Grape leaf skeletonizer infestations appearing

Grape leaf skeletonizier (Harrisina americana) larvae on wild grape leaves.  Photo: HJB

Grape leaf skeletonizer (GSL) larvae have begun appearing in large numbers on grape vines in the last 2 weeks.  I have received a few phone calls and emails about these insects.  The distinctive yellow and black caterpillars are gregarious and a group of them feeding close together can quickly skeletonize a leaf.  From a distance, leaves will appear light brown or gray.  Larvae will be clearly visible as will their feeding.

GLS rarely cause significant damage in commercial vineyards because they are often controlled by insecticides applied for other insects.  In homeowner plantings, they may reach damaging densities, but can be managed relatively easily (Bt is a good, effective choice, see a note about pesticide recommendations and hand removal may also be sufficient when the larvae are small and concentrated in a small area).

More information

Grape leaf skeletonizer, University of Florida

Wine flows near Haw River - Local/State - NewsObserver.com

An interesting note in this article on Iron Gate Vineyard and Winery in Mebane--they harvested their whites last week and are picking their reds now! A timely harvest will reduce bee, wasp, and green June beetle concerns.

Wine flows near Haw River - Local/State - NewsObserver.com

NCSU to the rescue!

Jennifer Keller, a member of the NC State Entomology Department's apiculture program lent the law a hand this morning when a swarm of honey bees engulfed a sheriff's car.  Video below:

Blueberry maggot monitoring concluded - An interesting year

We concluded blueberry maggot monitoring at all of our sites the last week of July. A grand total of 3 blueberry maggot flies (2 males and 1 female) were captured at our 14 southeastern NC sites, while 165 flies were captured at our Rockingham County validation site.

Our southeastern monitoring sites ranged from 0-5 applications of malathion. These trapping results suggest that we could reduce pesticide applications for blueberry maggot dramatically, although we need to be careful to assess the potential non-target impacts of reducing broad spectrum insecticide use before wholesale adoption of a reduced pesticide application program.

Results from this project were presented at the North American Blueberry Research and Extension Workers Conference in Kalamazoo, MI last month. You can see the poster from this meeting with our results here (use the zoom on the right to enlarge).

Blueberry maggot distribution and abundance in North Carolina

SWD trap captures continue in SC and NC

Spotted wing drosophila have been confirmed in 1 NC and 2 SC trapping sites. Randolph1, Saluda1, and Lexington1 have each had at least 1 SWD detected. See here for a full list of monitoring locations and links to trap captures.

As of now, more flies seem to be showing up in the yeast-sugar lure traps, but overall few flies have been caught, so we cannot draw conclusions yet.



Sponsored by the Southern Region Small Fruit Consortium, Project 2010 E-01.

What to Watch For - Wasps and bees in grapes

Wasps and bumble bees feeding on grapes. Photos: Ric Bessin, University of Kentucky Entomology

Today I had 2 phone calls and emails about wasps and bees feeding on grapes. Given our warm summer, this is not a surprise. In fact, last Friday when Turner Sutton, NCSU Plant Pathologist, and I were visiting vineyards last week we noticed several varieties (Marsanne & Viognier, to name a few) that were nearing harvest. Like many other crops, this is about 2 weeks earlier than normal. I said to Turner as we were leaving, "All this ripe fruit says to me is that I need to be ready for calls about bees, wasps, and green June beetles," and here we are!

Ripe or nearly ripe fruit coupled with the rain we have recently gotten is a recipe for splitting and other mechanical injury. These injured fruit will attract bees, wasps, and beetles, but they will not just feed on the damaged fruit. Once these opportunist insects are in the grapes, they can also feed on relatively sound fruit.

As I told both people I spoke with today, I do NOT advocate treating bees and wasps with insecticide. There are several reasons for this, with the foremost being that these are beneficial insects. They are our pollinators and predators that we work so hard to maintain all other times of the year. Pollinator heath is a major issue across agriculture systems, and is it irresponsible to be treating bees and wasps with insecticides in grapes. Even if pesticides were used, they will not solve the problem. Most bees and wasps are social insects with large colonies including foraging workers and reproductives. Only a fraction of the workers from a colony will be present in grapes at any given time, and no pesticide applied during harvest is going to have a long contact residual. This means that a pesticide application will kill the relatively small number of foraging workers in a field when it is applied, but leave the rest of the colony intact to re infest when the pesticide has dissipated.

What can be done to reduce bee and wasp injury?

Be ready to harvest.
I am not advocating harvesting fruit before you reach desired brix, but if fruit is ripe enough to split and attract bees and wasps, it is not far from harvest-ready. Harvest clusters as they become mature. This may mean picking several times and picking the early ripening areas (ie. the sunny side of the row) first.

Practice good sanitation.
Remove damaged fruit from the field promptly. Fruit left on the ground or on the vine will attract insects. Powdery mildew and thrips damaged fruit are more prone to splitting.

Be choosy about what you harvest.
Not all the grapes in the field will make it to the crusher. If wasps and bees are damaging a few early ripening clusters, remove them from the field preharvest. Do not harvest damaged fruit.

Consider trapping.
Several traps are marketed for wasps. Providing an attractive lure outside your planting may reduce populations in the vineyard. Suggested lures include soda, sugar syrup, and meat. Yellow trap are typically the most attractive.

