Effectiveness of the International Phytosanitary Standard ISPM No. 15 on Reducing Wood Borer Infestation Rates in Wood Packaging Material Entering the United States

Numerous bark- and wood-infesting insects have been introduced to new countries by international trade where some have caused severe environmental and economic damage. Wood packaging material (WPM), such as pallets, is one of the high risk pathways for the introduction of wood pests. International recognition of this risk resulted in adoption of International Standards for Phytosanitary Measures No. 15 (ISPM15) in 2002, which provides treatment standards for WPM used in international trade. ISPM15 was originally developed by members of the International Plant Protection Convention to “practically eliminate” the risk of international transport of most bark and wood pests via WPM. The United States (US) implemented ISPM15 in three phases during 2005–2006. We compared pest interception rates of WPM inspected at US ports before and after US implementation of ISPM15 using the US Department of Agriculture AQIM (Agriculture Quarantine Inspection Monitoring) database. Analyses of records from 2003–2009 indicated that WPM infestation rates declined 36–52% following ISPM15 implementation, with results varying in statistical significance depending on the selected starting parameters. Power analyses of the AQIM data indicated there was at least a 95% chance of detecting a statistically significant reduction in infestation rates if they dropped by 90% post-ISPM15, but the probability fell as the impact of ISPM15 lessened. We discuss several factors that could have reduced the apparent impact of ISPM15 on lowering WPM infestation levels, and suggest ways that ISPM15 could be improved. The paucity of international interception data impeded our ability to conduct more thorough analyses of the impact of ISPM15, and demonstrates the need for well-planned sampling programs before and after implementation of major phytosanitary policies so that their effectiveness can be assessed. We also present summary data for bark- and wood-boring insects intercepted on WPM at US ports during 1984–2008

Changes over time for wood-infesting insects entering the US in WPM by world region.

<p>Annual changes in the percent composition of six major world regions as the origin for bark and wood-infesting insects intercepted in WPM associated with imports to the United States during 1984–2008. Values were calculated for each year based on the total number of WPM-interceptions in PestID where the world region of origin was recorded (N = 13,607 interceptions. No world region was listed for 161 records). Abbreviations are: Cen Am = Central America+Caribbean Islands, Europe = Europe, including Russia and Turkey, N Am = Canada+Mexico, and S Am = South America. No data are shown for the relatively few interceptions made on imports from Australia, New Zealand, Philippines, and countries in the Middle East.</p

Summary data for the 13,768 interceptions of bark- and wood-infesting insects in WPM at US ports during 1984–2008 by country of origin and insect family or subfamily (Source = USDA APHIS PestID database).

a<p>The values for the weevil family Curculionidae do not include the two subfamilies Platypodinae and Scolytinae, which are listed separately.</p>b<p>Country codes: BE Belgium, CA Canada, CN China, DE Germany, ES Spain, FR France, GR Greece, IN India, IT Italy, MX Mexico, PT Portugal, RU Russia, and TR Turkey.</p>c<p>The category “Other” did not include 432 records for which no country of origin was listed.</p

Changes over time in major groups of wood-infesting insects entering the US in WPM.

<p>Annual changes in the percent composition of eight major groups of WPM-infesting insects intercepted at US ports during 1984–2008. Percent values were calculated for each year based on the total number of WPM-interceptions in PestID for those eight groups of insects in each particular year (N = 13,768 interceptions for all 25 years). Abbreviations are: BUP = Buprestidae, CER = Cerambycidae, COS = Cossidae, CUR = Curculionidae (not including Platypodinae and Scolytinae), PLAT = Platypodinae, SCOL = Scolytinae, SES = Sesiidae, and SIR = Siricidae.</p

Probability of detecting a statistically significant reduction in infestation rates if actual rates of infestation were reduced by the designated percentages after ISPM15 implementation based on post-hoc power analyses that used the observed pre-ISPM15 infestation rate and actual pre- and post-ISPM15 sample sizes from the Phase-1 scenarios presented in Table 2.

<p>Probability of detecting a statistically significant reduction in infestation rates if actual rates of infestation were reduced by the designated percentages after ISPM15 implementation based on post-hoc power analyses that used the observed pre-ISPM15 infestation rate and actual pre- and post-ISPM15 sample sizes from the Phase-1 scenarios presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone-0096611-t002" target="_blank">Table 2</a>.</p

Percent reduction in infestation rate on a consignment basis for bark- and wood-infesting insects in WPM associated with US imports after implementation of ISPM15, using two different dates to separate pre- and post-ISPM15 and different country groupings.

a<p>All countries were included in the analyses except various combinations of Canada (CA), China (CN), and Mexico (MX). See text for details.</p>b<p>Total = number of consignments analyzed after dropping the data from the selected countries listed. Pre- and Post-ISPM15 values, in order of appearance, are the number of pre-ISPM15 consignments with and without pests, and the number of post-ISPM15 consignments with and without pests. These were the values used in the contingency tables.</p>c<p>Analyses were conducted on AQIM records with WPM from 1 October 2003 through 30 September 2009. The United States implemented the first phase of ISPM15 on 16 September 2005 (Phase 1) and the final phase on 5 July 2006 (Phase 3).</p>d<p>Infestation rates were based on the table values presented here under ‘No. consignments.’ For example: (12/6327) *100 = 0.1897%.</p>e<p>Percent reduction is based on the difference between the pre- and post-ISPM15 infestation rates as given in this table. The formula used was [(Pre – Post) *100/Pre]. The <i>P</i> values were based on 2 x 2 contingency tables using the values presented in this table and analyzed with the Fisher’s exact test (right-sided).</p

Changes over time for wood-infesting insects entering the US in WPM by country of origin.

