Evaluation of pre-harvest applications of host defence elicitors against Botrytis infecting waxflower postharvest
S.Q. Dinh, D.C. Joyce, D.E. Irving, A.H. Wearing
Program and Abstract. 2007 Australasian Postharvest Conference. Crowne Plaza Terrigal, NSW, Australia. 12 September 2007. 87 p.
2007
บทคัดย่อ
Known host defence elicitors [e.g., methyl jasmonate (MeJA), benzothiadiazole (BTH), silicon (Si)] have demonstrated efficacy against fungal pathogens of various plant species. Botrytis cinerea causes flower abscission and grey mould disease on harvested Geraldton waxflower (Chamelaucium uncinatum). The efficacy of these elicitors against Botrytis on waxflower was evaluated. They were sprayed separately onto field-grown plants of cvs. Mullering Brook and My Sweet Sixteen at various concentrations (0, 500, 750, 1000 µM MeJA; 0, 50, 100, 150 mg BTH/L; 0, 500, 1000, 1500 mg Si02/L) and timings (once at 10 and 6 d before harvest or twice at 10 + 5 d and 6 + 3 d before harvest for the two cvv, respectively) of application. Harvested flower stems were either left uninoculated or inoculated with Botrytis spores. Disease severity and flower fall were recorded during subsequent incubation at 20°C and 95-100% RH. Stem vase life, relative fresh weight and vase water usage were also recorded during vase life evaluation at 20°C. BTH and Si treatments generally did not reduce either grey mould disease severity or flower abscission on either cultivar. Similarly, MeJA had no significant (P>0.05) effects on disease severity on Mullering Brook. However, pre-harvest spray treatments with MeJA at 500 and 750 µM significantly (P<0.05), but only slightly, reduced Botrytis on My Sweet Sixteen. No elicitor treatment reduced flower fall on either cultivar. Moreover, pre-harvest spray applications of MeJA, BTH and Si had little or no positive effects on cut-flower stem vase life, relative fresh weight and water usage.