Stone fruit shippers shift to systems approach

Pacific Northwest producers are able to ship peaches, nectarines, and apricots to British Columbia, Canada, under a systems approach, rather than having to fumigate the fruit as they did in the past. Growers and shippers interested in shipping fruit to British Columbia under the new program should register with the Washington State Fruit Commission by April 1.

The industry hopes to ship prunes and plums under a similar program in the future, Dr. Mike Willett, technical issues manager at the Northwest Horticultural Council, reported at Stone Fruit Day, held in Wenatchee, Washington.

British Columbia is an important export market for stone fruits from the Pacific Northwest. It is the third largest export market and has the advantage of being close by.

Oriental fruit moth is not found in British Columbia, and in the past, Northwest producers have had to fumigate fruit with methyl bromide before shipping it there. However, there has been a worldwide move in recent years to phase out use of methyl bromide, and there were concerns about the effect of fumigation on the quality of the fruit.

Oriental fruit moth is found in low numbers in the Northwest, and two seasons ago, Canada agreed to a systems approach, in place of fumigation.

The systems approach involves orchard monitoring for oriental fruit moth with pheromone traps starting in April, and a chemical treatment if trap catch averages two or more moths per week during each generation of the moth.

Alternatively, growers can spray for the pest based on a degree-day model and keep temperature records, or they can use mating disruption, in which case trapping is not required. Most growers are using mating disruption, Willett said.

Records of monitoring, treatment, and strikes must be submitted at harvest.

Three hundred fruit per orchard block must be cut and examined for larvae, and if a larva is found, the block is ineligible to export to British Columbia for the rest of the season.

At the packing house, inspectors must cut 300 fruit per day from the culls of each grower lot intended to be shipped to British Columbia, and at least one percent of the containers must be inspected, and at least two fruit in those boxes must be cut. In addition, all fruit in those boxes showing damage that could be caused by pest infestation must be cut.

The detection of a larvae eliminates the lot from export to British Columbia for the rest of the season. Re-sorting is not allowed.

Five percent of the cartons must be inspected on arrival in British Columbia. No more than 19 loads per week can be shipped from the Pacific Northwest and California into British Columbia because of limited inspection staff in Canada.

About 7,000 cartons were shipped under the systems approach from the Northwest during the 1999 season. In 2000, 42,000 cartons were exported under the systems approach, and fewer than 8,000 were fumigated.

In 1999, Canadian inspectors found no oriental fruit moth larvae, although they did find peach twig borer and leafrollers. Last season, one live larva was found in peaches grown in the Pasco area.

Willett said the industry would like the program to be changed to reduce the need for fruit cutting in the orchard, as producers don't want to cut fruit that could be sold.

The United States is negotiating an agreement to ship Northwest apricots to Mexico under a similar program. Willett said there have been meetings with Mexican plant quarantine officials, and he hoped a work plan would be signed soon. m