Tobacco Tour 2010 completed - pictures to come!

The 2010 Tobacco Tour proceeded this week Tuesday and Wednesday and visited 10 locations encompassing 20 Crop Sciences, Plant Pathology, Bio & Ag Engineering, and Entomology extension and research projects.  Over 120 people attended the eastern tour on Tuesday, and 50 people participated in the western tour Wednesday.  I, and Monique Rivera, took lots of great pictures, which I will post soon!

Grape phylloxera update

Grape phylloxera adults and eggs in foliar galls at RayLen Vineyard. Photo: HJB

Last Thursday I visited RayLen Vineyard to see the grape phylloxera (Daktulosphaira vitifoliae) infestation I posted about previously.  In person, the extent of the damage was even more impressive.  The Vidal Blanc vines were nearly completely infested.  This suggests that several generations have cycled through during this summer.  Vidal is a French-American hybrid grape.  Hybrids (ie. Traminette, Seyval Blanc, Chambourcin) are increasing in popularity among eastern grape growers because they are often more tolerant of our weather conditions that European varietals (ie. Merlot, Chardonnay, Cabernet Sauvignon).  However, it appears that some of these hybrids are more susceptible to foliar phylloxera.  Because they are grown on phylloxera tolerant rootstock, it is unlikely that phylloxera are also damaging roots.

Infested Vidal vines. Photo: HJB

Leaves at the base of the canes had no live phylloxera present.  I started to find live phylloxera about half way up the canes, and the youngest leaves had females and eggs in the galls as well as few crawlers.  

Mature grape phylloxera female and eggs (indicated by red arrow) and crawler (blue arrow) on a young grape leaf.  Photo: HJB

Donn Johnson, University of Arkansas small fruit entomologist, has posted several other images of eggs, crawlers and adults here.  The leaves with active infestations were near the end of canes and likely to be removed during hedging (which was planned for the next few days after my visit to RayLen), and because of this, I was reluctant to recommend a pesticide application.  Instead, I suggested removing as many infested leaves as possible during hedging/leaf removal and destroying them.  They could then follow this up with a pesticide treatment if crawlers or open galls (see below) were still present.  

Open galls on young leaves.  The insects in these galls are susceptible to contact insecticides.  Photo: HJB

It seems likely that phylloxera will continue to be a problem in French-American hybird grapes, which I am still a fan of for their many other good qualities.  The strategy at RayLen and other infested vineyards should include early season scouting for first generation phylloxera--likely to be a few galls near the base of cane in spring.  Once crawlers of this first generation appear, foliar treatments should be applied (some of the materials available for phylloxera management are listed in this University of Arkansas fact sheet). Regular scouting for subsequent generations should be conducted throughout the summer followed by treatment as they appear.  Severe phylloxera infestations weaken vines and leave them more susceptible to winter injury.

Phylloxera infested cane.  Photo: HJB

Watching the west: SWD organic trial results

Mark Bolda, University of California Cooperative Extension Farm Advisor in Santa Cruz County, has posted the results of a recent efficacy trial comparing organic management tools for SWD. According to this post, Pyganic and Entrust appeared to provide control of SWD in raspberries. Both of these materials are OMRI listed (organically acceptable).

More information
Results of Trial Testing the Efficacy of Several Organically Registered Pesticides for Control of Spotted Wing Drosophila in Raspberry

Hornworms in motion (not a pest alert!)

Those of us who work on and grow the crops they eat may think of tobacco hornworms (Manduca sexta) as pests to be controlled, but they are also import lab rats for all sorts of biological research. In fact, my undergraduate research studied hormone binding and transport in M. sexta in response to environmental stresses, so I have dealt with my fair share of hornworms in and out of the lab.

A recent study used hornworms as a model of locomotion and found that their gut and body move separately! See here for a nice summary and cool video!

