Latest Edition of Small Fruits News Now Available

The Southern Region Small Fruits Consortium's latest newsletter is now available.

Small Fruits News July 2012 (pdf)

1.  'Osage' a new blackberry for shipping and local markets
2. Blackberry and raspberry season checklist
3. Strawberry seasonal checklist

Pest News April 27, 2012

The latest edition of NC Pest News in now available.

In this edition you will find the following articles related to Fruits and Vegetables:

1. What causes misshapen strawberries?
2. Be on the look-out!  Garden diseases to watch for in May and June.

Strawberry Locater Map

Check it out! The NC Strawberry Growers Association has a new "Strawberry Farm Locator Map" powered by Google.

The map locates farms that are members of the NC Strawberry Growers Association. So if you grow strawberries think about becoming a member. The Association has all sorts of wonderful marketing materials and this year members will receive a free 24 x 36 "how to pick" poster, printed on vinyl banner material.

To become a member, fill out the form found here: http://www.ncstrawberry.com/docs/2012MembershipForm.pdf

Small Fruits Newlsetter Now Available

The April 2012 edition of Small Fruits News is now available on-line.

In this edition you will find (It is a very good one!):

• Blackberry Breeder John Clark Receives NARBA's Distinguished Service Award
• Southern Region Small Fruits Grant Awards
• Report: Grape Growers Should be Prepared
• Beware of Bermuda and Johnson Grass
• Blueberry Pre-Plant Diseases Associated with Nematodes
• Local Market Survey
• A History of the Blueberry Industry
• Blackberry and Raspberry Seasonal Checklist
• Strawberry Seasonal Checklist

To learn more about the excellent research going on in small fruits in the south, as well as some great resources, visit the Southern Small Fruit Consortium Website: http://www.smallfruits.org/

Strawberry Update: March 2012

I have been visiting with strawberry growers over the past couple of weeks and the crop looks good. Growth is not as vigorous as we usually see for this time of year, but the color is good. Some growers are reporting lots of blooms without abundant foliage. If you are a strawberry producer, what are you seeing?

Above: Strawberry plant in Leicester (Buncombe County) taken March 14

Above: Strawberry plant in Mills River (Henderson County) taken March 21

In addition, I have been seeing two spotted spider mites, and the populations have been over the economic threshold which is 5 mites/leaflet in a sample of 10 leaflets/acre. To learn more about two spotted spider mite thresholds and management, please review Dr. Hannah Burrack's blogpost from March 1, What to watch for: strawberry update.

In addition, don't forget to watch out for the spotted wing drosophila. With the warm temperatures we are experiencing this season, it is possible that we may see these pests in our strawberry crop. It is a very good idea for you to consider setting out traps and scouting for this pest. To learn more about the spotted wing drosophila, trapping and monitoring, identification, management and the monitoring network visit Dr. Burrack's blog: http://ncsmallfruitsipm.blogspot.com/p/spotted-wing-drosophila.html

Will Warm Winter Impact Small Fruit Production?

Small fruit need a certain period of time under 45F, this period is known as the chilling requirement. Different small fruit, and even different varieties, have different chilling requirements. For example, raspberries have rather high chilling requirements, between 800 and 1,800 hours, while blackberries have a low chilling requirement, between 200-900 hours. Chilling requirements of blueberry vary widely between types, i.e. northern highbush (approx. 800-1,000), southern highbush (approx. 150-800) or rabbiteye (approx. 300-600).

The blackberry variety Oachita, popular WNC, is thought to have a mid-chilling requirement of 400 hours. Navaho, another widely produced variety for our region, has a 800-900 chilling hour requirement. Tupy, the primary blackberry grown in Mexico, has a chilling requirement of 200 hours.

Because of the mild winter thus far in the Southeast, there is concern that the small fruits will not accumulate the chilling hours necessary for proper production.

