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Tuesday, December 14, 2010

Applications now being accepted for the 2011 Flue Cured and Burley Tobacco Production and Marketing Short Course

NCSU Entomology research plots at the Upper Coastal Plain Research Station, Rocky Mount, NC during the 2010 Flue Cured Tobacco Tour. Photo: M.J. Rivera

Applications are now being accepted for the 2011 Flue Cured and Burley Tobacco Production and Marketing Short Course. This annual, 1 week long short course is funded through the NC Tobacco Foundation and is open to NC tobacco growers, cooperative extension agents, research station personnel. The short course runs from January 31st to February 4th. This year, the course will visit US Tobacco Cooperative and have presentations about the fundamentals of tobacco production from NC State University faculty (including myself). On the final day of the course, participants will attend the NC Tobacco Growers Association annual meeting. Twenty five (25) participants will be selected. Applications are due January 6, 2011 but must be delivered to applicant's cooperative extension office by January 3 to allow agents to review and sign them. The application form with more information can be found here.

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Sunday, December 12, 2010

Tobacco Growers Information Portal

NC State University has developed an online resource for tobacco growers and associates.  The Tobacco Grower Information Portal has agronomic, economic, pest management, and curing information.  The online format allows us to present production and management information beyond the Tobacco Information Guides.  Spearheaded by Blake Brown, NC State University Department of Agriculture & Resource Economics, the portal includes information from Mina Mila (NCSU Plant Pathology), Grant Ellington (NCSU Biological & Agricultural Engineering), Loren Fisher (NCSU Crop Sciences), and Sandy Stewart (NCSU Crop Sciences).

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Tobacco Grower Information Portal

Friday, December 10, 2010

Final 2010 SWD Webinar Now Available

We just had our last SWD Elluminate webinar for 2010 this morning, and the recording is available here. You will need the session password (fruitfly) to log in. In this webinar, I present a national and regional research update and discuss future directions.

Recordings of SWD webinars 1 and 2 can be found here and here, respectively.

More information
SWD Webinar 3
SWD Webinar 2
SWD Webinar 1

Thursday, November 11, 2010

Strawberry high tunnel production workshop - November 17

NCSU specialists Jeremy Pattison, Barclay Poling, and myself will be at the Piedmont Research Station near Salisbury, NC on Wednesday, November 17th for a workshop on high tunnel strawberry production. I will be covering twospotted spider mite biology and management in tunnels (a project we have conducted for 2 years) as well spotted wing drosophila monitoring and management implications in tunnels.

You can find information on the workshop here.

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Tuesday, November 9, 2010

NC Blueberry Council's New Website

The North Carolina Blueberry Council, Inc. has updated and revamped their webpage. Included is information for growers, consumers, and the scientific community. It's worth a look!

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Southeast Strawberry Expo Handouts

I present at the Southeast Strawberry Expo in Virginia Beach, VA yesterday and today.  I am never sure exactly how many handouts to bring to this type of meeting, where attendees select the sessions they will attend the day of the meeting.  If you attended the Expo and did not get a handout, or if you were unable to make it this year, you can find links to two of my handouts below.  I will post the slides from my presentation later this afternoon.  I also distributed a draft of the 2011 NC Agricultural Chemicals Manual strawberry insect management guide.  The 2011 Manual will be online in mid December.  In the meantime, you can find the 2010 Manual here.

Southeast Strawberry Expo Handouts
Arthropod management in strawberries: a fall & winter update
Pesticides registered on strawberries and their possible efficacy against spotted wing drosophila (This document is adapted for NC and VA growers from a similar resource developed by Oregon State University entomologists.)

Friday, October 22, 2010

Spotted Wing Drosophila Page

You may have noticed a new feature on the top of the page.  I have created a Spotted Wing Drosophila page.  This page contains general information and resources on spotted wing drosophila as well as links to all SWD posts, in one convenient location.

