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Wednesday, March 31, 2010

New Small Fruit News now online

The latest edition of the Small Fruit News, a newsletter published by the Southern Region Small Fruit Consortium is available now. This quarter's edition has an update on southeastern strawberries following our cold winter, post harvest advice for blackberries and raspberries, blackberry marketing and price trends, and herbicide updates.

Sunday, March 28, 2010

What to watch for in 2010: Thrips

Over the next few weeks (0r until the field season gets busy), I will be posting pest watches for 2010. These are designed to provide updates on pests that may be problematic or for which management strategies may differ in 2010.

First up is a group that has become near and dear to me in the last 2 years: Thrips!

Western flower thrips (Frankliniella occidentalis), Photo: J.T. Reed

Thrips as pests
Thrips are of concern to southeastern growers for 2 reasons: 1. They vector potentially devastating plant viruses, and 2. Thrips can directly damage crops in their own right. In the cropping systems I work in thrips are both virus vectors (tobacco and caneberries) and cause direct fruit or plant injury (strawberries, blueberries, and grapes).

In tobacco, thrips vector Tomato Spotted Wilt Virus (TSWV) which can result in significant losses. Colleagues in the NC State Entomology Department developed a degree day model which predicts tobacco thrips (Frankliniella fusca, the most important TSWV vector in the southeast) flights. We have adapted these models for a website that will be launched for use by county agents and select growers this Thursday, April 1st.

Flue cured tobacco plant infected with TSWV. Photo:

Thrips also vector Impatiens Necrotic Spot Virus (INSV), which infects many plants, including caneberries. Caneberry viruses are the topic of a multi state USDA Specialty Crops Research Initiative (SCRI) project with which I am involved. Lead by the University of Arkansas, this project is designed to identify and development management strategies for virus complexes in caneberries. Unlike many other plant-virus pathosystems, caneberries are often infected with 2 to 3 virus before they show symptoms. The virus complex appears to vary regionally, as do the likely vectors.

Blueberry fruit damage caused by thrips oviposition (egg laying) and feeding. Photo: Insect Management in Blueberries in the Eastern United States, Tuner & Liburd.

In strawberries, grapes, and blueberries, fruit injury by thrips is of greatest concern. Thrips feeding on blueberry can also damage blooms. Blueberry injury by thrips is weather and variety dependant in NC. Late blooming varieties (rabbiteye and northern highbush) are more prone to damage, but growers generally do not need to treat these varieties every year. Thrips injury to strawberries is rare in NC, and other injury is often misdiagnosed as thrips-caused.

Thrips can cause bronzing near the calyx in strawberries. Photo: Jack Kelly Clark, UC IPM Program.

Thrips do not cause malformed fruit. The damage in this image is due to lygus bug injury, but malformed fruit can also be caused be poor pollination or dried calyx disorder. Lygus bug injury is also rare in NC and has only been observed on late season or day neutral strawberries. Photo: UC IPM Program.

Thrips injury to grapes is more common in NC than injury to blueberries and strawberries. Grapes bloom and develop later in the spring, when thrips populations have built to higher numbers and are less susceptible to spring weather conditions.

What to watch in 2010
Thrips management in 2010 will be different than in a typically year, because we will likely have fewer thrips than normal and they may move into crops later. If this holds true, we may have fewer problems with thrips in tobacco and small fruits in 2010 than in a typical year.

Tobacco thrips models currently indicate that this spring will have low numbers of thrips. This is not surprising because cool, wet weather negatively impacts thrips during March and early April. This spring, much like last year, has been both cool and wet, until recently. It is possible that weather patterns could become more favorable for thrips, but unless the weather changes dramatically (rapidly warming and drying), I suspect that thrips movements will occur later this year and that populations will be lower than normal.

What does this mean practically? I anticipate that thrips treatments in blueberries may not be needed, and that strawberry injury may also be rare. As always, SCOUT and SAMPLE before making any treatment decision!

We continue to track and model tobacco thrips populations, and we will not have concrete predictions until the end of April, but I will continue to update as this picture becomes clearer.

Friday, March 26, 2010

Frost update

Emails from this morning indicate that growers and agents are increasingly worried about the frost potential for this weekend. Barclay Poling is running temperature predictions for folks this afternoon (email preferred). The NC Market Ready Strawberry Portal also has a wealth of information on frost protection.

