Late July- Pest News for WNC Fruit and Vegetable Growers

FRUIT AND VEGETABLES

From: Hannah Burrack, Extension Entomologist

End of Harvest Concerns in Blueberries

As blueberry harvest nears the end in some areas of North Carolina, a few important insect related issues require some attention.  

Spotted wing drosophila in processing fruit

Rainfall makes spotted wing drosophila (SWD) management more challenging (http://strawberries.ces.ncsu.edu/2013/05/swd_in_rain/), as growers have discovered in the last two months.  As we move into the end of blueberry harvest, fruit being picked for processing is at higher risk for SWD infestation for several reasons: It is often softer than fruit picked for the fresh market and SWD prefer soft fruit (http://news.ncsu.edu/releases/wms-burrack-suzukii-2013/). Processing fruit may be harvested less frequently than fresh market fruit, increasing the time ripe berries are exposed to SWD. Finally, because processing fruit is often machine harvested, all the fruit in the field (good and bad) may be picked.

There are some strategies that growers can employ post harvest to decrease the likelihood that SWD infested fruit will be sent off for processing:

1. Hold fruit at cool temperatures. Work in our lab suggests that SWD eggs and larvae cease development at temperatures less than 41F. They will not necessarily die at cool temperatures, but they likely will not cause further damage to the fruit. The longer fruit are stored and the cooler the temperature of storage, the more likely that small SWD larvae will die. Holding fruit at cooler temperatures also give growers the added benefit of determining how significant the infestation, as large larvae will exit fruit as it cools.

2. Sort out soft fruit. Soft fruit is the most likely to be infested with SWD for two reasons – egg laying SWD are more attracted to soft fruit and blueberries become softer as SWD feed. If growers can remove soft fruit before sending fruit for processing, this will further decrease risk of infestation being present. I suspect our aggressive soft sorting standards for fresh market blueberries are one of the reasons that SWD has been a less significant issue in this crop than some other hosts.

3. Sample collection timing. When receiving fruit, processors can either collect samples before or after fruit are sorted/de-stemmed. Samples collected before fruit has been soft sorted are not necessarily representative of the status of the fruit that will be processed. Samples of fruit after chilling and sorting, prior to processing/freezing, are likely more representative.

Post harvest leafhopper treatments

Treatments to manage sharpnosed leafhopper (http://ipm.ncsu.edu/small_fruit/hopper.html) vectors of blueberry stunt disease typically begin post harvest (http://pemaruccicenter.rutgers.edu/assets/PDF/Blueberry/iSharp-nosed_Leafhopper.pdf). Blueberry stunt disease is caused by a phytoplasma, and symptoms include "bushy" growth due to short, stunted branches and yellowed leaving during the growing season which may prematurely turn red and fall off in late summer. Most importantly, plants infested with stunt-causing phytoplasma do not produce. 

Aerial applications of ULV (ultra low volume) malathion has been used in the past for leafhoppers due to effectiveness and ease of application. However, many growers have also used this material for SWD management during the season, and careful attention must be paid to label restrictions on the number of applications that can be made of materials when selecting tools to manage sharpnosed leafhopper. Application limits apply to the entire growing season, not just harvest season, so label limits on the number of applications also apply to leafhopper treatments. Application limits apply to the amount of active ingredient, not the trade names of those active ingredients. Sources for updated labels with current use restrictions include CDMS (http://www.cdms.net/Home.aspx) and Agrian (http://www.agrian.com/home/label-lookup/overview).

Alternatives to malathion that are effective against sharpnosed leafhopper include Assail (acetamiprid) and Asana (esfenvalurate).  Imidaclorprid and thiamethoxam are also options for sharpnosed leafhopper. The North Carolina Agricultural Chemicals Manual (http://ipm.ncsu.edu/agchem/agchem.html) has recommendations for the use of these materials. It's important to note, however, that all these materials pose some risks to pollinators. While blueberries are not in bloom, some of our most efficient blueberry pollinators (http://repository.lib.ncsu.edu/ir/handle/1840.16/7822) are ground nesting bees that may remain near fields after bloom. Therefore, any insecticide treatments should be timed to leafhopper flights, ideally determined through trapping, to provide maximum efficacy against target pests and limit unnecessary applications. See http://ncsmallfruitsipm.blogspot.com/2011/04/practicing-what-we-preach-implimenting.html for information on trapping and the following for images, http://ipm.ncsu.edu/small_fruit/hopper.html, to aid in sharpnosed leafhopper identification.

