Spraying of Pesticides to agricultural plantation. Source from Global Water Partnership, flickr.
Pesticides and fungicides, which are mostly man-made chemicals, are commonly used to eradicate or control the plants pests (rodents and insects) and fungi (mold), which are deemed to be harmful and affecting the health of the plants. This is so as to reduce the damage on the crops and livestock, and to increase farm productivity. It is estimated that about 5.2 billion pounds of pesticides are used worldwide annually (United States Environmental Protection Agency, 2011).
Scientists also estimated that only about 0.1% of the pesticides used reaches its targeted victims whereas the leftovers of 99.9% of the pesticides becomes residues in the environment. The residue that is left in the plants and the environment then contaminates the nectar and pollen that the honey bees collects. The dosage of these pesticides has been found not to be lethal to the honey bees. However, research has suggested that it changes and impairs the behaviours of the bees such as interference in foraging patterns and feed behaviours.
A warning sign for pesticides usage. Source from CPG Grey, flickr.
An experiment conducted to simulate exposure to pesticides to bees have shown to caused a 100% mortality rate in bees and many of the bees dies in the nesting box or failure to return to the hives.
The use of pesticides in the agricultural as well as in urban areas might be one of the leading causes in contributing to CCD. In addition, it also has other harmful environmental impacts, such as the loss of biodiversity and elimination of key species (e.g. bees and butterflies), water pollution as well as soil contamination.