Last year, Halloween was more trick than treat for the nation's candymakers. In the shadow of the Tylenol scare, many communities, fearing ''copycat'' poisoning incidents, banned trick-or-treating. As a result, candy sales were generally off 10 to 25 percent around the country.
This year the candy industry has geared up a big public-information program to reassure parents that Halloween can be a safe holiday and a tradition worth preserving - and incidentally to help sales of treats.
''We've been doing very well, with shipments well ahead of last year's,'' says Richard T. O'Connell, president of the Chocolate Manufacturers Association and of the National Confectioners Association.
A Hershey Foods Corporation spokeswoman echoes Mr. O'Connell's assessment. ''Customer response to our seasonal promotional program has been very enthusiastic, and actual sales have been very good,'' says Deborah Ryerson, manager of media relations at Hershey.
The industry safety program, sponsored by the National Candy Wholesalers Association along with the other two trade groups, includes a list of tips for parents as well as a telephone hot line for the nation's police forces. If suspect candy is turned in, representatives of the manufacturer can advise as to what chemical tests might be in order. ''We're very, very supportive of this hot line,'' says Robert Angrisani, director of communications of the International Association of Chiefs of Police.
Dr. Joyce Brothers, the well-known psychologist and advice columnist, has been enlisted to promulgate the safety tips and generally reassure people.
''The safety program isn't something brand new; we've been doing this for 10 years,'' says Lenore Cooney, spokeswoman for the trade associations. But the program is being pushed ''to a greater degree than last year.''
Ms. Cooney also stresses that this is a public-information campaign; actual advertising, that is, pushing of the products, is being done by the individual manufacturers.
Dr. Brothers, acknowledging that her work with the candy groups is ''an unusual project'' for her, told the Monitor: ''I really do think the holidays are meaningful, and the children shouldn't be deprived of them just because of a few sick people out there. Halloween is one time when the children can have a feeling of power - they can dress up as Wonder Woman or Superman. After all, we didn't stop celebrating the Fourth of July because fireworks are dangerous. We just put them in the hands of those who can handle them properly.''
The candymakers are urging parents to accept only packaged candy, and only from people they know. Parents are told to put the children in high-visibility costumes - reflective tape is recommended - and to be sure the kids' masks have adequate eyeholes. ''And if you can't cut them bigger, you should just use makeup on the children,'' Dr. Brothers says. ''They feel as 'disguised' in makeup as in a mask.'' Costumes shouldn't be so long the kids may trip.
Ms. Cooney says that of the 270 incidents of alleged tampering with candy reported to the Food and Drug Administration last year, 95 percent turned out to be false alarms. She adds that at a time when concern is high, people are often scared by harmless phenomena such as ''chocolate bloom'' - sugar coming to the surface of a chocolate bar, a result of storing the candy at too high a temperature. ''Or they see crystallized sugar and think it's broken glass.'' These are aesthetic rather than health and safety problem.
In any case, enough people overcome their fears to bring the per capita consumption of candy in this country to 16.3 pounds last year, according to Mr. O'Connell. ''Consumption was up six-tenths of a pound in 1982.'' Annual sales growth has been some 2 to 3 percent in recent years, a level O'Connell calls ''very good.''
Exact figures for the candy industry - which has an annual wholesale sales volume around $5.5 billion - are hard to come by, because so many candymakers are subsidiaries of larger food concerns, and so many independent companies are privately held. But industry sources agree that Halloween is a big season, after Christmas and Valentine's Day, although O'Connell notes, ''Our biggest 'holiday' is just everyday sales - candy bars from the supermarket and that sort of thing.''