Effect of pre-harvest calcium chloride applications on fruit calcium level and post-harvest anthracnose disease of papaya

Abstract

Anthracnose disease of papaya, caused by Colletotrichum gloeosporioides Penz, can cause extensive postharvest losses. The goal of this research was to use pre-harvest calcium applications to reduce anthracnose disease. Six pre-harvest foliar calcium sprays were applied biweekly to papaya trees in experimental orchards at Universiti Putra Malaysia. Additional in vitro and in vivo tests were carried out to test the effect of calcium on fruit calcium content, spore germination, mycelial growth and disease severity. Calcium chloride at 1%, 1.5% and 2.0% concentrations significantly decreased spore germination. Calcium content of papaya fruit was significantly increased by calcium sprays at a concentration of 2.0% in 2012 and 2013. In vivo studies showed that increasing calcium content in fruit by calcium sprays at 1.5 and 2.0% concentrations significantly reduced anthracnose incidence of fruits during five weeks storage at 12 ± 2 °C, and delayed initiation of disease symptoms by four weeks.

Effect of calcium salts on postharvest fungal pathogens in vitro

“…In this experiment, only the calcium salts at 2% concentration reduced mycelial growth of all tested pathogens, relative to the control. Our results are in agreement with those of other researchers who demonstrated that the fungal isolates grew similarly or stimulated in the presence of calcium salts compared to the control (Biggs, 2004;Madani et al, 2014). Tian et al (2002) recorded that calcium chloride at 2% inhibited the growth of R. stolonifer, although calcium chloride was tolerated by A. alternata and P. expansum in vitro where their growth was highly affected only at 6% concentration (Maouni et al, 2007).…”

“…Also, there are few reports about effects of calcium salts on infection of tropical fruits by Colletotrichum spp. (Chillet et al, 2000;Mahmud et al, 2008;Madani et al, 2014). The ability of calcium to reduce the development of postharvest diseases of fruit has been attributed mainly to the formation of calcium cross-linkages in the cell wall, resulting in decreased effectiveness of cell wall-macerating enzymes secreted by the pathogen (Conway et al, 1988).…”

Bioactive compounds and antioxidant activity of papaya inoculated withColletotrichum gloeosporioidesas affected by hot water-calcium chloride

“…In this regard, consumer trends are focused to fungicide-free and high-quality commodities (Sharma, Singh, & Pal, 2013), and many synthetic chemicals used to preserve the postharvest fruit quality have been restricted in some countries (Chávez-Sánchez, Carrillo-López, Vega-García, & Yahia, 2013;Sharma, Singh, & Pal, 2013). Consequently, alternatives to the application of chemical fungicides are required to protect fruit during postharvest (Madani et al, 2014). In this regard, it must be considered that fruit quality includes factors such as visual appearance, absence of diseases caused by biotic and abiotic agents, and the composition of nutrients and other bioactive compounds; thus, adequate technologies must be employed to reach the best quality of fruit (Sogi, Siddiq, Roidoung, & Dolan, 2012).…”

Quality of ‘Isabel’ grape treated pre-harvest with CaCl2 and citrus biomass-based elicitor

“…The pre-harvest application of calcium chloride promotes the strengthening of the cell wall of the fruit, providing greater resistance to the tissues, reducing, in addition to the fresh weight loss, the incidence of diseases in postharvest, being these responses closely related to increased calcium concentration in tissues (MADANI et al, 2014). 'Isabel' grapes treated postharvest with CaCl 2 under ambient and modified atmospheres showed reduced fresh weight loss .…”