Mycorrhizal fungi and Trichoderma harzianum as biocontrol agents for suppression of Rhizoctonia solani damping-off disease of tomato.
The objective of the present work was to examine the interaction between arbuscular mycorrhizal fungus (AMF) Glomus intraradices and Trichoderma harzianum in soil. Soil application with T. harzianum or/and G. intraradices significantly reduced tomato seedlings damping-off incited by Rhizoctonia solani. Moreover, more pronounced disease suppression was obtained when both bioagents were applied together. Application of T. harzianum to healthy or inoculated seedlings significantly increased phosphorous supply, which resulted in higher yield, associated with the accumulation of high phosphorus levels in tissues of tomato plants (4.7- 6.5-fold), compared with low P supply. Inoculation with both bioagents in the presence or absence of the pathogen gave significant rise (2.1 - 2.2-fold), compared with low P levels. Root length of inoculated plants treated with T. harzianum or G. intraradices appeared longer than those of inoculated untreated plants at all P levels. Phosphorus uptake (mg P/plant) of tomato plant increased in all treatments with increasing of P levels with R. solani, T. harzianum or their combination and untreated plants have vigorous response to phosphorus fertilization. At low P levels, there was a significant difference between treatments, P uptake of tomato plants inoculated with AMF, T. harzianum or in combination, either in absence or in the presence of the tested pathogen showed highly significant increase, compared to untreated plant, infected plants with pathogen, T. harzianum, and their mixture. At high P levels, there was no significant difference between control and both AMF and T. harzianum, either individually in health plants or in combination with the pathogen. Eventually, results presented here substantiate other studies reporting enhanced biocontrol performance.
Amer
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Agricultural Botany Department, Faculty of Agriculture (Saba-Basha), Alexandria University, P.O. Box 21531 Bolkley, Alexandria, Egypt.
Abou-El-Seoud
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D018551:Solanum lycopersicum / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D038821:Mycorrhizae / Q000502:physiology*; D010572:Pest Control, Biological / Q000379:methods*; D010758:Phosphorus / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000254:growth & development / Q000382:microbiology; D012232:Rhizoctonia / Q000254:growth & development*; D012988:Soil Microbiology; D014242:Trichoderma / Q000502:physiology*
D010758:Phosphorus