Biological control of Phytophthora megasperma var. sojae, causal agent of Phytophthora rot of asparagus, by Pseudomonas aureofaciens PA147-2: a preliminary field trial

Pseudomonas aureofaciens PA147-2 produces an antibiotic that inhibits the g rowth of Phytophthora megasperma var. sojae, the causative agent of root-ro t disease of asparagus (Asparagus officinalis). To assess the potential use of PA147-2 as a biocontrol organism, we report preliminary findings of a f ield application of PA147-2 to asparagus crowns. To determine the ability o f PA147-2 to suppress Phytophthora rot, asparagus crowns inoculated with PA 147-2 were planted in Eyre shallow fine sandy loam soil inoculated with P. megasperma var. sojae. During the 6-month trials, PA147-2 was isolated from inoculation points with a decreasing frequency. Harvesting and analysis of asparagus plants revealed that inoculation of crowns with PA147-2 resulted in a 55.8% increase of fern dry weight in comparison to untreated plants. Preliminary field trial results suggest the direct inoculation of asparagus crowns with PA147-2 before planting causes a statistically significant inc rease in the yield of plant material in the presence of P. megasperma var. sojae.