Some beekeepers use a combination of pesticides. Studies have confirmed traces of fluvalinate concentrations in honey and wax samples obtained from colonies that were treated with two strips of Apistan. [Gatien, 2003]
Besides these In-hive chemicals, bees are also affected by the agricultural pesticides when they feed on the pollens. Though these pesticides undergo a rigorous testing phase before they are made commercially available, the risk factors for Non-target ecosystems are not always fully understood. With newer pesticides appearing on the market to replace older ones, which have become less effective due to the development of resistance by pests, the risk for non-target species is also on the rise. A case in point is the recent study in France, which has implicated the new pesticide Imidacloprid (a Neonicotinoid insecticide) as the cause for the significant loss of bee colonies. Imidacloprid is found to be a safe pesticide due to its low toxicity among mammals and hence it is used extensively for pest control in big farms. While some studies report higher levels of the pesticide in pollens and nectar of the plants, others have failed to detect any residual levels of these chemicals or their metabolites. As Kimberly stoner, a Connecticut-based entomologist says, "the pesticide is put on the seed, and the plant takes in that pesticide and moves it through the vascular system of the plant" "Bees are potentially picking them up in pollen and nectar and low levels that don't kill the bees, but that might affect their behavior and immune system" [Susan Salisbury, 2008]
A study by Laurent and Rathahao (2003) analyzed the concentrations of Imidacloprid in sunflower plants that were grown from seeds treated with the pesticide. This study was prompted by reports of unusual bee behavior by colonies that fed on these Imidacloprid treated plants. Based on radioactivity measurements, the researchers found that the plants absorbed around 10% of the pesticide treated on the seeds. Of this, 75% of the radioactivity was noticed in the cotyledons. The study also showed that the radioactivity measurements were 20 times lesser in upper leaves compared with lower leaves. This study confirmed that seed treatment affected the entire plant due to vascular translocation of the pesticide indicating the potential for bee poisoning. [Laurent, 2003]
Other studies have also reported negative effects of Imidacloprid use on the memory and brain metabolism in honeybees. Decourtye et.al (2003) showed that oral administration of Imidacloprid affected the olfactory responses of honeybees in a 'proboscis extension reflex' test. When administered 15 minutes after a PER test, it was clear that Imidacloprid compromised medium term olfactory memory. Increase in levels of cytochrome oxidase indicated pesticide-induced changes in brain metabolism and changes in neuronal transmission. [Decourtye et.al (2003)]
Gm crops and Bio pesticides
GM farming is considerably developed particularly in the United States and South American countries. GM crops that have built in pesticides are generally thought to be environmentally friendly, as they do not require the usual treatment with toxic pesticides. However, these genetically modified crops that are programmed to selectively express genes that produce peptides that have insecticidal properties could be toxic to honeybees. Since commercial production of GM crops is already a practice in many farms, studies that assess the impact of the ingestion of pollens or nectar of such genetically modified crops on bee health acquire significance. Malone et.al (2000) is one such study. This research studied the bees foraging on transgenic crops and the effects on their gut physiology, olfactory memory and longevity. In particular the effect of 'protease inhibitors', 'chitinase,' 'glucanase' and 'biotin-binding protein genes' were observed. The study concluded on a cautionary note that the biological effect of the transgenic material would depend on their type and the quantity of ingestion. Besides GM, plants are a perennial source of insecticidal proteins (expressed in their pollens and leaves) the effects of which have to be studied further. However, the results from this study showed that transgenic insecticidal proteins were much less toxic to bees and other mammals when compared to the standard industrial chemicals. [Malone A, 2001] At the moment though, there is not much research evidence to implicate GM crops induced toxicity in the chronic collapse disorder of bees.
The Changing Bee culture
The beekeeping culture has changed dramatically over the last few decades. Colonies are transported from one place to other; queen bees are artificially bred and developed. Bees are fed with huge quantities of corn syrup with little concern about their digestive metabolism. In the opinion of some researchers, commercial lease of bee colonies for pollination purposes involving frequent transporting and shifting of the bees to distant and unfamiliar locations puts considerable stress on bees. The U.S. Department of agriculture reported that, "The number of managed honey bee colonies has dropped from 5 million in the 1940s to only 2.5 million today. At the same time, the need for bee hives to supply pollination services has continued to climb. This means honey bee colonies are trucked farther and more often than ever before." Entomologists argue that many crop varieties cause nutritional stress on bees and it is indispensable that bees are fed on high quality pollens to restore their nutritional balance. So the practice of translocation bees and limiting their foraging patterns to one particular crop may create severe nutritional problems. [Benjamin P. Oldroyd, 2007]
Some researchers also opine that the lack of genetic variation among the commercially bred honeybee colonies makes them very susceptible to pathogenic infections. There are also concerns that the introduction of foreign honeybees into our country exposes them to newer environmental conditions for which they are not genetically prepared. This increases their vulnerability to local pathogens. [Benjamin P. Oldroyd, 2007]
Integrated Pest management (The Best Solution)
Pesticide usage is not a perfect and environmentally friendly solution to pest problem. Also, honeybee keepers are cautioned against the use of pesticides during the honey-producing season during which time the V Destructor population seems to rise significantly. These dangers as well as the limitations with the use of pesticides necessitate a more controlled and integrated approach to pest control. The integrated pest control approach includes a careful consideration of the life cycle of the pests along with judicious usage of pest control measures to obtain better pest control with least impact on the ecosystem. For instance, an integrated pest management approach in the honeybee colonies would be the control of the parasite V destructor.
A recent research studied combinations of factors such as the bee stock, Hive bottom board type and the use of folic acid in the control of the mite. For the study, the researchers used domestic as well as Russian Primorsky honey bees. Both the bees were tested in one coating of formic acid treated hives with screened bottom board and solid bottom boards. As a control measure, the bees were also provided with non-treated hives with screened as well as solid bottom boards. Results from the study revealed that the combination of Primorsky honey bees in screened bottom boards treated with formic acid had only half the number of V destructors when compared to the domestic bees. The use of Formic acid reduced the mite numbers in either type of boards. [Rinderer TE, 2003].
Another study pertaining to the Integrated pest management approach in bee colonies also focused on the control of Varroa Destructor in the farms in the north eastern United States. This study by Sustainable Agricultural research and Education (SARE), found that formic acid fumigation would bear optimum results when the bee colonies had fewer drone broods or were totally broodless. The study suggests beekeepers to remove drone brood before the fumigation process as the mites are mostly found in the brood cells when the colony has broods where they are much safer than when they are in adult hosts where they are the most susceptible. For the successful control of the pest by fumigation process, removal of drone broods is a necessary condition. [SARE
Loss of bees is a serious threat to our national agriculture and food supply. The mystery of the honeybee vanishing remains a largely unsolved puzzle. Thus far, no single cause has been established for the Colony collapse disorder and scientists are beginning to approach the problem as a multifactorial symptom. A conjunction of factors are strongly suspected in the sudden disappearance of bees. These include the infestation by pests, the toxic effect of pesticides, Viral attacks (IAPV, DWV, etc.), stress induced by frequent translocation of bees for commercial pollination services, etc. Environmentally sustainable agricultural practice is the only way to arrest such catastrophical developments in the future. Pesticides not only incur considerable costs but also affect the natural purity of the Hive products. They also increase the risk of toxicity from the consumers' perspective. But most importantly, the indiscriminate and systemic use of pesticides threaten to destroy the keystone species -- the honeybee that controls our agricultural economy. Albert…