From: Lina Quesada-Ocampo, Extension Plant Pathologist

Cucurbit Downy Mildew Moves Towards Western North Carolina

Cucurbit downy mildew has been reported in Haywood, Polk, Ashe, Henderson and Chatham counties (http://cdm.ipmpipe.org/scripts/map.php) during this past week. Now that cucurbit downy mildew is present in several regions of North Carolina and surrounding states, it’s important that growers scout for the disease and keep up with preventive sprays to protect their crop and avoid yield loses.

If you are not familiar with cucurbit downy mildew symptoms on different cucurbits please see our previous alert (http://plantpathology.ces.ncsu.edu/2013/07/do-you-know-how-to-diagnose-cucurbit-downy-mildew-in-different-cucurbit-crops/) to assist you in diagnosing this foliar disease. If you think you have cucurbit downy mildew in your cucurbits please contact your local Extension agent (http://www.ces.ncsu.edu/local-county-center/) and send photos and/or physical samples to the Plant Disease and Insect Clinic (http://www.cals.ncsu.edu/plantpath/extension/clinic/submit-sample.html).

For more information about the disease and how to control it, see our factsheets in English and Spanish (http://projects.cals.ncsu.edu/veggiepathology/disease_factsheets). Control recommendations are also available in the cucurbit downy mildew IPM pipe website (http://cdm.ipmpipe.org/index.php), where you can also register to receive text, e-mail and/or phone alerts when new disease outbreaks are reported. We have also compiled previous cucurbit downy mildew alerts athttp://plantpathology.ces.ncsu.edu/tags/cdm/.

Follow us on Twitter (https://twitter.com/QuesadaLabNCSU) and Facebook (https://www.facebook.com/QuesadaLabNCSU) for more veggie disease alerts.

How Does Bt Work?

Some of you may be interested in this information especially in light of the Bt resistance that has been identified: Researchers Identify Insect Resistant to Bt Pesticide.

Thanks to Gene McAvoy in Hendery County Florida for passing along this great info!

Bacillus thuringiensis, the active ingredient in the “Bt” insecticides, is a commonly occurring soil bacterium that was first discovered in 1901. Since their commercial introduction in the 1950’s, Bt products have become the most successful and widely used of the biopesticides.

Insecticidal activity of Bt derives from proteins that are produced and crystallize during bacterial sporulation (thus referred to as “Cry” toxins).

Most Bt products contain a mixture of Bt spores and toxin crystals. When a caterpillar ingests Bt, the crystals are dissolved in the alkaline gut environment. The insect’s own digestive enzymes convert the protein to an activated “delta endotoxin” which binds irreversibly to receptor molecules on the surface of cells lining the insect’s midgut, opening holes in the membrane that destroy the cellular lining of the digestive tract. The larva stops feeding (typically within hours) and may die quickly from septicemia as Bt and other spores in its food germinate, or may linger and die eventually of starvation.

Many different subspecies and strains of Bt have been described, producing different combinations of unique Cry toxins. Bt insecticides used for worm control are based on two of these subspecies which produce a few important Cry toxins.

Bt subspecies kurstaki (Btk) products such as Javelin®, Deliver®, and Dipel® contain primarily Cry1A and Cry2 toxins. These give broad spectrum activity against loopers, diamondback moth, imported cabbage worm, tomato fruitworm/corn earworm, tobacco budworm, hornworms, and other defoliating caterpillars common to vegetable production.

Xentari® and Agree® are based on Bt subspecies aizawai, which produces another toxin (Cry1C) effective against beet armyworm and other Spodoptera species, which are not very sensitive to Cry1A toxins.

Agree® contains a “hybrid” Bta, the offspring of a cross (transconjugation) between parent strains of Bta and Btk. As a result, Agree contains Cry1Ac (from Btk) in addition to Cry1C (from Bta). Other products such as Condor® represent unique combinations of Cry toxins resulting from transconjugation between different Btk strains.

Still other advanced Bt’s are products of genetic engineering to create unique Cry toxin combinations or higher levels of expression. CryMax® is such a recombinant Btk product, producing high levels of Cry1Ac in addition to Cry1C. Lepinox® is engineered for high expression of a combined Cry1Ac/Cry1F toxin particularly effective against fall armyworm (Spodoptera frugiperda), which is not highly susceptible to other Cry toxins.

