Another natural option from the gardening section
Spinosad (and its successor spinetoram) is a biological pesticide, based on chemical compounds found in the fermentation of a soil bacteria called Sac char opolysp ora spinosa. It works by affecting the nervous system of the red mite at several stages of its lifecycle, described as ‘over-exciting’ it to death.
A study by Newcastle University sprayed spinosad and found a rate of 4g/litre was effective. It also found: • residual toxicity was maintained throughout the 28-day period; • peak efficacy came 14 days after spraying; • there was no effect on hen bodyweight or egg production.
The results also suggested the bigger the infestation, the more toxic the effect of spinosad. While the reasons for this were unclear, the scientists in this study speculated that conspecifics (naturally-occurring species that are very similar to spinosad) spread the product more efficiently when mite populations were higher. However, more research would be required to know exactly why this was the case.
About spinosad & spinetoram
Spinosad was the original ingredient test, but it has been surpassed by spinetoram. Spinetoram is so chemically close to spinosad, it is considered toxicologically to be the same. Both products are used in organic farming operations in countries around the world for the control of certain insect species, including mites, on plants. Note: spinosad/spinetoram is toxic to bees and fish.