Articles
Evaluation of different peats for the suppression of damping-off in cucumbers
Article number
1410_14
Pages
97 – 102
Language
English
Abstract
Pythium aphanidermatum causes damping-off and root rot in a wide range of plant species.
In cucumbers, it is a recurrent problem for growers in Almería, the main production area in Spain.
Plant production companies mainly use peat as a substrate for seedbeds.
It has been described that the incidence of damping-off by Pythium spp. increases as the degree of peat humification (decomposition) increases.
Therefore, this study aimed to evaluate peats with different degrees of humification, according to the von Post scale, and their microbial activity against the severity of damping-off in cucumbers.
Seven different peats, differing in their von Post scale, were used.
A randomized block trial with five replicates was conducted under controlled conditions.
Each replicate consisted of a 300 cm3 pot with ten seedlings of cucumber ‘Hyclos Mix’. For pathogenicity tests, a known pathogenic isolate of P. aphanidermatum was grown on a soil-potato substrate and three grams per pot was used as inoculum.
The disease severity was assessed after 14 days.
The betaglucosidase activity was measured for each peat before the trial.
The results showed no relationship between disease incidence and the von Post scale.
Similarly, there was not a clear decreasing pattern of microbial activity with the degree of humification, as would be expected.
However, a negative and significant correlation (P<0.05; R2=59.5%) was observed between the microbial activity of the peats and the severity of damping-off recorded.
In conclusion, microbial activity predicts the conductivity/suppressiveness of the peats better than the degree of humification by von Post.
In cucumbers, it is a recurrent problem for growers in Almería, the main production area in Spain.
Plant production companies mainly use peat as a substrate for seedbeds.
It has been described that the incidence of damping-off by Pythium spp. increases as the degree of peat humification (decomposition) increases.
Therefore, this study aimed to evaluate peats with different degrees of humification, according to the von Post scale, and their microbial activity against the severity of damping-off in cucumbers.
Seven different peats, differing in their von Post scale, were used.
A randomized block trial with five replicates was conducted under controlled conditions.
Each replicate consisted of a 300 cm3 pot with ten seedlings of cucumber ‘Hyclos Mix’. For pathogenicity tests, a known pathogenic isolate of P. aphanidermatum was grown on a soil-potato substrate and three grams per pot was used as inoculum.
The disease severity was assessed after 14 days.
The betaglucosidase activity was measured for each peat before the trial.
The results showed no relationship between disease incidence and the von Post scale.
Similarly, there was not a clear decreasing pattern of microbial activity with the degree of humification, as would be expected.
However, a negative and significant correlation (P<0.05; R2=59.5%) was observed between the microbial activity of the peats and the severity of damping-off recorded.
In conclusion, microbial activity predicts the conductivity/suppressiveness of the peats better than the degree of humification by von Post.
Authors
A.M. Pastrana, C. Borrero, M. Avilés
Keywords
Pythium aphanidermatum, peat, von Post scale, humification, microbial activity, soil suppressiveness
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