Distribution, Occurrence and Characterization of Entomopathogenic Fungi in Agricultural Soil in The Palestinian Area
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Date
2000
Authors
Abdel-Basit Basim Moh'd Mara'i
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Abstract
The occurrence of entomopathogenic fungi was investigated in 100 irrigated vegetable fields and 40 citrus orchards soils in four geographical locations in the West Bank, using the Galleria bait method (GBM).
Entomopathogenic fungi were found to occur in 33.57 % (47 of 140) of the soil samples studied, with positive samples yielding 70 fungal isolates, belonging to 20 species in 13 genera. Conidiobolus coronatus was the most frequent and abundant entomopathogenic species recovered comprising 31.43 % of the total isolates. Soil pH, soil moisture content and the geographical location had minor or no effect on the isolation of entomopathogenic fungi in the studied fields. On the other hand, organic matter content of soil, and vegetation type were found to significantly (P<0.05) affect the isolation of entomopathogenic fungi from soil, with orchard fields yielding larger numbers of isolates than in the vegetable fields. Using Koch's postulates the pathogenicity of fungal isolates recovered to Galleria larvae was found to range from 16% to 100% (mortality rate). Isolates of C. coronatus, proved to be the most pathogenic isolates recovered (87-100% mortality in about 5-8 days after infection). The effect of media and temperature on mycelial growth rate, conidial production and conidial germination of six entomopathogenic fungal species (one isolate/species) was studied (C. coronatus, Entomophaga grylli, Erynia castrans, Hirsutella jonesii, Paecilomyces farinosus and Sporodinielle umbellata).
Mycelial growth was significantly affected by media and isolates with maximum growth rate obtained with CMA and PDA. Optimum temperature for radial mycelial growth, spore production and spore germination ranged from 20-30°C. Mycelial growth rate, spore production and spore germination were significantly affected by temperature and isolate.
The occurrence of entomopathogenic fungi was investigated in 100 irrigated vegetable fields and 40 citrus orchards soils in four geographical locations in the West Bank, using the Galleria bait method (GBM). Entomopathogenic fungi were found to occur in 33.57 % (47 of 140) of the soil samples studied, with positive samples yielding 70 fungal isolates, belonging to 20 species in 13 genera. Conidiobolus coronatus was the most frequent and abundant entomopathogenic species recovered comprising 31.43 % of the total isolates. Soil pH, soil moisture content and the geographical location had minor or no effect on the isolation of entomopathogenic fungi in the studied fields. On the other hand, organic matter content of soil, and vegetation type were found to significantly (P<0.05) affect the isolation of entomopathogenic fungi from soil, with orchard fields yielding larger numbers of isolates than in the vegetable fields. Using Koch's postulates the pathogenicity of fungal isolates recovered to Galleria larvae was found to range from 16% to 100% (mortality rate). Isolates of C. coronatus, proved to be the most pathogenic isolates recovered (87-100% mortality in about 5-8 days after infection). The effect of media and temperature on mycelial growth rate, conidial production and conidial germination of six entomopathogenic fungal species (one isolate/species) was studied (C. coronatus, Entomophaga grylli, Erynia castrans, Hirsutella jonesii, Paecilomyces farinosus and Sporodinielle umbellata). Mycelial growth was significantly affected by media and isolates with maximum growth rate obtained with CMA and PDA. Optimum temperature for radial mycelial growth, spore production and spore germination ranged from 20-30°C. Mycelial growth rate, spore production and spore germination were significantly affected by temperature and isolate.
The occurrence of entomopathogenic fungi was investigated in 100 irrigated vegetable fields and 40 citrus orchards soils in four geographical locations in the West Bank, using the Galleria bait method (GBM). Entomopathogenic fungi were found to occur in 33.57 % (47 of 140) of the soil samples studied, with positive samples yielding 70 fungal isolates, belonging to 20 species in 13 genera. Conidiobolus coronatus was the most frequent and abundant entomopathogenic species recovered comprising 31.43 % of the total isolates. Soil pH, soil moisture content and the geographical location had minor or no effect on the isolation of entomopathogenic fungi in the studied fields. On the other hand, organic matter content of soil, and vegetation type were found to significantly (P<0.05) affect the isolation of entomopathogenic fungi from soil, with orchard fields yielding larger numbers of isolates than in the vegetable fields. Using Koch's postulates the pathogenicity of fungal isolates recovered to Galleria larvae was found to range from 16% to 100% (mortality rate). Isolates of C. coronatus, proved to be the most pathogenic isolates recovered (87-100% mortality in about 5-8 days after infection). The effect of media and temperature on mycelial growth rate, conidial production and conidial germination of six entomopathogenic fungal species (one isolate/species) was studied (C. coronatus, Entomophaga grylli, Erynia castrans, Hirsutella jonesii, Paecilomyces farinosus and Sporodinielle umbellata). Mycelial growth was significantly affected by media and isolates with maximum growth rate obtained with CMA and PDA. Optimum temperature for radial mycelial growth, spore production and spore germination ranged from 20-30°C. Mycelial growth rate, spore production and spore germination were significantly affected by temperature and isolate.