EFFECT OF COMMERCIAL FUNGICIDES AND POSTHARVEST TREATMENT WITH CALCIUM ON BOTRYTIS CINEREA OF GERALDTON WAXFLOWER.

A range of commercial fungicides was tested in vitro for efficacy against Botrytis cinerea Pers. as part of a larger project investigating causes of postharvest flower fall in Geraldton waxflower (Chamelaucium uncinatum Schauer.). Another part of the study examined the potential for control of fungal decay by postharvest treatment of flowering stems with calcium.

All 10 fungicides tested showed activity, compared to the control, against three isolates of B. cinerea from waxflower flowers when supplied in vitro at concentrations based on recommended application rates.
Mycelial growth was reduced least by copper oxychloride, and to a greater extent by mancozeb and chlorothalonil.
Iprodione, benomyl, procymidone, vinclozolin, flusilazole, propiconizole and dichlofluanid effectively prevented growth of mycelium.

Calcium (as CaCl₂.2H₂O) applied as a postharvest dip (25, 50, 100, and 200 mM for 30 sec) was ineffective in reducing the severity of fungal decay during simulated handling.
A water dip gave similar results to treatment with calcium, whereas iprodione dip reduced decay, flower abscission and ethylene levels in the package.
Calcium was also applied as a pulse via the cut stem (1, 5, 10, 25, and 50 mM for 48 hr). Neither disease nor flower fall were reduced when compared with a water control during subsequent simulated handling by calcium pulsing of either naturally infected or inoculated (post-pulsing) stems.

New Ornamental Crops and the Market for Floricultural Products

A.H. Wearing, D.C. Joyce, L. Toovey, U. Kumcha, S.E. Hetherington

Botrytis cinerea, calcium, Chamelaucium uncinatum, fungicides, Geraldton waxflower, postharvest

https://doi.org/10.17660/ActaHortic.1995.397.17