All Bt products must be ingested by the target caterpillars in order to be effective, and small larvae in earlier stages of development are more susceptible than large, mature larva. This means that proper spray timing and technique are important to ensure that vulnerable plant tissues are uniformly covered by Bt spray deposits when young larvae are actively feeding. Worms that enter fruit or stems soon after egg hatch (such as squash vine borer, melon worm, and European corn borer) or are protected within mined or rolled leaves (such tomato pinworm) are susceptible to Bt if applied before they enter these protected environments.

Bt is not a systemic insecticide and tends to have shorter residual effect compared to many chemical insecticides (one of the reasons they present little risk to the environment, workers, and consumers). Reapplication may be required, especially during periods of rapid crop growth when new, untreated tissues may be exposed to infestation. Be sure to read the Bt product label for specific information regarding crops, target insects, and application instructions (such as rates, timing, and reapplication intervals).

Bt in IPM and Resistance Management

Bt insecticides are an ideal tool for the grower focused on IPM due to their selective control and low environmental risk. Bt also provides a unique mode of action (IRAC group 11) that can complement other insecticides in resistance management strategies. No evidence of cross-resistance has ever been detected between Bt and other insecticides; insects resistant to multiple classes of insecticides are still susceptible to Bt. Btk and Bta products also can be rotated to reduce risk of resistance to specific Bt’s.

At a recent symposium on “Insect Resistance in Vegetable Production” organized by the Entomological Society of America (Southeastern Branch), entomologists and IPM specialists (including Dr. Dakshina Seal of IFAS in Homestead) pointed to Bt products as the best rotational partners for delaying resistance to new insecticide chemistries such as the diamides.

Symposium participants listed the following benefits of Bt insecticides in a rotation program:

• High efficacy on a wide variety of worm pests

• Very low impact on beneficial insects.

• Avoidance of secondary pest problems.

• Not toxic to bees and predatory mites.

• No preharvest interval required after application.

• No restrictions on amount used.

• Resistance to Bt is slower to develop than resistance to chemical insecticides.

Through proper field scouting, correct identification of the worm pest, good timing of applications, correct selection of the Bt used, and judicious application of the Bt’s in rotation with new or older conventional chemistries, growers can gain effective control while reducing the risk of resistance and maintaining beneficial insect populations.

For more information contact Dr. Brett Highland, Certis USA, at bhighland@certisusa.com, or visit www.certisusa.com.

NC Pest News for July 22

Sorry this is a little late. The latest edition of NC Pest News is now available.

In the July 22 issue:

1. My tomato plants are wilting...then they die
2. New website to report brown marmorated stink bug sightings in North Carolina

New Pests: Spotted Wing Drosophila and Kudzu Bug

There are two new insect pests that growers need to be aware of, spotted wing drosophila and the kudzu bug.

Spotted wing drosophila (SWD) is an invasive fruit fly pest of soft-skinned fruit (strawberry, blueberry, blackberry, raspberry, etc.). SWD was first observed in California in 2008 and then identified in 2009. In 2010, Dr. Hannah Burrack of NC State began an intensive monitoring plan for SWD in the Southeast. SWD was captured in NC and SC late 2010. SWD gets its name because the males have two spots on the end of their wings (one on each). Female SWD do not have spotted wings, but do have a serrated oviposter. This serrated oviposter allows the female to lay eggs in sound fruit, unlike common fruit flies which prefer decaying fruit. Because of this, SWD has potential to be an economically limiting crop.

SWD trapping is well underway throughout NC, in fact SWD was captured in Henderson County in mid-June. Small fruits producers are encouraged to start a monitoring program. Dr. Burrack explains how to construct and monitor SWD traps and how to identify them.

For treatment considerations, visit Dr. Burrack's post What to watch for: When treating SWD.

To read more about SWD or to view images, please visit Dr. Burrack's SWD page on her NC Small Fruits, Specialty Crops and Tobacco IPM blog.

If you would like assistance with monitoring, please contact me at sue_colucci@ncsu.edu or your local extension office.

Kudzu bug (adult) on soybean leaf.

Multiple kudzu bugs (adults) on soybean stem.

The next pest is the kudzu bug. This pest prefers legume crops, especially soybeans, but has also been observed feeding on potatoes, cotton and wheat. The kudzu bug was confirmed in central Georgia in 2009 and then spread throughout the state and to neighboring states in 2010. This pest has been identified in many NC counties, including Buncombe and Henderson Counties on soybeans. This pest isn't thought to be a problem on most vegetables, but those who grow edamame soybeans or potatoes should be concerned. The kudzu bug is a stem and leaf feeder, so far there have been no reports of the kudzu bug feeding on blooms or pods.

