Articles
Investigating the effect of three biological compounds against slow decline disease of citrus in southern Iran
Article number
1448_66
Pages
523 – 530
Language
English
Abstract
Citrus decline is considered one of the most significant diseases of citrus-growing areas in the southern part of Iran.
Both biotic factors (e.g., Tylenchulus semipenetrans, Phytophthora spp., Candidatus Liberibacter asiaticus) and abiotic factors (e.g., drought, salinity, and heat stress) have been identified as causative agents of this disease in Iran.
In affected trees, a heavy loss of capillary roots was observed which resulted in disrupting the absorption of water and nutrients.
This research aimed to mitigate symptoms and improve the health of citrus trees suffering from root decay using two groups of biological compounds, fungal and bacterial base.
The commercial fungal based compounds used in this study, were including Rhizophagus intraradices (as a arbuscular mycorrhiza at the rate of 1500 g tree‑1) and Trichoderma harzianum (as an antagonist, at the rate of 30 mL tree‑1). The commercial fertilizer of bacterial based compounds included Pseudomonas fluorescens plus Bacillus subtilis at the rate of 300 mL tree‑1. Before any treatment, the association of citrus nematode (T. semipenetrans), the fungus-like of Phytophthora, Fusarium, and the citrus greening agent Liberibacter, were confirmed in symptomatic trees.
The target compounds were applied in soil either alone or in combination.
The results were recorded at 3, 6, 9, and 12-months post-treatment using a scoring system.
The results showed that all three biological compounds had a positive effect on improving the root system and mitigation of tree to produce fresh young branches.
Among these, the compound containing Bacillus and Pseudomonas bacteria was particularly more effective in controlling root decay than the others.
The combined application of all three treatments had the most significant effect in reducing the decline rate.
It can be concluded that application of mentioned bio-fertilizers will positively reduce the citrus decline disease.
Both biotic factors (e.g., Tylenchulus semipenetrans, Phytophthora spp., Candidatus Liberibacter asiaticus) and abiotic factors (e.g., drought, salinity, and heat stress) have been identified as causative agents of this disease in Iran.
In affected trees, a heavy loss of capillary roots was observed which resulted in disrupting the absorption of water and nutrients.
This research aimed to mitigate symptoms and improve the health of citrus trees suffering from root decay using two groups of biological compounds, fungal and bacterial base.
The commercial fungal based compounds used in this study, were including Rhizophagus intraradices (as a arbuscular mycorrhiza at the rate of 1500 g tree‑1) and Trichoderma harzianum (as an antagonist, at the rate of 30 mL tree‑1). The commercial fertilizer of bacterial based compounds included Pseudomonas fluorescens plus Bacillus subtilis at the rate of 300 mL tree‑1. Before any treatment, the association of citrus nematode (T. semipenetrans), the fungus-like of Phytophthora, Fusarium, and the citrus greening agent Liberibacter, were confirmed in symptomatic trees.
The target compounds were applied in soil either alone or in combination.
The results were recorded at 3, 6, 9, and 12-months post-treatment using a scoring system.
The results showed that all three biological compounds had a positive effect on improving the root system and mitigation of tree to produce fresh young branches.
Among these, the compound containing Bacillus and Pseudomonas bacteria was particularly more effective in controlling root decay than the others.
The combined application of all three treatments had the most significant effect in reducing the decline rate.
It can be concluded that application of mentioned bio-fertilizers will positively reduce the citrus decline disease.
Publication
Authors
L. Ilkhan, M. Najafiniya, H. Rahimzade Behzadi, A. Abbasi, M. Nadi
Keywords
bio-fertilizer, citrus decline, root rot, biotic, abiotic, stress
Groups involved
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