The teachers stood between rows of sprouting plants, learning about a quiet war unfolding one summer day in the fields of Clagett Farm in Prince George’s County.

The Colorado potato beetle, an insect with an orange abdomen, was attacking the eggplant crop. This squadron of nine educators was tasked with finding the invaders.

During the school year, they teach classes from kindergarten to high school chemistry. On this day, they gathered to glean some teaching tips that would help county schools comply with a new Maryland standard for every student to graduate with “environmental literacy.”

Advocates call the state a leader in environmental education. The goal of the Maryland standard, which the State Board of Education approved June 21, is to teach students to examine ecosystems and make educated decisions on how to “create and maintain an optimal relationship between themselves and the environment.”

“It’s unique, and the implication is that their Board of Education takes environmental education seriously,’’ said Linda Rhoads, interim executive director of the North American Association for Environmental Education.

Rhoads’s group is lobbying for similar efforts throughout the country. In addition, Pennsylvania, Maryland, Virginia and the District signed a compact with the Chesapeake Bay Foundation in 2000 that guaranteed school systems would provide a “meaningful bay or stream outdoor experience for every student” before leaving high school.

Maryland’s environmental literacy initiative will take effect in the next school year. There are no plans for state testing to enforce the standard, said William Reinhard, a spokesman for the State Department of Education. The goal, he said, is to ensure that local schools have lessons ingrained within the curriculum.

To that end, a group of professionals met on the 285-acre farm in Upper Marlboro to squish bugs. Armed with latex gloves, the teachers examined leaves and tiny purple blooms for the crop-eating beetles. The teachers then squeezed the ones they found.

“My kids are going to love this,” said Karen Keith, a special education teacher at Oxon Hill Middle School. “They think bugs are icky.”

For eight years, the Chesapeake Bay Foundation has offered this training program at Clagett Farm to teach teachers about the environment. The goal is to give them ideas for lessons in the coming school year.

This summer, 425 teachers and principals signed up for the program, up 22 percent from the previous year, said foundation spokesman Tom Zolper. Over five days, participants spend time on the farm and visit a recycling plant and farmers markets.

Advocates say environmental education sometimes gets crunched out of the school day because of an emphasis on testing in math and reading under the federal No Child Left Behind Act. In response, some advocates have formed a coalition called No Child Left Inside to push for environmental education legislation at the federal level.

Budget strains also have threatened long-standing environmental education programs, such as Camp Schmidt in Prince George’s. This year, the county school board opted to preserve the camp after heavy lobbying from the community.

The new state standard calls for teachers to work biospheres, recycling, sustainability and outdoor field trips into their lesson plans. It does not require a separate class in environmental education.

At Clagett Farm, teachers displayed varying degrees of comfort with nature. As Melissa Simmons, an educator at the farm, pointed out how to tell whether an onion is ready to be pulled from the ground (when a brown film has formed on the outside), a first-grade teacher from Laurel froze. A caterpillar was climbing into her shoe.

“Get it off me!” screamed Latdavone Insyxiengmay of Scotchtown Hills Elementary School as another teacher came to her rescue. But by day’s end, Insyxiengmay was walking among the farm’s red Angus cows as she discussed the benefits of grass-fed cattle.

Manoranjan Kaur, a Surrattsville High School chemistry teacher, took notes at an experiment that showed how different land uses affect runoff into the bay. A similar experiment, she learned, could be performed at school with buckets and water.

“There’s so much that we can do with these lessons,” Kaur said. “I’m eager to take them back to the classroom.”