Wednesday, October 20, 2010

Spotted wing drosophila coverage in local media

Female SWD on a ripe red raspberry.  Photo: HJB

Two local media sources have stories on spotted wing drosophila and our recent detections. I spoke with the News & Observer in Raleigh and North Carolina Public Radio yesterday, and both cover SWD in stories today.

This is part of an effort to make as many growers and gardeners aware of SWD before next year's growing season so that, together, we can develop management strategies and determine the extent of the fly's spread though North Carolina and the east coast.

SWD was also featured in the Triad Business Journal, the Richmond County Daily Journal, and

More information
Asian fruit fly may plague state next year - Food -
NC Farmers Face New Foe - North Carolina Public Radio
Invasive Fruit Flies Found in NC - Triad Business Journal 
Heat May Have Helped Growers - Richmond County Journal
Invasive Fruit Flies Found in NC -
NC Small Fruits, Specialty Crop, and Tobacco IPM - SWD Posts

Tuesday, October 19, 2010

Hops news

North Carolina hops production continues to draw attention, as evidenced by this article in Carolina Country.  Another recent addition to online hops information is this website, set up by Rob Austin of the NC State Soil Science Department, which describes the project I became involved with this summer.

The group from this project will be getting together next month to discuss the lessons learned in 2010 and hops research plans for the future.

More information
Carolina Country - Hops: a new farm is adding to local flavor and the economy
North Carolina Hops Project

Monday, October 18, 2010

National Co-op week!

October is national co-op month, and the week of the 17th through the 23rd is national co-op week.  I have a long history with co-ops and am passionate about their mission.  I am an avid member and patron of food co-ops (two of my favorite are the Davis Food Co-op and Willy Street Co-op).  One of my regrets is that Raleigh lacks a good food co-op.  I lived for year in Summit Avenue Housing Co-op, and I spent one of the best summers in my life educating elementary through high school students about co-ops at Wisconsin Farmer's Union Kamp Kenwood.  Recently, I learned about a hops producing and marketing co-op in Wisconsin.

Co-ops are responsible for some the most well known brands, including REI, Ocean Spray, Blue Diamond, Organic Valley, and down in North Carolina, Southern States.  The center of density for co-ops has long been the upper midwest.  Moving to the south, this difference has become more aparent.  Hopefully, this good idea will continue to spread.

More information
National Co-op Month

Randolph County Newsletter

Mary Helen Ferguson, Randolph County horticulture agent and one of the volunteer SWD trappers, has posted a new newsletter.  It includes a SWD for growers and can be found here.

More information
Randolph County Horticulture News

Wednesday, October 13, 2010

Repost from Myrmecos: Honey bees as pawns

Alex Wild over at Mymercos has posted a thoughtful article in response to the media frenzy surrounding the Colony Collapse Disorder (CCD) findings published in PLoS One. This study linked CCD to two bee pathogens. The study itself was fairly small scale, and larger studies that will soon be published have been conducted (some at NCSU). What Alex was responding to, however, was not the validity of the work, but rather the media's interpretation, specifically those trying to link pesticides to CCD and who found fault with one of the study author's associations with Bayer Crop Sciences.

The fact is, all applied entomologists have at least some association with pesticide companies. They often provide research funding and materials, and much of the applied work that is conducted at universities would simply not be done without their support. However, no program I have observed, both mine and others, lets this relationship color their research results and interpretation. The reason pesticide companies fund university research is because we are objective. If we lose that objectivity, we would also lose industry funding (and our moral center). Further, at public universities, funding relationships are public as are all the results generated by funded research. I encourage growers, companies, and other researchers to request, view, and use results from my pesticide based trials. Sunshine is the best disinfectant.

More information
Honey bees as pawns

Tuesday, October 12, 2010

NC State Fair Wine Competition

The NC State Fair has named its 2010 award winners. The top wines as well as a link to the complete results can be found here.

Monday, October 11, 2010

NCES Photo Contest - Deadline October 22

"Texas skies" by Steve Frank. Winner of Best Adult Arthropod photograph, 2009 NCES Photo Contest.

The deadline for the NC Entomological Society Photo Contest is October 22. Members and non members are encouraged to enter, and the contest announcement along with all the submission details can be found here. Last year's award winners can be viewed here.

