Trichoderma harzianum
Control of Alternaria Spot Disease on Loquat (Eriobotrya japonica Lindl.) Using Detached Fruits and Leaf-disk Assay
Mon, 2014-01-27 13:33 — Yacoub A. M. BattaTreatments with four types of new, slightly toxic and non-residual fungicides and two preparations of Trichoderma harzianum were applied against Alternaria alternata, causal organism of Alternaria leaf and fruit spot disease of loquat. Preventive and curative effects of the above-mentioned treatments were bioassessed by measuring lesion diameter of A. alternata and its sporulation density on detached loquat fruits and leaf discs. Results indicated that preventive and curative effects of the treatment with difenoconazole (Score®) and cyprodinil+flodioxonil (Switch®) applied at a rate of 0.35% (V/V) and 0.20% (W/V), respectively, significantly reduced the lesion diameter of A. alternata on treated fruits and leaf discs compared to the untreated control fruits and leaf discs. Also, application of the above-mentioned fungicides at the same rates completely inhibited the sporulation of A. alternata at preventive and curative treatment with Switch® and at curative treatment with Score® on treated leaf discs compared to the untreated control organs. Conidia of T. harzianum (strain Th2) formulated in invert emulsion and applied at a concentration of 1.3X108 conidia/ml of the preparation, significantly suppressed lesion diameter of A. alternata and its sporulation density on treated fruits compared to treatment with conidial suspension of T. harzianum in sterile distilled water, and the control (blank formulation of invert emulsion or sterile distilled water only). These results should be confirmed under field conditions before large scale application.
Facebook
Google
LinkedIn
TwitterAlternaria Leaf Spot Disease on Cucumber: Susceptibility and Control Using Leaf Disk Assay
Mon, 2014-01-27 11:34 — Yacoub A. M. BattaResults obtained in the present research using leaf disk assay indicated significant differences in susceptibility of tested cucumber cultivars to Alternaria cucumerina-infection. Hasan cultivar was the most susceptible, but Rocket cultivar was the least susceptible. Assessment of treatment efficacy with fungicides and Trichoderma harzianum against the disease using leaf disk assay indicated the presence of significant differences between the treatments with 4 types of new, low-residual fungicides or 2 forms of T. harzianum and the control treatments with a blank formulation of invert emulsion or sterile distilled water. Treatments with fungicides just before the disease inoculation demonstrated that Score® and Switch® completely inhibited appearance of the disease-lesion on treated cucumber leaf-discs when applied at a rate of 0.35% (V/V) and 0.20% (W/V), respectively. Treatments with the same fungicides at the same application rates 24h after the disease inoculation also completely inhibited the disease-lesion appearance when Score® was applied. It suppressed the disease-lesion diameter to 2.5mm or reduced it by 83.5% relative to control when Switch® was applied. Moreover, application of formulated conidia of T. harzianum in invert emulsion at a concentration of 2.0X108 conidia/ml significantly suppressed the disease-lesion diameter on treated cucumber leaf-discs. Such application decreased the lesion diameter to 4.5 and 6.5mm or reduced it by 70.4 and 57.2% relative to control when used just before or 24h after the disease inoculation, respectively. It is, thus, concluded that the results obtained on susceptibility of cucumber cultivars to the disease infection and its control should be confirmed on whole plants under field conditions before being recommended to be applied by the farmers and extension agents.
Alternaria Leaf Spot Disease on Cucumber: Susceptibility and Control Using Leaf Disk Assay
Mon, 2014-01-27 11:34 — Yacoub A. M. BattaResults obtained in the present research using leaf disk assay indicated significant differences in susceptibility of tested cucumber cultivars to Alternaria cucumerina-infection. Hasan cultivar was the most susceptible, but Rocket cultivar was the least susceptible. Assessment of treatment efficacy with fungicides and Trichoderma harzianum against the disease using leaf disk assay indicated the presence of significant differences between the treatments with 4 types of new, low-residual fungicides or 2 forms of T. harzianum and the control treatments with a blank formulation of invert emulsion or sterile distilled water. Treatments with fungicides just before the disease inoculation demonstrated that Score® and Switch® completely inhibited appearance of the disease-lesion on treated cucumber leaf-discs when applied at a rate of 0.35% (V/V) and 0.20% (W/V), respectively. Treatments with the same fungicides at the same application rates 24h after the disease inoculation also completely inhibited the disease-lesion appearance when Score® was applied. It suppressed the disease-lesion diameter to 2.5mm or reduced it by 83.5% relative to control when Switch® was applied. Moreover, application of formulated conidia of T. harzianum in invert emulsion at a concentration of 2.0X108 conidia/ml significantly suppressed the disease-lesion diameter on treated cucumber leaf-discs. Such application decreased the lesion diameter to 4.5 and 6.5mm or reduced it by 70.4 and 57.2% relative to control when used just before or 24h after the disease inoculation, respectively. It is, thus, concluded that the results obtained on susceptibility of cucumber cultivars to the disease infection and its control should be confirmed on whole plants under field conditions before being recommended to be applied by the farmers and extension agents.
