Pre-harvest rindstain of ‘Encore’ mandarin: initial histological signs of epicarp disturbance and extent of the disorder

Abstract

Pre-harvest rindstain in 'Encore' mandarin starts by the injury of a few epidermal cells. The connection between the damaged epidermis and the collapsed layers of flavedo, extending in parallel with rind surface was only visible on cross-sections containing the narrow zone of injured epidermal cells. The individual cell alteration including loss of membrane integrity and the accumulation of large amounts of osmiophilic materials in the cytoplasm are the result of a degrading process. Minute disruptions in the cuticle may provide shelters for resting forms of amoeboid or plasmodial-like organisms living on the rind. Our results suggest that these organisms could be involved in the disorder expression.

Biotic and Abiotic Factors Causing Rind Blemishes in Citrus and Management Strategies to Improve the Cosmetic Quality of Fruits

“…"Encor" disease is reported in mandarin group where Note: Some symptoms are combination of more than one causes, however these are often tagged with the predominate cause injury starts by the development of pre-harvest rind stains in few epidermal cells also known as initial spotted zones of rind which may develop as disorder of fruit. In later stages of stain development, disruption in rind of the fruit provides habitat for amoeboid like microorganisms resulting in the expressions of chlorotic disorders Maia et al 2004). Similarly, citrus orchards especially grapefruit are susceptible to greasy spot (rind blotch) caused by Mycosphaerella citri, which also downgrades quality of fruit.…”

“…Internationally, huge resources are spent for managing causal organisms of citrus peel blemishes (Agostini et al 2003;Maia et al 2004) and to improve fruit quality. Experimental success does not always lead to commercial solution, since the field conditions and complexity of issues greatly varies.…”