6/27/2023 0 Comments Cosmic applesOften, the spots will color out as the season progresses with no harm done. (Ross Courtney/Good Fruit Grower)Īlso, the spots don’t seem to cause any lag in fruit quality, and, so far, it is unclear if they are related to tree vigor or calcium applications, also unlike bitter pit. In contrast, green spot is most evident only on the fruit surface. Bitter pit appears mainly in the cortex at the calyx end of the apple as cavities with corky cells and shows up on the surface as round, subtle brown or dark green lesions. ![]() Researchers suspect green spot is different than bitter pit, shown here for comparison. Unlike bitter pit, a calcium deficiency that starts inside the apple and works its way outward, green spot appears to stay on the surface, more commonly on shaded apples, but fruit in unshaded positions on the tree can also be affected. Lower levels of green spot don’t always affect eating or storage qualities.įor one thing, the condition is mostly cosmetic. However, green spot does not automatically mean a cull. Musacchi and Ines Hanrahan, executive director of the Research Commission, use a conservative grading system that counts even a single dot. Not all spots are equalĪpples show varying intensities of green spot. “Green spot is something that for me is a priority, because we need to understand the origin of it,” he said in follow-up comments to Good Fruit Grower. Regardless of this year’s official numbers, Musacchi aims to intensify his hunt for answers. Musacchi speculated differences in environmental conditions, management practices, tree vigor or a combination of those factors may explain the location variance. Rates were significantly lower both years at the Roza site, according to Washington Tree Fruit Research Commission reports. The incidence also topped 30 percent in 2016 at Sunrise. His initial observations suggest low efficacy, but he has yet to fully analyze the data and complete fruit mineral analyses before reaching firm conclusions.Īt the field day in early September, Musacchi estimated green spot affected roughly 30 to 35 percent of the Cosmic Crisp apples in Sunrise trials - unusual but precedented. This year, Musacchi conducted a trial at Sunrise to assess the effect of calcium sprays applied to alleviate the disorder. The unusual amount of green spot at Sunrise this year showed no clear pattern among training systems or rootstocks, Musacchi said. The disorder does not necessarily mean a culled apple, researchers have stressed. ![]() Green spot appears on the fruit surface as green, unpigmented dots of varying intensity. ![]() “This is a very strange situation,” Musacchi told attendees at a September field day at the Sunrise orchard.Īn example of green spot on Cosmic Crisp apples in WSU’s Sunrise research orchard. The disorder has occurred sporadically over many locations in the Sunrise orchard, but not everywhere and not every year with the same level of intensity, said Stefano Musacchi, WSU’s endowed chair of tree fruit physiology and management. WSU’s Roza Research Orchard near Prosser and research plots in two commercial orchards in Central Washington showed very few to no symptoms. The scientists behind the WA 38, to be marketed under the trade name Cosmic Crisp, have noticed green spot to some degree in the past few years, but the incidence seemed to be higher this year in Washington State University’s Sunrise Research Orchard east of Wenatchee, Washington. Researchers plan to double down on their efforts to unravel the mysteries of green spot, a cosmetic condition occasionally showing up on Cosmic Crisp apples in Washington State University’s trial orchards but not in commercially managed research blocks. The mysterious cosmetic condition on Washington’s newest apple doesn’t seem to be a problem in commercial orchards, though it has researchers scratching their heads in one test plot. Green spot is seen on Cosmic Crisp apples in early September at the Washington State University Sunrise Research Orchard east of Wenatchee.
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