scholarly journals IDENTIFICATION AND EVALUATION OF FIBER HYDROLYTIC ENZYMES IN THE EXTRACT OF TERMITES (Glyptotermes montanus) FOR POULTRY FEED APPLICATION

2016 ◽  
Vol 4 (2) ◽  
pp. 40 ◽  
Author(s):  
Tresnawati Purwadari ◽  
Pius P. Ketaren ◽  
Arnold P. Sinurat ◽  
Irawan Sutikno
Keyword(s):  
Organic Matter ◽  
Hydrolytic Enzymes ◽  
Black Pepper ◽  
Culture Technique ◽  
Poultry Feed ◽  
Cropping Pattern ◽  
Dual Culture ◽  
Feed Supplement ◽  
Optimum Ph ◽  
Soil Mycoflora

Foot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate) and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001), Trichoderma (125, 170, 171, 179, 180, 181), Gliocladium (109), Cunninghamella (165, 168), Mortierella (177), and Aspergillus (106) was space competitor (competition for nutrient) since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202) isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181) isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094), but the cropping pattern wPoultry are not able to digest fiber in the diet. Hydrolytic enzymes including cellulases and hemicellulases have been used as poultry feed supplement. Termites (Glyptotermes montanus) have the ability to digest wood that contains high fiber. The purpose of this experiment was to identify the cellulase and hemicellulase of termite extract. The hydrolytic (saccharification) activity of the termite extract on feedstuffs was then evaluated. It contained high endo-β-D-1,4-glucanase (CMCase) activity, but the activities of avicelase, β-D-1,4-mannanase, β- D-1,4-xylanase, and β-D-1,4-glucosidase were very low. The activities of the enzymes were higher in the fresh extract than those extracted after drying at 40oC with blower oven. CMCase (as cellulase), β-D-1,4-mannanase (as hemicellulase), and β-D- 1,4-glucosidase (as glycosidase) were reevaluated further to determine the optimum pH and temperatures for maximum activities. The optimum pH for CMCase, β-D-1,4-mannanase, and β-D-1,4-glucosidase were 6.2, 5.0, and 5.8 respectively, while the optimum temperatures were 45-50oC, 50-55oC, and 42-45oC, respectively. The enzyme mixture or cocktail was more appropriate in digesting feedstuffs with high lignocellulose (fiber) such as rice bran and pollard than feedstuffs with more soluble starch such as soybean and corn meals. The extracted enzyme could be immobilized with pollard, but CMCase recovery was low (28.6%), while β-D-1,4-mannanase and β-D-1,4-glucosidase recoveries were 89.2% and 272.9%, respectively. Termite extract contained enzyme cocktails of lignocellulases that potentially be used as feed supplement. However, its use is limited by its low activity.as negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease.

scholarly journals IDENTIFICATION AND EVALUATION OF FIBER HYDROLYTIC ENZYMES IN THE EXTRACT OF TERMITES (Glyptotermes montanus) FOR POULTRY FEED APPLICATION

2016 ◽  
Vol 4 (2) ◽  
pp. 40 ◽  
Author(s):  
Tresnawati Purwadari ◽  
Pius P. Ketaren ◽  
Arnold P. Sinurat ◽  
Irawan Sutikno
Keyword(s):  
Organic Matter ◽  
Hydrolytic Enzymes ◽  
Black Pepper ◽  
Culture Technique ◽  
Poultry Feed ◽  
Cropping Pattern ◽  
Dual Culture ◽  
Feed Supplement ◽  
Optimum Ph ◽  
Soil Mycoflora