ScienceShot: Caterpillar's Guts Crawl Independently of Their Bodies

SWD article in Growing Magazine

OSU Entomologist Amy Dreves checks a monitoring trap in an Oregon strawberry grower’s high tunnel crop for SWD.
Photo by Lynn Ketchum, OSU EESC.

An article highlighting SWD motoring and management efforts throughout the US has just been published in Growing, a magazine for fruit and vegetable growers. Our monitoring effort is highlighted. When the article was written, there were no SWD captures in SC, NC, or VA. What a difference a few weeks make! We now have trap captures in 2 locations (see trapping data here). More on these captures later this week.

Northern Fruit Growers on Watch

Grape root borer update

I visited 2 vineyards on Thursday, July 15th to discuss grape root borer presence and management. We hung 6 traps at RayLen Vineyard, which they will begin checking this week. I next headed up to RagApple Lassie, where owner Frank Hobson reported catching significant numbers of grape root borer moths in his 3 monitoring traps. After loaning one of his traps to a neighboring vineyard, they reported 60+ moths in a few days.

The growers I visited raised several great questions about grape root borer (GRB) that bear reviewing:

1. Why are we seeing this many moths now?

RagApple Lassie began trapping for moths this year in response to damage seen last year. Several vines were declining, and when they were dug up, GRB damage and larvae were present. This was the first GRB damage they recall seeing. It is hard to say why exactly multiple vineyards are seeing significant numbers of GRB, but I suspect that it at least partially due to weather and vineyard age. Last year was the first summer in 3 years with relatively normal precipitation, and soil dwelling insects are often sensitive to moisture--declining in years with low moisture and rebounding following years with moisture.

We also have several "middle age" vineyards in the Yadkin Valley. GRB take up to 2 years complete a generation, so it may take several (8-10 years) for moths to develop to detectable levels. We have several vineyards at or just older than this age.

2. How do we use control tools for GRB?

Lorsban (chlorpyrifos) is the only material registered for GRB, but as I mentioned in my previous post, this material is hard to time given the long GRB emergence time which coincides with harvest.

Soil mounding at the base of vines at the beginning of July is a cultural control option, but I have seem limited efficacy data on this tool.

3. Are there any non chemical options for GRB?

Soil mounding is a non chemical option. Other non chemical options that have been tested include entomopathenogenic nematodoes and pheromone mediated mating disruption. University of Florida researchers have demonstrated good results with mating disruption, but neither of these tools are commercially available at this time. These are both interesting options that bear examination under NC conditions.

New blueberry maggot trap captures in southeastern NC

Blueberry maggot flies were captured at our southeastern monitoring sites on July 14th. One male each were trapped at Site 2 and Site 12 (you cannot see Site 2 in the figure below). Both locations still have a considerable amount of fruit left to harvest. Southern highbush fruit have long been harvested, but rabbiteye berries remain on the bushes.

Blueberry maggot captures in southeastern monitoring locations.

Prior to this, only 1 blueberry maggot fly was captured at Site 5 (in Bladen County). All 3 locations where flies have been captured are treating aerially with malathion (the grower standard for BBM management in the Calendar spray program), while no flies have been captured at either of our 2 untreated locations (Sites 3 and 14). At our monitoring location outside of the commercial blueberry production region in Rockingham County, we caught 33 flies on July 14th. Our Rockingham County location is also not treated.

Because our last southeastern trap capture was a month ago, this begs the questions as to whether the flies we are observing now are part of the same emerging cohort of adults or if they are newly emerged, and therefore, targeting rabbiteye fruit. Either of these are possible, as many tephritid fruit flies can be fairly long lived (a one month life span would not be unheard of). Unfortunately, we cannot say how the old the flies we captured were because they were male. The ovaries of female flies can be dissected to roughly determine if flies are very young or relatively old, but there are not reliable tools or aging male flies. We'll be keeping an eye out for female flies to shed some light on this trapping pattern.

Live updated southeastern blueberry maggot captures