Wild and managed bees face many threats including agricultural intensification and the increasing use of pesticides. Researchers in the United States of America conducted a multi-year experiment in Indiana to compare a conventional insecticide program with an integrated pest management (IPM) system which used scouting and pest thresholds to determine if and when insecticides were required.
The researchers established fields of pollinator-dependent watermelon surrounded by corn to simulate conditions typical for their region. They compared the performance of managed pollinators (honeybees (Apis mellifera) and the common eastern bumblebee (Bombus impatiens)), along with the abundance and diversity of wild pollinators.
They found that integrated pest management led to higher growth, with the weight gain of honeybee colonies being 80% higher, and capped brood being 132% higher. They also found lower mortality of managed bees, with 57% of colonies under IMP successfully overwintering compared to only 10% of colonies from the conventionally treated fields. They also found that the integrated pest management resulted in higher wild pollinator abundance and richness species.
The researchers conclude that conventional pest management has a negative effect on the health of managed bees and the abundance and diversity of wild pollinators.
Read the full paper:
Pecenka, J.R., Ingwell, L.L., Krupke, C.H., & Kaplan, I. 2023. Implementing IPM in crop management simultaneously improves the health of managed bees and enhances the diversity of wild pollinator communities. Scientific Reports. 7;13(1):11033. doi: 10.1038/s41598-023-38053-5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10328965/