Wine where you would least expect it

Veritas Vineyard & Winery, Afton, VA.

No, I don't mean Virginia!

Among my small fruit research and extension responsibilities are grapes, and in North Carolina, this includes wine/bunch grapes (Vitis vinfera) and muscadine grapes (Vitis rotundifolia). This Tuesday, the Virgina IPM Program and Southern Region IPM Center held a Pest Management Strategic Plan meeting at Veritas Vineyard near Afton, VA. The purpose of this meeting was to construct a PMSP for NC and VA wine grapes. This document will provide research, regulatory, and education priorities for the industry and a valuable tool for those of us in the university as we write proposals to address these priorities. Not too long ago, Virginia and North Carolina were thought to be strange places to find wine. There are, however, much more unusual "wine countries" to be found.

This morning, I was reminded of another wine experience I had about 9 years ago while an international student at Thammasat University in Bangkok, Thailand. I chose Thailand and the Faculty of Economics exchange program because I was interested in rural development. During the school year, I took courses to better understand the dynamics of rural Thai societies, and in the summer, I had the unique opportunity to live with an NGO (Wildlife Fund Thailand, which apparently no longer exists) and learn about their development and preservation efforts. One of the locations I visited was GranMonte Vineyard & Winery, near Khao Yai National Park. They had just planted their vines the year before and had not yet begun to harvest grapes. Their main concern at the time was keeping the birds at bay, a common challenge the southeast shares. Now, several years later, they are bottling wine and drawing, at least, regional attention. My Virginia colleagues may not want to watch the video on their website, however! Thailand is always on my list of places to return to, and when I do get back, I will have to stop by and see how they have grown.

Thursday, March 25, 2010

Strawberry update and chilly weekend weather

Mite trial plots at the Central Crops Research Station. Plants were sourced from Aarons Creek Farms, Buffalo Junction, VA and made it through the cold winter with flying colors.

Today, we sampled our plots at the Central Crops Research Station in Clayton, NC for the 3rd time this season. Spider mite populations remain low, but we will begin calendar treatments for our threshold validation trial next week. This trial is comparing treating at threshold levels versus treating on a calendar basis. Specifically, we are comparing the following treatment regimes:

1. Untreated control
2. Frequent treatment (every 14 days)
3. Infrequent treatment (every 45 days)
4. Treatment at recommended threshold (5 TSSM/leaflet)
5. Treatment at reduced threshold (2 TSSM/leaflet)

Most plants have 2-5 blooms open, which means we plan to begin harvest in about 45 days, mid May. Strawberry plantings throughout NC are about 2 weeks later than normal.

We are assessing mite densities weekly and will also collect data on brix in the different treatments. Growers have been curious as to whether TSSM densities below yield reducing levels (our working threshold of 5 motile mites/mid tier leaflet) also reduce fruit quality, and the quality measure of greatest concern is brix. Last year, we conducted a similar trial with an organic cooperator and saw no correlation between brix and mite densities or mite days (a measure of mite density over time). This year's trial will be conducted with conventional miticides.

In addition to the threshold validation trial, we will also be conducting efficacy trials with conventional miticides, some of which are newly registered for strawberries.

Frost is called for this weekend throughout NC, and our plots were covered with floating row cover this afternoon. Dr. Barclay Poling, NCSU Horticulture, regularly posts updates on weather conditions and other production considerations at the NC Market Ready Strawberry Grower Information Portal. The latest update shares information on the upcoming cool weather as well and some pest management points from me regarding bloom and insecticide use.

Temperature maps from Envirsion, a weather modeling group based in Raleigh, illustrate the frost potential throughout NC for this weekend.

Monday, March 22, 2010

NC State Tobacco Connection

What's this? See NC State Tobacco Connection for the answer.

The first issue of a new newsletter, spearheaded by Dr. Sandy Stewart, is out. You can access an online version of the newsletter here. NC State Tobacco Connections will be published as needed, but probably at least once per month. If there are topics that you feel need to be covered, please let me know.

This edition includes articles on planting date timing, fumigation under sub optimal conditions, and an article by me on greenhouse pest management. Sandy is the newest member of our tobacco extension group, which means I am no longer the new kid! Sandy joined us in January, having previously served on the faculty of Louisiana State University as a cotton specialist, but he is an alumnus of NC State, and we're certainly glad to have him back.