Brown Marmorated Stink Bug - Guest post from Anne Nielsen

Anne Nielsen presents on BMSB as part of the Entomology Department seminar series at University of California, Davis. Photo: UCD

Anne Nielsen was among the first entomologists to study the brown marmorated stink bug after its introduction to North America.  I contacted her last week to get her insights on the pest potential of BMSB in North Carolina.  Dr. Nielsen is currently a post doctoral researcher at Michigan State University.  Below are her comments.

BMSB is predicted to have at least 2 generations per year in your region.  Given what populations have done in the Mid-Atlantic, it is highly likely that BMSB will become a pest in North Carolina as well.  In other states, significant feeding damage has occurred in pome or stone fruit. It will readily feed on vegetables (soybean, tomatoes, peppers and corn) and small fruit, although damage reports haven't been as severe in these crops to date.  I would expect it to feed on cotton, as other pentatomids do, but we don't have any data to confirm that yet.  Populations will be highest in late summer/early fall as the final adult generation prepares for diapause.  This adult generation is also highly attracted to blacklight traps, which are a very good way of identifying populations at low densities in the
farmscape.  Within two years of detection on farms in Pennsylvania and New Jersey, BMSB has negatively impacted the exant pentatomid community in terms of species richness and species evenness.  This is not surprising given the low rates of egg parasitism we have seen.  BMSB appears to be highly aggregated in the crops where it is present, although distributions can be patchy.

We noticed that new locations were usually first identified as a result of their overwintering behavior. George Hamilton and I set-up a website (which he still manages) that allows homeowners to learn about BMSB as well as report sightings.  We were able to learn of numerous new state records in this way and feel free to pass along the web site to your county offices and end-users.  I think it is important to have a centralized database for this type of information.

In other areas, there was a 3-5 year lag between the time of detection in a state and high numbers in agricultural crops.  However, I would not be surprised in BMSB has been in North Carolina for a few years already.

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Commercial Blackberry and Raspberry Field Day

The first NC Commercial Blackberry and Raspberry Field is being held Thursday, October 21 at the Sunny Ridge-Owls Den Farm in Lincolnton, NC from 9am to 12pm.  Antendees can rotate through a series of concurrent sessions on insect, cultural, fertility, and weed management followed by an equipment demonstration.  The program, which includes directions and presenter information can be found here.

I will be sharing information on our native caneberry pests as well as lots of updates on spotted wing drosophila.

Sunday, October 10, 2010

A fall visitor: Brown marmorated stink bug

Stink bug adult on the hood of my car. Photo: HJB
After running errands Saturday morning, I noticed the insect above on the hood of my car. My apologies for the poor photo quality, but it was the best I could manage on the fly with my cell phone camera. This morning, another greeted me inside my living room window, leaving behind the trans-2-decenal and trans-2-octenal to prove it. From the glimpse I got, it appeared to be a brown marmorated stink bug (BMSB, Halyomorpha halys). This invasive insect has temporarily taken the place of bed bugs as the go to pest, garnering attention from the New York Times, Washington Post, and even NPR's Science Friday. A multi agency work group has been established to study BMSB biology, management, and regulation.

Why has BMSB generated so much interest this fall? For two main reasons:
1. Large populations have caused extensive damage in agricultural crops, and
2. They aggregate in structures in large numbers in the fall, becoming a nuisance pest.

First detected near Allentown, PA in 1998, BMSB has been present in the United States since then, but this summer their populations increased dramatically in the mid Atlantic. BMSB has been present in North Carolina since at least 2009, but has not reached the damaging levels observed in Maryland, north east Virginia, and Pennsylvania this year.

