MUCH IN THE MANNER of locusts (but more often), the litterbug lobby -- the makers, takers and breakers of throwaway bottles and cans -- swarm in to gnaw at any sensible law calling for deposits on beverage containers. The latest invasion is in Fairfax County, where the people who manufacture tens of billions of throwaways every year have managed to get the 10 ears and five votes of a majority of the board of supervisors in a move to undo the law there.

"I believe in a statewide approach," said Supervisor Tom Davis, who sponsored this first step toward repeal of the county's 28-month-old deposit law. But rather than clinging to his belief and leaving the local law alone while pushing Richmond for a good state law, Mr. Davis is maneuvering to bring throwaways back to Fairfax. Joining in this retrogression as Chairman John F. Herrity and members Joseph Alexander, Nancy Falck and Sandra L. Duckworth.

Four other supervisors -- Vice Chairman Martha V. Pennino and members James M. Scott, Audrey Moore and Marie B. Travesky -- saw no reason to tinker with the county law and voted against Mr. Davis and Co. Preservation of the county deposit is important not only to the county's countryside and to energy conservation efforts, but also to moves by other local governments to join Fairfax in making the convenience and savings or returnable containers effective throughout the region. It is not, as the voices of metal and glass waste would have poeple believe, a matter of "forcing" consumers to bring back their containers; nobody need bring back anything, but the deposit laws provide an incentive for those who do.

Besides, smart shoppers have discovered that there can be considerable savings in returnables (though inflation keeps kicking all prices up). That's how it should be, after all, since purchasers of returnables are borrowing the containers instead of buying them and then either tossing them out or hauling them to recycling centers to be made all over again into new bottles and cans. Until the rest of the region joins in authorizing deposits, there are bound to be some transitional difficulties. But Fairfax County is one of the pioneer jurisdictions in the shift away from the cost, mess and waste of resources that accompany the use of throwaways -- and that is a distinction worth preserving.