Dr. Gina Fernandez, small fruit specialist at NC State, shared a link to a new tool offered by the NC Climate Office in collaboration with small fruits specialists. This tool offers data that shows the chilling units accumulated in different weather stations across the southeast for blueberries, blackberries and strawberries.

You can find the data here: http://www.nc-climate.ncsu.edu/products/ag/berries

For the Fletcher weather station, it appears that we are at almost 600 chilling hours for blackberry and 1210 for blueberry, therefore well on our way to meeting our chilling requirements this season.

To keep up with the latest from Dr. Fernandez and Team Rubus, check out the below social media and sites.

Twitter: @NCteamrubus
Blog: http://teamrubus.blogspot.com/
Facebook: TeamRubus

Web Portal: http://ncsu.edu/enterprises/blackberries-raspberries

Changing Consumer Demand Affects Small Fruit

This article from Fruit Growers News is a great history of the small fruit industry in the U.S.

Changing Consumer Demand Affects Small Fruit

Tim Nourse, owner of Nourse Farms in western Massachusetts- one of the largest plant suppliers- discusses how the consumer changed the small fruits landscape. In addition, Dr. Eric Hanson of the Michigan State University Horticulture Department discusses how California production of small fruit changed the industry.

October Small Fruits Newsletter Now Available

The latest edition of the Southern Small Fruit Consortium's Small Fruit News is now available.
You can download or view the pdf here: http://www.smallfruits.org/Newsletter/Vol11-Issue4.pdf

In this version you will find:

1. A Special Report on Exobasidium Fruit and Leaf Spot on Blueberries
2. Can Raspberries Be Picked Pink for Fresh Markets?
3. Information on the 2011 Strawberry Expo in Durham, Nov 6-8
   
4. Fumigation and the Options to Grow Strawberries Without Fumigation
5. Blackberry Flavor: Improvement is Key for Fresh Market Expansion
6. E. coli Outbreak on Oregon Strawberries
7. Blackberry and Raspberry Season Checklist
8. Quarterly Strawberry Grower's Checklist

The Blackberry and Raspberry Specialists have united to form Team Rubus!
You can follow them on social media, look for:

Twitter: @NCTeamRubus
Facebook: Team Rubus
Blog: teamrubus.blogspot.com

Attention Strawberry Growers: Phytophthora cactorum

By Dr. Frank Louws, NCSU Dept. of Plant Pathology with contributions by Dr. Barclay Poling, Professor Emeritus, NCSU Dept. of Horticultural Science; Dr. Chuck Johnson, Virginia Tech, SPAREC; Dr. Powell Smith, Clemson Extension, Lexington Co.; and David Dycus, NCDA Regional Agronomist

Berry Alert No. 99

September 9, 2011 (Friday)

Subject: Frequently Asked Questions about Managing Phytophthora cactorum (Pc) in strawberry tips and plugs

Introduction:

Since the Labor Day weekend, a NC nursery plant supplier with runner tips grown on PEI, Canada, has been in touch with their customers to inform them of a problem with Phytophthora cactorum (Pc), which is the causative agent of Phytophthora root and crown rot.

Growers who have received such a call from their plant supplier are understandably concerned, and in many instances, they have in turn called their local extension agent, NCDA field agronomist, or various specialists here in the Mid-south at NC State, Clemson and Va Tech. This is not a new problem for our industry, and quite frankly this particular disease does lend itself to some "cures". As Dr. Powell Smith wrote to a South Carolina grower on Wednesday this week:

"If you have suspicious-looking tips (necrotic [decayed] looking), you can send those to the Clemson Plant Problem Clinic. They will be able to find the Pc on the tips if it is there. Also, any plants looking to be suffering from root rot in the plug house, send those immediately to the PPC for diagnosis. Time is of the essence; there are cures."

Indeed, there are some "cures", and this where I think many growers need realize that this is a situation that can be reasonably well managed, and one important step is to get a "proper diagnosis" if you are seeing some suspicious-looking tips. If you are having any question on where to go with strawberry tips/plugs for diagnosis, let us know!

