The use of ethephon to promote uniform harvest drop of mature macadamia nuts in south-east Queensland

Abstract

Trials were carried out in 1982-83 on cultivars Keauhou, Kakea and Own Choice. Ethephon at 200 mg/litre + Plus 50 wetting agent at 0.25 ml/litre led to >90% of the nuts dropping within 14 days with Keauhou and Kakea. The response by Own Choice was more variable. Increasing the wetting agent concentration to 0.5 mg/litre enhanced ethephon effectiveness. Applying 200 mg/litre ethephon to Keauhou and Kakea to achieve a single harvest is considered economic. With Own Choice, inexpensive additives which significantly increase the effectiveness of ethephon are required before its use can be recommended. Leaf drop was not excessive with any of the treatments used.