Doug Pfeiffer, Fruit Entomologist at Virginia Tech has prepared a list of updates on grape insects that should be reviewed by all growers.
As predicted, this is shaping up to be a year of high JB populations. This is a result of the rainy season last year. JB and related beetles have eggs with a low ability to retain moisture. Consequently, in drought years there is high mortality of eggs, with low populations of adults in the following season. In years with higher levels of soil moisture, we can expect higher natural survival of eggs and high populations of adults the next summer. Recall that vines can tolerate a considerable amount of foliar feeding before grape yield or quality are affected. Vines are most susceptible of JB feeding following veraison, when the berries become the sinks for photosynthates. JB adults concentrate their feeding in the top of the canopy and sprays can be focused there. This will limit the impact of sprays on beneficial species in the vineyard. Vines are very vulnerable when they are young, and young vines should be protected more rigorously. Some varieties (e.g. Norton) are more vulnerable than others, as well. Sevin, Imidan, Belay, Actara, Assail and Avaunt are recommended for JB control, also with the organic alternatives Surround and a combination of Neemix and Trilogy. The latter two are neem-based materials, are best applied before JB adults become established on the vines.
GRAPE TUMID GALL:
Grape tumid galls are cause by a species of cecidomyiid fly, grape tumid gallmaker, Janetiella brevicauda. In general, these are dark red, irregularly shaped galls – within the galls are tiny fly larvae, bright orange in color. There is a lot of variation in the gall development – on leaves, tendrils, petioles and rachis. It was once thought that these galls were caused by different midge species; they are now known to be caused by one species. Larvae overwinter, and flies begin to emerge in early to mid May. There are 1-3 generations per season. The first generation is probably the most important. Galls on foliage are of little importance, however, galls in the rachis can cause failure of the cluster. This season, a significant infestation of grape tumid gall has been seen in a Niagara block. Some varieties appear to be more sensitive than others; in the past, high infestation have been seen in Traminette. Historically this has been considered to be a minor problem in managed vineyards; in sensitive varieties, control may be needed. Movento (spirotetramat) is registered for this use. There is no sampling method for this species, and sprays should therefore be timed for the first appearance of galls in the spring. I would be interested in hearing about your experience if you find this insect in your vineyards. Images and further biological and control information are posted (and linked) in the Virginia Vineyard site (http://www.virginiafruit.ento.vt.edu/grapegalls.html).
Yellowjackets are usually late season pests of vineyard blocks, breaking berries, injury that may be falsely ascribed to honey bees, though bees are unable to break the skin of grape berries. Yellowjacket control is usually difficult. Insecticides are limited in their efficacy because choices are limited by preharvest intervals, and any insecticide will kill only the active field force of workers. Killed workers will soon be replaced by others. Several candidate insecticides are listed under fourth cover of the commercial vineyard pest management guide; this is linked in a page further describing yellowjackets in the Virginia Vineyard page (http://www.virginiafruit.ento.vt.edu/yellowjacket.html). Baits may be tried, especially early in the season, when overwintered queens are in the process of initiating nests. Many baits were developed that were more effective against western species of yellowjackets, and success was limited against eastern species. If the location of nests can be found, the nest can be destroyed using several insecticide preparations available for this use. The wasps are quieter at night, and this is the best time to try to control the nest.
The Summer 2014 Grape Press is out! Highlights include articles on canopy management, weather issues, potassium nutrition in grapes, soil science and much more.
Summer 2014 Grape Press (pdf)
Lucie Morton is conducting a study for the Virginia Wine Board on the role of clay mineralogy on the uptake of potassium by wine grapes. If VVA members would like to participate and add baseline survey information to the study, they can provide data to this email address: firstname.lastname@example.org. Here’s what they’re looking for:
1. Digital copies of soil reports from their vineyard blocks. They can be from multiple years and can be in spread sheet form. Please provide information on how the sampling was done, and at what soil depths.
2. Digital copies of tissue analyses from those vineyard blocks. They can be from multiple years and can be in spread sheet form. Please specify whether they are from petioles or leaves. (Note: bloom is a standard time for petiole sampling.) You should provide the time of sampling and the age of the vines. Also, specify the cultivar and rootstock varieties.
3. Recommendations that were made about soil amendments.
4. Information about actions that were taken with regard to soil amendments.
The information collected for this study is not being examined for anything other than generic information and basic trends. It will be logged into the study database by geographic location with a code and not by name of business.
