KADIMA, Israel — Rafaat Mwasy hefted an etrog in his hand, testing the fruit's size and weight, poking at the thick, bumpy skin with a toothpick, looking for unsightly holes or bruises.
Seventeen years as an orchard foreman have taught Mr. Mwasy, an Israeli Arab from Baka al-Garbiyeh, a nearby town, what Yossi Ludmir, his Orthodox Jewish boss, looks for in an etrog, or citron fruit.
"It's about shape, cleanliness and a perfect stem," he said. "A perfect etrog should be a thing of beauty."
The global market for the citron, a pulpy cousin of the lemon, is not large. Nearly the only use it has is in celebrating the weeklong Jewish autumn holiday of Sukkot. But what market there is has been dominated by Mr. Ludmir and his family for generations. The family holdings here, some 74 acres of orchards, produce 70 percent of the world's supply.
The whole enterprise — growing, harvesting, packing and selling — takes place each year from April through September or October, depending on when Sukkot falls. This year, the holiday came fairly early on the secular calendar; it ends on Sept. 27.
In a typical year, the Ludmirs ship around 100,000 etrogim, as citrons for ritual use are called, to the United States for the brief selling season, and another 70,000 are sold domestically.
Supplies were a little tight this year because of a chilly spring in Israel and the early dates for Sukkot.
When Mr. Mwasy's pickers are busy in the orchards in early September, the etrogim are still green; those destined for export will have time to finish ripening and turn yellow during shipment. But color is not crucial: shape, size, bumps and bruises determine which fruit is acceptable and which is worthless.
Mr. Ludmir, whose father, brothers and cousins are also in the business, handed a few to a group of customers who visited the orchard to choose in person, magnifying glass in hand.
"They come every year to fulfill the mitzvah of picking their own," Mr. Mwasy said, using the Hebrew term for a positive commandment. "The rabbis want 110 percent."
In the Torah, the Israelites are commanded to celebrate the Sukkot harvest holiday with fruit of "a beautiful tree," an expression that in Hebrew includes the word hadar. Hadar also means citron tree, so over the years rabbis have interpreted the passage to call for etrogim. Etrog is an Aramaic word literally meaning "delightful."
"To the untrained eye, this etrog looks like that etrog," said David Wiseman, an Englishman who wrote a book on etrogim and grows some of his own at his home in Dallas. "But if you're looking closely at every square centimeter with a magnifying glass, you want the minimum number of blemishes."
Some imperfections render the fruit unfit for use in the ritual, when they are shaken in six directions while held with a lulav, palm fronds woven with myrtle and willow branches. Other imperfections merely reduce the fruit's value. Most etrogim sell for $10 to $15 retail; wealthy buyers might pay $1,000 for an especially fine specimen.
Prices like those for an unprepossessing citrus fruit have led some consumers to wonder whether the market has been rigged. With fewer than a dozen growers and dealers selling etrogim on a commercial scale, mutterings about collusion have been heard year after year.
The growers and dealers scoff at the idea, and Mr. Wiseman agrees. "Can two Jews agree on anything, much less the price and supply of etrogim?" he said. "There is competition, and it can be tough. But a cartel? That defies all logic."
Still, it is hardly an unfettered market, because of the religious imperative. "Observant Jews need an etrog, so the normal laws of pricing don't apply, because there's no substitution," said Meir Tamari, a retired Bank of Israel economist who lectures on Jewish business ethics.
Mr. Tamari said the rabbis who certify that the etrogim are kosher intervened a few years ago to halt a long period of rising prices. They encouraged dealers to begin packing etrogim in sets with lulavs, and to classify them in five grades from basic to choice for ease of comparison.
If there were fat profits to be made in the etrog business, Mr. Tamari said, more growers would jump in. A few have, in Italy, Morocco and Cyprus. But "there isn't an alterative use for it," Mr. Tamari said, so "there is a built-in factor to limit the number of etrogim."
Mr. Ludmir said production costs were rising, especially for water and labor in Israel, and demand had not grown much from year to year.
Yaacov Charlap runs an etrog distribution business in Kew Gardens, Queens, selling fruit that is grown by his twin brother, Chaim, in Israel as well as some shipped from Italy. He said that his prices had not changed in 10 years.
"It's a tough business," Mr. Charlap said. "You have to enjoy it to be in it."