Evaluation of TREE-äge-treated and untreated western white pine (Pinus monticola) use by Dendroctonus ponderosae in three experiments in the Warner Mountains of California (mean ± SEM). Bark samples were collected at breast height (1.4 m) and were approximately 210 cm2. Data are based on 10 trees per treatment, however, actual sample size varied due to the number of trees killed in each treatment and the adequacy of bark samples for measuring response variables. Larval data from experiment 2 were determined from 7 untreated trees; 3 were discarded due to a lack of discernible MPB activity caused by secondary agents in the phloem. Trees in experiment 1 were treated on 17 to 18 September 2007, baited with attractant semiochemicals to promote attack by MPB from 1 July to 4 September 2008, and had bark samples removed on 11 to 12 August 2009. Trees in experiment 2 were treated on 5 November 2009, baited from 7 July to 4 November 2010, and had bark samples removed on 27 October 2011. Trees in experiment 3 were treated on 11 June 2013, baited from 11 July 2013 to 21 May 2014, and sampled 15 October 2014.
| Experiment | Treatment | No. of attacks | Exit holes | Adult gallery (no.) | Adult gallery (cm) | Larval gallery (no.) | Larval gallery (cm) |
|---|---|---|---|---|---|---|---|
| 1 | Control | 3.4 ± 0.5 | 8.5 ± 1.1* | 11.5 ± 1.2* | 74.9 ± 7.5* | 41.6 ± 8.3 | 26.5 ± 5.2 |
| TREE-äge | 4.9 ± 0.7 | 1.1 ± 0.4 | 6.7 ± 0.5 | 21.8 ± 3.9 | 21.6 ± 5.1 | 13.8 ± 4.0 | |
| 2 | Control | 4.8 ± 0.4* | 17.8 ± 2.3* | 120.6 ± 13.4* | 47.1 ± 10.6* | 50.3 ± 11.2* | |
| TREE-äge | 8.3 ± 0.7 | 0.00 | 8.7 ± 1.4 | 10.1 ± 2.1 | 0.00 | 0.00 | |
| 3 | Control | 1.3 ± 0.26 | 5.6 ± 1.01* | 4.9 ± 0.38* | 38.7 ± 3.07* | 35.8 ± 4.12* | 43.2 ± 4.93* |
| TREE-äge/V/GLV | 0.6 ± 0.49 | 0.00 | 0.03 ± 0.03 | 0.08 ± 0.08 | 0.00 | 0.00 | |
| TREE-äge/PPZ | 1.9 ± 0.47 | 0.00 | 0.63 ± 0.42 | 0.66 ± 0.44 | 0.00 | 0.00 |
↵*Indicates significant difference between means within a year (t-test or Welch’s approximation; P < 0.05).