BMSB damage on an apple. The corky masses below the skin are distinctive of stink bug feeding. Photo: Penn State Extension
From mid summer through fall, BMSB has caused significant damage in the mid Atlantic to apples, peaches, caneberries, corn, and soybeans, to name a few of the crops it has been recorded from. Stink bugs, including our native species, the brown stink bug (Euschistus servus), green stink bug (Acrosternum hilare), and southern green stink bug (Nezara viridula), are difficult to manage with insecticides. Typically, broad spectrum materials, such as pyrethriods, carbamates, and organophosphates have been used to manage stink bugs, but may of these have the potential to create unintended consequences, like reducing natural enemies. Treatments for BMSB did not fit with carefully developed IPM programs for tree fruit in Maryland and Virginia, and resulted in greater pesticide use.

Stink bugs (native and non native) are emerging pests in many cropping systems due in part to their difficulty to control and in part to the increased number of insecticides (or other tools) that target a narrow range of organisms. For example, stink bugs are now a key pest of cotton due to the widespread adoption of Bt varieties that control caterpillars. Foliar applications of broad spectrum insecticides targeting caterpillars used to also control stink bugs but are no longer needed. The same scenario could apply to systems that have switched to other newer insecticides (i.e. Entrust, Delegate, Intrepid, Coragen, and many others) from broad spectrum materials.

The second reason BMSB has generated such wide attention is its tendency to aggregate in structures in the fall, much like the multicolored Asian lady beetle and another recently introduced bug, the "kudzu bug". All of these insects are native to roughly the same part of the world, China, Japan, and Korea, so it is possible that this fall aggregation behavior is associated with insects from these areas.

What should growers do if they suspect BMSB is present on their farm? Contact your cooperative extension agent to confirm identification and for management recomendations.

What should homeowners do if they suspect BMSB are present in their yards or homes? If BMSB are presents in your yard, there are few control measures that will be effective, and the most sustainable strategy is to tolerate injury to plants. If stink bugs are entering your home, seal entry points well (think of it as an entomological energy audit) and vacuum up the insects, disposing of your vacuum bag.

More information

Friday, October 8, 2010

A different story at the Sandhills

After yesterday's visit to the Upper Mountain Research Station, I was eager to check my spotted wing drosophila (SWD) traps at the Sandhills Research Station today.  My first stop at the station was the caneberry breeding plots.

Caneberry seedling plots at Sandhills Research Station.  Photo: HJB
Raspberries are grown at Sandhills not because they do well here but because most raspberries cannot tolerate high heat.  The plots here are intended to screen breeding material for heat tolerance traits that will be used to develop raspberries that can be grown in hot summers.  In other words, most raspberries are not happy at the Sandhills.

We began catching SWD adults at the Sandhills on 11 August 2010 and trap captures peaked on 18 August.  See trapping data here.  Dates are in ordinal days; see here to convert ordinal days into calendar dates.  There were no blackberries present at this time, few peaches were remaining, and no larvae were found in fruit.  No flies were captured during the month of September, and one fly was caught last week.

SWD and raspberries have a lot in common in terms of temperature tolerance.  Both like mild weather and, at least according to current literature for SWD, do not reproduce in hot weather.  I suspect that the record heat this summer may have limited SWD's initial spread through North Carolina, but now as fall temperatures cool, we may see more flies and more maggots.

There were a few raspberry plants with fruit, and most of what I observed did not contain visible larvae.  I did find one, otherwise perfectly sound fruit, that contained one early instar larva.

Early instar maggot (center of image), likely spotted wing drosophila, in a red ripe raspberry at the Sandhills Research Station, Jackson Springs, NC. Photo: HJB
Because this larva was so small, I collected a sample of other raspberries from the field and will be holding these to determine if any others contain SWD larvae.

Ripe and overripe raspberries collected to determine the presence of SWD larvae at the Sandhills Research Station. Photo: HJB
 So, why do we have a large amount of infested fruit at Upper Mountain and very little (apparently) infested fruit at Sandhills?  Fruit availability differs between these two site this time of year; Upper Mountain has strawberries, caneberries, and grapes ripe and open to infestation while Sandhills only has a few remaining raspberries.  But why did the Sandhills infestation not take off when the hundreds of peach trees at the station were loaded with fruit?  The flies were not present in high numbers at the height of peach season, but I also think climate played an important role.  The Sandhills are in the hottest part of North Carolina, and peach season is during the hottest part of the year.  This may have limited the spread of SWD into the Sandhills this summer.  Now that the fly is present and reproducing, it will be interesting to see what next summer holds.  We will be there to find out.

