Is Mummy Berry Starting Already?

I received the information below from University of Georgia Plant Pathologist Dr. Phil Brannen. It states that in Georgia, mummy berry infection is likely right now due to the warmer weather conditions.  We have also had these conditions in Mississippi, so it would be a good idea to keep mummy berry control in mind, especially for southern highbush blueberries.  Meanwhile, rabbiteyes are not far behind.

Dr. Harald Scherm ran the mummy berry model today, and it indicates that we are currently in a DANGER period for mummy berry disease initiation.  Harald stated that the temperature-driven model indicated that apothecium (spore-forming structure that develops from overwintered mummies on the ground and in debris) emergence should be well underway based on the balance of chill-hours and degree-days received. In fact, there could be a chance that the apothecia ejected spores earlier than normal, possibly allowing for infection of early-blooming southern highbush varieties. This assumes that soil moisture conditions have been favorable, which they likely have been.  Rabbiteyes will soon be showing green tip or early bloom, which should initiate the spray program for mummy berry management.  For additional information on fungicides which are available for management of mummy berry, refer to the blueberry IPM guide at www.smallfruits.org. “

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Some Tidbits Learned from the Southern Blueberry and Fruit Workers Meeting

Recently I attended the Southern Blueberry and Fruit Workers meeting in Atlanta, GA.  It is held as part of the Southern Region of the American Society for Horticultural Science annual conference.  Below are some new things I learned about at the meeting:

Ring nematode is prevalent in Georgia blueberry plantings

The nematode problem is worse in re-plant situations and may require fumigation

Southern highbush blueberries have more problems than Rabbiteyes, especially in re-plant situations

Using pine bark mulch appears to reduce nematode populations

The addition of humic acid to the soil does not appear to benefit blueberry plants

Botrytis resistance to fungicides has happened in GA.  Use of Captan or Ziram is now recommended because of low resistance possibility

Mummy berry sprays should be applied starting at first sign of green tissue.  Indar, Orbit, Pristine, and Proline (a new material) showed efficacy.  Serenade, an organic product, also had some efficacy.  Regalia, another organic product, had no effective control of the disease.

Exobasidium is becoming resistant to Pristine in GA.  ‘Premier’ has high infection rates, as does Tifblue.  A full Captan spray schedule is effective (about 8 sprays in GA), but not using Captan as a delayed dormant spray.  Use Lime Sulfur or Sulforix for best control as a delayed dormant spray.

Xyllela (blueberry scorch) has been found in various states.  In Rabbiteye’s  it leads to chronic symptoms, but in Southern Highbush scorch symptoms are readily apparent.  There may be different strains of this disease and more work is being done.

Blueberry Necrotic Ring Blotch is a non-systemic viral disease that is only in leaves.  Mites spread it.  It can lead to defoliation of the plant.

Broad mites have been found in blueberries and blackberries in Arkansas.  Damage resembles Roundup injury.  Leaves have a “silvery” look, with rosetting and stunting of plants, and necrosis of the petiole.  It will kill shoot tips.

Blueberry rust is a problem in Gulf Coast areas of Alabama.

Foliar calcium spray trials in GA on rabbiteyes have shown no efficacy

Three new Southern Highbush blueberries are being released from UGA soon.

One new Rabbiteye cultivars is also being released from UGA – Krewer, an early, large fruited cultivar that should pair well with Titan

Cherry fruitworm, an emerging pest of Mississippi blueberries

The cherry fruitworm (CFW) is a univoltine moth, native to the U.S., and whose larvae preferentially infest rosaceous and ericaceous fruits. CFW larvae have been confirmed infesting rabbiteye blueberries in Mississippi, and this typically northern pest’s appearance may represent a new State record.  Without careful pest scouting after petal-fall, CFW-induced damage and fruit drop will often go undetected until berry losses become too severe for effective insecticide management.  Scouting therefore is critical for managing CFW populations. Although the small and nocturnal adults of CFW can be elusive, there are excellent pheromone traps available for monitoring the activity of adult males, and by association, the destructive egg-laying females. Females oviposit on the calyx of blueberry fruit, much like cranberry fruitworms do. Upon eclosion, the larvae of CFW bore into fruit. It is at this stage of larval development that environmentally safe Bt insecticides are the most effective against CFW caterpillars. As larvae mature and become larger and more heavily sclerotized, they become harder to kill with Bt. However they are at greater risk of attack by predators and parasites because, unlike cranberry fruitworms, they do not erect silken webs around their feeding sites. Mature CFW larvae that are preparing to pupate avoid ground-based dangers by taking refuge in dead unproductive wood of blueberry bushes and other nearby vegetation. Removing old unproductive canes may reduce overwintering populations of CFWs and hence temper the severity of subsequent spring outbreaks.

The above information was written by:

Chris Werle1, Eric Stafne2, Blair Sampson1 and John Adamczyk1

1USDA-ARS Thad Cochran Southern Horticultural Research Laboratory, Poplarville, MS 39470

2Mississippi State University, Coastal Research and Extension Center, Biloxi, MS 39532

 

A longer article with a fuller description as well as photos is forthcoming in the July-Sept issue of the Mississippi Vaccinium Journal.

Addressing The Top Pests of Mississippi Blueberries

There are many pests of blueberries in Mississippi; however, most of them are easily controlled or do not create an economic amount of damage.  For many years blueberries in Mississippi have been grown with little pest control inputs, especially Rabbiteye blueberries.  This past year, 2012, initiated a whole different problem — Spotted Wing Drosophila.  We believe the pest has been here for some time, but perhaps it was the mild winter that allowed its populations to explode.  Many growers complained of its damage — mainly leaky berries.  The issue is, “How do we control it?”  A simple question, with a not-so-simple answer.  So, Mississippi State University-Extension Service and the USDA-ARS have teamed together to put on a workshop for growers to learn about this insect and potential control measures.  Other pests, Exobasidium and Xylella will be addressed as well.  The workshop is open to anyone, not just blueberry growers, who wants to learn about these pests.  The Gulf South Blueberry Growers Association has also been generous enough to bring in a couple of outside speakers — Dr. Oscar Liburd from the University of Florida and Sam Erwin from Superb Horticulture in Indiana.  See the information below for details and please pass it along to anyone who will find it useful.

MS Emerging Pest Workshop 2013

MS Emerging Pest Workshop 2013