Foot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate) and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001), Trichoderma (125, 170, 171, 179, 180, 181), Gliocladium (109), Cunninghamella (165, 168), Mortierella (177), and Aspergillus (106) was space competitor (competition for nutrient) since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202) isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181) isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094), but the cropping pattern wPoultry are not able to digest fiber in the diet. Hydrolytic enzymes including cellulases and hemicellulases have been used as poultry feed supplement. Termites (Glyptotermes montanus) have the ability to digest wood that contains high fiber. The purpose of this experiment was to identify the cellulase and hemicellulase of termite extract. The hydrolytic (saccharification) activity of the termite extract on feedstuffs was then evaluated. It contained high endo-β-D-1,4-glucanase (CMCase) activity, but the activities of avicelase, β-D-1,4-mannanase, β- D-1,4-xylanase, and β-D-1,4-glucosidase were very low. The activities of the enzymes were higher in the fresh extract than those extracted after drying at 40oC with blower oven. CMCase (as cellulase), β-D-1,4-mannanase (as hemicellulase), and β-D- 1,4-glucosidase (as glycosidase) were reevaluated further to determine the optimum pH and temperatures for maximum activities. The optimum pH for CMCase, β-D-1,4-mannanase, and β-D-1,4-glucosidase were 6.2, 5.0, and 5.8 respectively, while the optimum temperatures were 45-50oC, 50-55oC, and 42-45oC, respectively. The enzyme mixture or cocktail was more appropriate in digesting feedstuffs with high lignocellulose (fiber) such as rice bran and pollard than feedstuffs with more soluble starch such as soybean and corn meals. The extracted enzyme could be immobilized with pollard, but CMCase recovery was low (28.6%), while β-D-1,4-mannanase and β-D-1,4-glucosidase recoveries were 89.2% and 272.9%, respectively. Termite extract contained enzyme cocktails of lignocellulases that potentially be used as feed supplement. However, its use is limited by its low activity.as negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease.

scholarly journals SOIL MYCOFLORA OF BLACK PEPPER RHIZOSPHERE IN THE PHILIPPINES AND THEIR IN VITRO ANTAGONISM AGAINST Phytophthora capsici L.

2016 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Rita Noveriza ◽  
Tricita H. Quimio
Keyword(s):  
Organic Matter ◽  
Phytophthora Capsici ◽  
Black Pepper ◽  
The Philippines ◽  
Culture Technique ◽  
Organic Substrate ◽  
Cropping Pattern ◽  
Dual Culture ◽  
Soil Mycoflora

Foot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate) and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001), Trichoderma (125, 170, 171, 179, 180, 181), Gliocladium (109), Cunninghamella (165, 168), Mortierella (177), and Aspergillus (106) was space competitor (competition for nutrient) since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202) isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181) isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094), but the cropping pattern was negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease.

scholarly journals SOIL MYCOFLORA OF BLACK PEPPER RHIZOSPHERE IN THE PHILIPPINES AND THEIR IN VITRO ANTAGONISM AGAINST Phytophthora capsici L.

2016 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Rita Noveriza ◽  
Tricita H. Quimio
Keyword(s):  
Organic Matter ◽  
Phytophthora Capsici ◽  
Black Pepper ◽  
The Philippines ◽  
Culture Technique ◽  
Organic Substrate ◽  
Cropping Pattern ◽  
Dual Culture ◽  
Soil Mycoflora

Foot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate) and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001), Trichoderma (125, 170, 171, 179, 180, 181), Gliocladium (109), Cunninghamella (165, 168), Mortierella (177), and Aspergillus (106) was space competitor (competition for nutrient) since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202) isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181) isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094), but the cropping pattern was negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease.

scholarly journals EFIKASI TRICHODERMA HARZIANUM DENGAN BERBAGAI BAHAN ORGANIK DALAM PENGENDALIAN PENYAKIT BUSUK PANGKAL BATANG PADA LADA

2011 ◽  
Vol 11 (2) ◽  
pp. 147-156
Author(s):  
Cipta Ginting ◽  
Tri Maryono
Keyword(s):  
Organic Matter ◽  
Disease Severity ◽  
Trichoderma Harzianum ◽  
Disease Incidence ◽  
Black Pepper ◽  
Culture Technique ◽  
Wood Dust ◽  
Dual Culture ◽  
Foot Rot ◽  
Trichoderma Spp

The objective of this research was to determine the influence of the kinds of organic matter on the efficacy of Trichoderma harzianum Rifai to control foot rot of black pepper caused by Phytophthora capsici Leonian.  Trichoderma spp. were isolated from suppressive and non-suppressive soils taken from black pepper fields with high disease incidence.  Screening of Trichoderma spp. isolates was conducted through antagonistic test with dual culture technique.  Treatments were arranged in a completely randomized design with six replications.  Treatments were rice husk, rice straw, wood dust, Arachis pintoi, mixture of the four organic matters, the mixture without T. harzianum, and without organic matter.  The test was conducted in greenhouse with media consisted of soil, organic matter, and sand (2 : 2 : 1, v/v).  After being otoclaved, the medium was infested with T. harzianum and P. capsici each with five mycelium plugs of 1-cm diameter.  Black pepper seedlings were planted 5 days after fungal infestation.  After planting the seedlings, five leaf cuts were partly inserted into the soil on each pot.  The variables observed were disease incidence on the leaf cuts inserted into the soil and disease severity on the stems and roots.  The results show that all 16 Trichoderma isolates inhibited P. capsici colonies and some isolates showed stronger inhibition than the others.  T. harzianum reduced disease severity, but there was no effect of the kinds of organic matter on the ability of T. harzianum to control foot rot.