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

SWD appears with a vengeance at Upper Mountain Research Station

Male D. suzukii on raspberry leaf, Upper Mountain Research Station.  Photo taken 30 September 2010 by Absalom Shank, NC State Horticulture Department

Yesterday, I spent the day at the Upper Mountain Research Station near Laurel Springs confirming the first spotted wing drosophila (Drosophila suzukii) larval infestation in North Carolina.  Spotted wing drosophila (SWD) is a potentially devastating invasive pest of soft skinned fruit which has been present in North American since late 2008.  See here for more background.  Blackberry, raspberry, and strawberry research plots are heavily infested.  SWD were first observed on 30 September in high tunnel primocane fruiting raspberry plots by Absalom Shank, research technician in the NC State Horticulture Department.

Up until last week, no larval SWD had been observed in North or South Carolina, despite the fact that adults have been captured in high numbers.  This is likely due to the fact that most of our trap captures occurred after the majority of susceptible host fruit had been harvested.  It is likely that larvae have been present but in low enough numbers that they escaped detection.

The first thing I did after arriving at the station was to place 6 SWD traps in 3 of 4 high tunnels, where the highest number of flies had been observed.  These tunnels contain primocane and floricane fruiting blackberries and raspberries. Three of the traps were baited with apple cider vinegar, and 3 were baited with a yeast and sugar mixture, as are being used in our regional monitoring program.  Within 20 minutes, the first adults appeared at the apple cider vinegar baited traps.  A total of 4 flies were captured in 3 hours.

Apple cider vinegar baited SWD trap in primocane fruiting blackberry tunnel.  Photo: HJB

Male SWD at apple cider vinegar baited trap entry.  Photo: HJB

SWD larvae were observed last week in fruit from guard plants and caneberry seedling plots, both of which are not regularly harvested.  This week, larvae were found in trial plots, which are harvested twice per week, so flies are not restricted to unharvested plantings.

Fallen raspberries in breeding plots.  These fruit can harbor SWD populations. Photo: HJB
Adult SWD were readily observed and collected in high tunnel plots (and the most of those were in primocane fruiting raspberries), but were not as numerous in outside plots.

Female SWD on ripe raspberry fruit in a high tunnel.  Photo: HJB
Primocane fruiting blackberries in high tunnel.  Photo: HJB.
Primocane fruiting raspberries outside. Photo:; HJB
Many fruit in raspberry breeding/seedling plots were heavily infested, which is not surprising considering that these plots have never been harvested.  Most of the fruit collected contained multiple larvae.

Ripe yellow raspberry from breeding plot.   This single fruit contained 5 SWD larvae.  Photo: HJB
Strawberry plots at the station also contained large numbers of SWD larvae.  Because it was very windy, adult fly presence could not be confirmed in these plots.  Flies which appeared to be SWD females were present, but these are more difficult to sight identify than males.  The fruit damage observed, however, was consistent with SWD.  Sound appearing fruit contained multiple maggots when cut open.  Larvae were collected to rear out adults.

Strawberry containing multiple SWD larvae.  Photo: HJB
These strawberry plots had also not been harvested for several months and contained sound, rotting, and decomposed fruit, all of which are attractive and suitable for SWD larval feeding.

Strawberry plots containing heavily SWD infested fruit.  Photo: HJB
Strawberries with recently laid SWD eggs were also found.  These fruit appeared sound except for a slightly abraded area where the eggs were.

Strawberry fruit with slightly abraded area containing SWD eggs.  Photo: HJB
Enlarged view of SWD eggs.  Photo: HJB
I collected several adult flies and numerous infested fruit to bring back to laboratory to start a research colony.  These insects will be used to test host fruit preference, monitoring tools, and control strategies.  This afternoon I am heading to check my traps at the Sandhills Research Station and check the caneberry breeding plots there for larval infestation. Update: I visited the Sandhills Station today.  See here for a summary of what I found.