Friday, March 19, 2010

The politics of tomato paste

I just read this interesting article from on recent legal drama in the California processing tomato industry and was reminded of my time in California. I spent 5 years in California while conducting my doctoral research at the University of California, Davis. For an agricultural economics course I took in my first year at Davis, we spent 2 weeks in the summer visiting agricultural sites. One of the most impressive was the Morning Star Company's processing facility. This is the largest tomato processing plant in the world and a large player in this market. It's not necessarily a surprise how cutthroat agriculture can be, but it is always interesting to see places you are familiar with appear out of the usual context.

Tuesday, March 16, 2010

NABREW meet in Michigan, July 25-28, 2010

The North American Blueberry Research & Extension Workers Conference will be held in Kalamazoo, Michigan July 25-28th. This meeting will highlight work in entomology, horticulture, and plant pathology, and presentation abstracts are due April 1st. Details about abstract submission and the meeting can be found at the NABREW webpage.

I will be attending and plan to present some of our preliminary pollinator findings from NC.

Mid afternoon diversion

I recently discovered Floating Sheep, a blog by 3 geographers (two from University of Kentucky) that draws upon Google data to develop fun and informative maps. While I was initially drawn to this post highlighting states bar:grocery store ratio (being from Wisconsin, the trends presented were no surprise), I was also intriguing by this map...
...which compares "minor" vice references for caffeine, alcohol, and tobacco. Tobacco references are noticeably higher in the southeast, particularly in North Carolina, the largest flue cured tobacco producing state.

Monday, March 15, 2010

Wine grape PMSP meeting 3/23/2010

Members of the wine grape communities in NC and VA will be meeting on March 23, 2010 in Afton, VA to develop a Pest Management Strategic Plan for wine grapes in these 2 states. A PMSP is a one day meeting where agents, specialists and stakeholders (growers) describe the pests of a crop, the currently used management strategies, and the priority research and extension pest management needs. The documents are very useful when extension specialists (like me) are developing research proposals and are a requirement for some grants.

Cooperative extension agents and extension specialists will be attending, but we still need grower participation from NC. Grower and agent travel is covered by the Southern Region IPM Center. Grower cooperation is crucial to the success of this process. If you grow wine grapes (aka. Vinifera grapes or bunch grapes) in North Carolina and are interested in participating in this meeting, contact me, Dr. Sara Spayd (NCSU Horticulture), or Steve Toth (SRIPM) for more information.

As the covers come off...

Those strawberry growers who have had row covers on their plants all winter are now removing them and performing sanitation on the plants (removing dead leaves and stray weeds). As these covers come off, I am getting reports of lots of arthropods appearing.

Spider mite management begins in earnest now, and growers should begin their weekly sampling of 10 leaflets/acre. The undersides of these leaflets should be examined for spider mites with a 10x hand lens (or microscope if you're well equipped). If the average number of mites/leaflet is 5 or great, miticide treatments should be applied. Scouting should continue post treatment to ensure they are effective and to determine if and when re treatment is needed.

Twospotted spider mite female and eggs on the underside of a strawberry leaf. Photo: HJB

Threshold based treatments are helpful because not only do they often reduce the number of applications, but they also allow us to select the best material for the job by providing a weekly pattern of information. This means we have a better idea if populations are small and newly established (best treated with an ovicide/larvicide) or are already large (best treated with an adulticide plus ovicide/larvicide).

Cast aphid skins (white) and dead aphids (brown) on tunnel strawberries at the Piedmont Research Station, Salisbury, NC. Photo: HJB
Click to enlarge this image for a much better view.

Aphids are also showing up as covers are removed, but I have yet to hear about damaging numbers in NC. It takes a lot of aphids to reduce yield in strawberries, and we have excellent native biological control agents. In fact, also found under the covers have been lady beetle larvae, feeding on the captive aphid buffet. Most of the aphids that were present under the covers morphed to winged (alate) forms, and have dispersed off the plants leaving only their cast skins. These cast skins appear white against the plastic or leaves.

Lady beetle larvae found on newly uncovered strawberries in the Sandhills. Photo: David Dycus.

As the weather warms and spring is finally here, the real fun begins!

