kompong siem district, Kompong Cham province – Army worms are ravaging hundreds of hectares of rice and vegetable fields here in what may be the worst infestation of the caterpillar the province has ever seen.
Farmers in the area expressed fears for the survival of their entire wet-season crop, which, if destroyed, could spell economic disaster for the approximately 200 families affected by the outbreak.
“I used to clean rubbish out from under my stilt house,” Sun Lay, a 50-year-old farmer, said Friday, “but now I’m busy cleaning out the army worm instead.”
Thach Trim, a 44-year-old farmer living about 10 km west of Kompong Cham town, said the army worms have infiltrated his
2 square hectares of newly planted seedbeds and have started to eat the rice seedlings.
“In all my life, I’ve never seen such huge amounts of caterpillars,” he said.
The soft-fleshed brown army worms—a subspecies of caterpillar—are about half the length of a finger. They are so-called because they move in large groups in search of plants for food.
The worms were crawling all over Thach Trim’s plants Friday.
On one seedling, four or five of the worms clung to a single leaf.
The outbreak has local officials scratching their heads over where the insects came from.
“We are sending our officials down to almost every district to examine the situation,” said Taing Vanna, chief of the provincial Agriculture office. Officials said 94 hectares in Kompong Siem district alone were destroyed.
Army worms generally hatch with the first rain after their eggs are laid. The worms have come out in record numbers this year because their parent moths had an abnormally long dry spell in which to lay eggs.
Agronomists have said the global weather phenomenon El Nino caused the last wet season to end prematurely.
Ministry of Agriculture officials last week undertook a large-scale pesticide-spraying campaign to help stop the worms’ migration.
The Agriculture officials also advised farmers to dig troughs around their fields and fill them with ash to trap the worms.
On Friday, Hean Vanhan, deputy chief of plant protection for the Ministry of Agriculture, and a group of ministry officials carted 40 liters of the “Decis” pesticide to Kompong Cham and spread it with two pressure tanks.
However, the campaign drew criticism from experts who said spraying may have been a waste of time and money because army worm populations are due to decline naturally.
After four to five weeks of feeding, the worms head underground to pupate into moths. Flooding from heavy rains also makes it difficult for the worms to feed, and encourages them to burrow underground.
And the particular use of harsh pesticides Friday raised questions about whether a gentler pesticide could have been employed.
“It’s highly likely that nature will take care of itself,” one expert said Sunday.
The Agriculture officials acknowledged that the outbreak, which they say damaged rice seedlings in at least four Kompong Cham districts, may decline soon if rains increase.
Officials from the Integrated Pest Management unit in the ministry also criticized the use of Decis, saying it can kill aquatic and insect life. That could ensure that the army worm and other crop-destroying insects do not have any natural insect enemies left to curtail their populations, officials said.
Pest management and International Rice Research Institute officials said they prefer the “Thuricide” pesticide because it is less of a health hazard to people and has minimal effect on the environment.
Hean Vanhan insisted that his people must use the Decis pesticide as it is the most efficient control of emergency outbreaks.
Gary Jahn, a crop protection officer with the Cambodia-IRRI-Australia Project, said there are reports of army worm infestations in Kompong Speu and Kompong Thom provinces. He said that while this is the first outbreak of its kind in Kompong Cham, he has seen similar cases in the past in Thailand, Laos and Vietnam.
(Additional reporting by Marc Levy)