Me and the grower are of one mind that the brown spots recently showing up on fruit (this is Monterey variety), are from the strong winds we've had for the last four or so days. Makes sense, especially since there is no signs of disease or insects, and above all these spots are fairly firm. It's almost like the fruit has callused a bit there.
What do you think?
A growing body of research out of Cornell University is showing that low doses of UV light can be quite effective against powdery mildews in agriculture, including Podosphaera aphanis, which challenges strawberry growers every year. The dose, delivered by a special UV emitting lamps mounted on a tractor pulled wagon, is enough to kill the mildew but does not harm the plant. As a non-chemical alternative to fungal management, this certainly is an attractive candidate for research.
This project was a collaboration with Dr. David Gadoury from Cornell University, Plant Sciences, Inc. and UC Cooperative Extension.
A pdf of the presentation put together by Clare Taylor from Plant Sciences, Inc. is linked as an attachment below, and I also give a short review of the study highlights here:
The UV light treatment is effective on mildew: This trial is of the efficacy compared to a course of standard fungicides of a UV light apparatus for efficacy on powdery mildew in strawberry and incidentally spider mites. The test was done on four UC strawberry varieties (Monterey, Victor, Fronteras and San Andreas), the untreated control was a proprietary variety which is not included here. This untreated check confirmed that powdery mildew pressure was quite high, with severity (% of leaf coverage) ranging 30%, and incidence (# of leaves affected) at 100 % from May 8 onwards.
The UV light was very effective in managing the mildew, over a total of 45 applications, done twice a week after dusk, the results were equivalent to the grower standard fungicide course. It was observed too that these plants appeared healthier than those treated with fungicides, likely because they were spared the deleterious effect of pesticide use.
The UV light treatment does not result in declines in fruit yield: To understand whether or not the regular use of UV light affects fruit production, yields in all four of the UC varieties were collected twice weekly through the course of the study from mid March through mid August.
Differences between the plots treated with fungicides and those treated with UV light were not found.
No effect has been found by the UV light treatment on spider mites: Spider mites were evaluated along with mildew for susceptibility to UV light.
No effect whatsoever was found on populations of Lewis mites, twospotted spider mites or P. persimilis predatory mites. This work was replicated this past spring (more detailed report to come later), again, the UV light had no efficacy on populations of spider mites.
Pay attention to safety requirements of this UV light treatment: Growers and pest managers should take close note of the SAFETY requirements when working with this UV light apparatus. It is VERY intense, and skin and eyes exposed to it without covering or shielding will be damaged. Please review these prior to engaging in this work - the last slide has a picture of Dr. David Gadoury in recommended gear.
Great, great work by the people at Plant Sciences, Inc. in collaboration with Santa Cruz County UC Cooperation Extension.
Saw this file shared on Twitter the other day, it comes from a presentation made at a talk for tech start ups. What do you think? Pretty crude characterization of academics, but still made me laugh pretty hard. Sort of hard to deal with us University folk huh.
Have a nice weekend all!
Great article here from Growing Produce about how researcher Hannah McIntosh out in Wisconsin obtained serious reductions in SWD in raspberries by underlaying the crop with plastic mulch (three colors tested: metallic, black and white). All three colors worked in reducing SWD numbers by something like 50% (!!) and in some cases increased yields. The researchers are thinking it has to do with increased UV interfering with the insects' navigation, grower feels the larvae are getting cooked on the plastic (I'm with the grower, but I'm going to wait for more data before firming up on this opinion).
This is pretty interesting and some good work.
Good article here from the Wall Street Journal. I provided a good amount of info to Jesse over the past couple of weeks, in particular walking her through some of the financials and cultural practices of the business. There's some good discussion of what not only berry growers, but also veg people dealt with last March as the country went into lockdown and normal outlets for sales were closed.
Should be without paywall.