The Canadian government ordered four wheat-laden Russian vessels to leave for international waters because of insect infestations.

The move thwarted attempts by a European firm to seize the ships in lieu of alleged money owed, government officials said.The order to move out of Canadian waters was served on Saturday and came after the discovery of Asian gypsy moth infestations on the ships, said Barb Edwards, senior program officer for the Plant Health, Food Production and Inspection Branch of Agriculture Canada.

The four ships, the Amderma, the Vladimir Mordinov, the Kapitan Tysrul and the Kapitan Dublitsky, departed Saturday evening, Ms. Edwards said, adding that the Canadian Navy tracked the vessels until they were out of Canadian waters.

Two of the four vessels had their cargoes seized on behalf of the European shipping line Eurorose Navigation earlier this month, she said.

After the arrest of the two vessels, inspectors began searching for and confirmed the presence of Asian gypsy moth eggs.

During the loading of grain on the two other vessels, inspection services found more eggs on one and suspected similar infestations on the second, Ms. Edwards said. The vessels were arrested upon completion of loading last week.

Irene Arseneau, media relations for Justice Canada, told Knight-Ridder

Financial News that Eurorose Navigation, through the legal representation of Langloysis, Robert, Gaudreau of Montreal, obtained the seizure orders of the cargoes through the federal courts of Canada.

The reason cited for the seizure was for alleged non-payment by Exportkhleb of previous freight services performed by Eurorose, Ms. Arseneau said.

However, Ms. Edwards said the threat posed by the insects to the Canadian forestry industry grew during the seizure and facilitated the need to remove the vessels from Canadian waters.

While European gypsy months are common in North America, the Asian variety is considered much more destructive, feeding on conifer and deciduous trees.

In Ottawa, Andrew Lam of Plant Inspection Services said under the Plant Protection Act, Agriculture Canada has the power to request the vessels move out of Canadian waters if there are reasonable grounds to do so.

The federal court-order seizing the cargo and Agriculture Canada's requirement for the vessels to leave Canadian waters is currently before the courts, Mr. Lam said.