Based on Georgia data the economic threshold is one bug per sweep with large nymphs present, or three bugs per plant with large nymphs present. This pest is very mobile and will re-invade after treatment, so capturing or observing nymphs is important. According to the latest edition of NC Pest News, killing this pest has been relatively easy with conventional insecticides except the neonicotinoids (kudzu bug seem to be attracted to areas that have been treated with neonicotinoids). For organic producers, PyGanic is recommended. Other options are options are azadirachtin (Azagard) or kaolin clay (Surround), but the efficacy of these products is unknown.

To read more about the pest, see more pictures and a map of kudzu bugs movement in the southeastern US, see the June 24th of NC Pest News.

Sustainable Insect Management Workshop

Yesterday I had the pleasure of attending the Sustainable/Organic Insect Management for Vegetable Growers Workshop in Clinton, SC. Our first stop was Parson Produce, a certified organic farm located at Bush River Farm.


Here we were greeted by Daniel Parson, a young and gregarious farmer who has been farming for 12 years. Daniel is a great presenter and has a Master's degree from Clemson University. Some of you may know Daniel from his presentations at SSAWG.

Daniel discussed his farm and showed us his farming equipment, which he stated is a piece of his pest management strategy. In true organic fashion, his production is a whole-farm system and pest management starts with productive soils, adequate not abundant nutrition, cover crops and good weed management.

Next, we moved to the field where Dr. Powell Smith (Extension entomologist and vegetable specialist from Clemson University) showed us some insect collection tools. These include sweep and butterfly nets, aspirators (used for catching small insects by sucking them into a container) and fabric sheets.

Below you can see Daniel's cover crop mixture of sorghum-sudangrass and buckwheat.

A great place to find insects!

Check out this field of pure buckwheat! A quick summer cover crop and insect attractor.

Insects, especially those that are predators to some plant-eating insects love the small buckwheat flower and will visit often for a source of food.


Daniel allows his buckwheat to go to seed and therefore re-seed the field.


Here is a group of workshop participants learning about the insects they collected in the buckwheat.


Next, we moved on to look at the broccoli to see what kind of insects we could find in this crop.


Here we saw some bad insects, but also some natural predators. We also learned about 'banker plants'. 'Banker plants' are plants that have some kind of problem and attract crop destroying insects and the predators that feed on them. Daniel has chosen to leave his 'banker plants' in order to keep the good insects in the planting. His 'banker plants' had lots of aphids (typically a sign of excess nitrogen). In addition to the aphids, they contained aphid predators. Below is a lady beetle larva feeding on the aphids.


Syrphid fly larvae were also present and feeding on the aphids(below). These insects are known as "aphid killers".


We also found harlequin bugs, a yearly problem on brassica crops. Below are nymphs of the piercing/sucking pest.


Exploring the eggplant crop we noticed a lot of flea beetle damage. Management for flea beetles is difficult. Some have found that row covers are effective for crops that do not require pollination. The covers cannot have open spaces for the beetles to enter. This control method is not effective if the flea beetle larvae are present in your soil. If they are, you will be trapping them in and may have a big problem on your hands.

Below you can see some flea beetle damage (the shot holes). The insect pictured below is an adult two-lined spittlebug, which is a plant-feeding insect.


Another plant-feeding pest that we found on the eggplant was a some kind of leaf-footed bug (below).


Thrips damage was also noted on the eggplant crop. Thrips are usually found in the flower of crops. These insects have rasping mouthparts. Damage on eggplant appears as green to brown streaking on the fruit. Sorry, I don't have a picture.

After all of our fun in the field, we enjoyed a delicious lunch prepared by the owners of Bush River Farm and Bed and Breakfast.

After lunch the group headed to Presbyterian College to learn some more about insect pest management and to do some more insect identification. Dr. Powell Smith discussed the different characteristics of identifying insects and the major plant-feeding and beneficial insect groups. The group discussed management options and the importance of attracting beneficial insects, as well as learning about the life cycle of an insect pest.


Overall, managing insects in vegetable crops organically is similar to a conventional IPM approach. Like discussed above, healthy soils, adequate nutrition and weed management will go along way. IPM includes cultural control methods (including proper selection of vegetable varieties for your area, avoiding insects by changing planting date, eliminating insect overwintering areas, attracting beneficial insects, planting trap crops, etc), using mechanical or physical control methods (tillage to disturb life cycle, row covers, hand picking or vacuuming) and finally the use of organically approved insecticides. Keep in mind that many insecticides will also kill or disturb your beneficial insects, that is why it is your last line of defense.