In North Carolina, we have the Plant Disease and Insect, and here is the website to get directions for submitting a plant sample:

http://www.cals.ncsu.edu/plantpath/extension/clinic/submit-sample.html

Here is the form for Clemson: http://www.clemson.edu/agsrvlb/plant-prob-diag-form.PDF

Phytophthora problems in plug plants. Notice the distinct black lesions. Botrytis will be brown and usually have gray fuzz. Also, note the poor root formation resulting in plant collapse as the misting frequency decreases.

(photo courtesy of Dr. Frank Louws)

In the interest of time today, we review below questions we have received in the last day or two about this situation:

Question 1. We have received some tips from the nursery that has reported having some Pc on the tips/plugs, and we are seeing plugs at our location that are doing fine, and rooting well after 8 days. We have no idea how we could dip 60,000 tips now that they have been set and we were told that Aliette was our best option. We need your advice!

Answer 1. First: Aliette is a fungicide product that is in the phosphorous acid family of fungicides. Since Aliette is off-patent, multiple other products have been registered and include Prophyt, Phostrol and others. These are commonly referred to as phosphonate or phosphite fungicides and do not provide any nutrient benefit to the plant. These products are not to be confused with products in the phosphoric acid family commonly used as a source of nutrients to the plant (e.g. Nutri-Phite and similar products). The label for the phosphite fungicides is written with perennial or field production systems in mind and therefore it is very difficult to directly interpret the label for this type of need. “Preplant dips” are allowed and applications within 14 days”after planting” are allowed. Thus, timing in plug facilitates is unclear but the label does not prohibit use of treating transplant trays or other “nursery” type setting.

Second, it is encouraging that you are not seeing suspicious-looking tips (necrotic [decayed] looking)! The moment symptoms appear, it would be productive to send samples to the local clinic for diagnosis asap. You are quite correct in questioning how you might go about dipping 60,000 tips, as you are already past that point! If you were just now receiving an order of tips for plugging, then perhaps a dip of a phosphite fungicide would be in order. In your case, the plugs have now been growing 8 days, and it turns out that phosphite fungicide treatment even at 4-7 days should be helpful, and a second treatment may be appropriate 4 to 7 days before going to the field (usually plugs root for a full 4 weeks, and for the first full week they are typically under some type of misting schedule in the day, and by about 7-8 days, the plugs have established enough of a root system so that much less misting is required). In one experiment done at NCSU, dipping the tips prior to plugging, spraying the plants soon after setting, and early dip/sprays followed by a second foliar application 14 days later all gave similar results for controlling Phytophthora problems in plug plants. Prophyt and Aliette gave similar results. As far as the actual "treatment", you would need to spray your 8 day old plugs with Aliette at the rate of 2.5 lbs/100 gallons/acre, 2 pints/100 gal (ProPhyt), or 2.5 pints/100 gal (Phostrol). Now, if you have 60,000 plugs, your plugs are covering about 2600 sq ft, or only 0.06 acre (2600/43560). Thus, using Aliette as an example, the amount of product needed to spray this much area would only be 0.15 lb, or 2.4 oz. Foliar spray volumes to deliver this phosphite product work best with sprays applied just prior to runoff, but if we were to stick with 100 gallons/acre, then for an area of 2600 sq ft you would need to apply 6 gallons of water. The key concept is that the phosphites are absorbed by foliage and roots, not just by roots as with Ridomil, and the phosphite product should be in sufficient water to promote as much uptake as possible by the leaves and other plant parts without creating drenched conditions in the potting medium or promoting splash dispersal among plugs on the pad. Aliette is known to cause damage in other crops if excess amounts go into the soil and if other products may be present (e.g. certain insecticides, copper, surfactants etc).