A note about pesticide recommendations.

Tuesday, March 9, 2010

SEB ESA meeting wraps up!

I have been attending the Southeastern Branch of the Entomological Society of America's annual meeting this week and head back to Raleigh tomorrow morning. I presented some of our strawberry tunnel/spider mite biological control research in a symposium devoted to non-insect arthropods organized by the student affairs committee, headed by Ana Cabrera. Ana studies mite and tobacco budworm molecular biology under the direction of Mike Roe in our department.

The NCSU Linnaean Games team also competed and placed 3rd. However, they played extremely well, and I am extremely proud of them. Because we did not place in the top two, we will not be completing at the national ESA meeting this winter, but we plan to come back strong next spring at SEB. The venue for next year's meeting is San Juan, Puerto Rico, which I am certainly looking forward to!

UPDATE: Elijah Meck, NCSU graduate student working with Jim Walgenbach and George Kennedy was the big winner in the SEB Photo Salon. Congratulations!

Defending the land grants - reposted from Myrmecos

My friend Alex Wild has an excellent post detailing Michigan State University entomologist Anthony Cognato's appearance on Fox News in defense of stimulus funds for entomological endeavors. I urge you to read the post and watch the clip. This antipathy is part of a larger, disturbing trend of attack against the public institutions who have been the greatest single engine of economic growth and sustainability in the history of the US. I am deeply passionate about the land grant mission. It's as important now as it was 150 years ago.

Friday, March 5, 2010

Spring fire ant management in small fruits

Fire ant (Solenopsis invicta) colonies surrounding strawberry plants in Chowan County, NC. Photo: HJB, 2008

In addition to crop pests, spring also brings other potentially problematic arthropods. Last week, I detailed spring pest management chores in strawberries, but I did not mention fire ants. Fire ants are an invasive pest in NC, but are common concerns in small fruit production in counties where they have become established. NCDA maintains a quarantine program for fire ants in these counties, and the 2010 quarantine areas can be found here. Fire ants are not crop pests in small fruits (although they can be in tobacco greenhouses) but are instead a public health hazard, particularly for pickers in commerical operations and customers in you pick operations.

Fire ants can often infest strawberry fields in the fall spring and may chose these sites because the ground stays warmer under black plastic and/or because they are attracted to water from drip lines.
Fire ant mounds near strawberry fields in Orange County, NC. Photo: HJB, 2008

There are 2 methods of controlling fire ants chemically: contact materials and baits. I prefer bait products because they are more likely to eliminate colonies when used properly. Contact materials (mound drenches) may provide a short term knock down, but unless the entire colony is treated, the fire ants will eventually rebound. Spring is a good time to use baits for fire ants because these materials take a few weeks to eliminate colonies, which means they will do their job by the time picking begins. Consult the NC Agricultural Chemicals Manual and the Southeastern Small Fruit IPM Guides for the specific baits registered and label rates in the crop you will be treating. (A note about pesticide recommendations)

In anticipation of some of the questions I may get from the strawberry community--applications through the drip may be tempting for fire ants, but these will probably not go deep enough into the soil to treat entire mounds and therefore will only offer at the most temporary benefit.

The most important consideration when using baits in the spring is timing. In order to be effective, baits must be applied when fire ants are actively foraging, because the ants must pick them up and return baits to the nest where they will kill the colony. The best time to apply baits is mid morning, on days where the temperature is greater than 70 F and ants are foraging. You can check for foraging activity by using the "potato chip test". Place a potato chip or cheese puff near mounds. If within 30 minutes, ants have found the chip, they are foraging and it's a good time to treat.

The "Two-Step Method", developed by extension specialists in Texas (of course!), follows bait treatments with a mound drench 2-3 weeks later and is a good tool for dealing with large, persistent infestations. It's best to contact your cooperative extension agent for recommendations on drench treatments because there are few products labeled for this purpose in small fruits.

There are organic bait and drench treatments which may be used in small fruits, and I or your cooperative extension agent can provide more information on these as well.

A group of NCSU extension entomologists conducted an Elluminate webinar on fire ant management in a wide range of cropping systems in February 2009. I participated in this webinar, which can be viewed online here. The entire webinar is 2.5 hours and covers fire ant management in homes, nurseries, field crops, fruits, and vegetables as well fire ant regulations in NC. Log in as a guest to view the presentation, which will download as a Java document. The password for the presentation is rifa. You will need speakers and/or headphones to hear the presentation.