Please note, this is a research project that will ultimately lead to improvements in viticultural practices in Virginia, but it is not intended to provide immediate information to growers. There will be no reply to growers beyond an acknowledgement that the information has been received. There will be no follow-up contact or opinions from the study team including Lucie. She and her team are simply amassing as much raw data about linkages between soil analyses and tissue analyses in as many Virginia vineyards as possible.
On Saturday, June 7, Lucie Morton will reprise a class on Ampelography that she first taught at Piedmont Virginia Community College last year. Ampelography involves the identification of grapevine varieties through the study of the shape and color of the vine’s leaves, and Lucie is one of only four certified Ampelographers in the entire world. The class will begin, as it did last year, with a lecture at PVCC’s Stultz Center in Charlottesville, and will move on from there to Veritas Vineyard and Winery for an afternoon of field work in the vineyard. The class starts at 9 a.m., and lunch is included. To register, call PVCC Workforce Services at 434-961-5354.
The VVA is in need of an official Glass Keeper, preferably a winery or someone with a commercial dishwasher in the Charlottesville area. Responsibilities:
- Bringing clean VVA wine glasses to the Omni the Wednesday before the Winter Technical begins and taking them away again after the meeting
- Storing the wine glasses between events
- Bringing clean wine glasses to the Summer Technical the morning of the meeting and take the away again after the meeting
Hence the title ‘Glass Keeper! Perks of said volunteer position:
- Free entry to the Winter Technical Meeting, including meals and reception, for one (a $250 value)
- Free entry to the Summer Technical Meeting, including lunch and Summer Social (a $70 value)
The passing of the glasses will take place at the end of the Summer Social on June 5th at Bourboursville. To be considered you must have a vehicle large enough to handle approx. 1800 glasses packed in boxes (a pickup or such).
Please email or call Tracy at 571-236-8074 if you have any questions or are interested. Thank you!!
The Virginia Vineyards Association and Virginia Cooperative Extension are pleased to present the 2014 Summer Technical Meeting: Wildlife Management Strategies and Economics of Mechanization. The program and the social will take place on Thursday, June 5, 2014 at Barbourville Vineyards in Barboursville, Virginia.
Tremain Hatch has worked with local VCE agents to schedule a series of spring/early summer vineyard meetings which will involve Virginia Tech specialists, local Cooperative Extension agents, and occasionally other speakers. These meetings follow the IPM meetings and pruning workshops held earlier this year.Please note that the timing of these meetings is variable. For those who have not attended these meetings in previous years, the format for most includes a discussion about season topics by extension specialists (pest considerations, pertinent viticultural issues, and usually an introduction by the host vineyard owner/operator. Attendees can bring problem samples from their own vineyards for ID or discussion. Depending on numbers and weather, we also try to do a walk-through of the host vineyard. We hope to see you at some of these meetings. (Included here also is the upcoming Virginia Vineyards Association summer technical meeting scheduled for 5 June)
VVA Summer Technical: Wildlife Management Strategies & Economics of Mechanization
9-4:30, Social 5-8pm
Contact: Virginia Vineyards Association
Vineyard Meeting w/LWGA
Boxwood Winery, Northern VA
6 – 8 pm
Contact: Beth Sastre, Loudoun County
Vineyard Meeting in Southeastern VA
11 to 3pm
Contact: Marcus Williams, Suffolk County
Barrel Oak Winery
3 – 5 pm
Contact: Tim Ohlwiler, Fauquier County
DATA SHOWS CLOUDS… WINDS… VERY LOW DEW POINTS OVER NIGHT WHICH MAY “SAVE THE DAY ” AND PREVENT MAJOR FROST – FREEZE IN SOME AREAS WEDNESDAY MORNING.
*2nd frost possible for the Shenandoah Valley – Thursday morning 4/17?*
NWS ISSUES FROST ADVISORIES FOR SOME PORTIONS OF VA | MD | NC | WVA FOR WEDNESDAY MORNING
MODEL DATA KEEPS TEMPS OF 20-25 DEGREES WEDNESDAY MORNING FOR
western NC mountains
all of southwest VIRGINIA
all of the SHENANDOAH VALLEY
All of WEST VA
All of western and Central MD
All of southwest and south central PA
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