Organic bait spells hope for cherry growers

For anyone who has a cherry tree or two in the yard, this is decision-making time.

The western cherry fruit fly has been the scourge of local growers in recent years. In early June growers must either begin an insecticide spray regime or accept that their often abundant crop will soon be worm-infested and inedible. Some residents have instead opted to cut down their cherry trees.

Yet there is a new alternative available, says Kesten Broughton, a local environmental activist. In the past few years an organic spray, GF-120, has been approved for use in cherry orchards.

"There is a little bit of a catch to it," he said. "It's not approved for cosmetic use (in B.C.), so I'm looking for a way around that."

GF-120 is classed a naturalyte, a bait with the active ingredient spinosad.

Robson Rogan, an agrologist with Purity Feed, said spinosad is also used in Success 480 SC, the more common defence used by commercial growers.

"It's classified as reduced risk, or IPM (integrated pest management) friendly," Rogan said. "It is out there for commercial and agricultural growers."

While Purity Feed can order in the bait in one-litre containers, it is generally sold in large volumes exceeding the needs of most residential growers. It also has a limited shelf life.

Commercial spray services tend to spray with Fruit Guard, which has an active ingredient called Sevin. Though Sevin is classified for domestic use, there is a movement to get more IPM products onto the market, Rogan noted. He suspects GF-120 will become more available for residential use as demand increases for organic alternatives.

Broughton is trying to develop alternative treatments, hoping to tap into the emerging market while raising awareness of alternatives. In terms of providing alternatives he's ahead of the curve, since the City will ban consumer use of cosmetic pesticides next year.

Commercial spraying regimes - cherry trees must be treated several times over - can add up costwise, he noted.

"I'm quite happy to take a lower profit margin to use an organic alternative."

He doesn't see the bait, an insecticide, as the ultimate solution but part of an integrated strategy that includes cleaning up trees - removing unused and fallen fruit - after harvesting. That prevents the fly from regenerating and spreading.

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