scholarly journals EFIKASI ISOLAT TRICHODERMA TERPILIH DENGAN BAHAN ORGANIK UNTUK MENGENDALIKAN PENYAKIT BUSUK PANGKAL BATANG PADA LADA DI LAPANGAN

2017 ◽  
Vol 17 (1) ◽  
pp. 77
Author(s):  
Cipta Ginting ◽  
Joko Prasetyo ◽  
Aris Nurhidayat ◽  
Tri Maryono
Keyword(s):  
Organic Matter ◽  
Statistical Analysis ◽  
Rice Straw ◽  
Culture Method ◽  
Black Pepper ◽  
Disease Symptom ◽  
Dual Culture ◽  
Foot Rot ◽  
Coffee Husk ◽  
Trichoderma Isolate

Efficacy of selected Trichoderma isolate and organic matter to control foot rot of black pepper in the field. The objective of this experiment was to determine the efficacy of selected Trichoderma isolatand organic matter to control the disease. Dual culture method was used to select a Trichoderma isolate. The experiment to evaluate the efficacy of selected isolate consisted of control (no application of T. harzianum or organic matter), T. harzianum and rice straw, and T. harzianum and coffee husk. As starter, T. harzianum was grown in broken rice. Two liters of organic matter was infested with suspension of 10 g starter in 100 ml steril water and incubated for 2 weeks. The mixture was applied around the base of black pepper stem. The results showed that all plants treated with T. harzianum and organic matter did not show disease symptom. Ten percent of the control plants showed symptoms. However, statistical analysis showed that the occurrence of the disease was not significantly different between treatments. Applications ofT. harzianum and rice straw increased the density of Trichoderma for 1 and 2 months after application. T. harzianum and coffee husk increased the density of the fungus 1 month after application.

scholarly journals Highly-Efficient Release of Ferulic Acid from Agro-Industrial By-Products via Enzymatic Hydrolysis with Cellulose-Degrading Enzymes: Part I–The Superiority of Hydrolytic Enzymes Versus Conventional Hydrolysis

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 782
Author(s):  
Karina Juhnevica-Radenkova ◽  
Jorens Kviesis ◽  
Diego A. Moreno ◽  
Dalija Seglina ◽  
Fernando Vallejo ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Ferulic Acid ◽  
Hydrolytic Enzymes ◽  
Structural Complexity ◽  
Triticum Aestivum L ◽  
Feed Supplement ◽  
Degrading Enzymes ◽  
Secale Cereale L ◽  
Pre Treatment ◽  
By Products

Historically Triticum aestívum L. and Secale cereále L. are widely used in the production of bakery products. From the total volume of grain cultivated, roughly 85% is used for the manufacturing of flour, while the remaining part is discarded or utilized rather inefficiently. The limited value attached to bran is associated with their structural complexity, i.e., the presence of cellulose, hemicellulose, and lignin, which makes this material suitable mostly as a feed supplement, while in food production its use presents a challenge. To valorize these materials to food and pharmaceutical applications, additional pre-treatment is required. In the present study, an effective, sustainable, and eco-friendly approach to ferulic acid (FA) production was demonstrated through the biorefining process accomplished by non-starch polysaccharides degrading enzymes. Up to 11.3 and 8.6 g kg−1 of FA was released from rye and wheat bran upon 24 h enzymatic hydrolysis with multi-enzyme complex Viscozyme® L, respectively.

