TABLE 5 .

Contingency table of the relationship of aggressiveness on cantaloupe to the ice nucleation activity of 203 water strains of P. syringae

	No. of strains in ice nucleation activity classb:
Aggressiveness classa	0	1	2
0	24	22	37
1	3	10	35
2	6	12	54

^aStrains in aggressiveness class 0 (nonvirulent strains) did not cause symptoms on more than 1 of the 12 seedlings inoculated per strain, strains in aggressiveness class 1 caused disease on 2 to 8 seedlings, and strains in aggressiveness class 2 caused disease on 9 or more of the 12 seedlings.

^b Strains in ice nucleation activity class 0 had no detectable capacity to induce freezing at temperatures warmer than −9°C in a population of 10⁶ cells. Strains in ice nucleation activity class 1 had at least 1 cell among 10⁶ able to catalyze ice formation at −6 to −9°C. Strains in class 2 had at least 1 cell among 10⁶ able to catalyze ice formation at −2 to −5°C. P = 0.0000, Fisher’s exact test.