Pesticides linked to decline of bees needed for crop diversity: Experts

Kolkata: Widespread use of pesticides for enhanced crop yields has led to the decline of pollinators such as honey bees which are needed for increase in yields and quality of 84 per cent of the crops grown for human consumption, experts said here on Saturday.

"Because of pesticides most pollinators, including wild bees, are dying. We don't have enough pollinators. We need to protect their nesting sites, food plants and nectar plants and without that crop diversity would be affected," Renee M. Borges, Professor, Centre for Ecological Sciences, Indian Institute of Science, Bangalore said here.

Explaining the linkages of pollinator population with food security, she said: "Micro-nutrient diversity, especially in a largely vegetarian population as exists in many parts of Asia, requires crop diversity, not just rice and wheat. 

"Crop diversity is directly linked with pollinator diversity. We can get rice and wheat which are wind pollinated but vegetables, spices, horticulture, apples, peaches, strawberries, even tomatoes require pollinators."

Coupled with the pesticide use, the other factors leading to the reduction in numbers of pollinators are the destruction of nesting habitats for wild pollinators due to intensification of agriculture worldwide and alteration of cropping patterns and land use practices leading to loss of adult and juvenile food resources for pollinators, she said.

According to V.P. Uniyal, a senior entomologist with the Wildlife Institute of India, who is documenting pollinators in the Himalayan landscape, bees are key ecosystem service providers.

"A decrease has been described from crop lands. Some 84 per cent of the crops grown for human consumption need bees or other insects to pollinate them to increase their yields and quality," he said quoting a Food and Agricultural Organisation statistic.

Although, introduction of pollinators is going in a "limited way" in some parts of India, Borges said more studies are needed to document the status of pollinators.

"We hope to do state-wide studies," she added.