Chemical fruit thinning in loquat with NAAm:: dosage, timing, and wetting agent effects

Fruit size is essential for loquat profitability. However, loquat often set too heavily making fruit thinning mandatory. Loquat is usually thinned by hand in February, but this practice is expensive and of limited usefulness due to its late execution. Here, we report the results from a three year study that supports the alternative procedure of chemical thinning with the amide of naphthaleneacetic acid (NAAm). NAAm at doses of 30 and 60 mg l(-1) applied at the end of bloom produced an average increase of fruit diameter of 11 and 18%, respectively. Fruit size increase led to improved grading. Fruit earliness was also improved enabling earlier harvest. Total yield was only slightly diminished by NAAm. The major shortcoming of NAAm treatment was a variable thinning rate within the trees.