A study undertaken by the Royal Horticultural Society has found that organic slug pellets are almost as effective in controlling gastropods as synthetic alternatives, as well as some surprising news about mulch.
After only a year into the two year study, the RHS has published preliminary findings that champion the use of organic controls for slugs and snails but also controversially found that mulch can actually encourage these pests in certain circumstances.
The study used daffodils, hostas, lettuces and beans to tests the efficacy of various controls for slugs and snails. Early findings found that synthetic pellets performed best overall, but that organic pellets were a very close second. The news is simple – organics will perform very nearly as well as potentially harsh chemical alternatives. In the hostas’ case, organic pellets actually outperformed synthetics.
BASF, a large chemical company out of Germany, funded the study to test the efficacy of nematodes to control slugs and snails (they sell a nematode to control snails and slugs in the EU and UK), but the results thus far have been a tad murky as to nematodes’ effectiveness when combined with other cultural practices.
When applied preventatively, beneficial nematodes were found to be a good control of slugs with daffodils, but only intermediately effective on lettuces. The murkiness comes in when nematodes were combined with mulch, they were less effective on hostas and beans.
The effects were a surprise to leading RHS scientist Dr Haley Jones, who said:
“The data gathered so far shows some interesting complexities, the most notable being the increase in damage caused by the mulch on some plants. The high levels of slug and snail damage found on the plants protected by mulch was unexpected, especially as many mulches are billed as being repellent to slugs and snails. It is possible that the negative impact of the mulch affected the effectiveness of the other control treatments when they were combined.”
In the second year of the study the RHS hopes to get to the bottom of effects they’ve seen with increased damage when using certain mulches. We wait with (organic) baited breath for the results!
Check out the RHS website for more about the study and these early results.