Asian Gypsy Moth male

Introduction to Asian Gypsy Moth

Published: 06 May 2021

Agm_pic_female Agm_pic_male Agm_pic_larva01
Female Moth Male Moth Larva (caterpillar)

Asian Gyspy Moth - why it is dangerous

Lymantria dispar (L.) Family Lepidoptera, commonly known as Asian Gypsy Moth (AGM) is a serious insect pest species. Its caterpillars are known to feed on the leaves of up to 600 species of trees.

It can be carried on ships and cargo. The female moth has the ability and capability during the flight season, of travelling up to 21 nautical miles, causing potential wide spread destruction in a country’s agricultural and forest industries. Due to the destructive nature of the AGM, many countries where the pest is not indigenous, have procedures in place to ensure that vessels entering their ports are AGM-free or subject to an AGM inspection. The countries that have well-established regulations to prevent the introduction of AGM by vessels that have called at ports in the AGM high risk areas are Australia, Canada, Chile, New Zealand and United States. Argentina is the latest country to put in place AGM regulations in 2021.

Below is a description of how AGM can infest itself and spread very quickly across a wide range of surfaces and locations.      

Life Stages

The AGM matures through four life stages: egg, larva (caterpillar), pupae (cocoon), and moth.

Egg mass

Agm_pic_eggmass Each egg mass can contain more than 1,000 eggs. The mass is covered with buff or yellowish fuzz from the abdomen of the female. While the velvety egg masses average about 38 mm long and about 20 mm wide, they can often be smaller. Each egg has a diameter slightly greater than 1 mm.

Eggs are laid indiscriminately, usually in sheltered locations on a wide range of surfaces. I.e., on ships' structures, containers and other cargo which aid in the spread of AGM.

AGM egg masses are tolerant of extremes in temperature and moisture and travel well on logs, pallets, shipping containers, and on the hulls and riggings of ships.

Eggs are laid between July and September, depending on weather and location. The eggs remain dormant during the winter and develop and hatch into caterpillars in the following spring.

Larva (caterpillar)

Agm_pic_larva02All of the damage caused by the AGM is done during the caterpillar stage, as the insects feed on leaves during this active period of growth. AGM caterpillars stop feeding when they enter the pupae or cocoon stage.

The larva are highly variable in colour with long hairs covering the body. Two distinctive rows of large spots lie along the back, usually arranged in five pairs of blue and six pairs of red from head to rear.

Newly hatched larvae can survive one week without feeding. Newly hatched larvae move up host plants to newly emerging foliage and begin feeding or if this is not available they can feed on the egg debris or be cannibalistic. The 1st and 2nd larvae instars also spin silken threads and can spread by ballooning long distances in the wind. Hence, vessels close to the coast may become infested by larvae ballooning or aerial drifting.

Larvae mature through six instars. During the first instar larvae are between 3 to 4 mm long, hairy and mostly dark brown and black in colour. During the second instar, they are between 10 to 12 mm long and are mostly black with orange markings down the back. The third instar stage (12 to 25 mm long) is similar to the second instar stage with the addition of pairs of blue spots along most of the back. During the fourth instar larvae are approximately 25 mm long; the pair of blue spots behind the head remains blue and the rest turn red. During the fifth and sixth instars, larvae become fully grown, are between 40 - 60 mm long and develop additional pairs (6) of brick red spots. This last stage is the period during which extensive defoliation of hosts occurs.

Pupae (cocoon)

Once mature larvae develop into the pupae stage in 2 to 4 days. This stage begins in June or July, depending on weather and temperature. Pupae are reddish brown in colour. After 10 to 14 days the adult moth emerges.


Agm_pic_moths Adult males have greyish-brown wings and a wingspan of about 38 mm. Adult female moths are white and larger, with wingspans up to 50 mm or more. AGMs do not feed in the moth stage (which lasts 1 to 3 weeks) but only mate and lay eggs. The male moth dies shortly after mating and the female after laying her eggs. Female AGMs are capable of flying up to 40 kilometres which also increases the likelihood of their spread and distribution. Furthermore, as the female AGMs are attracted by light they may lay their egg masses on surfaces of the ship exposed to night lights. However, if a ship is lit with shore based flood lights, egg masses could be found in all locations.



The AGM is indigenous to China and the Russian Far East. It has since become established in Korea and Japan.

The general areas*  considered to be a potential risk for the introduction of AGM are:

Russian Far East

1 July to 30 September
Nakhodka, Ol'ga, Plastun, Pos'yet, Russkiy Island, Slavyanka, Vanino, Vladivostok Vostochny, Zarubino, Kozmino


1 June to 30 September
All ports in northern China, including all ports north of Shanghai.
Note 1: USA & Canada defines this as all ports on or north of 31°15' north latitude.
Note 2: Chilean authorities defines this as all ports in China. 

