4.4.2. Regional variations in reported damage thresholds

Table 5 gives some published field-derived damage thresholds and their geography of origin.

Table 5. Field-derived varroa damage thresholds and month of occurrence at various locations. aDelaplane and Hood (1999); bDelaplane et al. (2010); cStrange and Sheppard (2001); dCurrie and Gatien (2006); eGatien and Currie (2003).

 Varroa damage thresholds and month of occurrence

location

Reference

 

 

 

Feb.

Aug.

 

1. colony mite population: 7-97

1. colony mite population: 3172-4261

Southeastern USA

a

2. 0.4 mites per 100 bees

2. 13 mites per 100 bees

 

 

3. mites on overnight bottom board sheets: 0.6-10

3. mites on overnight bottom board sheets: 59-187

 

 

 

1. colony mite population: 1111

2. 10 mites per 100 bees

Southeastern USA

b

Apr.

Aug.

 

1. 1 mite per 100 bees

2. mites on 48 hr bottom board sheets: 24

1. 5 mites per 100 bees

2. mites on 48 hr bottom board sheets: 46

Northwest USA

c

May

Late Aug. – mid Sep.

 

1. 2 mites per 100 bees (to prevent honey loss)

1. 4 mites per 100 bees (to prevent winter loss)

Manitoba, Canada

d

 

1. 5-8 mites per 100 bees

Manitoba, Canada

e