Pelagonic acid (60% a.i v/v) is registered in the USA as a blossom thinner under the trade name of ‘Thinex’.
- Trials in the USA have shown it to have some useful activity as a blossom thinner (Williams, 1994).
- However, in trials conducted at East Malling and by researchers in Holland the product performed poorly as a blossom thinner and caused significant phytotoxicity to spur leaves (Webster, and Spencer, 1999; Webster and Spencer, 2000).
- In the East Malling trials, rates of 750-3000 ppm were compared in high volume sprays to the varieties Royal Gala and Queen Cox. Phytotoxicity and variable responses have also been observed in USA trials with this product (Andrews and Collier, 1995).
- Pelargonic acid seems to offer little promise as a flower thinner in UK climatic conditions.
- Pelargonic acid is not approved currently for use as a flower thinner in UK orchards.