Efficacy of foliar insecticides applied at label rate for scale insects (see text) against settled calico scale crawlers on leaves of individually sprayed shoots.
| Trial and treatment | Crawlers per shootz | Percent mortalityy | Adjusted percent mortalityx |
|---|---|---|---|
| Trial 1, treated 23 June 2001, on sugar maple | |||
| Control | 544 ± 126 | 27.7 ± 4.5 | 0.0 ± 0.0 |
| Insecticidal soap | 482 ± 87 | 50.0 ±7.8* | 32.6 ± 7.5 |
| Horticultural oil | 515 ±80 | 54.5 ± 7.9* | 37.7 ± 9.7 |
| Bifenthrin | 478 ± 99 | 96.8 ± 1.9* | 94.4 ± 2.8 |
| Acephate | 638 ±161 | 100.0 ± 0.0* | 100.0 ± 0.0 |
| Trial 2, treated 22 July 2002, on hackberry | |||
| Control | 1375 ±192 | 10.2 ± 2.5 | 0.0 ± 0.0 |
| Insecticidal soap | 1230 ±151 | 7.7 ± 1.8 | 0.7 ± 0.7 |
| Pyriproxyfen | 1388 ±303 | 8.7 ± 1.6 | 2.8 ± 0.4 |
| Horticultural oil | 1930 ± 843 | 54.5 ± 13.4* | 50.2 ± 14.0 |
| Bifenthrin | 1139 ±208 | 90.2 ± 3.2* | 89.0 ± 3.7 |
| Acephate | 1328 ±361 | 99.2 ± 0.3* | 99.1 ± 0.3 |
| Carbaryl | 855 ±132 | 100.0 ±0.0* | 100.0 ±0.0 |
| Trial 3, treated 23 June 2003, on hackberry | |||
| Control | 1609 ± 230 | 4.8 ± 1.2 | 0.0 ± 0.0 |
| Pyriproxyfen | 982 ± 135 | 88.6 ± 3.9* | 87.8 ± 4.3 |
| Cyfluthrin | 1291 ±368 | 99.4 ± 0.4* | 99.4 ± 0.4 |
↵z Mean total crawlers does not differ significantly among treatments in any trial (two-way ANOVA, P > 0.32).
↵y ANOVA results: trial 1: F = 79.3; df = 4,35; P < 0.001; trial 2: F = 91.4; df = 6,40; P < 0.001; trial 3: F = 385.3; df = 2,14; P < 0.0001.
↵x Abbott’s (1925) formula used to adjust for mortality in untreated controls.
Data are means (± standard error); efficacy was evaluated 18, 13, and 38 days after treatment in trials 1–3, respectively. Within trials and columns, means followed by an asterisk (*) differ significantly from the untreated control (Dunnett’s test, α = 0.05).