Bioassay and characterization of soil microorganisms involved in the biodegradation of the fungicide, metalaxyl

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:6110356

Bailey, A M

A sensitive bioassay was developed to detect low concentrations of metalaxyl in soils. The quantitative estimation of metalaxyl in soils was based on a significant positive relationship between the radial growth of Phytophthora boehmeriae and the log concentration of the fungicide in the agar. The isolate of P. boehmeriae was chosen for its sensitivity to metalaxyl as manifested in a linear growth response on cornmeal agar over a range of 2 to 30 ng/ml. The sensitivity and quantitative nature of the bioassay was confirmed by comparison with data obtained by using /sup 14/C-metalaxyl. Metabolism of metalaxyl was detected in three of five avocado soils that had repeated applications of the fungicide over 2-5 yr. The average disappearance of metalaxyl was 28 days, and in the most active soils was 14 days. The composition and level of the microbial populations of soils, either active or inactive in the breakdown of metalaxyl, did not differ. Fungal and bacterial microflora recovered from these two soils by use of either selective media or filtration techniques were capable of metabolizing metalaxyl over a 45-day period.

• Research Organization: California Univ., Riverside (USA)
• OSTI ID: 6110356
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
59 BASIC BIOLOGICAL SCIENCES
FUNGICIDES
BIODEGRADATION
MICROORGANISMS
GROWTH
BIOASSAY
CARBON 14 COMPOUNDS
METABOLISM
SOILS
TRACER TECHNIQUES
CHEMICAL REACTIONS
DECOMPOSITION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
PESTICIDES
510200* - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)
550501 - Metabolism- Tracer Techniques