As we saw in theprevious article, sublimation (vaporization) of oxalic acid turns out to be one of the best methods of controlling Varroa Destructor mite infestations.
Treatments give maximum effectiveness only if they are part of a precise strategy called “Integrated Control.” A key part of integrated control is “Brood Blocking,” a particularly fruitful method for varroa control.
In this guide, Oxalika’s technical experts explain in detail how to prepare hives for effective treatments during the summer period using a method popular in Italy: the Campese method.
How to Make Brood Block – Campese Method
In the context of modern beekeeping, varroa has been a major challenge for beekeepers for decades. Varroa in beekeeping has become, in the last 40 years, the main problem, surpassing even climate change and crop modifications. This has created enormous difficulties for beekeepers, putting the bee population at risk.
The Varroa Problem in Beekeeping.
Before understanding the process on how to make the Brood Block, it is essential to consider the context in which it fits. Varroa is a parasitic mite that feeds on the larvae within the brood and adult bees and in particular their “fat body“.
The fat body is an organ of the bee that functions to regulate metabolism and growth, detoxify the body, and many other vital functions. Damage to the fat body, contributes to the spread of viruses and bacteria. Over time, varroa has become an increasingly serious threat to bees, compromising colony survival and adversely affecting the production of honey and other bee products.
To defend themselves, beekeepers have used various products over time, including many synthetic (neurotoxic) acaricides. However, this practice led to the selection of a very resistant varroa, now known as the varroa destructor. Consequently, the products used are effective only if they are part of a precise strategy called “integrated varroa control” (see https://unaapi.it/sanita-dell-alveare/varroatosi/varroa-lotta-integrata-3969/ ) .
A key part of integrated pest management is the “Brood Blocking”, a particularly fruitful method for varroa control.
In this article, we will examine one part of the Campese method, namely the summer brood block.The Campese method also involves a winter brood block to be performed with a different technique and on which we will devote a separate article. The brood block is intended to hatch all operculated cells before making the oxalic acid treatment. In this way, the effectiveness of oxalic acid treatment increases considerably, as it would not act on the varroa present within the operculated cells.
Summer brood blockade, followed by oxalic acid administration, is a buffer treatment which is used to reduce the amount of varroa mites so that we have healthy families in the fall season. It should then be followed by a definitive treatment, following the winter brood block, which will aim to get healthy colonies to the following spring. The final treatment, in the absence of any re-infestations from poorly managed neighboring hives, will ensure productivity without mortality problems until the following summer.
Summer Brood Blockade
Summer blocking is usually done between July 15 and July 20 and requires little equipment:
– a suitable cage to hold the queen
– a queen excluder grid
– a frame capable of accommodating a nesting frame in a horizontal position
– oxalic acid for drip or, if you prefer sublimation, an oxalic acid sublimator:
Brood block execution
After identifying the queen, we transfer the queen to the cage to keep her safe.
It is important to act gently and quickly so as not to scare her away. This way it will not go into hiding and we will find it in the honeycomb where it is laying eggs.
Next we go in search of the honeycomb to insert into the frame. Since this honeycomb, at the end of the block, will have to be burned, it is preferable to locate the oldest honeycomb, preferably if it also contains kelp brood. It is important that this honeycomb contain brood at all stages of growth. The prescient beekeeper marks the honeycomb to be used in the block on previous visits to the apiary.
The presence of brood in the honeycomb will stimulate the queen to continue laying. In fact, in the absence of queen laying, we will not be able to achieve optimal cleaning of the hive from varroa and the problems it causes to the bees.
After identifying the suitable honeycomb we pick it up and set it aside.
We rearrange the nest by bringing the frames closer together, put the queen excluder grid, put the frame. After that we insert the identified honeycomb inside the frame.
The following pictures show how to properly arrange the queen excluder net, frame and honeycomb.
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Note1:
As can be seen, the honeycomb is in an unnatural position, however, the bees adapt quite well and continue to brood. This is very important since this we are describing is a block that we call “active” meaning that the queen continues to lay. This has 3 advantages:
1)when, after 20 days, we go to remove the blockage , the queen will be laying and will not suffer any trauma favoring a quick recovery of the family.
