Varroa un problema de gran impacto a nivel sanitario y productivo en la apicultura, métodos de diagnóstico, tratamientos y prevención
Fúquene Achury, Brayan Smith | 2020-05
Apis mellifera is an insect that plays a very important role in pollinating the environment, therefore, any problem that affects the hive will be of great environmental and economic importance to the beekeeper; Thus, biological invasions are one of the biggest problems that lead us to propose new treatment and prevention alternatives, having Varroa as one of the most serious dangers for beekeeping (Evans & Cook, 2018).
The decline of the bee population globally is triggering a social and environmental deterioration due to an evident decrease in the production of food for human consumption and the loss of biodiversity in all environments; the bee is an animal that evolved morphologically to have the most suitable morphological characteristics in the work of pollination, that is, it is an animal designed specifically for environmental sustainability (Aizen & Garibaldi, 2009). Therefore, the three main factors that are generating the loss of the bee population are industrial agriculture, climate change and infectious diseases, mainly those of parasitic origin.
In this order of ideas, this work is based on a deep search about the ectoparasite called Varroa jacobsoni and now known as V. destructor thanks to the investigations of Anderson and Trueman in 2000; This is a mite that spreads easily through the hive, feeding on the hemolymph of bees, both in the adult stages and in the larval stages; This mite has taken on great importance throughout the world since its first report in 1904 and its subsequent spread towards the Second World War when it left its Asian environment and quickly invaded most of Asia, Europe, spreading to Africa and finally America changing its natural host Apis cerana by Apis mellifera (Nazzi & Le Conte, 2015); Varroa's most relevant concern is that, the mite alone does not cause the collapse of the hives, but rather that it acts as a vector of viral diseases, where together they lead to the death of bees (ALLEN & BALL, 1995; Tantillo et al ., 2015; LEAL et al., 2016).
The 6 viruses that can be transmitted by Varroa are the Acute Paralysis of Viruses of Viruses, Viruses of Queen's Black Cells, Deformed Wing Viruses, Viruses of Acute Paralysis of Bees in Israel, Kashmir Viruses, Viruses Sacbrood or bagged offspring belong most to the Dicistroviridae family, which is a virus family that mainly infects insects (Bailey & Woods, 1977; BüChler, 1994; Calderón et al, 2009; Frigolí & Poffer, 2019; Galego, 2018) ; additionally, each one will produce a symptomatology that will show at an individual level and also at a social level in the hive, that is, individually from deformed wings, gradual darkening, loss of hair, to reduction in the useful life of the bee; Also at a social level, symptoms such as decreased honey production, decreased defensive response of the hive, evident decrease in the hive population, among others (Galego, 2018; Rosenkranz et al., 2010) can be evidenced.
When the mite interacts with the bee, there is a close relationship between the biological cycle of both species; The life cycle of the mite comprises two distinct phases (the phoric phase and the reproductive phase), the phoretic phase occurs on the adult bee and the reproductive phase occurs only within the sealed brood cell (Rosenkranz & Aumeier, 2010). The mite has evolved in such a way that it can carry out chemical espionage that helps it to camouflage itself between larvae and adult bees by capturing chemical signals that help it avoid the defense mechanisms of bees (Nazzi & Le Conte , 2016). The female mite enters the cell through the adult bee and begins the cycle and the male mites since they cannot survive outside the cell, fulfill their reproductive function inside the cell and later die, being then that the females can pass through two or three more cycles throughout his life before dying (Nazzi & Le Conte, 2015).
Additionally, the colonies of bees infested by V. destructor develop a pathology known as “bee parasite mite syndrome”, which presents with complicated and variable symptoms, which are accompanied by a negative synergism due to the contagion with one or more Bee virus (Tantillo, 2015). The Varroa destructor mite has been confirmed as a vector in the transmission of viral infections, since the presence and accumulation of viral particles in the saliva of the mite have been found similar to viruses of the Picornaviridae family, indicating that the virus replicates in V. destructive and acts at the same time as a biological vector, however, the transmission mechanism is not completely known (Fujiyuki & Takeuchi, 2004; Tantillo, 2015).
Faced with the presentation of group signs such as decay of the bees or weak behaviors in the hive, the diagnosis of the possible infestation with Varroa becomes imperative and thus maintain the good health of our apiary, preventing honey production from starting to Additionally, the early diagnosis of the presence of the mite helps us to prevent the evolution of pathologies that occur due to synergism with viral agents, in this way, methods such as the clear background panel, the use of powdered sugar or the method of the bottle, will help us to demonstrate the presence of Varroa and additionally to quantify our level of infestation and, based on the results, propose a possible treatment (Bayer, 2019; de Guzmán et al., 2017).
Various treatments against Varroa have emerged over time, from chemical treatments with fluvalinate, flumethrin, coumaphos or Amitraz that have gradually created resistance to these chemicals by the mite, to more natural methods such as the use of herbal oils, propolis, use of kariomonas and allomonas, entomopathogenic fungi, thymol, among others; Other investigations to counteract the mite populations in the hive have also suggested the use of physical techniques such as heat treatments, smoke, water, ultrasound, plastic panels with reduced size, among others (Rosenkranz et al., 2010); Vásquez et al., 2000) (Ritter, 1981; Pérez, 2015. Being clear in this way that Varroa is one of the greatest risks for bees due to the combination with viral diseases and treatments that have generated resistance over the years, it is clear that the genetic selection of hives resistant to infestation and with desired behaviors such as "Varroa Sensitive Hygiene" is the best way to prevent the disease, thus raising queens using techniques such as the Dolittle method, the Nicot method or the Jenter method represent a beneficial future for beekeeping. which are easy and inexpensive methods for the beekeeper (Nazzi & Le Conte, 2015; Vásquez et al., 2000).
Finally, having clear the importance of bees, the biological cycle of mites, chemical, physical and biological treatments; prevention against the disease is the most important issue that we must adopt in our hives and thus establish a sanitary status that favors improving beekeeping genetics, preventing the spread of viruses by the mite and also preventing the emergence of more Varroa-borne diseases.