SWD Monitoring
We have been monitoring SWD in NC, SC, and VA for 5 months and have detected flies in Montgomery County, NC; Lee County, NC; Randolph County, NC; Davidson County, NC; Edgecombe County, NC; Saluda County SC; Spartanburg County, SC; and Lexington County, NC.  We can now add Ashe County, NC to that list.

Small fruit and tree fruit growers should be aware that SWD populations are present at potentially damaging levels and should carefully monitor their plantings for adult and larval presence.  Caneberry growers with primocane fruiting berries and strawberry growers with fall fruiting or day neutral plantings should be especially aware.  Adult traps can be constructed from plastic containers or bottles (see here for a description of trap construction and here for videos demonstrating trap construction and use).  Sticky cards for use in traps can be obtained from a variety of sources.  We get ours from Great Lakes IPM.  Male SWD are readily distinguished from other flies by their spotted wings.  Females are more difficult to distinguish, and growers should consult their county extension agent for identification confirmation if males are not present.  See here for examples of SWD and non SWD flies on sticky traps.  Traps should be checked at least weekly.

Growers should also monitor fruit for larval infestation.  Large larvae will be visible in fruit, but small larvae may not.  Larvae can most easily be detected via the "fruit dunk" method.  Fruit are gently crushed and floated in sugar water.  After several minutes, larvae float to the surface and can be counted.   See here for a video and here for a description.  A hand lens may be necessary to observe small larvae.  It is important to remember that many native Drosophila feed on rotting fruit.  Observing infestation in relatively sound fruit and confirming adult presence minimizes the likelihood that you will confuse SWD with native relatives.

SWD Management
Sanitation is extremely important in managing SWD.  In areas where SWD is present, all ripe fruit should be removed from the field or plants should be treated with insecticide regularly, with the interval depending upon the material used.  Unmarketable fruit should be destroyed or removed from the site.  Composting may not be sufficient to kill SWD larvae and may attract adults to rotting fruit.  This presents a challenge to fruit breeding activities at research stations and will need to managed with care.

SWD populations in the western US (California, Oregon, and Washington) appear to respond well to a number of insecticides, which is encouraging news.  I am preparing a document listing the registered materials that are effective against SWD by crop and will have this available early next week.  Growers who have confirmed SWD should contact their county cooperative extension agent or myself for management recommendations.  It is especially important to rotate insecticides used to treat SWD to minimize the likelihood of resistance development.

More information
OSU SWD Website
Spotted Wing Drosophila Updates - WSU Mount Vernon Research Center
Strawberries and Caneberries - Blog by Mark Bolda (UC Farm Advisor)
NC Small Fruits IPM SWD Posts

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

Tuesday, October 5, 2010

Fall NC Entomological Society Newsletter

October is a busy month for the North Carolina Entomological Society! Read all about our recent and upcoming events in the NCES Fall Newsletter.

More information
Fall 2010 Newsletter - NCES

Sunday, October 3, 2010

Saturday, September 25, 2010

North Carolina Entomological Society seeks outstanding teachers!

Do you know a teacher (K-12) who uses insects in creative ways in their classroom?

If so, the North Carolina Entomological Society wants to know!
We are seeking outstanding teachers who use entomological tools in their classroom, whether to teach students about the wonderful world of insects or to assist in the teaching of other concepts. Last year, we recognized 3 teachers, Susan Dixon (Western Alamance Middle School, Elon), Kathleen M. Dorn (Hunter Huss High School, Gastonia), Teresa Garrou (Hudson Elemenary, Hudson), one each for elementary, middle, and high school.

Teachers can nominate themselves or others. Strong applications typically include examples of of the insect learning activities used. This can include lesson plans, photos, example assignments, and more. Applications are due to me either via mail (NC State University, Campus Box 7630, Raleigh, NC 27695-7630) or email ( by October 15, 2010. Application information can be found here. This year's awards will be presented at the NCES banquet on November 5th at the JC Raulston Arboretum and comes with a monetary award to be spent on school supplies. Travel and registration to the banquet are included in the prize, and we hope winners will be able to join us to be recognized.

