Percentage of brood frames inspected

Pitfalls of taking shortcuts

There is always the temptation to decrease the number of brood frames inspected in a beehive when time is at a premium and other beekeeping management tasks have to be performed. However, the fewer frames that are inspected, the lower is the chance of finding an AFB infection. As well, the infection will almost certainly be more advanced before it is identified, increasing the chances that the AFB colony will be robbed.

If there is only one frame showing AFB symptoms in a hive with 12 frames of brood, there is a 75% chance of the infection being missed if only three frames of brood are checked (Table 4). Nevertheless, some beekeepers only ever inspect three brood frames per hive, and often only in the top super.

Brood Frames

3

4

5

6

7

8

9

10

11

12

Frames inspected

 

 

 

 

 

 

 

 

 

 

1

66

75

80

83

86

88

89

 90

 91

 92

2

33

50

60

67

71

75

77

 80

 82

 83

3

0

25

40

50

57

63

66

 70

 73

 75

4

 

 0

20

33

43

50

55

 60

 64

 67

5

 

 

0

17

28

38

44

 50

 55

 58

6

 

 

 

 0

15

25

 33

 40

 46

 50

7

 

 

 

 

0

13

 22

 30

 36

 41

8

 

 

 

 

 

0

 11

 20

 27

 33

9

 

 

 

 

 

 

 0

 10

 18

 25

10

 

 

 

 

 

 

 

 0

 9

 17

11

 

 

 

 

 

 

 

 

 0

 8

12

 

 

 

 

 

 

 

 

 

 0


Table 4: Percentage chance of not identifying an AFB hive with diseased larvae on ony one brood frame, when different numbers of frames are inspected 

It takes about four times longer to disassemble a two-box hive and inspect all of the brood frames than to inspect three brood frames in the top box. However, this increase in labour is negligible compared with the time and expense required to simply get to the apiary. Since considerable effort is taken to visit each apiary, it makes sense to do a thorough and effective job once there.

There are good examples of beekeepers in New Zealand with above average levels of AFB in their hives significantly decreasing the incidence of AFB, by simply increasing the number of brood frames inspected in every hive.

When inspecting hives for AFB, all brood frames should be checked.