2) on blocking days, as the operculated brood present in the nest hatch, the hatched varroa will be attracted by the fresh brood present in the horizontal honeycomb and will go right into that honeycomb to reproduce. Unfortunately for them, these varroa will not be able to reproduce because, as anticipated above, we are going to burn the horizontal honeycomb before the cells of this honeycomb hatch.
3)Foretic bees will remain healthier as they will be less attacked by varroa, which transmits viruses to the bees through its stings.
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Having placed the honeycomb we put the queen in it and close it with the inverted honeycomb cover for the purpose of creating a good air chamber.
The frame will need to be supported, leaving about 1 cm of space from the queen excluder, to allow circulation of the queen and other bees both below and above.
Next we cover with the roof placed slanted. In this way, an additional air chamber is formed so that, given the summer time, excessive heat will not damage the queen.
The following pictures show how to properly arrange the cable cover and roof.
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Note 2
In case of blooms, an additional queen excluder net can be placed over the frame and the honeycombs over the nets.
Note 3
It is possible to take advantage of the summer brood block to replace the old queen with a new one. Replacement should be carried out after 8-10 days from the start of the blockage. This is because, after 8 days from the start of the blockage, there is no young brood left in the nest, and the bees will not be able to build real cells.
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Optimal Time for Summer Brood Blocking.
The ideal time for the summer brood block. varies by geographic area, but generally occurs in early summer, after the last harvest. In northern Italy, for example, this intervention can usually be implemented in July; in other places it may be necessary to advance or postpone the blockade depending on local conditions.
Oxalic Acid Treatment
After 18-20 days, when in the nest the brood has almost all flickered and the horizontal honeycomb is full of brood, the next steps will be:
- Remove the honeycomb from the grid;
- Take the queen back from the honeycomb and release her back into the nest;
- Burn the honeycomb as it is loaded with varroa;
- Wait another 3-4 days to complete the flickering of the brood remaining in the nest.
After this further waiting, we will move on to the treatment with oxalic acid, which affects varroa and blocks the replication of viruses carried by this mite, such as the deformed wing virus.
If you decide to treat with an oxalic acid sublimator, you can refer to the following link for choosing the right OXALIKA sublimator for your needs.
Benefits of Oxalic Acid Treatment during the Summer Brood Blockage
Oxalic acid treatment during the summer blockade offers numerous advantages. In addition to preventing varroa from reproducing, oxalic acid treatment exterminates varroa still present on the bees. In addition to this, it reduces the number of stings on bees and hinders the replication of viruses that varroa carries. In particular, replication of deformed wing virus, a virus that peaks in late summer-early fall, is reduced.
This virus greatly reduces the bees’ immune defenses making overwintering difficult. The new brood will be healthy and strong and able to face the winter without problems and resume production early when the first spring blooms appear.
After oxalic acid treatment
After 3-4 days after oxalic acid treatment, it is appropriate to feed the bees with candy that will be consumed slowly and stimulate the bees to enlarge the brood and stockpile. The brood that will be born after the summer brood block will consist of winter bees; their quantity and health will help to promote overwintering. Liquid feed should not be given because it is consumed too quickly and ages the bees prematurely.
In families where varroa and virus presence were too high before starting the blockade, restarting may be difficult or impossible, and a drastic reduction in bee numbers may be seen. In this case the family is doomed to die unless it is supplied with brood taken from another family that has plenty.
Conclusions
Proper synchronization of operations is essential to ensure the success of the method and maximize its benefits.
The summer brood block is a valuable resource for beekeepers engaged in varroa control and promotion of bee health. This method, based on biological and sustainable principles, offers an effective and environmentally friendly alternative to traditional neurotoxic drug treatments. Through proper implementation and judicious planning, beekeepers can maximize the benefits of the summer brood block, ensuring the viability and productivity of their colonies throughout the season.
After the summer brood block, about 30 to 40 varroa remain within the family. This is not a large amount but still enough to cause serious damage by the following summer. This is why winter brood blocking is also necessary to be carried out in different ways, which will be described in a future article with the second part of the Campese method for brood blocking.