More information
NCES Outstanding Teacher Award Application
North Carolina Entomological Society

Wednesday, September 1, 2010

SWD trapping update - Identification overview

One male spotted wing drosophila (circled) and 3 non SWD. Trap from Davidson County, NC. Photo: HJB
Drosophila suzukii (spotted wing drosophila) trap captures are increasing throughout the Carolinas. Last week, SWD were confirmed from our monitoring site in Davidson County, NC, and we continue to catch flies at 7 other locations in NC and SC. The table below summarizes these locations and the total flies detected to date. See here for links to trap capture data for all of the southeast monitoring locations.

Date of first capture
Total flies to date
Davidson County, NC
Edgecombe County, NC
Lexington County, SC
(Site 1)
Lexington County, SC
(Site 2)
Spartanburg County, SC
Saluda County, SC
Randolph County, NC
Montgomery County, NC

In addition to SWD, several other flies have been caught in the traps, many of which can be confused with SWD. The image above includes 1 male SWD with clearly visible wing spots (circled) and 3 other flies which could be confused with SWD. The image below notes the key characters to distinguish between these 3 flies.

Non SWD flies. Left: fly with "cloudy" cross veins (cross vein circled). This cross vein will not be cloudy in SWD wings. Center: fly with spotted abdomen. SWD will have no discrete spots along the abdomen. Photo: HJB
Also found in yellow sticky traps have been flies with 3 spots on each wing (below).

Drosophilid fly with 3 wing spots (indicated by blue boxes). Photo: HJB
In addition to flies which may potentially be confused with male SWD, there are also flies which may be difficult to distinguish from female SWD. The most important female feature is the prominent ovipositor (below). The ovipositor can be hard to distinguish when insects are on yellow sticky traps, but can be teased out and still appears different than that of any other female fly.

SWD ovipositor. Fly captured in Edgecombe County, NC. Photo: HJB
Female SWD on yellow sticky trap, ovipositor indicated by blue box. Photo: HJB
Ovipositors of non SWD females are much smaller and lack the dark brown teeth on the anterior margin.

Non SWD females. Note much smaller ovipositors that lack dark marginal teeth (click to enlarge). Photo: HJB

More information

Watching the west: SWD in grapes

Washington State University has assembled several SWD fact sheets on spotted wing drosophila (SWD) in grapes.  They have also shared an update on no-choice laboratory assays on SWD in grapes.  The results from this first round are promising (see here), indicating that grapes may very in the suitability to SWD by age and variety.  These results are highly preliminary, but interesting.

Tobacco splitworm damage spiking throughout NC

Tobacco leaf with damage from tobacco splitworm larvae (Phthorimaea operculella). This leaf had at least 20 galleries. Photo: HJB
Damage due to tobacco splitworm larvae has dramatically increased at sites in Johnston, Columbus, and Chowan Counties in the past two weeks. Masters student Monique Rivera has been studying the seasonal biology and behavior of tobacco splitworm for the last 2 years and is wrapping up her thesis research this fall--just in time to see the damage this insect can do in the field.

The accepted ESA common name for the tobacco splitworm is the potato tuber moth, which reflects the fact that this insect is also a pest of potatoes, feeding on the tubers. For at least the past 5 years, however, the tobacco splitworm has been present in tobacco plantings where no potatoes have been found. This suggests that the insects are coming from other sources into tobacco fields. Although little work has been done on tobacco splitworm as a pest of tobacco, research conducted in the early 1900s in Maryland suggested that dry, hot years resulted in the greatest amount of tobacco splitworm injury. This observation appears to hold true for our recent NC infestations, with widespread injury in 2007, 2008, and now 2010.

