The Spoils of Winter
Or why postharvest researchers are the P.I.s for pathogens.
From November through February, icy winter winds reach down from the Arctic and grip the Pacific Northwest where Good Fruit Grower is based. During the height of winter, shortened hours of daylight have staff coming to and going from work in blackness, and the grey days aren’t much cheerier. If that’s not a big enough potential for depression, we also schedule this, our disease-theme issue, for February 15.
To date—though our researcher friends keep telling us a close-up photograph of a blue mold-oozing Gala would make an inspiring cover—we’re not convinced that rotting fruit would make the average (earth-bound) reader ecstatic. Having said that, however, the intrigue, the in-depth investigations, and the massive effort to protect agriculture and the public is not unlike the content that makes an exciting detective novel.
In this issue, we report on a plum pox virus discovery at Michigan State University’s tree fruit breeding program that requires the destruction of most of the center’s 12,000 susceptible trees. This tragic loss clearly demonstrates why our breeding programs cannot afford to work in isolation. Luckily, MSU had developed growing blocks away from their breeding center that included many of the most important new varieties being studied, and that will greatly lessen the impacts on that program, but the loss will be serious and expensive for the university.
National Clean Plant Network
We also discuss a proposed National Clean Plant Network that is designed to protect the United States from exotic plant pests and pathogens. Although provisions for the network were introduced in the last Congress, they will have to be reintroduced in the new Democratic-led Congress if the network is to be funded. Growers should let their representatives know why such an effort is necessary.
In British Columbia, grape growers have discovered an innocent-sounding pathogen Bois noir, which is a disease new to Canada that is grouped in what is commonly referred to as grapevine yellows. The Canadian government was concerned enough with this outbreak to pass strict new requirements for the import of vines and rootstocks from France and Germany where grapevine yellows, including Bois
noir and Flavescence dorée, have caused extensive damage in some wine regions.
In addition to the threat of new pathogens, resistance to existing controls may be as big a problem in the future. Like mildew on grapes, powdery mildew on sweet cherry may be developing resistance to fungicides currently used in the Pacific Northwest. Although data is preliminary and the mildew likely can be controlled, growers will need to practice resistance management.
As dismal as the subject of diseases in fruit crops can be, particularly at the end of winter, it’s as important as any we cover during the year. And why spoil a beautiful spring day with a lengthy discussion of rot?