<p>Annual changes in the percent composition of the top 10 countries of origin for bark and wood-infesting insects intercepted in WPM that were associated with imports to the United States during 1984–2008. Values were calculated for each year based on the total number of WPM interceptions in PestID where the country of origin was recorded (N = 13,328 interceptions. No country of origin was listed for 440 records). Abbreviations are: BE = Belgium, CN = China (not including 24 interceptions from Hong Kong and 42 from Taiwan for all years), DE = Germany, ES = Spain, FR = France, IN = India, IT = Italy, MX = Mexico, RU = Russia (including 32 interceptions coded as Soviet Union from 1984 to 1993), and TR = Turkey.</p

Summary data for the incidence of live insects found in association with WPM during surveys of imported goods that were conducted before or after implementation of ISPM 15 in various countries.

a<p>Seaport = maritime seaports; Con = containerized cargo; Non-Con = non-containerized cargo, also called break bulk cargo; Land ports = land border crossing between Mexico and USA.</p>b<p>WPM = wood packaging material. Consignment = typically these are imported goods that are similar in nature, have a similar origin, have been packaged and shipped in a similar manner, and have arrived at a port-of-entry at the same time. WPM items = individual units such as one entire pallet, or all crating associated with one imported product, or one piece of dunnage.</p>c<p>WPM infestation levels were based on values reported by the authors or on calculations based on data they included in their published papers. The infestation rate in Bulman <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-Bulman1" target="_blank">[33]</a> was based on the 1366 consignments that definitely contained WPM (i.e., cases, crates, pallets, and skids) as presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone-0096611-t003" target="_blank">Table 3</a> of that paper. These inspections were based on a random sample of less-than-full container loads. The rate in Bulman <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-Bulman2" target="_blank">[34]</a> was based on the 7916 consignments listed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone-0096611-t004" target="_blank">Table 4</a> of that paper that definitely contained WPM, using the same categories listed for Bulman <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-Bulman1" target="_blank">[33]</a>. These inspections targeted primarily containers with full-container loads of cargo considered high-risk by the inspector and consisted of “door inspections” in which the doors at the end of the container are opened and all commodities are inspected as well as possible without removal. The values given in Salvage <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-Salvage1" target="_blank">[35]</a> were the published infestation levels and the containerized cargo was for less-than-full container loads; no information was given on how the consignments were selected. Values in Sánchez-Salinas <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-SnchezSalinas1" target="_blank">[37]</a> were for all consignments with WPM that arrived at the maritime port of San Antonio, Chile, during the 30-month inspection period (18 mo pre- and 12-mo post-ISPM15), and were based on data in Tables 8 and 10 in the thesis <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-SnchezSalinas1" target="_blank">[37]</a> after deleting the bostrichid data so that the analysis would be similar to our analysis of the AQIM data. Using the sample size data presented in Sánchez-Salinas <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-SnchezSalinas1" target="_blank">[37]</a>, the calculated 47% reduction in infestation rate of WPM entering Chile after implementation of ISPM15 was not statistically significant (<i>P</i> = 0.23, Fisher’s exact test, one-tailed). Zahid et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-Zahid1" target="_blank">[36]</a> presented actual infestation levels of individual WPM items with the ISPM15 mark that were sampled at three maritime seaports; however, the authors did not state how the WPM items were selected. Haack and Petrice <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096611#pone.0096611-Haack4" target="_blank">[28]</a> presented infestation levels of individual WPM items sampled at five seaports and one land border crossing during a 2-wk period at each port; the sampled WPM items were from containers that were selected for inspection during normal port operations.</p>d<p>Percentage values for the frequency at which bark was found is based on the same sampling protocol described above in footnote c.</p

Changes over time for wood-infesting insects entering the US in WPM by associated commodity class.

<p>Annual changes in the percent composition of five major commodity classes of imports that entered the United States during 1984–2008 and were associated with interceptions of bark and wood-infesting insects in WPM. Values were calculated for each year based on the total number of WPM-interceptions in PestID where the imported commodity was recorded (N = 8661 interceptions. No imported commodity was listed for 5107 records). Abbreviations are: FM = fabricated metal products (e.g., ironware, metalware, tubes, and wire), ME = machinery and equipment, PM = primary metals (e.g., aluminum, iron, and steel), QT = quarry products and tiles (e.g., granite, marble, slate, and tiles), and VF = vegetables and fruit.</p

Summary details for four studies where the effects of heat treatment were tested on emerald ash borer (EAB), <i>Agrilus planipennis</i>, and how these studies compared with ISPM15 standards.

<p>Summary details for four studies where the effects of heat treatment were tested on emerald ash borer (EAB), <i>Agrilus planipennis</i>, and how these studies compared with ISPM15 standards.</p