To learn more about attracting beneficial insects and biological control, visit NCSU's Biological Control Information Center or the Biological Control Resources page on GrowingSmallFarms.org.

Overall, the day was successful. We learned a lot about identifying insects, management options and even got to take a few specimen home with us. Below you can see our insect collection.


I took a wheel bug (a predator in the assassin bug family), a leaf-footed bug and larva, a squash bug and a running ground beetle (a voracious eater in the Carabidae that will feed on cutworms) home with me!

To learn more about insect identification, insect collection and insect control visit the following links:

ATTRA's Links to Insect Management
Growing Small Farms Links to Insect Management Web Resources
Collecting and Preserving Insects and Arachnids

Insect Pests Plaguing Vegetable Growers

This article is from the latest edition of NC Pest News from Entomology Extension Specialist, Dr. Mark Abney.

"A variety of insects are currently plaguing vegetable growers across North Carolina. Armyworms and corn earworms have been abundant and moth flights are continuing. European corn borers have been abundant in many of our research trials this year after several years of low numbers. Heavy European corn borer infestations occurred in sweet corn at the Central Crops Research Station in Clayton and large numbers were seen in bell pepper trials near Kinston and in the mountains near Fletcher.

Melon growers have not been immune to insect problems, and there have been a couple cases recently of corn rootworm larvae feeding on the undersides of cantaloupes. We do not see this on a regular basis, but it seems to happen somewhere every year. Larvae feed on the undersides of fruit, usually after a heavy rain, and there is no technology currently available to effectively control the problem.

As we approach late August, home gardeners and commercial growers alike will be faced with managing pickleworms in cucumber and squash. Commercial growers are forced to rely on preventative insecticide applications as tolerance for pickleworms in harvested produce is essentially zero. Home gardeners are faced with an uphill battle against this pest as management options available are not likely to provide good control. The best advice for gardeners is usually to plant early and harvest before pickleworms arrive from the south each year.

Another perennial foe of the cucurbit grower, the squash bug, is making its presence known in backyard gardens, commercial organic production, and in research trials. Large populations recently moved into research plantings of squash and cucumber at the Horticultural Crops Research Station near Clinton. It only takes a couple squash bugs to kill a young squash plant, so scouting and timely management are critical. These bugs can be difficult to kill, and the adult stage is particularly tough to control. Targeting the nymphs is important.

Scouting vegetables is absolutely essential to prevent losses due to insects and to maximize the effectiveness of insecticide applications. For control recommendations in specific crops, please refer to the North Carolina Agricultural Chemicals Manual (http://ipm.ncsu.edu/agchem/5-toc.pdf)."

Blackberry Borers Can Mean Big Problems

From the latest issue of North Carolina Pest News:

"From: Hannah Burrack, Extension Entomologist

Blackberry Borers Can Mean Big Problems

Gina Fernandez, the North Carolina State University caneberry specialist, has just returned from sabbatical and has wasted no time getting out for field visits. Yesterday, she brought me several samples from blackberry fields in Guilford County that were in severe decline. Their problems were almost all insect related. There were more cane boring pests from these few sites than I have seen my entire time at North Carolina State University! I'd like to use these samples as an overview of the key cane boring insects in North Carolina, what symptoms to look for, and what the management strategies for these pests should entail.

Evidence of borer damage is often visible from a distance. Plants will appear weakened, and in the case of raspberry crown borer, floricanes will be loose and easily removed. There are 3 key cane boring insects in North Carolina, and these locations had all of them!

Rednecked Cane Borer

The rednecked cane borer (Agrilus ruficollis) is part of a family of beetles known as metallic wood boring beetles. The adults (http://www.ca.uky.edu/entomology/entfacts/images/redneck.jpg) lay their eggs on the surface of primocanes and the larvae bore into them. When used, insecticide treatments target the adults, since the larvae do not spend time outside the plant. Larval rednecked cane borer feeding produces galls on the canes. The larvae are flat and found within the cane. As they grow, larvae will tunnel above the gall and reduce plant vigor and yield.