Question 2. Since the phosphite fungicides can be applied as a foliar spray my next question has to do with how much of a "drying period" is needed after you have sprayed the plugs? (of course, if the plugs are still under mist during the first week, then the only dry period is the evening)

Answer 2. The phosphites are unique chemicals in that they are absorbed by the roots and the foliage and they become systemic in the plant, moving up and down. They are absorbed fairly readily into the plant and as a rule of thumb for systemic fungicides, they probably require about 90 minutes of drying time for the majority of the product to be taken systemically into the plant. The fungicide has direct as well as indirect (changing the biochemistry of the plant) activity against the pathogen offering curative control (it can stop the pathogen from growing more inside the strawberry tissue). Therefore, if plants are under a mist schedule, the best time to apply the fungicide is towards the end of the day when the misting cycles are off. This allows maximum absorption into the plant and limits excess runoff into the soil. Avoid excess saturation of the growing media. Phytophthora is a water mold and the more free water there is the more the pathogen can spread.

Question 3. Once my plugs are out from under the mist in the 2nd week and thereafter, can you advise on whether a follow-up treatment with Aliette may be needed?

Answer 3. As mentioned above, a second treatment did not seem to offer an advantage. The product is systemic in the plant and seems to persist for long periods of time. However, if a second application is made, it is probably best done 4-7 days prior to planting to allow the fungicide to be absorbed into the plant but to limit worker exposure problems and any plant stress issues.

Question 4. Since I have plans to inject Ridomil Gold through the drip after planting my plugs (I am thinking about 1 week after transplanting), don't you think that it would be better to use Ridomil in that way, or do I also need to make an application with Ridomil to the plug trays before planting?

Answer 4: Ridomil is clearly not labeled for use in plug production facilities. The label specifically prohibits use in transplant trays, as a foliar application or in transplant water. There are two good reasons for this – possibly among others. First, Ridomil use prior to field setting strawberry transplants can result in slow grow-out of the plants once they are field set. Second, resistance to the fungicide can develop easily as use in transplant facilities favors the development of resistant populations which then get transferred to the field – a serious issue for future control of the pathogen in the field. Resistance to the phosphite fungicides is much less common.

Ridomil is a superior product in the beds. If growers cannot set up their drip irrigation system prior to or right after planting, then Ridomil can be incorporated into the beds when beds are being formed. This was the case for a grower who asked today. Application during bed formation in pepper fields that had Phytophthora problems worked better than applying Ridomil through the drip after planting but no data is available for strawberries. If excess overhead irrigation is not required, the product could be injected into the beds though the drip tape prior to planting. Finally, alternatively and the method most growers seem to prefer, Ridomil can be applied into the beds when excess overhead watering is done and when plant roots begin new growth (5-7 days after planting). If the transplants were not treated, the sooner the Ridomil is in the bed the better keeping in mind it will wash down into the soil if excess overhead watering occurs and will not be absorbed if the roots are not active. Detailed studies on timing for strawberries are not available. Ridomil should be considered again as a second application in the early spring when new plant growth starts. Strawberry plants grow lots of roots right at this time and protection is critical during early spring growth.

Question 5. I am having difficulty in my area in finding Aliette, so my question is whether the other Phosphites listed in the SR SFC IPM Guide are just as effective as Aliette, and should I stick with the rates suggested in the 2011 IPM Guide? I have heard that the Phostrol label calls for rates of 3.75-5.0 pints/acre when disease pressure is severe?

Answer 5. Overall, the phosphite chemistries are very similar in terms of their efficacy. Different rates relate to different concentrations of the active ingredient and in a plug facility there is concern about using high rates. In NCSU trials, we know Prophyt, Aliette and another similar product were all equally effective. In turf studies, some phosphites did prove superior to others and this is likely related to formulation but the differences were minor.

Question 6. Is there any advantage to mixing other materials with Aliette (e.g. potassium carbonate)?

Answer 6. Potassium carbonate is used to adjust the pH of the spray mixture and this protects against plant injury problems when Aliette is used before or after other products such as copper. There is no advantage to tank mixing with other products and there may be real disadvantages with mixing other products due to the presence of surfactants or other compounds that result in plant injury when combined.

Question 7. What is your general impression about the availability of extra tips this season?

Answer 7. Growers can certainly "check around" but the thing worth stressing is that in the tip and plug nursery business, it is very unusual to find much extra supply in any season, as these are grown under contract (very little speculative production). Used correctly, it is possible to "manage this problem", and with the products mentioned in this advisory, it is possible to turn this problem around. However, as Powell Smith says, Time is of the essence. We have seen low plant death problems where plants have been treated in accordance with the observations above. Although there is no experimental data, it makes sense to remove healthy plants or rogue out diseased plants to prevent the pathogen from spreading more. Excess free water in the and around the trays should be avoided and don’t work plants when wet. Moving plants from an infested plug facility, even if symptoms are no longer present, will introduce the pathogen into the field soils. Many farms already have Phytophthora in the field but this can be a long term risk, especially in fields where the highly susceptible variety Sweet Charlie will be planted in future years.

Fumigation Workshop, Fit-Testing June 20th

Big changes are coming for fumigant application. These changes affect not only strawberry growers, but producers of other fruits and vegetables. As a result, ALL GROWERS that may be affected by the changes in fumigant application are invited to the 2011 Strawberry Pre-Plant Meeting sponosored by The NC Strawberry Growers Association and NC Cooperative Extension.

Prior to the meeting we will be offering respirator fit-testing and medical clearance at a very reduced price for NC residents. Click here for more information. Don't miss this opportunity to save money and get up-to-date!

Individuals interested in this opportunity MUST have medical clearance for respirators from their physician or complete the questionnaire (see flier for more information).

Fit-Testing will be scheduled throughout the afternoon. You MUST make an appointment with Robin Tutor at 919.880.4225 or tutor@ecu.edu or Barb Gallagher at 910.567.7159 or bgallagher@commwellhealth.org.

Where?: The fumigation workshop and fit-testing will take place at the Mountain Horticultural Crops Reserach and Extension Center located at 455 Research Dr. Mills River, NC

What time?:
Fit-testing will be scheduled thorughout the afternoon on a first-come, fisrt-served basis. See above on how to schedule your appointiment.

6 pm Dinner sponsored by Crop Production Services Group discussion on concerns about fumigation

Gwen Minton from the NCDA&CS will guide us through Fumigant Management Plans.

Please RSVP to the Henderson County Cooperative Extension Office by June 16 to let us know you are coming for dinner. 828.697.4891

NC Pest News for June 3

Squash bug adults feeding on the stem of squash. Squash bugs love to hide below plastic!

Squash bug nymphs just hatched from bronze eggs.

This week's issue of NC Pest News is now available. It includes a review of strawberry disease issues from 2011 and the vegetable insect update. The insect update discusses the pest in the photo above, the squash bug. We have been seeing many squash bugs in WNC as of late, as well as cucumber beetles, a few stink bugs and thrips.

You can receive vegetable pest updates from North Carolina State University via Facebook (NCSU Vegetable Entomology) and Twitter (ncsuveg).

Check out these cucumber beetles feeding on summer squash! (below).


To view past issues of NC Pest News click here.

Tailgate Markets and Fresh Strawberries!

This is a very exciting weekend for local produce growers and lovers! Many local tailgate markets opened this week or will open this weekend. Check out this article in the Hendersonville Times-News about the markets in the Hendersonville area, Tailgate Markets Open for Business.

If you aren't in the Hendersonville area, check out ASAP's listing of opening dates and locations of markets all over WNC and beyond: 2011 Market Opening Dates

The strawberry season is in full swing. The crop looks great this year and the berries taste great (trust me!). Though we had some cold weather this week that caused a frost situation in some areas of WNC, the crop looks great and berries are abundant. Check out the Hendersonville Times-News article about the strawberry crop in Henderson County, Plentiful Crop has Henderson Growers Smiling.

Looking for strawberries near you? Visit ASAP's On-line Local Food Guide or check out the NC Strawberry Growers Association website for more information on strawberries in NC.

Speaking of ASAP's Local Food Guide, it's the guide's 10th Anniversary! To celebrate there will be a Local Food Guide Release Party tomorrow, May 7 at Highland Brewery from 4-8pm. There will be music buy Uncle Mountain (from 6-8 pm)and food from Tupelo Honey Cafe.
More details.

Small Fruits Newsletter April 2011

The latest edition of the Southern Region Small Fruits Consortium newsletter is now available.

Inside this edition:

• Strawberries - Why Cut-Offs May Make Sense for Your Operation
• Growing Gourmet Strawberries Commercially
• Mid-South Greenhouse Strawberry Production
• Blackberry Varieties For Tunnel Production in Northern Areas
• Inspection Recommendations for Colletotrichum gloeosporiodes in Strawberry
• 2011 Georgia Rabbiteye Blueberry Budget
  
• Strawberry Spring Checklist
• Blackberry and Raspberry Seasonal Checklist
  

Berry Alerts for Strawberry Growers

As some of you might know, Dr. Barclay Poling, professor and strawberry extension specialist in the Horticultural Science Department at NCSU retired at the end of 2010. Dr. Poling is known for his great extension work, including his berry management emails that helped to answer questions and give weather alerts.

In his retirement, Dr. Poling is continuing with the updates, which are very helpful for strawberry producers. If you would like to subscribe to the new Berry Alerts, please see the message below from Dr. Poling.

"Dear Growers, Agents and NCDA & CS Agronomists,

As was announced in the NC Strawberry Grower newsletter (January/February 2011 Vol. 18, No. 1, p 2), there is now a new advisory called 'berry alert' that is available through the StrawberryWeather.com website. This advisory is free.

TO SUBSCRIBE TO BERRY ALERT:

Step 1. go to: www.StrawberryWeather.com

Step 2. on the home page click on 'Berry Alerts - FREE' tab

Step 3. in the gray panel box you will need to provide some brief information about yourself and your operation (agents and agronomists can simply answer the name of location question by typing in their county name or a region of the state). You will also be given the option to subscribe to daily weather forecasts. The berry alerts do not follow a fixed schedule, though there will be an advisory sent out at noon tomorrow. The weather forecasts are sent out daily.

The first Berry Alert was actually sent out on Saturday, Feb. 12th, and so far everything seems to be working well. I heard from several strawberry growers today who said they had no problem in subscribing. If you encounter a problem, you can reach me at this email address: strawberrydoc@gmail.com

I will not be sending out any further berry mg's this strawberry season, so please be sure to get subscribed to Berry Alert in the near future!"

Winter 2011 Small Fruits Newsletter

The latest edition of the Southern Small Fruit Consortium's Small Fruit Newsletter is now available. You can download the pdf here.

In this edition:

• Possibility of Research and Promotion Program for Blackberries?
• Fumigant Regulations - Information for Handlers
  
• The Great Glyphosate Debate...Too Much of a Good Thing?
• Two New Virus Diseases in Rubus: Blackberry Yellow Vein and Blackberry Crumbly Fruit
• Red Cell, Red Drupelet, Color Reversion: What's Happening to those Packaged Blackberries?
• Blackberry and Raspberry Seasonal Checklist
• Quarterly Strawberry Plasticulture Checklist
  

High Tunnel Strawberry Workshop Nov 17

There will be a high tunnel strawberry workshop on November 17 at the Piedmont Research Station in Salisbury, NC.
Registration begins at 9:30 am.

This workshop will include sessions from NCSU specialists on:

• Strawberry Breeding
• Trials with High Tunnel Strawberries
• Biological Mite Management in Winter High Tunnels
• Demonstration on Low Tunnels
• 'Camarosa' Outdoor Plasticulture Trials with Winter Row covers
• Taste testing of Fresh High Tunnel ‘Albion’ Strawberries from Piedmont Research Station vs. Low Tunnel ‘Albion’ Strawberries from Upper Mountain Research Station

For more information and details visit the NCSU Strawberry Growers Information Portal Trainings and Events page.

The workshop is sponsored by NCSU and the NC Tobacco Trust Fund.

October 2010 Strawberry Grower Newsletter

The October 2010 Strawberry Grower Newsletter is now available.

In this issue:

• The NC Strawberry Growers Association Receives Grant for Marketing and Promotion
• Southeast Strawberry Expo in Virginia Beach
• Scientists and Chefs: A New Strawberry Partnership
• Dr. Barclay Poling: My Impending Retirement
• New Processing Plant for Strawberries
• October-November Growers Checklist
• Grant Programs for Farmers, Researchers and Extension
• Study on Organic Strawberry Farms
• Calendar
• Intensive Workshops
• and more!

Want to learn more about the NC Strawberry Growers Association? Visit http://www.ncstrawberry.org/

WNC Strawberry Pre-Plant Meeting, July 28

It's hard to believe its already time to start planning for the 2011 strawberry season!

Planting will start in a few short weeks so come and get some great tips and information on strawberry production at the WNC Strawberry Pre-Plant Meeting. Details below.

What?: WNC Strawberry Pre-Plant Meeting When?: Wednesday July 28, 6:30 pm

Where?: Mountain Horticulture Research and Extension Center, 455 Research Dr. in Mills River, NC

Who should attend?: All strawberry producers who are looking for the most up-to-date information on strawberry production in WNC and the entire region.

Agenda:

1. Day neutral varieites and high tunnel production for WNC - Dr. Barclay Poling, NCSU Dept. of Horticultural Science. Work is sponsored by the Tobacco Trust Fund.
2. Integrated Pest Management for Strawberries - Dr. Hannah Burrack, NCSU Dept. of Entomology.
3. Disease Management and Fumigation Changes - Mr. Rob Welker, NCSU Dept. of Plant Pathology

1.5 Pesticide Credits are available in the categories of N, O, D and X

January Edition of Small Fruit News Now Available

The latest edition of the Southern Region Small Fruit Consortium's Small Fruit News is now available.

In the January 2010 Edition:

• Berries as One of “Ten Riskiest Foods”?
• ‘Suziblue’: A New Southern Highbush Blueberry Variety from The University of Georgia
• Prime-Ark 45, a New Blackberry Variety
• Bramble (Caneberry) Winter Checklist
• Quarterly Strawberry Plasticulture Checklist
  

Strawberry Row Covers Update

This just in from Dr. Barclay Poling about row covers:

"In trying to decide whether now is a good time to pull covers, or not, I always begin by thinking about the "crop stage" and how hardy the plants may be in mid-December.

Unlike last year, we have not had as much good hardening weather, and so I believe the idea of delaying the cover application has been justified. Right now, I think uncovered Chandler plants could handle cold temperatures in the upper teens, but mid-teens and lower would make me nervous.

In looking ahead into next week, I see that areas of the Piedmont like Gibsonville, NC (near Burlington) could experience a minimum of 18 F on Wed morning (12/23), whereas at Clayton (southeast of Raleigh) we will reach a minimum of 20 F. Leading up to Wednesday we will have a series of what I consider ideal hardening off temperatures (40's in day, 20's in night). It is best to allow the plants to be fully exposed to these kinds of outdoor air temperatures before pulling the winter blanket. In the milder Clayton area, we will not pull covers at all this winter unless there is a severe freeze threat, and a forecast in the low teens or single digits will tell us to go ahead and cover. We will then leave the covers in place through January, provided that we do not encounter a week of abnormally mild temperatures. The row covers can really elevate temperatures during the day, and if the forecast is for a week with daytime highs in the 60s we will pull the covers to the side.

In colder areas, like Gibsonville, NC and through the Piedmont, foothills and mountains, it is typical for strawberry plasticulture growers to pull covers in mid-to-late December. Pulling this late will help harden plants off for winter - all those days in late Nov and early Dec with day temperatures in the 40s, and nights in 20s are perfect for hardening off.

Other important factors in deciding "when" to actually pull the cover (if at all), depends on the variety and how far along the crop is right now. Chandler is a very cold hardy variety by comparison to Camarosa, and it it can grow "too well" under row covers if you are not careful. If you have large Chandler plugs that are nearly touching in the row the last thing you want to do is stimulate more plant development with row covers. Row covers work against you they cause the plant to produce too many crowns and ultimately flowers. As a rule, if I see a plant with 5-6 inch diameter on the plastic at Thanksgiving, I am quite satisfied -- this is what I refer to as a nicely balanced plant. If I see plants that are 8-9 inches in diameter, then I know to hit the brakes! Row covers will force even more plant development and I have seen situations where row covers can cause so much branch crown development that the flower numbers per plant are truly excessive. When bloom counts on Chandler get above 80 in the spring, you're in trouble. Ideally we would control plant development well enough so that you would not get in excess of 60 berries per plant and many growers would much prefer a plant with around 45-50 fruits (better berry size). At Thanksgiving time it has been my experience that the 6 inch diameter plant on the plastic is just about right.

So, to summarize this discussion on when to cover up:

1. Look at plant development in late Nov (Thanksgiving) and determine if your plant size is small (3-4 inch dia), medium (5-7 inch), or larger (8 inches and higher)

2. If the plant size is small, then you would want to apply rows covers earlier than later. If the plants are in the right range of around 6 inches, then the main idea is to simply offer "cold protection" as needed. If the plants are relatively hardy in mid- December, then you are will want to protect the crop from temperatures in the mid-teens and lower as they may not be hardy below this level. But, if the temperatures are not threatening, then there is no hurry to cover. In this advisory I have indicated that with temperatures in Gibsonville heading into upper teens in the middle of the week next week, I would probably then plan to cover by next Tuesday (12/22). At Clayton, we are not going to worry about low 20s. When covers are applied in late December in Piedmont, Foothills and Mountains, it is customary to leave the covers on for about the next 5-7 weeks (unless we get a Jan. thaw of some kind). I do not like to leave covers on too late into the winter. Ideally, you would get them off again in late winter to keep the plants in more of dormant condition (usually 2nd week in Feb in Raleigh area). I generally don't recommend that covers be left on through early March (when you begin to see new blossoms in this area). With larger plants (e.g. 8 inches and higher), you need to be extremely careful with Chandler - it can become a "beast" by next spring and your pickers are not going to like picking all that small fruit. Thus, with larger plants at this time of year you need to use the covers strictly for protection against extremes in temperatures and then try not to leave the covers on for any extended period.

3. Row cover weight - we still stick to 1.5 oz covers for the Mountains and 1 to 1.2 oz for the piedmont and sandhills. In eastern NC we do not use row covers for extended periods - just for protection against serious freezes. By the way we have seen some excellent yield benefits associated with pulling covers in mid-December at the Upper Mountain Research Station in Laurel Springs. We seem to get the best overall yields and fruit size with 1.5 oz covers pulled in mid-Dec vs. mid-Nov, or mid-Jan., in this colder location (3,000 ft elevation). It is interesting that last year we did a Camarosa trial in Salisbury, NC with 1 oz covers pulled in mid-Nov, mid-Dec and mid-Jan, and there was no difference! We are repeating that trial again at Salisbury in 2009-2010.

4. Chandler can grow too aggressively in winter under covers, and so if you already have large plants now, watch out! With the more cold sensitive Camarosa, the practice by growers in the Piedmont has been to pull covers even in early November. We have a lot more to learn about with managing Camarosa with row covers in colder regions, and I look forward to the data set that will be coming out of the Salisbury (Piedmont) research station next spring to give us some better guidance on row cover timing and duration with this variety (we also have different weight covers in this study).

I'll be back with some actual photos from Clayton in an advisory this Sunday. Please email your questions. For the next few days I will be traveling (again) and the cell number is best.

Have a good weekend!

Barclay Poling"