addition of water. Like carbolic acid, propionic anhydride proved to be ineffective on cool days. Contact with skin or clothing must be avoided, and water should be available to wash any splashes on the skin. There have been heated arguments for and against the use of propionic anhydride for removing bees from honey supers; it is notable that the 1967 U.S.D.A. handbook Beekeeping in the United States does not mention it. C3. BENZALDEHYDE The failure of propionic anhydride under some conditions encouraged the search for still other materials and the best so far found is benzaldehyde, a substact tested among many others in 1962 and 1963 at Ontario Agricultural College. Benzaldehyde is also known as artificial almonds, and is used in foodstuffs. As a bee repellent, benzaldehyde seems to work best between 15 O and 27 O C (60 O 80 O F), on either cloudy or sunny days. A little smoke should be used first to start the bees moving. Pure benzaldehyde is sprinkled lightly (one-half to two table-spoonfuls, 4-5 cc) on a fume-board made of insulating board such as pressed-fibre mounted on a rim 5 centimeters (2 inches) deep, like a simplified acid-board. Benzaldehyde is so volatile that direct sunlight falling on the metal cover a standard acid-board would produce fumes too rapidly, stupefying and confusing the bees, which must then be brushed off the combs. On warm days, it may be helpful to use a white cover or additional insulation on the fume board, or to insert an empty shallow hive body beneath it. In may help to use less benzaldehyde. (At extremely high temperatures it would be better to use propionic anhydride). The bottle of benyzaldehyde should be kept tightly sealed, and in a cool place away from light. Water should be available in case the liquid is split. More than most chemical repellents, benzaldehyde has a limited depth of action in the super; it is effective in clearing bees from shallow frames, but not from deep frames. D. COMPRESSED AIR No chemical repellent is suitable under all local conditions, and no escape-board works perfectly on every occasion. The use of a stream of air to blow the bees out of the supers has recently been given trials in North America, Israel, Australia and elsewhere. More and more bee-blowers are now being advertised by bee-supply houses in different countries. This method has the great advantages of speed, safety from contamination of the honey, and effectiveness at a wide range of temperatures. The bees are dislodged more quickly if the frames are spread apart slightly while blowing. The colonies reorganize themselves rapidly, and robbing does not seem to present a problem. A side benefit in dry weather may be the removal of some moisture from uncapped cells. A bee-blower involves more capital outlay than other methods. We are not yet in a position to recommend any specific machine, because so many developments are still taking place, but a number of firms supply leaflets about bee-blowers they offer for sale, and advertise in the bee journals. The engine usually generates 2 to 6 b.h.p., and can supply an air stream up to say 150 m.p.h. (13,000 feet or 4,000 meters, per minute). The U.S.D.A. recommends a large volume of air, 65 cubic feet (1,800 litres) per minute, blown out at low pressure, 2 pounds per square inch (0,14 kg/sq cm). The current of air is usually applied to the top of a super (already removed from the hive) through a vaccum-cleaner type flexible tube of about 4 inches (10 cm) diameter. Many bee-blowers incorporate a stand on which the super is placed; with a suitable deflector below, the bees are then blown forward, toward their hives. OTHER METHODS Acetic acid is included in the patent obtained for the use of propionic anhydride, but it has not met with general acceptance; careful smoking is required when the acid is applied, to prevent stupefaction of the bees.

Carbon dioxide in the form of dry ice has been suggested as a repellent, but has not so far received much attention. High-frequency vibrations have also been suggested. The use of fixed-frame supers constitutes a specialized form of beekeeping; here; provided the frames in the supers are widespaced, a bee-blover would seem to be the most useful method for cleaning the bees from them.