Good Fruit Grower

March 15

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www.goodfruit.com GOOD FRUIT GROWER MARCH 15, 2014 17 least susceptible, and Braeburn did not appear to be susceptible at all. Nonchemical tools, such as monitoring, biological control, phenology models, or cultural practices, are of limited use for managing this insect, Dr. Elizabeth Beers, WSU entomologist, reported at the North Central Washington Apple Day in January. Sampling for campylomma has traditionally been done with a beating tray. Although it can indicate if the pest is in the orchard, it has some drawbacks as a sam- pling method. Campylomma tends to aggregate, rather than spread out evenly across the orchard, so it takes more sampling to monitor the pest accurately. Reports from Canada indicate it can take up to 47 beating tray taps per acre to get a good indication, Beers reported. In real life, growers are lucky to have time to do 20 to 50 taps in a 10-acre block, she said, because sampling might have to be done several times during bloom until the pest is found. Beers studied whether monitoring with pheromone traps during the fall would give an indication of the amount of damage a grower could expect from cam- pylomma in the spring, but the trap catches failed to provide an accurate prediction. "I don't think it's going to save you from going out and tapping the trees the following spring," she said. Although there is a phenology model for campy- lomma, damage relates more to the development of the blossoms and fruitlets than the development of the insect, Beers said, with the crop being most susceptible between bloom and petal fall. By the time the apples reach ten millimeters in diameter, they are no longer susceptible and the insect causes no further damage for the rest of the season. In fact, many of the campylomma leave the orchard for the summer in search of other hosts, such as weeds. Mullein is one of its favorite plants. Carzol alternatives Over the years, Beers has tested a number of alterna- tives to Carzol. Coatings such as Raynox and Surround had no effect. Many pesticides have labels that restrict use around bloom in order to protect bees. In Beers's tests, Safers soap provided some suppres- sion, as did Neemix, which can be applied any time. Controlling campylomma in organic orchards can be challenging, requiring multiple applications. Actara (thiamethoxam) is labeled only for use pre- bloom, but looked promising when applied at the pink stage. Provado (imidacloprid) cannot be used before or during bloom. Assail (acetamiprid), which can be applied between the pink stage and bloom, performed fairly well in sev- eral tests, occasionally beating Carzol. Beers said that in WSU's spray guide (Crop Protection Guide for Tree Fruits in Washington), Assail is rated as less hazardous to bees than Carzol, which was a Class II bee material that could only be applied between 6 p.m. and midnight during bloom. Assail can be applied in late evening or early morning. • "I don't think it's going to save you from going out and tapping the trees the following spring." —Dr. Elizabeth Beers

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