599 - 9/08 - Asian Gypsy Moth - USA


During the past month Customs and Border Protection (CBP) inspectors have intercepted live Asian gypsy moth (AGM) egg masses on seven commercial vessels at U.S. berths, mostly from Japan.

Three of these events have been severe enough to consider vessels significantly infested.

These vessels were ordered into international waters and not allowed to re enter until all egg masses and life forms were removed and destroyed. In all cases, delays in cargo loading and in routine clearance were significant. These incidents can be avoided by adherence to strict sanitation standards of removing and destroying all AGM egg masses prior to port arrival.

This emerging situation is a very serious pest concern that could result in widespread pest infestations in the U.S. forests in a relatively short time. In comparison, there was only one AGM vessel detection in each of the years 2006 and 2007 in the U.S. These recent events are leading U.S. officials to believe that AGM populations in seaport areas in Japan, and other parts of Northeast Asia, have risen dramatically.

It is imperative that industry representatives and the U.S. collaborate on measures closely to reduce these incidents as soon as possible. Since the shipping industry is interested in quarantine compliance and maintaining schedules, cooperation in support of measures to reduce AGM risk at origin for exports to the U.S. is needed.

Reports are coming in of swarms of moths at various ports in Japan, and elsewhere where AGM is known to exist. This is occurring especially during night operations for cargo loading and unloading. Bright lights are attracting the gypsy moths to the vessels. The periods of risk for Asian gypsy moth flight and infestation ranges from June 1- August 15 in Southern Japan to July 15 - October 1 in Northern Japan and Far East Russia. China and Korea have similar flight periods of risk.

Port inspectors have developed inspectional expertise and better targeting over the past two years. The U.S. believes that we may be dealing with a major AGM population spike in Japan this year, as Russia has experienced during the past two years. These spikes occur in 10- 15 year cycles. We also suspect that this may happen in Korea and China.

Populations of gypsy moth worldwide are known to spike almost simultaneously, within 1-2 years of each other. Populations then decline for a couple of years before later collapsing. Until populations decline, we will need to have increased collaboration with shipping lines, agents, and associations in order to try to minimize these events with support of port monitoring and vessel pre inspection techniques. While these interceptions are presently occurring on the U.S. West Coast and Texas, shipping lines can expect increased AGM inspection nationwide.

It will be necessary for shipping lines to order all vessel crews to conduct intensive vessel inspection to remove (scrape off) and destroy all egg masses prior to entering U.S. waters. The egg masses can be found anywhere on the vessel superstructure and anywhere that doors were open while in port. Locations include barrel containers used for trash or liquid, etc.

Egg masses may also be found on the lines used to moor the vessel to the dock, extra lines laying on the deck, very high on the vessel super structure, on air intake vents, vessel smoke stack, on the tracks used for crane movement, on the outside hull, on a container stored on the deck, and inside a wheel/tool house or room on the aft deck.

The egg masses will also be seen throughout the vessel meaning on the aft deck, starboard and port sides of the deck and housing, on the bow, and on the main deck and upper decks of the main super structure, cargo hold framing, and other vessel framing including safety rails. The outside of containers must also be inspected.

In significant infestations CBP inspectors have detained vessels with 50 to over 100 live viable egg masses located throughout the ship. Each egg mass can contain several hundred eggs.

Please note that this includes bulk cargo, grain, and container vessels.  Vessels are not authorized to load or unload cargo until they are free of AGM life forms (egg masses, live larvae, and live adults).

These vessels will be ordered into international waters and, under the Plant Protection Act, will not be authorized until all egg masses and life forms are removed and destroyed. The agent may contact pest control companies for assistance. Due to North American coordination to prevent entry of this pest, vessels are informed that they cannot redirect to Canada or Mexico, but can choose to proceed to other foreign locations.

In the past, Industry associations and agencies have maintained excellent cooperation with U.S. agricultural compliance. Since 2007, pre departure inspection for AGM in Japan is in place and going well. USDA is not recommending avoidance of any foreign port.

However, due to these extreme conditions, we are recommending that vessels transiting in Far East Russia and Japan during designated periods maintain compliance by obtaining certification prior to departure from these countries. In addition, all vessels must insist on high levels of vigilance and self inspection to insure that no egg masses remain on board the vessel when it arrives in the U.S.

The consequences of inadequate preparation are very high.

Source of information:

Michael Simon

Senior Staff Officer

Quarantine Policy, Analysis, and Support


Riverdale, MD 20737

PH: 301-734-4374

FAX: 301-734-5269

E mail



Staff Author