Prices Soar as Infestation of Insects Slashes Lettuce Crop

An insect infestation in Imperial County that may eventually claim more than a third of the country’s iceberg lettuce crop has led to high prices for consumers and big profits for lettuce farmers in such unaffected parts of the country as Ventura County.

Iceberg lettuce prices on the wholesale level quadrupled in November, leading to a jump at supermarkets from 49 cents a head to as high as $1.89. At the same time, farmers of such mixed lettuces as romaine, butter and red leaf are reporting the best season in memory.

“No matter what disaster happens, it doesn’t get spread evenly,” said Wade A. Whitfield, executive director of the California Iceberg Lettuce Commission in Monterey. “There are some growers who have nothing to sell and then there are others who do.”

Production Off Considerably

He said that head lettuce production in California and Arizona, which accounts for 90% of the country’s $768-million crop, may dip by between one-third and two-fifths as a result of losses in November and December.

The problem began in early fall, when hordes of gnat-like sweet potato whiteflies infested the winter lettuce crop in the Imperial Valley and near Yuma, Ariz., spreading a virus called the infectious yellows.

In September, the air in the Imperial Valley was so thick with the insects that “if you looked toward the direction that the wind was blowing, you’d have to close your mouth to keep from chocking on them,” said Keith Mayberry, University of California farm extension adviser in El Centro.

Lettuce plants “no bigger than your thumb may have had 20 to 30 flies on them,” he said.

The plants did not show signs of the disease, which results in misshapen, discolored and underdeveloped heads of lettuce until two to three weeks before harvest in late October and November, said industry spokesmen.

“The plant would be all nice and green one Friday, but you’d go back and look on Monday and you couldn’t believe it’s the same thing,” said Mayberry. “The leaves are all yellow and browning. In a week it’s garbage.”

Lettuce ‘Brown and Leathery’

In some fields, only a fraction of the customary volume was salvaged for sale because the lettuce heads were so badly discolored that they were “brown and leathery,” said Chris Sumner, district director of Arizona’s Commission of Agriculture and Horticulture in Yuma.

The quantity of head lettuce being harvested continues to lag by up to one-half in Arizona and California, but cooler temperatures may prevent the whiteflies from infesting winter lettuce planted later in the season, industry spokesmen said.

Monterey County, the state’s largest producer of romaine and red leaf lettuce, had already wrapped up its season by the time of the market shortage in early November.

But in Ventura County, the state’s second-largest producer of mixed lettuce, 5,000 acres of red leaf, romaine, butter and other mixed lettuces were just coming into production, opening a lucrative window of opportunity, said Earl McPhail, county agricultural commissioner.

“People are buying more leaf lettuce than head lettuce because of the difference in price,” he said. “When head lettuce is $1.79 a head, people try to find alternatives.”

Tom Tanita, sales manager with Seabord Produce Distributors in Oxnard, said that romaine lettuce, which he normally sells wholesale at between $10 and $12 for a 24-head carton, has been going for as much as $25 a carton. Red leaf lettuce, which normally goes for between $6 and $8 a carton, has been selling for as much as $20 a carton.

“We haven’t seen any leaf get this high in 15 years,” he said.

At the Vons supermarket chain, the price of lettuce in one month went from 49 cents to $1.39 for iceberg and from 59 cents to 99 cents for other leafy lettuces. And Dick Spezzano, Vons’ vice president for produce, said he has not passed all the wholesale price increase on to consumers.

Tanita, the Oxnard grower and distributor, said some of the stores he supplies have been selling romaine for as high as $1.59 a head, while Whitfield said iceberg lettuce has been retailing for as much as $1.89.

From Nov. 3 to Dec. 7, the wholesale price of lettuce jumped from $6 to $25 a carton for iceberg and $18 for red leaf, according to Market News, a governmental report that tracks fluctuations in produce prices.

Different Species

Ventura County has whiteflies, said McPhail, but they are of a different variety--the greenhouse whitefly--which does not carry disease known to damage produce.

“The species they have down there (Imperial County) doesn’t like the coastal climate,” McPhail said. “It’s a hot-weather species.”

Sweet potato whiteflies are rarely found above the Mexican border because they survive only in hotter climates, said Nick Toscano, an entomologist with the University of California. However, a 10-year warming trend has made the desert region more hospitable to them, and farmers have been powerless to fight the insect because of the pest’s increasing resistance to pesticides, he said.

The species of whiteflies was first discovered on sweet potatoes, which are still considered to be their preferred host, but they feed on a wide range of fruits and vegetables, said Toscano, who is being funded by the California Iceberg Lettuce Commission to study ways of eradicating the pest.

The whiteflies had been feeding on the Imperial Valley’s melon crop before it was harvested, said Mayberry, who theorizes that they were attracted to the next available crop.

Toscano said researchers are looking into ways to fight the whitefly without pesticides by introducing a wasp-like predatory insect. Genetic engineering techniques may also breed into lettuce resistance against the infectious yellows virus, he said.