A group of Israeli bee experts has gone to the US to study the reasons for the mysterious reduction in that country's bee population, which threaten to affect Israeli bees as well. Yoram Paz, director of an Emek Hefer beehive company, said there were already worrying signs that the problem had begun to reduce honey and fruit production here. A drop of between 70 percent and 90% in the bee population has been reported in parts of the US, Brazil, Central America, Germany, Italy, Poland, Spain and Portugal in the past few years. In Israel, too, there has been a decline in honey production, although it is not as severe as abroad. Bees are also needed for pollination of avocado, almond, cherry, apricot, plum, apple, pear and mango trees; without bees to transfer pollen from one flower to another, the production of fruit would be severely hampered, Paz said. Experts have already given an official name to the phenomenon, in which whole colonies of bees have disappeared - "Colony Collapse Disorder" - but there is no agreement on exactly what factors cause it. Among the theories are that electromagnetic radiation from cellphone systems, global warming, unknown viruses or changes in the bees' diet have done them in.