A Dutch scientist who raised 75,000 virgin cockroaches has successfully isolated their aromatic sex lure.

A newly synthesized artificial form of the chemical excitant can confuse or trap eager males and prevent them from mating.

The payoff could be a way to control some roach infestations. But only some, for several reasons. For one, the excitant is that of the American cockroach, which is less common than the German cockroach as an American pest.

The German cockroach is more common in homes and home kitchens. But the American cockroach is a frequent basement and restaurant dweller, and scurries around in some home kitchens too.

Female American cockroach eggs can sometimes hatch without male benefits.

They produce only female offspring, but offspring as annoying as their male unbrothers.

In short, say scientist, it's too early to say goodbye to the roach, and in fact that may never happen.

But in man's unceasing war against the 275-million-year-old breed, any victory at all may be of cheer.

"After decades of effort," the American Chemical Society, has reported, the Dutch scientist's feat - and the synthesis of the compound at Columbia University - may provide "a new avenue for control of the city dweller's nemesis."

"This compound won't eradicate the American cockroach - I don't think we'll ever eradicte the cockroach," said Dr. Louis Roth of the Army's Natick (Mass.) Research and Development Command, one of the worldhs great cockroach scientists.

"But this compound may well be of practical use in cockroach control," he added. "The Dutch say they've trapped large numbers using the crude attractant."

"I think we may see control of infestations in some homes," said Dr. Martin Jacobson of the Agriculture Department experiment station at Beltsville, a leader in the field of insect sexual attractants.

The whole field is "slowly exploding," said Dr. Merrill Cleveland at Beltsville. The sex excitants of the gypsy moth, cabbage looper, pink bollworm, Oriental and Mediterranean fruit files, western pine bettle, peach tree borer, codling moth, Japanese beetle, tobacco budworm and the corn ear or cotton boll worm have all been isolated and synthesized, some just in recent years.

Few have come onto the market, however. Last August an article in Harper's magazine accused the Enviromental Protection Agency of requiring so many years of testing, costing from $500,000 to $1 million that pesticide-makers lost interest in developing these products.

"I don't think the issue is that simple," Cleveland maintained. One problem, he said, is that each attractant affects just one species, so "there isn't the profit motive" of a multipurpose pesticide.

However, another Agriculture Department official said, "Harper's had it about right. We understand that, partly as a result of the Harper's article, EPA is going to be greasing the skids for faster approvals."

"I wouldn't say we're greasing the skids," said EPA's Dr. Martin Rogoff. But he reported that "in a few weeks" EPA will publish a new biological pesticides policy in the Federal Register in a more expeditious way."

Then "over the next 20 months," he said, EPA will develop simplified guidelines for biological pesticide testing already," to make regulation move faster.

This may help the new sex war against the cockroach.

But don't overlook that word "may." "A well-known scientist," according to Roth, "predicted that the last creature left on Earth would be a dying grasshoper on a dying blade of grass.

Roth and co-workers first reported in 1952 that the female American roach produced a pheromone, or attractant, that was spread by its feces to entice males. In 1963 Beltsville's Jacobson and Morton Beroza - the scientists who isolated and synthesized the female gypsy moth's sex lure - reported doing the same for the American raoch.

It turned out that they hadn't made a pure enough isolation. Not until 1976 did C. J. Persoons of the Centraal Laboratorium TNO in Delft isolate a mere 200 millionths of a gram of periplanone B, the American roach's principal lure.

Persoons worked out some of the compound's tricky chemistry. W. Clark Still at Columbia University worked out more of it. Jon Clardy at Cornell University and Koji Nakanishi and Michael Adams at Columbia added to the picture of the complex chemical structure.

When synthesized by Still and tested by Persoons, a mere hundredth of a gram turned out to be enough to excite 100 billion males.

For an even more powerful attractant, the scientists still want to solve the structure of a companion substance, periplanone A, and of seducin, the chemical that males excrete to make females receptive.

They would like to find a way to use sexual attractants against the German cockroach. Its sex excitant was actually isolated and synthesized five years ago by Japanese scientists, without much publicity. Unlike the American cockroach excitant, which can be whiffed by prowling males, the German roach compound turned out to be only a "surface excitant," luring a male only if he happens to touch it.