CHERRYFIELD — Blueberry growers in western Washington County say that the continued availability of labor, especially in the processing plants, will determine how this season’s harvest will compare with the record-breaking 1988 crop.

All who are involved in the industry appear to agree that more than one third of the potential crop is still on the bushes and still in good condition. The fields that are being harvested this season are the same fields that produced the record crop of 1988. Dr. Fred Olday of Columbia, a research horticulturist with the Jasper Wyman and Son Co., said the set of fruit buds for the 1990 crop was the best he had ever seen on the barrens.

Maine has 50,000 acres of blueberry land, of which half is harvested each year, according to the Maine Department of Agriculture, Food and Rural Resources. The average yield per acre of 1988’s record 52.3 million-pound crop was 2,094 pounds, according to the same sources. By contrast, the 1989 crop of only 26.8 million pounds was harvested from fields that yielded only slightly more than 1,000 pounds per acre.

Olday has said repeatedly that the limits of the crop-yielding potential of the blueberry barrens were yet to be determined.

The main harvest effort began this year during the second week of August. Thirty-two crews, ranging in numbers from 45 to 200, were deployed by four of the state’s largest growers across a swath of blueberry fields extending from Beddington to Jonesboro. The names of many of the individual harvest fields were taken from geographical features: Grassy Pond, Otter Pond, Pretty Pond, Schoodic Barrens, “Oxbow Part,” and “Behind Hills 5.” Other names, such as “The Velvet” and “The Smooth Plain,” appear to refer to terrain conditions.

Support services for the migrant and seasonal agricultural workers in the annual blueberry harvest became available July 30 at a “rakers’ center” at the Columbia Town Hall and on Aug. 6 at a migrant-education program for youngsters under 12 years of age at the Milbridge Elementary School.

More than 900 families of migrant and seasonal workers, more than half of whom are from the eastern Canadian provinces, are served at the rakers’ center during the harvest season, according to Keith E. Small of East Orland. Small administers the center, where social, medical and legal services are provided under the sponsorship of the Washington-Hancock Community Agency.

Many migrant families already have left the area because schools in eastern Canada start earlier than Maine schools. The rakers’ center was shut down on Thursday, Aug. 23. By Friday, classes at the migrant school had ended for the season.

As yet, no one in the industry is willing to predict the value of Maine’s 1990 blueberry crop. The record crop of 1988 had a field cash value of about $24 million, according to the New England Agricultural Statistics Service. The growers of the 1988 crop received an average of 46 cents per pound, according to the same source.

The most recent five-year average of per-pounds prices paid to the growers of Maine’s blueberry crop is 34 cents, according to the Agricultural Statistics Service. During years such as 1987 and 1989, when the crop volume fell off sharply from that of the preceding year, the per-pound blueberry price either held steady or increased.

A rule of thumb in the industry holds that processing doubles the annual value of the blueberry crop.

The North American blueberry crop, wild and cultivated, reached a production peak in 1987 of 216.3 million pounds, of which wild blueberries from Maine and eastern Canada made up 86.9 million pounds.

The distinction between the so-called “wild” and “cultivated” blueberries is two-fold, according to specialists in the industry. The blueberry industry in Maine and Canada is based on plants that grew naturally and are stimulated to proliferate by means of pruning and also by the use of herbicides to extirpate competing plant species.

Another distinction is a genetic one, according to Olday. The low-bush blueberry species of Maine and Canada are very diverse genetically, while the cultivated blueberry exists in fewer than 20 varieties.