- Author: Mark Bolda
I had a brief chat concerning albino strawberry fruit this morning. Maybe it shouldn't be surprising that I get a call concerning this disorder since it has been rather cool and cloudy for close to a week.
Anyway, as one can see from the picture of some albino fruit off of Diamante strawberry (it's from a few years ago), the fruit takes on a pale whitish color, with just a bit of red around each achene. The lack of ripe red color comes from an inadequate supply of sugar during maturation, and indeed such fruit are insipid and tasteless.
On the Central Coast, strawberry fruit albinism tends to come in fields experiencing heavy nitrogen fertility or really frequent irrigation during an overcast period on the heels of a spell of sunny and fairly warm weather. The symptoms might be exacerbated in the shadier parts of the plant canopy, and the literature says it shows up more in closely spaced plantings.
So in order to minimize the occurrence of albino fruit, especially during a stretch of overcast conditions following warm weather, one would want to be a little more reticent about nitrogen and water use. Regardless, a change in the weather, i.e. from overcast conditions back to warm sunny weather such as we are experiencing today, is going to go miles in clearing up a spate of albino fruit.
Hat tip to the PCA for bringing this up with me. It's always great to be in touch with the experts out in the field looking at this stuff day in and day out and figuring through these problems.
- Author: Mark Bolda
The following is an addition to the post from August 2 concerning a case of yellowing strawberry plants in a field in Castroville. To summarize, we concluded that the plants are turning yellow because they are being poisoned by excess amounts of sodium and chloride accumulating in the bed.
So of course, and indeed the question was asked right away, what can we do about this problem? The three points below are a start:
1. The dramatic accumulation of sodium and chloride at the surface of the bed in this study indicate that these are not being adequately leached, which was verified by our observation of soil saturation at depths below the bed. If this is correct, by increasing drainage we will be able to ameliorate the situation and restore a normal leaching pattern. Short of installing a system of subsurface drainage, there has been some anecdotal evidence of success in using a certain “Yeoman’s plough” which is essentially a shank going some 16 inches deep into the soil next to the bed opening a deep cut in the soil improving aeration and water infiltration. This has not been tested in replicated trials however, so I can’t make a firm recommendation of this method at this time.
2. We have every indication in this study that substantial amounts of calcium are precipitating out as lime, and is therefore not replacing exchangeable sodium. We could reduce the amount of precipitation of calcium (increasing the exchangeable calcium) by acidifying the irrigation water which would go some lengths to mitigate the sodium hazard (SAR).
3. Finally, there are other useful steps which can be taken to reduce the amount of sodium and chloride being introduced into the field. For example, a grower experiencing a situation of high sodium and chloride should avoid using sodium nitrate or potassium chloride fertilizers.
- Author: Mark Bolda
UC Cooperative Extension and the California Strawberry Commission have a major entomology meeting planned for this upcoming September 18. Topics covered will be lygus bugs, predatory mites, brown marmorated stinkbug, strategies regarding managing invasive pest invasions and a full suite of talks covering numerous facets of the spotted wing drosophila. Speakers are coming from academia, grower supported institutions and private industry and are among the most informed people on entomological topics on the Central Coast. This meeting is not to be missed by anybody with an interest in insects and their management in strawberries and caneberries.
Agenda can be viewed through the link below:
http://ucanr.org/2012 berry entomology
- Author: Mark Bolda
For those who missed yesterday's field meeting, the following is a short summary of the presentation of a robotic harvesting machine for strawberries.
The machine, called "Agrobot", is the creation of a research group in Spain headed by Engineer Juan Bravo, who is seen driving the machine in several pictures below.
Rather than futilely attempt to match the profound and unique complexity of the human hand, the principle of the "Agrobot" is instead a construction of visualization technology which guides a rubber lined basket to the red, ripened strawberry fruit and removes it in a lifting motion from the pedicel with a small round razor buttoned to one side of the basket (photo 2 below). The picked fruit is then deposited on a conveyer belt, which carries it up to a worker seated at the front of the "Agrobot" for quality inspection and placement in a container, be it a clamshell, crate or bucket.
There are a series of arms holding the harvest baskets on either side of the machine to enable picking on both sides of the bed. Much has been of the fact that these arms, having a modular design, are replaceable in case of damage or malfunction. The unit containing the arm and its automated guide snaps easily out to make room for an identical unit, causing minimal delay in the progress of harvest.
Nice video by Luis Macario posted on youtube:
http://www.youtube.com/watch?v=nm3WS5y3kCk&feature=youtu.be
While the "Agrobot" automated harvester is being seen as technology's response to the strawberry industry's increasing problems obtaining harvest labor, many challenges remain nevertheless. For one, the varieties currently in use on the Central Coast produce many fruit in one cluster, which the machine has difficulty distinguishing from one another. Secondly, as the reader can see from picture number three below, the strawberry field must be radically reshaped to accommodate the machine, including farming strawberries in single rows (reducing plant count and subsequently lowering yield per acre) and raising the beds substantially. Third, the machine cannot think for itself and will not find fruit behind foliage or sequestered within the canopy of the plant.
At any rate, the "Agrobot" is a remarkable invention and worthy of a look and consideration by those who haven't seen it yet.
- Author: Mark Bolda
A workshop on anaerobic soil disinfestation (ASD) will take place at the Watsonville UC Cooperative Extension office on August 17.
Anaerobic Soil Disinfestation (ASD) was developed in the Netherlands and Japan as a biological alternative to methyl bromide fumigation. Funded by USDA and the California Strawberry Commission, our research team has been working on optimizing ASD for California strawberries since 2007. Recent data showed that the ASD technique produced comparable marketable fruit yield with a fumigant (Pic-Clor 60) treatment. Although ASD technology is still a work-in-progress, many growers have expressed interests in learning about ASD. This workshop is designed to cover the basics and key aspects for successful ASD implementation.
When: 8/17/12 (F) 9-11am
Where: Auditorium at Santa Cruz County Cooperative Extension 1432 Freedom Boulevard, Watsonville, CA 95076-2796
Phone: (831) 763-8040
Agenda:
9-9:30am:
Anaerobic Soil Disinfestation (ASD): Basics and Research Update
Carol Shennan, Professor, Dept. of Environmental Studies. University of California, Santa Cruz.
9:30-10am:
Key Practices for Successful ASD Implementation
Joji Muramoto, Associate Researcher, Dept. of Environmental Studies. University of California, Santa Cruz.
10-10:20am:
Carbon Source Supplies and Consulting Services for ASD
Kurt Jacobson, Farm Fuel. Inc.
10:20-11am:
Questions and Answers
11am:
Adjourn
For more information, call Joji Muramoto at 831-247-3804.
