Arboriculture & Urban Forestry 41(2): March 2015 cloprid, but the imidacloprid treatments pro- duced no effect relative to controls (Figure 4A). As mentioned, the method of exposure and mode of activity of systemics against bark bee- tles suggest that gallery length measures are important for evaluating their effects. Two-way ANOVA (trial and treatment plus trial*treatment interaction) on ln transformed GLA resulted in a NS effect for laboratory trial*treatment inter- action (F8, 25 sprays again performed better than other treat- ments, allowing for significantly shorter galleries per attack (Tukey’s HSD with pooled error; Figure 4B); however, their effectiveness at elim- inating attacks resulted in the availability of only one bolt each for evaluating this response. error, the treatment effect was highly signifi- cant (F4, 33 Determination of Imidacloprid Residues Because the experimental time frame (trees were cut between 58–124 days aſter treatment) and tree-level replication (one to two trees per expo- sure period) were limited, residue results were combined across sites and times for analysis. Untreated control samples (matrix only) aver- aged 0.19 ± 0.06 µg/g dry weight (n = 9) and were significantly lower than either imidaclo- prid treatment. The two imidacloprid treatments did not differ in concentration of residues in the phloem: Dominion samples averaged 0.74 ± 0.16 (n = 9) and Xytect samples 1.31 ± 0.26 (n = 9). DISCUSSION Southern pine beetle is not foreign to New Jersey but outbreaks are infrequent. New Jersey is included in early range maps and the species was previously observed in the United States in southern Pennsyl- vania, West Virginia, and Maryland (Hopkins 1909; Hopkins 1921). Prior to 2002, the last outbreak in New Jersey appears to have been in 1939 (The Phila- delphia Inquirer 2011), but researchers have not located references that describe it. Although native, SPB are invasive and damaging when populations increase to high levels. Outbreaks are unpredict- able, costly, and highly disruptive to forest man- agement. High-value trees in urban forests, recre- ational areas, and homeplaces suffer mortality with = 0.95, P = 0.49). Using pooled = 658.5, P < 0.0001; Figure 4B). Bole 97 few options for their protection. Cutting, to provide more optimal tree spacing, remove brood trees, or provide buffer zones, is oſten difficult or unfeasible in environments with high-value trees, leaving insecticides as the only known effective option for protecting selected trees. Research on the identifi- cation and deployment of disruptant semiochemi- cals is ongoing, but efficacious alternatives have yet to be identified for SPB (Strom and Clarke 2011). About 62% of forestlands in New Jersey are owned by families, and 73% of that group own between 0.4 and 4.9 ha (Crocker et al. 2008). Among these own- ers, aesthetics and nonindustrial uses are central to their objectives (Crocker et al. 2008), suggesting trees will be managed as high-value entities and their protection from identifiable hazards, like SPB, will be considered. Insecticide treatments can be expen- sive and are generally ineffective for goals other than protection of individual trees or resources. That is, they are not effective for population suppression, although infested boles may be cut and sprayed to reduce or eliminate the emergence of viable SPB brood (Swain and Remion 1983). Although there exist limited options for protecting pines from SPB, registered insecticidal products include bole sprays and systemics. In this and other studies with bark beetles, systemic products have underperformed bole sprays during the year of application (DeGo- mez et al. 2006; Grosman and Upton 2006). Against other forest insects, soil drenches in particular have shown inconsistent or delayed effects (Xu et al. 2008; Doccola et al. 2012). This is not surprising because soil drenches are subject to additional environmen- tal influences through the soil and over time, but it is an important consideration for tree protec- tion treatments against bark beetles. Stem-injected products are less susceptible to those influences but usually require some level of tree injury for applica- tion and may introduce other heterogeneities via the spatial pattern of injection points. They also, how- ever, may provide multiple-year effects and have more impact against bark beetles (Grosman et al. 2002; Grosman et al. 2010) along with a wider range of available AIs; the utility of stem-injected prod- ucts against bark beetles continues to be evaluated (e.g., Grosman et al. 2010; Strom et al. unpublished). Regardless of application method, systemic AIs now available, including imidacloprid, must be ingested by the attacking beetles to be most effec- ©2015 International Society of Arboriculture
March 2015
| Title Name |
Pages |
Delete |
Url |
| Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait
