Worker Protection Standard Meeting – Wednesday, May 10, 2017 1:00pm to 4:00pm at the Alson H. Smith, Jr. AREC in Winchester, VA

Worker Protection Standard Meeting – May 10, 2017 1:00pm to 4:00pm at the Alson H. Smith, Jr. AREC in Winchester, VA

This is an opportunity to remind you of the revised Worker Protection Standards (WPS) and to provide resources from VDACS to address questions that you/we have on implementation of the revised standards. Personnel from VDACS’s Office of Pesticide Services, who are responsible for on-site compliance checks related to the WPS, will be on hand. These will be great opportunities to ask questions that you might have on the specific requirements of the revised WPS.

10 May 2017 (Wednesday)

1:00 – 4:00 pm

AHS Jr. Agricultural Research and Extension Center

595 Laurel Grove Rd., Winchester VA 22602

Topics:

    • Seasonal viticultural updates, canopy management, nutrient management
    • Seasonal pest management updates
    • Discussion of revised Worker Protection Standards, time for questions and answers
    • Vineyard walk-through for those interested

Directions from I-81: take Stephens City exit (Exit 307).  Go west into Stephens City on Fairfax Street and proceed straight through the traffic light onto Rt. 631 (Fairfax Street becomes Marlboro Rd.) and continue west approximately 3.5 miles.  Turn right (north) onto Middle Road (Rt. 628) at the “T”.  Go 1.5 miles north on Middle Road and turn left (west) onto Laurel Grove Road (Rt.629).  Go 0.8 miles to the AREC on the left.

 

Mark Sutphin

Extension Agent | Agriculture and Natural Resources, Horticulture | Unit Coordinator (Frederick)

Virginia Cooperative Extension – Frederick County Office | 107 North Kent Street | Winchester, VA 22601

Phone – 540.665.5699 | Fax – 540.722.8380 | Cell – 540.398.8148 | Email – mark.sutphin@vt.edu |http://offices.ext.vt.edu/frederick/

 

Serving the counties of Frederick, Clarke, Page, Shenandoah, & Warren

 

VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY

Extension is a joint program of Virginia Tech, Virginia State University, the U.S. Department of Agriculture, and state and local governments.

 

Apple Carbohydrate Thinning Model-Updates-(May 02 – 05)

Unlike last week, weather forecast predicts conditions that will likely lead to carbohydrate surplus and subsequently, less thinning efficiency this week (May 01-05). As shown in the images below, the carbohydrate model predicts accumulation of up to 35g/day carbohydrate this Friday. This, in turn, will necessitate a 30% increase in the rate of chemical thinners that will be applied tomorrow, Thursday or Friday. I believe we are still within the good thinning window in terms of fruit size, but this week might be the last chance for (6-BA + Carbaryl), or (NAA + Carbaryl) sprays to show an effect.
The following is the carbohydrate model for Winchester and Central Virginia.

Apple Carbohydrate Thinning Model-“Updates” for April 28 – May 1

The weather forecast predicts a hot and cloudy day for tomorrow (Saturday, April 29), which certainly will lead to more carbohydrate deficit. As you see from the graphs below, the carbohydrate balance will increase again by Tuesday and Wednesday, but the carbohydrate reserve will be below 20 g/day, which is not too high to influence thinning treatments (if needed) at this time.
For defruting you young apple trees (to fill the space and get a good tree structure), tomorrow might be a good day to do so. The temperature will be high (>85 oF) in Winchester and Central Virginia and the carbohydrate balance is very low (< -60 g/day) which together encourage for more fruit abscission. To defruit your trees, you can apply:
A) NAA (5-8 ppm) + Carbaryl (1-2 pt) + Superior oil (1qt)/100 gal; or
B) Ethephon (1-1.5 pt) + Carbaryl (1-2 pt) + Superior oil (1qt)/100 gal.
Although Ethephon should result in more aggressive thinning at such high temperatures; it might also cause tree growth reduction and might increase flowering the following year.
The following are the carbohydrate model outputs for both Winchester and Central Virginia.

Is it “Risky” to thin tomorrow?