Low levels of rednecked cane borers can be managed with cultural control, specifically by removing and destroying all infested canes during the fall. The larvae overwinter inside the cane, so pruning will remove next year's generation of adults. For large infestations, chemical control of the adults may be necessary (for chemical information, see the Southern Region Brambles IPM Guide online at http://www.smallfruits.org/SmallFruitsRegGuide/index.htm). Dr. Donn Johnson, University of Arkansas fruit entomologist, has also had success removing primocanes in the early summer after the adult beetles laid their eggs (a June removal date worked the best in Arkansas and did not impact fruiting). This strategy may work well in North Carolina, because our long growing season allows plenty of time for primocane regrowth.

Raspberry Cane Borer

Raspberry cane borers (Oberea bimaculata), members of a family known as long horned beetles due their prominent antennae (http://www.virginiafruit.ento.vt.edu/raspcane), were also present in the Guilford County plantings. The adult beetles create paired girdles at primocane tips in summer. These tips wilt and will eventually fall off, and the entire cane may die. Larvae tunnel downward from the tip and have a 1 to 2 year life cycle in the southeast.

Cultural control, via pruning, is also an effective means of managing raspberry caneborers. Insecticide treatments may be targeted to the emerging and ovipositing (egg laying) adults just after bloom in cases where large infestation exist.

Raspberry Crown Borer

Raspberry crown borer (Pennisetia marginata) is perhaps the most severe pest of caneberries in the southeast. The larvae of this clearwing moth feed on the roots and crowns of caneberry plants and can kill an entire plant. Because they spend most of their 1 to 2 year larval stage underground, they are extremely hard to manage. Work conducted in Arkansas demonstrated that late fall or early spring soil drench pesticide treatments are most effective at reducing raspberry crown borers. These timed treatments target the early instar larvae before they are ensconced in the crown.

Insecticides are, at this time, the most effective means of raspberry crown borer management. Infested plants should be completely removed, since mature larvae will not be impacted by pesticide treatments.

In addition to the damage caused by these three wood boring insects, there were also several canes with damage at the tip that were dying back.

It is possible that this damage was cause by raspberry cane borers, but no larvae were found in the canes, and what tunnels there were stopped several inches from the top. If this was raspberry cane borer injury, we would expect to see tunnels continuing to the soil level or larvae present. These canes may have been injured during tipping and then feed on be opportunistic secondary pests. I dissected one of these canes, and there was fungal growth in the gallery, although this may also be secondary.

Wood boring insects are a fact of life for caneberry growers and can easily get out of control if a planting is not management carefully. There are abundant feral and wild brambles in the landscape, which serve as hosts for all three of these insects. Carefully scouting, good cultural management, and insecticide treatment when needed will keep borers from destroying caneberry plantings.

For the latest information on insect management in small fruits in North Carolina, see the NC Small Fruit, Specialty Crop, and Tobacco IPM blog at http://ncsmallfruitsipm.blogspot.com/."

Hops Pest: Eastern Comma Butterfly

A few weeks ago a number of our local hops producers were noticing large holes in some of their hops leaves. Upon closer inspection, they found spiky, white caterpillars feeding on the leaves.

Larva of Eastern comma butterfly found on hops in WNC (picture courtesy of R. Pelczar).

The entomologists at NCSU agreed that the caterpillars are larvae of the Eastern comma butterfly, Polygonia comma.

Larva of Eastern comma butterfly found on hops in WNC (picture courtesy of R. Pelczar).

Hosts:
Hosts plants of the Eastern comma butterfly are American elms, hackberry, nettles, false nettles and other members of the Urticacea. But, perhaps the favorite food of the Eastern comma butterfly is hops.

Beginning in the early 1900's, the Eastern comma butterfly was referred to as the "hop merchant" because hops farmers would predict the future price of hops based on the variation in the silver and gold spots on the pupae.

Larvae:
The larvae ranges in color from white to green-brown to black and are typically just over 1 inch long. The spikes also range in color from black to white with black tips. The larvae rest on the underside of leaves and make nests by silking together the sides of the leaf. The larvae rest during the day and feed at night.

Eastern comma butterfly larva. (Picture courtesy of Echoview Farm).

Eggs:
The eggs are green with vertical ridges and are laid singly or in stacks. I was lucky to find these (sorry they are not the greatest pics)!

Eggs of Eastern comma butterfly on underside of hops leaf.

Close-up of the eggs of Eastern comma butterfly. Notice the vertical ridges.

Pupae:
Pupae are variable in color but always have prominent ventral gold or silver spots.

Adults:
The adult is an orange and brown butterfly with a wingspan of 1.75 to 2 inches. With its wings folded it looks like a dead leaf.

