Abstract
BackgroundFoot rot/gummosis of citrus, caused by Phytophthora spp., is the most important disease of citrus, responsible for the yield losses of 10 to 30% in fruit production in major citrus growing countries. Considering the burden of disease, the present study was undertaken to evaluate different native potent strains of Trichoderma spp. against the foot rot/gummosis of citrus.ResultsBased on molecular characteristics, i.e., ITS ribosomal DNA sequence analysis, 3 isolates of Phytophthora nicotianae var. parasitica and 7 isolates of Trichoderma (6 isolates of T. asperellum and one of T. harzianum) were identified. Trichoderma isolates and Metalaxyl-M + Mancozeb were used to assess antagonistic activity against the foot rot/gummosis under field conditions. T. asperellum T20 mutant reduced gummosis lesion size (95.67%), improved feeder root density (0.0236 cm3), increased number (990.16), and yield of fruits (168.83 kg).ConclusionsThe talc-based bioformulation of T20 mutant (T. asperellum) strain, used as a soil treatment, was able to manage effectively the gummosis/foot rot of citrus and also exhibited the highest yield.
Highlights
Foot rot/gummosis of citrus, caused by Phytophthora spp., is the most important disease of citrus, responsible for the yield losses of 10 to 30% in fruit production in major citrus growing countries
Genus-specific primers viz. Ph2 and ITS4 hybridized for all isolates of Phytophthora gave a single band of 700 bp and species-specific primers viz. Pn5B and Pn6 gave a single band of 120 bp (Fig. 1)
Results obtained from molecular characterization confirmed that P1, P2, and P3 isolates of Phytophthora were P. parasitica var. nicotianae
Summary
Foot rot/gummosis of citrus, caused by Phytophthora spp., is the most important disease of citrus, responsible for the yield losses of 10 to 30% in fruit production in major citrus growing countries. Citrus is one of the most economic groups of horticulture crops worldwide and the second-largest fruit crop grown in over more than 50 countries commercially under different agro-climatic conditions (Naqvi 2003). Foot rot/gummosis in citrus, caused by Phytophthora spp., is a serious and common disease and is responsible for significant economic losses. It attacks citrus species in nursery beds causing damping-off to fibrous root rot, crown rot, premature leaf fall, foot rot, and gummosis in mature orchards and infects almost every part of citrus plants (Shekari et al 2012). Foot rot/gummosis of citrus has been managed by chemical treatment but chemical control causes an imbalance in the microbial community, destroys the activity of beneficial microorganisms, causes chemical environmental pollution, toxicity in foods, and development of resistance in the pathogens
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