Table 2.

Black spot (Marssonina rosae, anamorph Diplocarpon rosae) disease severity in roses (Rosa spp.) treated with different products under field environments.

Treatment^{^z}	Highest disease severity (0–5 scale)^{^y}
Treatment^{^z}	Application rate (product/L of water)	2002	2003
Equate®	18.3 mL/L (1.8%)	1.50 cd	1.00 e
UltraFine®	14.0 mL/L (1.4%)	1.80 bc	1.50 bcde
Ajax®	18.3 mL/L (1.8%)	1.10 d	1.13 de
Surround®	30 g/L (0.25 lb/gal)	1.50 cd	1.75 bcd
Neem Gold®	10.0 mL/L (1.0%)	2.20 ab	1.25 cde
M-Pede®	8.3 mL/L (0.83%)	1.80 bc	1.63 bcde
Armicarb®	6.6 g/L (0.05 lb/gal)	1.30 cd	2.00 b
Bayleton	0.9 g/L (0.12 oz/gal)	2.10 bc	2.00 b
Triact 70®	10.0 mL/L (1.0%)	1.20 cd	1.75 bcd
Insecticide and fungicide	0.3 g/L (0.04 oz/gal)	2.80 a	1.05 de
Control	—	3.10 a	4.50 a
^LSD(0.05)		0.63	0.65

↵^zFungicides Bayleton (triadimefon) and Compass® (trifloxystrobin) were applied starting early May and the insecticide Sevin® (carbaryl) was added in a tank mix starting in mid-June when Japanese beetles were detected in insect traps.
↵^yDisease severity readings: 1 = 1% to 10%, 2 = 11% to 25%, 3 = 26% to 50%, 4 = 51% to 75%, and 5 = 76% to 100% plant showing symptoms. Numbers followed by common letters in the same column are statistically similar at P = 0.05 according to analysis of variance (Proc GLM) and least significant differences (LSD) calculated by Statistical Analysis Systems (SAS Institute 1990).