DNA Polymerases of Newborn Rat Brain and Liver

1971 ◽  
Vol 49 (8) ◽  
pp. 978-986 ◽  
Author(s):  
A. D. Bharucha ◽  
M. R. V. Murthy
Keyword(s):  
Rat Brain ◽  
Specific Activity ◽  
Hydrolytic Enzymes ◽  
Polymerase Activity ◽  
Newborn Rat ◽  
Newborn Brain ◽  
Rat Brain And Liver ◽  
Mammalian Tissues ◽  
Optimum Ph ◽  
Sulfhydryl Compounds

DNA polymerase activity was found to be present in appreciable quantities in the extracts of whole tissue (TS) as well as of nuclei (NS) isolated from newborn rat brain and liver. The NS fractions of either of the two tissues exhibited a higher specific activity per unit protein than the corresponding TS fractions. The optimum pH requirements as well as the ability to support DNA synthesis over a long period indicate that the NS fractions were also comparatively less contaminated by interfering substances than the TS fractions.The reaction requirements for the incorporation of TMP residues into DNA by the NS fractions of newborn rat brain and liver and the effect of various inhibitors and hydrolytic enzymes on this reaction were also investigated. These extracts resembled preparations from other mammalian tissues in that they exhibited absolute requirements for the primer DNA, the four complimentary deoxynucleoside triphosphates, and Mg2+ ions. When three of the four deoxynucleoside triphosphates were omitted and only TTP-2-14C was added to the reaction mixture, a limited incorporation of TMP-2-14C into DNA occurred. Other investigations such as the effect of actinomycin and of sulfhydryl compounds revealed that a large part of incorporation by the TS and NS fractions of newborn brain and liver was due to the replicative DNA nucleotidyltransferase enzyme.

scholarly journals COMPORTAMENTO ESPACIAL DA FUSARIOSE E DOS ATRIBUTOS DO SOLO NO CULTIVO DA PIMENTA-DO-REINO

Nativa ◽  
2018 ◽  
Vol 6 (2) ◽  
pp. 113
Author(s):  
Carla Da Penha Simon ◽  
Ana Carolina Lyra Brumat ◽  
Marcelo Barreto Da Silva ◽  
Bernardo Torres Olmo ◽  
Edney Leandro da Vitória ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Texture ◽  
Fusarium Solani ◽  
Nutrient Content ◽  
Black Pepper ◽  
Irregular Sampling ◽  
Piper Nigrum ◽  
Soil Attributes ◽  
Calcium Magnesium ◽  
Chemical Attributes

A pimenta-do-reino é a especiaria mais consumida no mundo e o Brasil destaca-se como um dos maiores produtores. Um dos grandes limitantes no seu cultivo é a fusariose (Fusarium solani f. sp. piperis). Objetivou-se com a realização deste estudo caracterizar a variabilidade espacial da fusariose em pimenta-do-reino, verificando a existência de relação com os atributos físicos e químicos do solo. O estudo foi desenvolvido em uma lavoura localizada no município de São Mateus-ES, na qual foi estabelecida uma malha amostral irregular com 79 pontos, abrangendo uma área de um hectare.  Para a amostragem da fusariose foi realizado um levantamento, onde uma planta por ponto da malha amostral foi classificada em sadia, doente ou morta.  Os atributos do solo amostrados foram: pH em H2O, matéria orgânica, cálcio, magnésio, potássio e textura do solo. Os dados foram analisados através da estatística descritiva e ferramentas da geoestatística. Os semivariogramas ajustados apresentaram uma forte dependência espacial para as variáveis intensidade da fusariose, altimetria, matéria orgânica, textura do solo, pH, cálcio, magnésio potássio (89, 94, 92, 94, 93, 91, 100 e 85 % respectivamente). Os mapas gerados indicam que não há relação da intensidade da fusariose com os atributos do solo estudados no experimento.Palavra-chave: epidemiologia, Fusarium solani f. sp. piperis, geoestatística, Piper nigrum L. SPATIAL ANALYSIS OF FUSARIOSE AND SOIL ATTRIBUTES IN THE BLACK PEPPER CULTIVATION  ABSTRACT:Black pepper is the most consumed spice in the world, Brazil stands out as one of the largest producers. One of the major constraints in cultivation is fusariosis (Fusarium solani f. Piperis). The objective of this study was characterize the spatial variability of fusariosis in black pepper and verify the relationship of chemical attributes of the soil. The study was developed in a tillage located in the municipality of São Mateus - ES, which exist an irregular sampling network was established with 79 points, covering an area of one hectare. For the sampling of fusariosis intensity, the survey was performed, where one plant per point of the sample mesh was classified as healthy, symptomatic or dead. The attributes of the soil sampled were: pH in H2O, organic matter, nutrient content (calcium, magnesium, potassium) and soil texture. Data were analyzed through descriptive statistics and geostatistics tools. The adjusted semivariograms indicated a strong spatial dependence for the variables intensity of fusariosis, altimetry, organic matter, soil texture, pH, calcium, potassium magnesium (89, 94, 92, 94, 93, 91, 100 and 85%, respectively). The generated maps indicate that there is no relation between the incidence of fusariosis and the soil attributes studied in the experiment.Keywords: epidemiology, Fusarium solani f. sp. piperis, geostatistics, Piper nigrum L. DOI:

scholarly journals ​Antagonistic Activity of Panchagavya and Trichoderma spp. against Wilt Complex causing Pathogens of Chickpea (Cicer arietinum L.)

