Current Status and Future Prospects of White Root Rot Management in Pear Orchards: A Review

Abstract

The current social demand for organic, sustainable, and eco-friendly approaches for farming, while ensuring the health and productivity of crops is increasing rapidly. Biocontrol agents are applied to crops to ensure biological control of plant pathogens. Research on the biological control of white root rot disease caused by a soil-borne pathogen, Rosellinia necatrix, is limited in pears compared to that in apple and avocado. This pathogenic fungus has an extensive host range, and symptoms of this disease include rotting of roots, yellowing and falling of leaves, wilting, and finally tree death. The severity of the disease caused by R. necatrix , makes it the most harmful fungal pathogen infecting the economical fruit tree species, such as pears, and is one of the main limiting factors in pear farming, with devastating effects on plant health and yield. In addition to agronomic and cultural practices, growers use chemical treatments to control the disease. However, rising public concern about environmental pollution and harmful effects of chemicals in humans and animals has facilitated the search for novel and environmentally friendly disease control methods. This review will briefly summarize the current status of biocontrol agents, ecofriendly methods, and possible approaches to control disease in pear orchards.

Characterization of Bacillus velezensis RDA1 as a Biological Control Agent against White Root Rot Disease Caused by Rosellinia necatrix

“…R. necatrix , a causal agent of white root rot, is a devastating pathogen for which neither curative nor control methods are available. Several approaches have been used to control this pathogen, including soil solarization, soil fumigation [ 2 , 25 ], biological control using the antagonistic rhizobacteria [ 5 , 6 , 24 , 26 ], and the fungus Trichoderma harzianum [ 27 , 28 , 29 ]. However, no study has focused on the control of different strains of R. necatrix using a single bacterium.…”

“…Ex. Prill., is a necrotrophic phytopathogenic fungus that affects several important crops such as pears, cotton, avocados, nuts, apples, citruses, cherries, and mangoes [ 1 , 2 , 3 ]. Its host range, comprising more than 350 plant species, has been listed by the USDA-ARS (Fungal Databases, U.S. National Fungus Collections ( )), which is regularly updated as new hosts are discovered.…”

“…Its host range, comprising more than 350 plant species, has been listed by the USDA-ARS (Fungal Databases, U.S. National Fungus Collections ( )), which is regularly updated as new hosts are discovered. R. necatrix infects both the surfaces of roots and tissues under the bark, thereby damaging the established orchards and causing severe losses in the nursery [ 2 ]. White root rot disease affects fruit trees and causes canopy decline, leaf drop, wilting, and eventually death of the infected tree, it remains a major agricultural challenge worldwide [ 4 ].…”

“…Controlling the white root rot disease is difficult since R. necatrix can tolerate drought conditions and a wide range of soil pH, has a wide host range, and is resistant to common fungicides [ 7 ]. Multiple strategies have been applied to control R. necatrix , such as cultural control, soil disinfestation, and solarization [ 2 ]. For instance, in orchards, chemicals such as chloropicrin, carbendazim, fluazinam, benzimidazole, and carbendazim are used to control this pathogen [ 1 , 3 , 8 , 9 ].…”

Effect of host genotype on biocontrol of white root rot in Pyrus communis L. rootstocks by Trichoderma harzianum and Bacillus spp.

“…An important disease of pear is white root rot caused by the soil‐borne Ascomycete, Rosellinia necatrix Prill. ( Dematophora necatrix Hartig) (Sawant et al., 2021). The pathogen is found worldwide causing symptoms including rotting of roots, foliar chlorosis and wilting, which can be severe enough to result in plant death (Sawant et al., 2021).…”