Effect of postharvest dipping in insecticides on the vase life of Geraldton waxflower

Abstract

In postharvest dipping treatment of Geraldton waxflower (Chamelaucium uncinatum), 13 insecticides tested at recommended application rates caused no visual injury, but some reduced vase life. Flowers of cv. Purple Pride were more sensitive to insecticides than leaves. There was no loss of vase life of flowers following dipping in chlorpyrifos, dimethoate or permethrin. Following dipping in deltamethrin, carbaryl, dichlorvos, cypermethrin, endosulfan or fenvalerate there was 31-49% loss of vase life. No loss of vase life was observed for cv. Alba, after dipping in carbaryl, fenvalerate or dimethoate. Insecticide dips containing wetting agent and a fungicide (e.g. a combination of deltamenthrin, Aqua and benomyl) was a suitable dip for Geraldton waxflower. Wetting agents varied in their effect on vase life. Aqua shortened vase life less than Agral, and D-CTrate less than D-C-Tron. Stems rapidly lost weight when held out of water following dipping, and vase life was reduced when ambient temperatures were above 30¦C or drying times exceeded 60 min. It was concluded that flowers should be kept cool and well hydrated following dipping treatment.