Check the field for nests.
Wasps in particular can make nests on trellis wires or vines. If there are nests present in fields, these can be spot treated with insecticides or removed. Surrounding areas should also be scouted for nests, which can be spot treated.

Protect yourself.
Wear gloves, and if necessary, a head net when harvesting.

Ripening fruit at Junius Lindsay Vineyard. Photo: HJB

The early season means we need to be prepared for more wasp and bee presence as ripe fruit develops, but this are not unmanageable issues. Happy harvesting!

More information
Harvest pests of grapes - University of Kentucky

What to Watch For - Caterpillars in blueberries

Yellow necked caterpillar damage on a blueberry bush. Photo: HJB

Last fall, I posted about blueberry feeding caterpillars. Several caterpillars species in the genus Datana feed on NC blueberries and are generally called yellow necked caterpillars. More information on this group can be found here. Yesterday, I visited Vollmer Farms near Bunn, NC to discuss organic blackberry management (this is their first year growing blackberries) and took a look at their blueberries as well. There was some light Japanese beetle injury on a few bushes, but one plant was fairly defoliated. A few yellow necked caterpillars were still present on this plant, but most were close to pupation. I did not start getting calls about these insects until September last year, so like many other things this summer, it appears the caterpillars are also earlier than normal.

Yellow necked caterpillar larva on blueberry bush. Photo: HJB

These caterpillars are gregarious, meaning they feed in large groups, often on a single plant. This grouping also means that yellow necked caterpillars can readily defoliate bushes. This time of year, blueberry bushes develop flower buds for next year and severe defoliation could impact fruit set for next year. Fortunately, only one of the bushes at Vollmer's Farm was damaged.

Nearly mature yellow necked caterpillar and young caterpillar. Photo: HJB

If yellow necked caterpillars are observed early on blueberry plantings, they can be easily managed with both conventional and organic materials (a note of on pesticide recommendations). In addition to the caterpillars, we found a surprise, a large female praying mantis. One caterpillar on the bush had clearly been killed by the mantis, but that didn't seem to deter another from tempting fate by climbing onto the same branch she was on.

A brave caterpillar. Photo: HJB

Western NC Hops Tour handout

This past Saturday I attended the second Western North Carolina Hops Tour.  We visited 2 small, recently established hops plantings, and after the tour, I visited a third.  I'll have a longer post on the tour itself, but I wanted to share the link to the handout I prepared for this event.  It's a summary of some of the arthropods we have seen this summer in samples from hops plantings. 

This handout is designed to serve as a tool for folks with hops plantings to identify the arthropods they may see on their hops, not as an exhaustive list of hops pests or management recommendations.  It's also extremely important to make sure that the right culprit is implicated in damage seen.  One thing that was very clear on Saturday is that some hops varieties are not very happy in NC.  This is not surprising given that commerical hops varieties are adapted to the Pacific Northwest, which has very different day length and climate. Leaf and cone yellowing and drying are more likely due to senescence,  nutrient issues, water stress, or other abiotic problems than insects--certainly based on the density of arthropods observed in the planting.

Hops Tour Handout - Insect Identification in NC Hops

The future of endosulfan in small fruits and tobacco

In June, the EPA moved to terminate the use of endosulfan (an organochlorine insecticide). Among the crops I work on strawberries, blueberries, and tobacco will be potentially impacted by this termination. Endosulfan (trade names include Thiodan, Thionex, and many others) is registered for use against cyclamen mites, aphids, lygus bugs (strawberries); blueberry bud mites (blueberry); aphids, green June bugs, and stink bugs (tobacco).

This termination will mean different things for these different crops.

For tobacco, little will change. We have not recommended the use of endosulfan in tobacco for the last 4 years, because of pesticide residue concerns among buyers and because good, effective alternatives exist for the target pests. If the current agreement holds, no endosulfan can be used on tobacco after July 31, 2012, with sales restrictions taking effect sooner.

In strawberry, the same timeline also applies. No endosulfan can be used after July 31, 2012. We have removed endosulfan from the 2011 Southern Region Small Fruit Consortium Strawberry IPM Guide (update to be published this winter). Endosulfan is registered for cyclamen mites, aphids, and lygus bugs in strawberry. The UC IPM guide for strawberries recommends Kanemite and Agri-mek for cyclamen mites, both of which are also registered in NC strawberries (a note about pesticide use), and we have several tools for use against aphids. Lygus bugs are a trickier proposition. Pyrethriods are effective, but may have undesirable non target effects on mites (they may flare them). However, our spring strawberry season is typically complete before large lygus populations appear. Lygus, or tarnished plant bugs, have greater pest potential in day neutral, ever bearing, or perennial strawberry production.

Finally, of the crops I work on blueberries face the greatest challenge with the removal of endosulfan. Blueberry bud mite, BBM, (Acalitus vaccinii) is difficult to control in some varieties, and endosulfan is the only conventional material available. The pest severity of BBM varies by variety, and can be mitigated in the southeast with post harvest pruning. This is not an option in areas with shorter growing seasons. In recognition of the greater difficulty imposed by the loss of endosulfan on blueberries, there will be a longer phase out. Again assuming the current agreement holds, blueberry growers will be able use endosulfan until July 2015. This will give researchers and regulators time to develop and/or register alternatives to endosulfan for blueberry bud mite.


More information
EPA action to terminate endosulfan