Although the carbohydrate model still suggests thinning applications until Friday, I would consider any thinning application tomorrow and for the rest of this week as RISKY.
Today (April 26) is a perfect timing for thinning as you still have at least three days before the carbohydrate balance reaches to critical levels and it’s highly likely that fruitlets that will respond to today’s spray will be found on the ground in the weekend or early next week.
However, the weather forecast predicts conditions that will lead to more carbohydrate deficit this week and probably next week; and the carbohydrate model shows critical levels of carbohydrate balance (-60 to -80 g/day) this Saturday. At such low levels of carbohydrate reserve, the natural abscission of small fruitlets is highly likely. So, even if you do not apply any thinning treatments tomorrow (Thursday, April 27) or after tomorrow, some natural thinning will likely occur within and after the weekend.
The following are the recent updates of the model outputs, for Winchester and Central Virginia.

Note: I have noticed some delay between the time I post on the Horticulture blog and the time the updates can be seen by the public. I would advise that you keep this link (http://blogs.ext.vt.edu/tree-fruit-horticulture/2017/04/26/apple-carbohydrate-thinning-model-updates-for-april-23-30-2017/) in your bookmarks and go directly to the “Recent Posts” icon on the right-hand side of your screen to remain updated.

Apple Carbohydrate Thinning Model-“Updates” for April 23-30, 2017

As I mentioned in my last post, this week is a perfect timing for chemical thinning. However, I thought of sending daily updates as the weather forecast predicts more cloudy/ and or hot days this week that may lead to more carbohydrate deficit. Therefore, we should keep our eyes open for any change in the rates of chemical thinners that we intend to apply today (Wednesday, April 26) or tomorrow.

The following are the carbohydrate model outputs for Winchester and Central Virginia.

Apple Carbohydrate Thinning Model for April 23-30, 2017

This week of April 24-30 is the perfect timing for chemical thinning applications for both Winchester and Central Virginia. It’s as the books says about the optimal thinning conditions. Apples are in the size of 6-9 mm, compete aggressively with each other and consume a lot of the tree carbohydrate reserve; temperatures are above 80’s in most days and subsequently the transpiration rate will be high; some days are partially cloudy and will lead to fewer photoassimilates; and more importantly, the carbohydrate model predicts carbohydrate deficiency up to -60 g/day. The only thing that works against us is the high chance (90%) of rain tomorrow (Monday) and after tomorrow (Tuesday). However, we still have this Wednesday and Thursday as two ideal days to chemically thin our fruitlets.
If you were wondering about the best thinning applications to use at this stage, I would recommend using 6-BA for most varieties. Best results will be obtained when you mix 6-BA with carbaryl. NAA is another thinner you can use at this stage and also will give better results when mixed with carbaryl (i.e. Sevin). The mix of 6-BA and NAA might work well with most varieties and there is a good logic of having these two thinners mixed together at this time. However, this mix (6-BA + NAA) SHOULD NOT BE USED with Delicious and Fuji as it will likely result in the development of pygmies. With the coming hot weather this week, adding oil to the tank may result in overthinning. There are many variations among apple varieties and some are more sensitive to chemical thinners than others. The following table (Table 1) gives some indications about the sensitivity of different apple varieties to chemical thinners.

One final note, I run the model for Winchester and Central Virginia based on the information I retrieved today (April 23) from the weather stations in AHS Jr. AREC, Winchester and Batesville, respectively, and there is no guarantee that weather forecasting will remain unchanged the whole week. However, if I have detected any major change in the temperature and solar radiation values over the week, I will run the carbohydrate model again and keep you posted.

Apple Carbohydrate Thinning Model for April 17, 2017

The outputs of the carbohydrate model for Central Virginia area is based on the Batesville (Crown Orchard) weather station. The solar radiation and temperature values suggest carbohydrate deficiency through this week (until Friday, April 21). Since it’s rainy today in most parts, thinning applications (at the standard rate) tomorrow and till Friday should be efficient. Although it will be sunny and warm tomorrow and probably Saturday, leading to some carbohydrate accumulation (the blue line), interruptions with hot and/or cloudy days will reduce the 4-day average (red line) balance and promote fruit abscission.

