Treatmentz | Application rate (product/L of water) | Highest disease severity (0–5 scale)y | |||
---|---|---|---|---|---|
Bacteria leaf spot in oakleaf hydrangea | Powdery mildew in crapemyrtle | ||||
2002 | 2003 | 2002 | 2003 | ||
Surround® | 30 g/L (0.25 lb/gal) | 0.67 d | 1.50 c | 0.00 d | 0.00 d |
Neem Gold® | 8.3 mL/L (0.83%) | 1.17 bcd | 1.67 bc | 1.92 bc | 1.10 bc |
Triact 70® | 8.3 mL/L (0.83%) | 1.25 bcd | 2.00 abc | 1.83 c | 1.00 bc |
Ajax® | 18.3 mL/L (1.8%) | 1.00 cd | 2.00 abc | 1.92 bc | 1.10 bc |
UltraFine® Oil | 14.0 mL/L (1.4%) | 1.83 ab | 2.33 a | 2.17 bc | 1.50 abc |
M-Pede® | 8.3 mL/ (0.83%) | 1.33 abcd | 1.67 bc | 1.58 bc | 1.20 bc |
Equate® | 18.3 mL/L (1.8%) | 1.08 cd | 2.0 abc | 1.58 bc | 1.20 bc |
Armicarb® | 6.6 g/L (0.05 lb/gal) | 1.42 abc | 2.0 abc | 2.17 bc | 1.50 abc |
Bayleton | 0.9 g/L (0.12 oz/gal) | 1.58 ab | 2.17 ab | 2.33 bc | 1.50 abc |
Sevin®/Compass® | 0.3 g/L (0.04 oz/gal) | 1.33 abcd | 1.83 bc | 1.95 bc | 1.20 bc |
Control | — | 2.08 a | 2.17 ab | 3.5 a | 2.10 a |
LSD(0.05) | 0.77 | 0.50 | 1.13 | 0.75 |
↵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).