Life Cycle:
There are two generations per year for Eastern comma butterflies. During the summer, the new butterflies are inactive during the hot period and then become active again in the fall. The fall brood of adult butterflies overwinter and start the cycle again in the spring.

Management:
The feeding damage caused by the Eastern comma butterfly larvae ranged in the individual hops yards here in WNC. One grower experienced quite a bit of initial damage, but was able to prevent further destruction by hand-picking the caterpillars.

Growers at another farm reported shaking the bines to knock off the caterpillars and then destroying them. This appeared to work well and little damage has since been noted. This grower also applied BT (Bacillus thuringiensis, a bacterial biological control material that is labeled for Lepidopteran pests) and reported that it was effective.

Hopefully, the Eastern comma butterfly will not be a problem for our hops growers in the future. At least now we know what the pest is and how to control it.

Thanks to all the folks who helped in the identification of the larvae and for the great growers for sharing their experience and their wonderful pictures!

To learn more, read the University of Florida's fact sheet on the Eastern Comma Butterfly.

Cucumbers and Pollinators: (Some) Questions Answered

When I first started my job in WNC in 2008, I was so excited to see that vegetable producers were growing cucumbers. Cucumber was the crop I worked with in my graduate work, so it was the only crop I felt mildly comfortable talking about (though it was still awkward at first).

To my surprise, in many of these production fields, I never saw a beehive. The areas that I had experience with in eastern NC, brought in at least one strong hive per acre of production. To learn more about bees, read Beekeeping and Cucumber Pollination.

How were these folks getting cucumbers? A cucumber flower must be visited multiple times by a pollinator to optimize fruit set. The answer was wild populations on pollinators and the nice sunny, warm weather that promotes activity and foraging of pollinators.

But, in 2009, growers noticed that yields were reduced and that fruit formation was off. The same varieties were grown and there was not downy mildew or other diseases in their early season crops. So what was different?

We were cool, cloudy and wet. How could you forget? The fact is, bees don't aggressively begin to forage until temperatures reach 70 F and they prefer dry conditions.

Could this lack of fruit also be due to a reduced population of wild pollinators? At this point we don't know, but it was obvious that the growers needed to do something. That something was to bring in some honey bee hives.

Here are some pictures of a female cucumber (top) and male cucumber flower (bottom), courtesy of Pollinator.com.


Below is an improperly pollinated fruit.

To see more pictures, visit pollinator.com's Cucumber Pollination: Visual Aids.

But, the growers were concerned. Bringing bees into their production was new and they had many questions - especially in regards to applying pesticides.

Here are a few of the questions that I received. Most answers are from NCSU Beekeeping Note 2.12.

• Where can I find honey bee hives to rent?

The NCDA&CS Apiary Services and NCSU Apiculture Program have developed Bee Linked, an online market for beekeepers and growers. www.ncagr.com/beelinked
You can also find local beekeepers through the North Carolina Beekeepers Association Website. www.ncbeekeepers.org.

• When should I apply pesticides to protect the bee hives?

Pesticides that are considered toxic to bees should be applied in the late afternoon (after 3:00 pm) or in the evening. Most honey bees have stopped foraging and have returned to the hive by 3:00 pm. This precaution will allow maximum time for the pesticide to break down before the bees come into contact the next day.

• What other considerations are important when applying pesticides?

Do your best to minimize drift. Drifting of the pesticide from the target pest and/or crop to areas frequented by bees should be minimized and pesticide formulation is the key to this problem. "Dusts" are prone to drift and are generally more dangerous to bees that sprays or granular applications. For more specifics, read Beekeeping Note 2.12.

Aerial applications are generally more dangerous than ground equipment. This is directly related to drift. Air-blast sprayers are more dangerous that pressurized pump sprayers. Never apply pesticides when wind velocities exceed 8 miles per hour.

Never apply any pesticide directly over a beehive.

Notify beekeepers who have beehives near an area to be treated, so that they may attempt to protect their bees from inadvertent exposure.

• Are there pesticides that are less toxic to honey bees?

Most pesticides are at least somewhat toxic to honey bees; however, the degree of toxicity varies considerably from product to product. Insecticides are generally the most likely to cause a bee kill. Below are some common pesticide active ingredients listed based on their toxicity to honey bees for a more complete list, see Beekeeping Note 2.12.