For Winchester area, I ran the model based on the data retrieved from our weather station at the AHS Jr. AREC. As it appears in the figure below, the outputs look similar to that of Batesville and hence the timing for thinning applications will be similar as well. However, the predicated temperature and solar radiation values for Winchester don’t support any carbohydrate accumulation this week and hence it’s recommended to decrease the chemical thinner rate by 15%.

Crop load management of apples by chemical thinning

In modern apple production systems, chemical thinning of young fruitlets within the first four weeks after petal fall has become a key management element. Inadequate thinning of fruit during this period increases the need for hand thinning, which is generally more laborious and expensive. On the other side, if trees are left without thinning at all, the chances of having low quality fruits and less return bloom in the following year are very high. To achieve adequate thinning using chemical thinners, many factors should be taken into consideration. These include, but are not limited to, fruit size, carbohydrate reserve status of the tree, weather conditions and -to a lesser extent- variety sensitivity. As a general rule, sunny days and cold nights promote the accumulation of photoassimilates and consequently trees become less prone to shed any of their fruits and are less sensitive to thinning applications. Whereas, cloudy days and warm nights lead to carbohydrate deficit and therefore trees tend to retain only a limited number of fruits and become more sensitive to chemical thinning. This associating between weather conditions and the total carbohydrate reserve has encouraged scientists (Alan Lakso and Terance Robinson) at Cornell University to establish a model known as “The Cornell Apple Carbohydrate-Thinning Model” that provides instructions on the dose and timing of thinning applications based on the solar radiation, temperature and day length records acquired from a weather station in a grower’s orchard blocks. This model can be accessed online through the Network for Environmental and Weather Applications (NEWA)(http://newa.cornell.edu/index.php?page=apple-thin).
It is a good practice to visit the NEWA website and make yourself familiar with the inputs and outputs of this model, especially if you have a weather station in your orchard that is connected with NEWA server, or you know the one that is close to your operation and that you can depend on.
As we are moving toward a heavy crop load and, luckily, less frost damage for apples this year, we have to consider looking at the outputs of the carbohydrate model in order to decide the timing and the dose of the chemical thinner. Typically, the efficiency of thinning applications applied from petal fall until a fruit size of 20 mm correlates well with the carbohydrate reserve of the tree and these are the times where the model outputs will serve as useful guidelines.
This year, we, at AHS Jr. AREC, Winchester, will run the model weekly and provide the outputs of this model as graphs that show the carbohydrate reserve of apple trees, and the recommended applications. The following table (Table 1) describes the recommended dose of chemical thinners based on the carbohydrate balance of the tree.
Table (1): Decision rules for using the output of the carbohydrate model to adjust chemical thinning rate.

Fruit size is another major factor that determines the efficiency of chemical thinning. When fruits are young (~ 6 mm), their demand of carbohydrate is not much and hence thinning becomes relatively challenging. However, chemical thinners such as naphthaleneacetic acid (NAA) and Sevin (carbaryl) and, to some extent, naphthaleneacetamide (NAD; Amid-Thin) can be successfully used at this stage. As fruits grow to the size of 7-14 mm, their cells divide rapidly and their demand of carbohydrate becomes more than what vegetative tissues can supply, especially if weather conditions do not largely support photoassimilation. At this stage, fruits become more sensitive to chemical thinners such as 6-benzyladenine (6-BA), NAA and NAD. However, if thinning is not adequate at this stage due to unsuitable weather conditions, then another round of thinning application will be essential. As fruit develops to the size above 20 mm, the chemical thinning becomes a tangible challenge. At such an advanced stage of development, fruits become more tolerant to abscission as they have more carbohydrate reserve and the seeds produce auxin which interferes with ethylene action preventing abscission. Chemical thinning at this stage (known as delayed/ rescue thinning), relies mostly on the combined application of 2-chloroethylphosphonic acid (ethephon) and 1-naphthyl methylcarbamate (carbaryl). The following table (Table 2) shows the recommended thinning applications in each stage of flower/fruit development and the dose of each application.
Table (2): Materials, rates and timing of chemical thinning application (Source:2017 Spray Bulletin for commercial tree fruit growers).

2017 Early Season Commercial Tree Fruit Meetings – Winchester Area

Below are the dates for the upcoming commercial tree fruit meetings.  Drs. Chris Bergh, Sherif Sherif, and Keith Yoder will be providing updated information and will be available for discussions and concerns regarding the upcoming season. 