2022 ◽  
Author(s):  
H.V. Parmar ◽  
N.M. Gohel
Keyword(s):  
Low Cost ◽  
Trichoderma Viride ◽  
Macrophomina Phaseolina ◽  
Antagonistic Activity ◽  
Culture Technique ◽  
Plant Diseases ◽  
Dual Culture ◽  
Trichoderma Spp ◽  
Soil Borne Pathogens ◽  
Chickpea Wilt

Background: Chickpea wilt complex caused by several soil-borne pathogens is the major yield-reducing malady worldwide. Biological control is one of the best, low-cost and ecologically sustainable method for managing plant diseases caused by soil-borne pathogens. Methods: In this present investigation Panchagavya and Trichoderma spp. were evaluated by following poisoned food technique and dual culture technique against wilt complex causing pathogens i.e. Fusarium oxysporum f. sp. ciceri, Fusarium solani and Macrophomina phaseolina. Result: Among the different isolates of Trichoderma spp. evaluated, Trichoderma viride (AAU isolate) was highly antagonistic to F. oxysporum f. sp. ciceri (52.78%) and F. solani (65.37%) whereas, Trichoderma asperellum (AAU isolate) was highly antagonistic to M. phaseolina (65.93%). Panchagavya at the highest concentration (50%) showed significantly higher efficacy (80.74, 66.62 and 49.67%) in inhibiting the mycelial growth of all three pathogens and at the lowest concentration it was moderately effective.

scholarly journals Suppression of Stem-End Rot on Avocado Fruit Using Trichoderma spp. in the Central Highlands of Kenya

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
E. K. Wanjiku ◽  
J. W. Waceke ◽  
J. N. Mbaka
Keyword(s):  
Growth Inhibition ◽  
Fungal Pathogen ◽  
Mycelial Growth ◽  
Culture Technique ◽  
Global Market ◽  
Dual Culture ◽  
Postharvest Diseases ◽  
Trichoderma Spp ◽  
Lasiodiplodia Theobromae

Demand for organic avocado fruits, together with stringent food safety standards in the global market, has made producers to use alternative, safe, and consumer-friendly strategies of controlling the postharvest fungal disease of avocado fruits. This study assessed the in vitro efficacy of Trichoderma spp. (T. atroviride, T. virens, T. asperellum, and T. harzianum) against isolated avocado stem-end rot (SER) fungal pathogens (Lasiodiplodia theobromae, Neofusicoccum parvum, Nectria pseudotrichia, and Fusarium solani) using a dual culture technique. The Trichoderma spp. were also evaluated singly on postharvest “Hass” avocado fruits. Spore suspension at 5 × 104 conidial/ml of the Trichoderma spp. was applied on the avocado fruits at three time points, twenty-four hours before the fungal pathogen (preinoculation), at the same time as the fungal pathogen (concurrent inoculation), and 24 hours after the fungal pathogen (postinoculation). In the in vitro study, T. atroviride showed the highest mycelial growth inhibition against N. parvum (48%), N. pseudotrichia (55%), and F. solani (32.95%), while T. harzianum had the highest mycelial growth inhibition against L. theobromae. Trichoderma asperellum was the least effective in inhibiting the mycelial growth of all the pathogens. Similarly, T. virens showed the highest mycelial growth inhibition against N. pseudotrichia at 45% inhibition. On postharvest “Hass” fruits, T. atroviride showed the highest efficacy against N. parvum, N. pseudotrichia, and F. solani in all the applications. Trichoderma virens and T. harzianum were most effective against all the pathogens during postinoculation, while Lasiodiplodia theobromae was best controlled by T. virens, T. harzianum, and T. asperellum during postinoculation. Both T. atroviride and T. harzianum present a potential alternative to synthetic fungicides against postharvest diseases of avocado fruits, and further tests under field conditions to be done to validate their efficacy. The possibility of using Trichoderma spp. in the management of SER on avocado fruits at a commercial level should also be explored.

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