Republic of Korea/Democratic People's Republic of Korea

1 June to 30 September
All ports


Region Port Location Non-inclusive List of Ports Within Flight Region AGM Flight Period
Northern Aomori, Fukushima, Hokkaido, Iwate, or Miyagi Perfectures Aomori, Hachinohe, Hakodate, Ishikariwanshinko, Kushiro, Muroran, Otaru, Rumoi, and Tomakomai 1 July to 30 September
Western Akita, Ishikawa, Niigata, Toyama, or Yamagata Perfectures Fushiki, Kanazawa, Nanao, Naoetsu,
Niigata, Sakata, and Toyama Shin
25 June to 15 September
Eastern Aichi, Chiba, Fukui, Ibaraki, Kanagawa, Mie, Shizuoka, or Tokyo Perfectures Chiba, Gamagori, Kashima, Kinuura, Kisarazu, Nagoya, Shimizu, Toyohashi,
Tsuruga, and Yokohama
20 June to 20 August
Southern Ehime, Fukuoka, Hiroshima, Hyogo, Kagawa, Kagoshima, Kochi, Kumamoto, Kyoto, Miyazaki, Nagasaki, Oita, Okayama, Osaka, Saga, Shimane, Tottori, Tokushima, Wakayama, or Yamaguchi Perfectures Aboshi, Amagasaki, Fukuyama, Hakata, Hannan, Hibikinada, Hirohata, Hiroshima, Kakogawa, Kobe, Kokura, Komatsushima, Kudamatsu, Matunaga, Mizushima, Nagahama, Niihama, Oita, Osaka, Sakai, Sakai-Senboku, Takamatsu, Tobata, Tokuyama, Ube, Uno, and Yahata 1 June to 10 August
Far Southern Okinawa Perfecture Naha 25 May to 30 June


According to Chilean requirements, the risk area covers ports located in the North East and Far East Asia, between 60° and 20° North latitude and this appears to include Vietnam. Further reference can be found under the Chilean AGM section.

* These areas may change from time to time and should always be double-checked with the port agent when going to these areas. 

Phytosanitary Certificates and Pre-departure Inspection Certificates

It is highly recommended (and in some cases necessary) that owners/operators obtain a so-called AGM certificate issued by an approved body. Such a certificate must state that the ship has been inspected and is free of any life cycle stages of the AGM. In order for the certificate to be valid, the Inspection must be undertaken on the day of departure from the last high risk port visited.

List of Recognized Sources of Phytosanitary Certificates and Pre-departure Inspection Certificates ( as at July 2017)

Phytosanitary Certificates issued by FGBU All -Russian Centre of Plant Quarantine ( FGBU VNIIKR).

A Pre-departure Inspection Certificate is an approved certificate if issued by the International Plant Quarantine Accreditation Board (IPAB) in the Republic of Korea.

A Pre-departure Inspection Certificate is an approved certificate if issued by the China Certification and Inspection Co. Ltd (CCIC) in the People’s Republic of China.

A Pre-departure Inspection Certificate is an approved certificate if issued by the following recognized third party inspection bodies in Japan:

  • All Nippon Checkers Corporation (ANCC)
  • The Japan Cargo Tally Corporation (JCTC)
  • Japan Export Vehicle Inspection Center Co., Ltd. (JEVIC)
  • Japan GrainExport Inspection Association (JGIA)
  • Hokkaido Bouekikunjyo Co. Ltd. (HBKC)
  • Hokuriku Port Service Co., Ltd. (HPS)
  • Intertek Testing Services (Australia) Pty Limited – Japan Branch (INTERTEK)
  • Kanto Fumigation Co. Ltd. (KFCO)
  • Kobe Plant Quarantine Association (KOBEPQA)
  • Keiyochiku Plant Quarantine Association (KPQA)
  • Kyoritsu Sanitary Co. Ltd. (KRS)
  • Muroran & Tomakomai Plant Quarantine Association (MTPQA)
  • Navrex & Corporation (NRX)
  • Nikkun Co. Ltd. (NCL)
  • Nippon Kaiji Kentei Kyokai (NKKK)
  • Okayama-Ken Plant Quarantine Association (OKYPQA)
  • Osaka Plant Quarantine Association (OPQA)
  • Osaka Timber Quarantine Association (OSKTQA)
  • Shin Nihon Kentei Kyokai (SNKK)
  • Techno Kasei Co. Ltd (TKL
  • Tokai Plant Quarantine Association (TOKAIPQA)
  • Tokyo Plant Quarantine Association (TPQA)
  • Yokohama Plant Protection Association (YPPA)

Asian Gypsy Moth Ship Poster
In order to increase the awareness of the Asian Gypsy Moth in the shipping industry the Australian Quarantine and Inspection Service, Biosecurity New Zealand, Canadian Food Inspection Agency and the United States Department of Agriculture jointly issued a Asian Gypsy Moth Ship Poster entitled "Inspect Before Entry". Owners are encouraged to provide copies of the poster to their vessels as a reminder to be vigilant of this threat.

Asian Gypsy Moth Inspectional Pocket Guide and Inspection Program For The Maritime Industry
The U.S. Department of Agriculture Animal and Plant Health Inspection Service has prepared the pocket guide and in cooperation with the U.S. Department of Homeland Security Customs and Border Protection, prepared also an inspection program, both of which are to  provide guidance to vessel operators on the recognition and response to AGM interceptions.

Asian Gypsy Moth Clause for Time Charter Parties

Please click here for the BIMCO AGM clause placing the basic obligations and responsibilities of the owners and charterers in respect of the AGM. 

Download RELATED Documents

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    Asian Gypsy Moth Ship Poster - Inspect Before Entry (JPG) 19.5 MB

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    Asian Gypsy Moth Inspectional Pocket Guide issued March 2006 0.1 MB

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    Asian Gypsy Moth Inspection Program For The Maritime Industry 2.5 MB

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    NAPPO RSPM No. 33: Guidelines for Regulating the Movement of Ships and Cargo from Areas Infested with the Asian Gypsy Moth revised 1 August 2017 0.4 MB

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Ai Cheng Foo-Nielsen


Ai Cheng Foo-Nielsen

Manager, Maritime Information

Copenhagen, Denmark