AllanfromWales1 t1_ivs3pmg wrote on November 10, 2022 at 4:53 AM

It would be helpful if the summary of the study could make clearer which fertilisers are considered a problem. Clearly this does not apply to all fertilisers. The summary refers to 'synthetic fertilisers and herbicides'. That herbicides are harmful to bees is pretty much a given, but it's unclear (to me) which types of fertilisers this applies to.

DomesticApe23 t1_ivsnfi4 wrote on November 10, 2022 at 8:59 AM

Why would herbicides being harmful to bees be a given?

DomesticApe23 t1_ivso0zg wrote on November 10, 2022 at 9:07 AM

The most commonly applied fertilizers in horticulture, gardening and increasingly agriculture are compound fluid fertilizers composed of a mixture of nitrogen (N2), Phosphorus Pentoxide (P2O5), Potassium Oxide (K2O), in which N:P:K ratios can differ depending on purpose. Throughout this study, we used a commercially available compound fluid fertilizer (Nitrogen, Phosphorus Pentoxide, Potassium Oxide, 10.6:4.4:1.7; Bayer, Leverkusen, Germany) following manufactures instructions (5mL/L). Neonicotinoid insecticide imidacloprid (99.7% purity, CAS Number: 138261-41-3) purchased from Sigma-Aldrich (Zwijndrecht, The Netherlands). Nominal concentration of imidacloprid was 3.5 μg/L dissolved in demineralized water in glass bottles (Solubility: 610 mg/l H2O at 20 °C). Throughout the study, chemical were applied using a single spray with a commercially available gardening spray bottle.