ISHS Acta Horticulturae 265: International Strawberry Symposium
ANTAGONISTIC BACTERIA AS A BIOLOGICAL CONTROL AGAINST ICE NUCLEATION ACTIVE PSEUDOMONAS ON STRAWBERRY |
| Authors: | O. Leonardi, M. Leonardi, A. Catara |
| Abstract:
A survey carried out in many strawberry fields of different regions in Italy showed a wide distribution of fluorescent Pseudomonas on flowers and leaves both in open fields and under plastic covers. There were mostly P. fluorescens or P. syringae. Some isolates of the latter were ice nucleation active (INA+). Total bacteria populations reached 6.3×106 cells/gram fresh weight of strawberry tissue and INA+ cells were over 2.5×105. Biochemical and physiological characterizations have shown only minimum differences among isolates. In vitro assays indicated that more than 50 percent of isolates inhibit the growth of INA+ bacteria. In the growth chamber, blossoms sprayed with an INA+ strain (FG3) nucleated at -2 °C whereas those sprayed with the antagonistic strain FF1 started to nucleate at lower temperatures (down to -5 °C); the mixture of FF1 and FG3 strains has given intermediate results. In the open field, strain FF1 survived on sprayed plants about 30 days. | |
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