Tobacco splitworm larvae are leafminers in tobacco, creating distinctive galleries. Female moths lay eggs at the base of tobacco plants, on the soil surface. After the larvae hatch, they move up the stalk and begin feeding on leaves. Damage first appears on lower stalk leaves, but the larvae are capable of feeding on leaves throughout the plant if lower stalk leaves are not present. Newly hatched larvae are roughly 2 mm long, and the galleries they create are also small. Splitworms typically spend their entire larval lifespan in a single gallery, although they may feed internally on leaf veins, making it appear as though they create multiple galleries. In total, a single mature gallery takes up roughly 2 square inches (see above image).

Sites in Johnston, Columbus, and Chowan Counties have had in excess of 50 galleries per plant. Work conducted in the NCSU Entomology Department in 2006 through 2007 found that very high numbers of splitworm larvae like this may reduce total yield. Yield, however, was not the primary concern of growers in Johnston County. It is possible that even fairly low (5 or more full size galleries per leaf) could reduce leaf quality.

Tobacco splitworm gallery (circled). Photo: HJB
Late instar (nearly mature) tobacco splitworm larva in opened gallery. Photo: HJB

Partially cured tobacco leaf with tobacco splitworm injury. Photo: HJB
Growers first noticed the infestations in Johnston County after harvested leaf had been placed in barns. Large numbers of larvae began to flee through the base of the barns and were killed in yellowing leaf.

Tobacco splitworm larvae outside curing barn. Photo: Bryant Spivey, Johnston County NCCE
Dead tobacco splitworm larvae near the door of a bulk barn. Photo: HJB
Curing leaf without tobacco splitworm damage. Photo: HJB
Curing leaf with high levels of tobacco splitworm infestation. Photo: HJB
Although they can be potentially devastating, tobacco splitworms are an occasional pest of tobacco, and preventative treatment is not recommended. It is also not recommended to treat adult moths because they likely do not spend the majority of their time in tobacco. Instead, management strategies should be targeted to the larval stages.

Scouting is key to effective splitworm management in tobacco. Based on trapping and field monitoring conducted since 2007, it appears we have 2 to 3 splitworm generations during the tobacco growing season. Years where 3 generations occur are likely to result in the greatest crop damage because each successive generation will attack the same tobacco. Damage from the early generations indicates that a population is present in a field and that this field should be observed carefully. Early generation damage will appear on the lowermost leaves, and scouting before and after topping should focus on these parts of the plant. Pesticide treatments should be applied if damage begins appearing up the stalk and live larvae are present in these mines.

Treatments should be made when new mine formation begins. Treating mature larvae in mines will likely not be economically beneficial, because large larvae have already caused most of the damage they will do at this stage.

Adult moths can monitored using pheromone baited sticky traps, which are attractive to males and appear to be relatively specific. This means they do not appear to attract large numbers of non target moths which could be confused with tobacco splitworms. Monitoring data conducted in North Carolina for the last 3 years suggests that adult moth trap captures peak 3 to 4 weeks before infield damage. This suggests that adult trap capture peaks could be used to time in field applications of pesticides to control larval infestation. Moths are also caught in fields where no damage occurs, however, so relying only on trapping is not advisable. It is possible that traps could be deployed in fields where early season injury is noted in order to effectively time late season, potentially economically damaging, populations.

Male tobacco splitworm moth captured in pheromone baited trap. Moths appear as similar to many other species to the naked eye. Photo: HJB

Two insecticides, Belt (flubendiamide) and Coragen (chlorantroniliprole) are registered for tobacco splitworm in North Carolina. However, there is very little data on either of these materials against tobacco splitworms, and I cannot recommend one over the other for control at this time. We are working to generate more data on these materials and their appropriate rates.

Why now?
Historical data suggest that tobacco splitworm injury is most problematic in hot, dry years. I suspect that the fields where we are seeing injury now may have received less rainfall than other areas. The marked decrease in the use of broad spectrum, foliar insecticides may also have contributed to increases in splitworm injury. A behavioral shift in the larvae or adults may have resulted in preference for tobacco over other hosts, which may explain why injury is occurring in areas where no other commercial hosts (ie. potatoes) are present.

Thursday, August 26, 2010

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).

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