Controversy has emerged from recent publications pointing out at possible linkages between neonicotinoid insecticides and honey bee die-offs. Here we would like to comment on our current position on the use of neonicotinoids in blueberries and cranberries in New Jersey. First, we need to mention that in general neonicotinoids are highly toxic to honey bees and native bees, and caution needs to be taken when using these insecticides. However, based on the information available so far, we advise growers not to blame bee colony declines and Colony Collapse Disorder (CCD) solely on neonicotinoids. Most researchers agree that the current bee situation is likely caused by a variety of stress factors, including pesticides (insecticides and fungicides), diseases (parasites and pathogens), malnutrition, migratory beekeeping, among other. Thus, it is likely that CCD is due to a combination of these factors.
Neonicotinoids are systemic insecticides, and thus the possibility exists to find residues in the pollen and nectar. These residues can reach lethal or sub-lethal concentrations under certain circumstances. Neonicotinoids can also persist in the soil for months or years after an application. However, this is strongly influenced by the rate and timing of application. Growers also need to be aware that not all neonicotinoids are equal. For instance, acetamiprid (Assail) is considered safer to non-target beneficials than other neonicotinoids. For blueberries and cranberries, we recommend not to use neonicotinoid insecticides pre-bloom and never use them during bloom. Neonicotinoids are only recommended post-bloom, i.e., after removal of honey bees. For example, applications of the neonicotinoids thiamethoxam, imidacloprid and acetamiprid for aphid (blueberries), grub (blueberries and cranberries), and leafhopper (blueberries and cranberries) control can be made only post-bloom.