Mites & Nosema Survey

NOSEMA & MITES SURVEY

IPM Strategy

Integrated Pest Management (IPM) suggests that the beekeeper makes a decision for treatment based on level of pests in the colonies. It is no longer advisable to make use of pesticides year after year, because this leads to resistance of the mites to the active ingredient. Instead, it is now recommended to monitor the pests or diseases, to know the level of infestation. If the level of infestation observed exceeds a pre-determined value (called Economic Threshold Level-ETL), then it is recommended to take action, i.e. treat with a soft chemical like formic acid or oxalic acid.   Organic acids are found in nature at lower levels, and are not such a big problem for residues.   Moreover, honeybees are not known to become resistant to such products.

In our breeding program, we have followed this method to allow the Russian stock to defend itself against mites on its own merit. What we found is the level of mites reaches dangerous levels after 3 years without treatment. Therefore, we concluded that a treatment should be applied once a year or every 2 years at thee most.   This is an improvement because we use to treat twice a year before.

The key is monitoring the pests regularly, not to get caught behind, where it becomes too late. We make extensive use of sticky boards inserted on the floorboards of the colonies to trap dead mites falling off the cluster.   We survey a minimum of 25% of all colonies. This gives us a good idea of the mite situation. We leave the sticky board in for a period of 24 to 48 hours. We then calculate the 24-Hour mite count for each colony surveyed.   This gives us a standardized 24-hour apiary average for each apiary. We use this value to decide if we are going to treat this apiary or not.   We do this survey in early spring and late summer.

Using these results, we have established the following guidelines as of fall 2009:

In the spring, late April:

If level are > 5, treat with Mite Away II in May when daytime temperature reaches 10° C.

In early September:

If levels are < 20, treat with Oxalic acid in November.

If levels are > 20, treat with Formic Acid in September and treat with Oxalic Acid in November.

 

2002

This is the year where we requeened most of our colonies with Russian stock. We therefore treated all colonies, in all apiaries with Check-Mite to start afresh with very low mite counts.

 

2003

We conducted the survey in September and found very low level of mites (between 0 and 3). We treated one apiary with Mite-Away II, and 2 apiaries with Check-Mite in late fall (partial treatment).

 

2004

In September 2004, we conducted an extensive Varroa mites survey, using sticky boards in all our apiaries, to determine the average level of mites infestation in each particular apiary.   Our survey indicated that only 2 apiaries needed treatments out of 10.

 

2005

We conducted the survey in the spring and fall. In the spring many apiaries showed level of infestation >10, so we treated with Mite-Away II or home-made formic acid pads using veggie bags. All apiaries showed high levels of mites in the fall as well, therefore we treated all apiaries with formic acid or Check-Mite. All nucs were treated with oxalic acid.

 

2006

We conducted the survey in the spring and fall. In the spring levels were below 5 for the most part, with an average of 2.1, so we did not apply any treatment. In the fall, levels were much higher with an average of 24, so we treated all apiaries with formic and oxalic acid.

 

2007

No survey in the spring.   In September, composite bee samples (10 colonies per sample of 150 bees each) from all colonies were sent to the Bee Lab in Eganville (Tanglewood Honey-Jim Anderson) to check for nosema spores. Also in September, sticky boards were used to evaluate varroa mites population in every apiaries. The results are shown below in table 1. We treated 3 apiaries with Fumagillin, and 5 apiaries with formic acid (Mite-Away II). All colonies were treated with oxalic acid later in November. Nosema are shown as million spores per bee and varroa is shown as # mites in 24 hour natural mortality.

 

Table 1 – Survey Results for Varroa and Nosema – Apiaries’ Averages and Treatments – 2003 to 2007

