Francis M. Mullen Jr., head of the Drug Enforcement Administration, says that this year 40 states will participate in a program to eliminate home-grown marijuana.

The 25 states that took part in the DEA's domestic marijuana eradication program last year reported the seizure and destruction of more than 2.5 million marijuana plants, more than had been believed to be growing.

National Guard troops will assist this year in the crackdown in 10 states.

Meanwhile, the DEA is using U2 spy planes with NASA pilots to locate and photograph marijuana fields in northern California and southern Oregon and three other unspecified states. The U2s are reportedly perfect for the mission because they can take high-quality photographs without being spotted from the ground.

The flights will continue through August, when state and local authorities will move in on areas that the photographs indicate are marijuana fields.

The DEA is paying $200,000 of the program's costs. State and local authorities are supposed to pay the rest, an unspecified amount.***

STOP THIEF . . . DEA agent William N. Aldridge recently went through an experience that is every agent's nightmare.

Aldridge was waiting at the airport in Sao Paulo, Brazil, enroute to another city where he was scheduled to pay off an informer.

He reportedly stopped in the airport coffee shop and set down his briefcase to take off his jacket. As he bent down to drape the jacket over the briefcase, he realized it was gone--along with the $2,000 in payoff money inside.

Local police searched the airport but were unable to locate the thief. They reported that they were in the midst of an epidemic of briefcase snatchings.

Meanwhile, the unfortunate agent was left with some explaining to do. But Aldridge will not have to repay the money. After an investigation, the General Accounting Office has declared that the money was not lost due to negligence.***

TAKE A BITE OUT OF CRIME . . . The third National Crime Prevention Fair is scheduled to be held Wednesday from 10 a.m. to 7 p.m. on the Mall opposite the Air and Space Museum.

Featuring McGruff, the anti-crime dog, the fair will include exhibits from the FBI, the Secret Service and many other federal and state agencies. It will include police helicopters, a police boat and members of three canine corps.

There will be films, lectures and brochures on topics ranging from locks and burglar alarms to self defense and neighborhood crime watch programs.

Even the Boy Scouts of America will be there to offer tips on crime prevention.