Thursday, March 30.  In-Depth Meeting 7:00 p.m. – 8:30 p.m.  Seasonal Updates

Program: Dr. Keith Yoder (Pathologist – Virginia Tech AHS Jr. AREC)

 

Thursday, April 13.  Breakfast Meeting 7:00 a.m. – 8:00 a.m.

Seasonal Updates and Breakfast Provided

 

Thursday, April 27.  In-Depth Meeting 7:00 p.m. – 8:30 p.m.  Seasonal Updates

Program: Dr. Sherif Sherif (Horticulturist – Virginia Tech AHS Jr. AREC)

 

Thursday, May 11.  Breakfast Meeting 7:00 a.m. – 8:00 a.m.

Seasonal Updates and Breakfast Provided

 

Thursday, May 25.  In-Depth Meeting 7:00 p.m. – 8:30 p.m.  Seasonal Updates

Program: Dr. Chris Bergh (Entomologist – Virginia Tech AHS Jr. AREC)

 

All meetings will be held at the Alson H. Smith Jr. AREC (Winchester Fruit Lab) at 595 Laurel Grove Road, Winchester, Virginia.  Directions from I-81: take Stephens City exit (Exit 307).  Go west into Stephens City on Fairfax Street and proceed straight through the traffic light onto Rt. 631 (Fairfax Street becomes Marlboro Rd.) and continue west approximately 3.5 miles.  Turn right (north) onto Middle Road (Rt. 628) at the “T”.  Go 1.5 miles north on Middle Road and turn left (west) onto Laurel Grove Road (Rt.629).  Go 0.8 miles to the AREC on the left.

 

Mark Sutphin

Associate Extension Agent | Agriculture and Natural Resources, Horticulture | Unit Coordinator (Frederick)

Serving the counties of Frederick, Clarke, Page, Shenandoah, & Warren

Virginia Cooperative Extension – Frederick County Office | 107 North Kent Street | Winchester, VA 22601

Phone – 540.665.5699 | Fax – 540.722.8380 | Cell – 540.398.8148 | Email – mark.sutphin@vt.edu

 

2017 Rappahannock-Fauquier-Madison Orchard Meetings

The Rappahannock Extension Office invites each of you to attend a series of in-orchard meetings scheduled from April through July. These meetings will be held in orchards located in Rappahannock, Fauquier, and Madison Counties.

We will meet at the host orchard at 11:00 a.m. for a tour of the orchard, followed by a discussion of current orchard management recommendations. Virginia Tech fruit specialists from the Alson H. Smith Jr. Agricultural Research and Extension Center will be present to address specific topics. We encourage you to bring samples of insects, diseased foliage or scaffolds for treatment recommendations. We will adjourn around 2:00 p.m. A schedule of meeting locations and directions to the orchards are listed below.

Please call the Extension Office at 540-675-3619 for additional information about these programs.

April 12th In Orchard Meeting
Williams Orchard, Tommy and Eddie Williams, Flint Hill Rt. 211 east to Ben Venue. At the crossroads, turn north on to Rt. 729 and go approximately 2½ miles. Orchard is on the left.

May 10th In Orchard Meeting
Jenkins Orchard, James Jenkins, Woodville, From Rt. 231, turn right on to Rt. 621, go about 2 miles. The orchard is on the left by the packing shed.

June 14th In Orchard Meeting
Stribling Orchard, Robert Stribling and Alex Jeffries
From Flint Hill: Rt. 522 N, turn right on Rt. 635, turn N/left on Rt. 688, the orchard is located near the intersection of Rt. 688 and Rt. 55 in Markham; 11587 Poverty Hollow Ln, Markham, VA 22643

July 19th In Orchard Meeting
Graves’ Mountain Farm, Jimmy Graves, Syria
Rt. 231 to Rt. 670, meet at the picnic shelter on left just past Syria.

If you are a person with a disability and desire any assistive devices, services or other accommodations to participate in this activity, please contact Kenner Love, VCE at (540-675-3616/TDD*) during business hours of 8 a.m. and 4:30 p.m. to discuss accommodations 5 days prior to the event. *TDD number is (800) 828-1120.