Assessment of Pseudomonas syringae pv. tagetis as a biocontrol agent for Canada thistle

Autor: John W. Gronwald, Kathryn L. Plaisance, Donald L. Wyse, Donald A. Ide
Rok vydání: 2002
Předmět:
Zdroj: Weed Science. 50:397-404
ISSN: 1550-2759
0043-1745
DOI: 10.1614/0043-1745(2002)050[0397:aopspt]2.0.co;2
Popis: Growth chamber and field experiments were conducted to assess the potential of Pseudomonas syringae pv. tagetis (Pst) as a biocontrol agent for Canada thistle. Silwet L-77, an organosilicone surfactant, was required to facilitate Pst penetration into Canada thistle leaves. Growth chamber experiments indicated that maximum Pst populations inside leaves were obtained with a Silwet L-77 concentration of 0.3% (v/v) or greater. High Pst populations (109 colony-forming units [cfu] per gram fresh weight) were found in leaves 48 h after treatment with 108 or 109 cfu ml−1 Pst plus Silwet L-77 (0.3%, v/v). In growth chamber experiments, foliar application of Pst (109 cfu ml−1) plus Silwet L-77 (0.3%, v/v) on 4- to 5-wk-old Canada thistle reduced shoot dry weight by 52% (measured 14 d after treatment) and chlorophyll content of emerging leaves by 92% (measured 10 d after treatment). In field trials conducted in 1999 and 2000, Pst (109 cfu ml−1) plus Silwet L-77 (0.3%, v/v) were applied at 700 L ha−1, and th...
Databáze: OpenAIRE