Tomato disease seen as threat to state potato crop

Jace Radke

Tuesday, June 16, 1998 | 10:58 a.m.

The attack of the killer tomatoes has hit Nevada and that could mean trouble for the state's potato crop.

The Department of Business and Industry's Division of Agriculture has placed a temporary quarantine on out of state tomato plants after discovering that some plants arriving from California nurseries were infected with a fungus disease known as late blight.

"Once the disease was positively identified, Division nursery inspectors canvassed nurseries in Reno, Sparks and Winnemucca to determine the source of the infected tomatoes," said Paul Iverson, Division of Agriculture Administrator. "Although the greatest concern is for commercial potato fields near Winnemucca, this is a statewide quarantine."

Late blight, or Phytophthora infestans, is known to infect and kill tomato and potato plants. Although it infects a food source, late blight poses no threat to human health. It may however threaten Nevada's potato producing industry.

Winnemucca Farms, the biggest single potato producer in the state, dedicates around 5,000 of its 15,000 acres to potatoes. In all, some 7,000 to 8,000 acres are used to produce potatoes in Nevada, according to Division of Agriculture sources.

"We haven't seen any infections in the potato crop yet," said John O'Brien, spokesperson for the Division of Agriculture. "It looks like we caught it in time and took the necessary steps to ensure crops."

Those steps include tighter regulations on tomato plant shipments from out of state. Shipments bound for Nevada nurseries now must be accompanied by a certificate that shows the plants have been inspected and are free from disease.

The Division of Agriculture stressed that the quarantine affects only tomato plants and not tomatoes in local supermarkets.

"This quarantine will have no affect on the price of tomatoes offered for sale in stores," Iverson said. "Unfortunately, one of the side effects may be a scarcity of tomato plants in retail nurseries this summer."

Late blight is the same disease which caused the famous potato famine in Ireland which makes such regulations necessary, according to Division of Agriculture plant pathologist Dr. Bill Jones.

"This disease is one of the most rapidly spreading fungus diseases known, and can wipe out a potato field in a matter of days," Jones said.

The first sign of late blight are pale to dark green shaped spots on the leaves or stems of plants. Once the disease enters the stem the plant will quickly collapse and die.

The disease thrives in cool, wet weather which makes Northern Nevada more susceptible to infestations of late blight.

If any home gardeners or nurseries suspect the disease they should contact the cooperative extension office to verify their plants are infected, Jones said.

Aggie Roberts, a spokesperson for the cooperative extension office, said that she has not heard of any cases being brought into the Southern Nevada office.

"It's probably more of a threat in the northern part of the state," Roberts said. "Down here we mostly get heat and and wind but planters should still be careful."