Seed giant Monsanto Co.'s $45bn unsolicited takeover bid with Switzerland's Syngenta AG, the world's largest producer of agricultural chemicals, has sparked opposition across the globe.Together they would control one-third of the globe's seeds and pesticides market.Today, six American and European companies - Monsanto, Dupont, Syngenta, Dow, Bayer and BASF - control the entire genetically-modified seeds planted in the world. More than three decades ago there were thousands of seed manufacturers, none controlled more than 1 percent of the market.Seeds aside, a real concern for many, is that one of the chemicals in Monsanto's flagship weed killer was, according to the World Health Organization "probably carcinogenic". In various parts of the world Monsanto's Roundup weed killer that contains glyphosate has been banned.Al Jazeera's Minelle Fernandez reports from Sri Lanka, where glyphosate is already banned.The European Union has banned other chemicals known as neonicotinoids in pesticides because they have been linked to serious harm to bees. Bees are essential for crops, but pesticides, loss of habitat and disease are bringing down their numbers. What are the effects of agricultural pesticides on the environment and human health? Are seed and fertiliser makers killing biodiversity?Dominic Kane reports from Germany on the impact of neonicotinoids on bees; and Gergely Simon, the regional toxic expert at Greenpeace, joins us to discuss the impact of pesticides, genetically-modified foods, and who is killing the bees.