1. Highly Toxic: Severe bee losses may be expected if these products are used when bees are present. Abamectin, aldicarb, avermectin, azinphos-methyl, carbaryl, carbofuran, chlorpyrifos, dimethoate, imidacloprid, malathion, methomyl, pemethrin, spinosad...
2. Moderately Toxic: These pesticides can be used in the vicinity of bees IF dosage, timing, and method of application are correct. Bifenazate, disulfoton, endosulfan, fluvalinate, oxamyl, propamocarb, pyrethrum, tartar emetic, temephos, terbufos, thidicarb, zephyr...
3. Relatively Non-Toxic: These pesticides cam be used around bees with a minimum injury IF dosage, timing and method of application are correct. Bacillus thuringiensis, chlordimeform, cryolite, cymiazole, dicofol, dinobuton, esfenvalerate, methoxychlor, myriproxyfen, nicotine, Nosema locustae, pyrethrum, rotenone, tebufenozide, trichlorfon.

Visit the NCSU Apiculture Website for more details on honey bees.

To learn about cucumber production in NC: Fresh Market Production Cucumbers and Commercial Production of Pickling & Slicing Cucumbers in North Carolina.

To learn more about Bee Colony Collapse Disorder, read a scholarly article about the problem in Colony Collapse Disorder: A Descriptive Study.

Movento to be Pulled From Shelves!

Big Win for Bees: Judge Pulls Pesticide

NEW YORK (December 29, 2009) - A pesticide that could be dangerously toxic to America's honey bees must be pulled from store shelves as a result of a suit filed by the Natural Resources Defense Council (NRDC) and the Xerces Society. In an order issued last week, a federal court in New York invalidated EPA's approval of the pesticide spirotetramat (manufactured by Bayer CropScience under the trade names Movento and Ultor) and ordered the agency to reevaluate the chemical in compliance with the law. The court's order goes into effect on January 15, 2010, and makes future sales of Movento illegal in the United States.

Here is a full article on the matter Bayer 'Disappointed' in Ruling on Chemical that May Harm Bees

Important: Postively I.D. the Insects on Your Farm

This week in my Transitioning/Beginning Organic Production class we talked about insects. We had 2 great presenters. First up was Diane Almond from Honey Bees and Heather Farm in Fletcher. Diane discussed pollinators and the importance of maintaining pollinator habitats on your farm or garden. Diane's talk had me on the edge of my seat!

Second up was Amanda Stone, agriculture agent in Buncombe County who works with the Green Industry. Amanda's presentation included, not only a peek into her insect collection, but insect management techniques in organic systems, which includes increasing biodiversity, employing cultural methods and mechanical means and finally the use of OMRI-approved materials. One aspect of Amanda's discussion was the importance of scouting. Scouting for insects, mites and disease problems is the foundation for Integrated Pest Management or IPM. Scouting for insects on your farm lets you know what is on your crops, when they arrive, how many are present and if there has been changes in severity of infestation, and will help you to decide whether or not to take action.

Interestingly, this week a grower sent me some pictures of a "worm" he found in his Napa Cabbage. Because I had never seen this before, we sent the images to the NCSU Plant Disease and Insect Clinic. We got results just a day or so later!

Syrphid fly maggot (larva) found on Napa Cabbage. Photo courtesy of Michael Porterfield.

Syrphid fly maggot (larva) found on Napa Cabbage. Photo courtesy of Michael Porterfield.

The entomologist at NCSU informed us that it was the larva of a syrphid fly (some call these hover flies or flower flies - check our Debbie Roos photo an adult and some other incredible photos of syrphid flies and larvae).

The syrphid fly is actually a good guy, a beneficial insect, in the farm or garden! When syphids are present, you can just about guarantee there are aphids present as well. Syrphid larvae can do a remarkable job of cleaning up low aphid populations. Each larva can consume up to 400 aphids during their development!

Syrphid fly larvae do not cause damage to the plant. Syrphid fly larvae may cause a problem if they are present on your crops at the time of sale. At the point of sale, essentially all insects are considered "insect contamination". For folks selling directly to consumers, education may be the key to overcoming this notion. For growers who are not selling directly, know the level of contamination that your market will tolerate.

It was a great thing that the grower was scouting his fields! As a result, the grower was able to positively identify the larvae and decide whether or not to take action. We also learned more about biocontrol on the farm and syrphid fly and aphid relationships.

Please take the time to scout your fields as often as possible, you will learn a lot about your crops!

**Special thanks to Dr. Mark Abney for doing a bang up job identifying the syrphid fly and to Michael Porterfield for taking these great images!**