APIARY ID 2003 2004 2005 2006 2007
SPRING VARROA FALL VARROA SPRING VARROA FALL VARROA SPRING VARROA FALL VARROA SPRING VARROA FALL VARROA FALL VARROA FALL NOSEMA
2 N/A N/A N/A N/A N/A N/A N/A 15
Mite-AwayII
Oxalic Acid
7.8
Oxalic Acid
0
3 0 3.4
Check-Mite
0.3 1.2 3.6 67.0
Mite-Away II
6.7
no treatment
28
Mite-AwayII
Oxalic Acid
18.6
Mite-AwayII
Oxalic Acid
2.0
Fumagilin
4 N/A N/A N/A N/A N/A N/A N/A 10.3
Mite-AwayII
Oxalic Acid
6.4
Oxalic Acid
0.2
8 0 0.1 0.3 4.8 6.2
Formic Acid
87.2
Check-Mite
0.8
no treatment
9.8
Mite-AwayII
Oxalic Acid
5.0
OxalicAcid
0.07
12 0 0.4 1.2 7.7 8.9
Formic Acid
65.9
Check-MIte
0.6
no treatment
17.5
Mite-AwayII
Oxalic Acid
5.1
Oxalic Acid
0.08
14 0 3.1 3.1 10.4
Mite-Away II
0.8 55.6
Check-Mite
2.4
no treatment
61
Mite-AwayII
Oxalic Acid
8.7
Oxalic Acid
0.08
15 0 0.3 0.9 3.7 13.9
Formic Acid
55.4
Mite-Away II
4.8
no treatment
33.2
Mite-AwayII
Oxalic Acid
6.5
Oxalic Acid
0.33
17 0 3.1
Check-Mite
1 1.8 7.6 62.8
Mite-Away II
1
no treatment
19.3
Mite-AwayII
Oxalic Acid
36.8
Mite-AwayII
Oxalic Acid
0.48
Fumagilin
19 0 0.4 N/A 1.1 20.0
Formic Acid
92.1
Mite-Away II
1.3
no treatment
36.25
Mite-AwayII
Oxalic Acid
14.4
Mite-AwayII
Oxalic Acid
0.02
21 0 0.3 N/A 5.6 9.9
Formic Acid
114.9
Check-Mite
0.4
no treatment
3.6
Oxalic acid
21.3
Mite-AwayII
Oxalic Acid
1.28
Fumagilin
22 0 0.3 0.6 2.9 11.3
Mite-Away II
34
Mite-Away II
2.0
no treatment
31.0
Mite-AwayII
Oxalic Acid
N/A N/A
23 0 8.8
Mite-Away II
N/A N/A N/A N/A
Check-Mite
N/A N/A N/A N/A
24 0 0.1 0.5 10.4
Mite-Away II
0.6 78.4
Check-Mite
0.8
no treatment
26.4
Mite-AwayII
Oxalic Acid
41.5
Mite-AwayII
Oxalic Acid
0.05
AVG 0 2 1 5 8 71 2 24 15.6 0.38

2008

This is the year we realized Nosema apis & Nosema ceranae has appeared in force to devastate many colonies around the world. We found it in our own bees with alarming level. We decided not to treat in the fall but to sample bees at the entrance door in September, in order to find breeder colonies with lower levels in comparaison to the apiary average. We treated with Formic Acid and Oxalic acid as usual. Table 2 shows results. Nosema are shown as million spores per bee and varroa is shown as # mites in 24 hour natural mortality.

Table 2 – Survey Results Varroa and Nosema

Apiaries’ Average and Treatments – 2008

APIARY ID FALL
VARROA NOSEMA TREATMENT
2 8 N/A Oxalic acid
3 13 2.97 formic acid pads Mite-Away II
Oxalic acid
4 11 N/A Oxalic acid
8 39 6.15 formic acid pads Mite-Away II
Oxalic acid
12 35 2.38 formic acid pads Mite-Away II
Oxalic acid
14 11 3.14 formic acid pads Mite-Away II
Oxalic acid
15 74 5.15 formic acid pads Mite-Away II
Oxalic acid
17 12 5.62 formic acid pads Mite-Away II
Oxalic acid
19 34 5.04 formic acid pads Mite-Away II
Oxalic acid
21 14 3.74 formic acid pads Mite-Away II
Oxalic acid
24 45 N/A formic acid pads Mite-Away II
Oxalic acid
AVG 27 4.27

2009

We sampled again for nosema levels in early spring and found that most levels had increased since fall 2008. We decided to treat with Fumagillin, using the baggie method, at the recommended dosage for Nosema ceranae, 4 applications at 1 week interval. No other treatment in the spring. In September, we treated again with Fumagillin, one application with baggie method, dosage for Nosema apis. We could not treat all colonies because in some apiaries we first fed heavily, consequently the bees would not take the baggie afterwards. We plan to treat these apiaries early next spring. No formic acid, only oxalic acid applied to all colonies.   Results are shown in table 3. Results for nosema levels in fall will be available later this winter. We will post the results when we receive them from the Tech-Transfer Team. Nosema are shown as million spores per bee and varroa is shown as # mites in 24 hour natural mortality.

 

Table 3 – Survey Results and Treatment for 2009

APIARY ID SPRING FALL
VARROA NOSEMA TREATMENT VARROA TREATMENT
2 0.5 N/A Fumagilin-B 5 Fumagilin-B
Oxalic acid
3 1.5 6.5 Fumagilin-B 7 Oxalic acid
4 3.9 N/A Fumagilin-B 10 Oxalic acid
8 0.5 10.1 Fumagilin-B 3 Fumagilin-B
Oxalic acid
12 0.8 13 Fumagilin-B 6 Oxalic acid
14 0 16.7 Fumagilin-B 2 Fumagilin-B
Oxalic acid
15 1 11.1 Fumagilin-B 17 Oxalic acid
17 0.7 5.4 Fumagilin-B 4 Fumagilin-B
Oxalic acid
19 0.3 13.3 Fumagilin-B 8 Oxalic acid
21 0.4 6.73 Fumagilin-B 3 Oxalic acid
22 N/A N/A Fumagilin-B 16 Fumagilin-B
Oxalic acid
24 0 N/A Fumagilin-B 4 Fumagilin-B
Oxalic acid
AVG 0.9 9.8 7