More on fire ant biology and management can be found in this Structural, Residential, and Community Insect Pest Note by Charles Apperson & Mike Waldvogel from the NCSU Entomology Department.

Embedded below are the slides for my section of the 2009 Fire Ant Webinar for those of you who do not want to listen to the entire session.

Thursday, March 4, 2010

Blueberry pollination site visits begin

My colleague, David Tarpy, and I are beginning a project studying blueberry pollinator diversity and abundance in the southeast, lead by masters student Shelley Rogers, and this week Shelley conducted the first site visits. Our locations span the state and include conventional, organic, commercial, and unmanaged sites.

We have experience a record number of chilling hours this winter, which means bloom will be concentrated this spring.

O'neal, one the early blooming varieties was already pushing buds this week, which means we have about 2 weeks before pollinator assessments begin in earnest. The goal of this project is to determine which pollinators are most abundant and efficient in our blueberry agroecosystem and what landscapes are most conducive to these insects. This project will run for 2 years and encompass at least 14 locations and supported in part by the NC Blueberry Council.

Small strawberries to start the season

Yesterday, we set up our 2010 spring miticide trials at the Central Crops Research Station in Clayton, NC and the plants are 2-3 weeks behind a typical season. Our samples from this week had no mites on them, which is not surprising given the cold winter. We will continue to sample biweekly until mite populations increase and will then sample weekly.

Once mite populations develop, we will begin our trials, which include validation of treatment thresholds for NC conditions and comparisons of registered and unregistered materials for mite management. A portion of these studies are supported by the NC Strawberry Association.

Flue Cured and Burley Tobacco Information Guides online

The 2010 editions of the Flue Cured and Burley Tobacco Production Guides are available online through the NC State IPM Program. These guides are also available in hard copy form from county extension agents and NCSU tobacco specialists. I have several copies of both on hand and always carry at least one in the truck while in the field.

Because the guides are revised once a year, some information may change before the next revision comes out. The biggest change in insect management for 2010 not reflected in these guides is the recent federal registration of Coragen (a newer insecticide from DuPont) for use in tobacco. The state labels are currently pending, and I will post again once these have been finalized. We have conducted 10 trials in the last 3 years with Coragen and Belt (another newer insecticide from Bayer with a similar mode of action) and data on how these materials compare to standard materials is in the production guides (Belt) or has been shared at grower meetings (Belt and Coragen).

Updated 4.8.2010
I also wanted to include a link to an "oldie but goodie" resource: Scouting Tobacco in North Carolina, developed by my tobacco predecessor, Sterling Southern.

Monday, March 1, 2010

Blueberry research plot planted!

Burrack lab folks and research station crew planting our blueberry plot.

After 2 weeks of delay due to our unseasonably cool and wet weather, we transplanted our entomology blueberry research plot at the Horticultural Crops Research Station in Castle Hayne, NC this morning.

The station crew was great, and between the 9 of us, we planted 400 plants in less than 1 hour. We planted 0.14 acres in total, 0.063 acres Premiere (a rabbit eye variety), 0.07 acres Legacy (a southern highbush variety--and one of my favorite eating varieties), and 0.007 acres Columbus to round out the rabbit eyes.
A 3 year old Legacy plant settling in.

Our plants were from Finch Blueberry Nursery in Bailey, NC. The Legacy were 3 year old plants, while the Premiere were 2 years. There's a noticeable size difference between the varieites now, but when fully grown, rabbit eye bushes can be much larger than SHB.

This will be an establishment year, so no fruit yet and no research projects planned unless some establishment year pests show up (whitefringed beetles might be one). Once the plants are larger, we plan to conduct blueberry maggot projects and to study emerging pests of blueberries in the southeast, including whiteflies.

Large numbers of whitefly larvae & pupae on the underside of a blueberry leaf (Photo: Bill Cline). These densities have become common in recent years in southeastern NC, include at the Castle Hayne station. We do not yet know what impact (if any) these insects have on plant health and productivity. The highest densities appear in late summer before leaf fall.

Adult whiteflies on the underside of young blueberry leaves, August 2008. Photo: HJB