Postharvest Biological Control of Apple Gray Mold by Trichoderma Harzianum Rifai Formulated in an Invert Emulsion
Mon, 2013-02-18 19:58 — Yacoub A. M. BattaAn invert emulsion (water-in-oil formulation) based on coconut and soybean oils provided the most stable emulsion layer (93% V/V) and lowest viscosity (27±0.81 cps), suitable for a formulation of Trichoderma harzianum conidia. Conidia remained viable for 36 months (shelf-life) with 50% reduction in viability (half-life) after 5.3 months at 20±1°C., compared with 2.7 and 0.7 months, respectively, for dry non-formulated conidia. Stability and viscosity of the formulation remained constant during the time period of viability study. Bio-assay tests on wounded apple fruit indicated the presence of significant preventive effect of formulatedTrichoderma conidia against the causative organism of apple gray mold Botrytis cinerea. The diameter ofBotrytis lesions was significantly reduced (P<0.05) 5 days after inoculation and treatment with formulatedTrichoderma conidia. Botrytis sporulation on the lesion surface was also inhibited 10 days after inoculation. These results were confirmed under simulated natural conditions by spraying a Botrytis conidial suspension on microwounded apple fruit following treatment by dipping fruit. Treatment of healthy non-wounded apple fruits resulted in protection from Botrytis infections for >2 months following inoculation and treatment.
Postharvest Control of Soft-Rot Fungi on Grape Berries by Fungicidal Treatment and Trichoderma
Sun, 2013-02-17 21:27 — Yacoub A. M. BattaThe present research deals with the effect of postharvest treatment of grape berries with four commonly used fungicides and two forms of Trichoderma harzianum on the infection with soft-rot fungi- Rhizopus stolonifer and Mucor piriformis. This effect was evaluated by comparison of the external diameter of rot-lesion in treated and untreated berries, in addition to comparison of percent reduction in external rot-lesion diameter relative to control. Results indicated that the infection with R. stolonifer and M. piriformis was significantly reduced (P<0.05) in all treated berries in comparison with untreated control berries. The highest reduction in mean external rot-lesion diameter was obtained for both R. stolonifer and M. piriformis when inoculated berries were treated with Score® (difenoconazole) applied at 0.35%(v/v) or Switch® (cyprodinil + flodioxonil) applied at 0.20%(w/v) or formulated T. harzianum conidia in invert emulsion applied at 9.6x108 conidia/ml of formulation (13.5, 13.2, and 19.3 mm, respectively for R. stolonifer; 7.2, 7.5, and 19.2mm, respectively for M. piriformis). The greatest decrease in percent reduction in external rot-lesion diameter relative to control was also obtained for both the fungal species when inoculated berries were treated with the same type of fungicides (Score® and Switch®) and Trichoderma (formulated T. harzianum in invert emulsion) (60.9, 61.7, and 44.1%, respectively for R. stolonifer; 74.5, 73.4, and 31.9%, respectively for M. piriformis). Overall results indicate that the most effective treatment obtained on grape berries could be integrated with other control measures being usually used in grape berry-rot management plans by alternating fungicidal treatment (e.g. Score® or Switch®) with application of formulated T. harzianum conidia in invert emulsion.
Control of Postharvest Diseases of Fruit with an Invert Emulsion Formulation of Trichoderma Harzianum Rifai
Sun, 2013-02-17 19:18 — Yacoub A. M. BattaControl of primary postharvest diseases caused by Rhizopus stolonifer, Botrytis cinerea, and Penicillium expansum on a variety of fresh fruit was evaluated with an invert emulsion formulation of Trichoderma harzianum. Diseases evaluated were quantified by the period of protection conferred by the antagonist and the diameter of decay lesions. Treatment of the various fruit species with formulated T. harzianum conidia in an invert emulsion significantly (P ≤ 0.05) reduced the mean lesion diameters of R. stolonifer on apple, pear, peach and strawberry, B. cinerea on grape, pear, strawberry, and kiwifruit, and P. expansum on grape, pear, and kiwifruit in comparison with the control treatment. Significant differences (P ≤ 0.05) were obtained in the mean percent reduction in lesion diameter caused by the same postharvest pathogens on the same fruit species due to the treatment with the formulated T. harzianum conidia relative to control treatment. The greatest mean percent reduction (86.7%) was obtained on apple fruit for the infection with R. stolonifer. Significant differences (P ≤ 0.05) were also obtained in the mean durations of the minimum protection period due to treatment with the formulated T. harzianum against the infection with the same postharvest pathogens on the same fruit species. The longest mean duration of the minimum protection period (up to 59 days) was obtained for unwounded apple fruit against the infection with R. stolonifer. Overall, the results indicate that the treatment with the invert emulsion formulation of T. harzianum protected fruit from infection by the primary postharvest pathogens of the fruit tested for up to 2 months and reduced the diameters of decay lesion up to 86% and is a promising treatment to prolong the postharvest shelf-life of fresh fruit.
