2023 Revisions to Fruit Pest Management Recommendations

Hello, everyone, We now have this year's updated pest management guides posted. The guides are available free online in PDF, and will also be available for purchase. 2023 Pest Management Guides
2023 Commercial Horticultural and Forest Crops (including Commercial Small Fruit, Commercial Vineyards, Commercial Hops)
2023 Home Grounds and Animals (including Home Fruit)
2023 Field Crops

2023 Spray Bulletin for Commercial Tree Fruit Growers.

Watch for more later!
Doug

2023 Orchard Fruit Schools

Hello, everone, This year's orchard fruit schools will be held the week of Feb 20-24. Details are provided below (Agendas are posted in the What's Hot in Apple section of the Virginia Fruit web site)

Mon, Feb 20, 8:30 AM - The Winchester Area Fruit School, Alson H. Smith AREC, Winchester.
Tues, Feb 21, 8:30 AM - The Madison-Rappahannock Fruit School, Graves Mt Lodge, Syria.
Wed, Feb 22, 8:30 AM - The Nelson-Albemarle (Central Virginia) Fruit School, Lovingston Fire Hall, Lovingston.
Thur, Feb 23, 8:30 AM - The Botetourt-Roanoke school, Brambleton Center, Roanoke.
Fri, Feb 24, 8:15 AM - Patrick-Carroll Fruit School, Lambsburg Community Center, Lambsburg.

Hope to see you at one of the schools!
Doug P.

Update on Spotted Lanternfly

Hello, everyone, It's time for an update on spotted lanternfly (SLF), as it continues its spread through the state. After the discovery of SLF in Winchester in 2018, a quarantine zone was erected - the insect was first found in Winchester and Frederick County, but as it spread, the quarantine zone included, in addition to those areas, Clarke and Warren Counties. In 2022, the zone was significantly expanded to include Albemarle, Augusta, Carroll, Nelson, Page, Prince William, Rockingham, Rockbridge, Shenandoah and Wythe Counties, plus the cities of Buena Vista, Charlottesville, Harrisonburg, Lexington, Lynchburg, Manassas, Manassas Park, Staunton and Waynesboro. The map of the quarantine zone is here:

The disjunct part of the range, in Wythe and Carroll Counties (near the North Carolina border), is almost certainly due to human-assisted transport. The site in Carroll County is near a parking lot at the junction of I-77 and Rt 58. A notable new find late this season was in the New River Valley, in the city of Radford (this does not yet show up in the quarantine zone - there is always a lag in the quarantine map because of administrative issues in expanding a quarantine zone). Dead adults were found at office windows across the street from private land with tree of heaven. The discovery was aided by spiders, whose webs on the window sills ensnared the adults!

At this time of year, SLF is in the egg stage. Eggs are laid not only on tree of heaven, but the bark of other trees, as well as inanimate objects. In vineyards with established populations, egg masses may be seen in high numbers on trellis posts. In one vineyard in northern Virginia, masses were seen in high numbers on treated wood end posts, shown here. Note how the presence of protective covering over the eggs deposited by the female varies from complete to absent.

One troubling observation was the concentration of egg masses in the inner (concave) surfaces of roll-formed steel trellis posts. This protective behavior will likely result in difficulties in achieving spray coverage with the development of effective ovicides. See the video here.



There will be further updates as this pest increases its presence in Virginia. More later, Doug P.

Resources to Help in SLF Quarantine Compliance and Management

Hello, everyone,

Spotted lanternfly (SLF) is a potentially devastating pest of grape, now expanding its spread in Virginia. In July 2022, VDACS expanded a quarantine zone from 3 counties to 12, including contained independent cities.

Many vineyards and wineries will now need to deal with the quarantine protocol. At least one person per company will need to get certified through a short, on-line training session ($6.00). That person may train others in the company to assure compliance. All shipments and vehicles leaving the quarantine zone will need to be inspected. Information on the quarantine protocol may be found here (https://www.vdacs.virginia.gov/plant-industry-services-spotted-lanternfly.shtml). This site contains the protocol as well as the current version of the quarantine map.

The training required for certification is easy and inexpensive. Access to the training may be found here (https://register.ext.vt.edu/search/publicCourseSearchDetails.do;jsessionid=E3FEE1B1C1921BA6848B382063FC0BDE?method=load&courseId=1066947).

When doing inspections for quarantine compliance, it will be necessary to know what life stages of SLF can be expected. We have graph posted online that conveys this information clearly (https://www.pubs.ext.vt.edu/ENTO/Ento-268/ENTO-268.html). This can be posted where appropriate in your operation.

Theresa Dellinger and Eric Day in the Department of Entomology have created a useful aid for the public on the SLF quarantine, entitled "What Virginians Need to Know About SLF Quarantine expansion" (https://www.pubs.ext.vt.edu/ENTO/ENTO-319/ENTO-319.html).

Beyond matters of quarantine compliance, we have online resources for SLF management. There is a fact sheet on SLF management, available in English and Spanish, available here (https://www.pubs.ext.vt.edu/ENTO/ENTO-323/ENTO-323.html). In a similar fashion, a fact sheet for SLF management in residential areas (https://www.pubs.ext.vt.edu/ENTO/ENTO-322/ENTO-322.html).

Needless to say, SLF is covered in our annual chemical control recommendations for vineyards and home fruit. The risk to tree fruits is not considered to be as great; SLF will be included here as needed. It should be noted that orchardists will still need to deal with quarantine issues.

VCE Pest Management Guide for Commercial Vineyards (https://www.pubs.ext.vt.edu/content/pubs_ext_vt_edu/en/456/456-017/456-017.html)

VCE Pest Management Guide for Home Fruit (https://www.pubs.ext.vt.edu/456/456-018/456-018.htmls.html)

Last but not least, I maintain a spotted lanternfly page in the Virginia Fruit Site ( https://www.virginiafruit.ento.vt.edu/SLF.html). I intend for this to be one-stop shopping for matters on SLF, and all the above links are active there.

I hope this is useful. More later, Doug

Spotted lanternfly update: Large expansion of quarantine zone

Hello, everyone,

In May 2019, the Virginia Department of Agriculture and Consumer Services (VDACS) announced the establishment of a quarantine zone for spotted lanternfly (SLF). I posted on this here on 28 May of that year, and again on 3 June, when a public open house was announced to discuss compliance with the program. The quarantine zone initially contained Frederick, Clarke and Warren Counties plus the City of Winchester. A significant expansion of the zone is now planned, and will be formally announced in the next week or so. The quarantine zone additions will include the counties of Albemarle, Augusta, Carroll, Page, Prince William, Rockingham, Rockbridge, Shenandoah and Wythe, plus the cities of Buena Vista, Charlottesville, Harrisonburg, Lexington, Lynchburg, Manassas, Manassas Park, Staunton and Waynesboro. Here is the new zone map:

Here is a link to more information on the quarantine (https://www.vdacs.virginia.gov/pdf/spotted-lanternfly-quarantine.pdf). There will be public informational sessions to discuss the program, and facilitate compliance. One such meeting will be held on Aug 1, 5:50-8:30 PM, at King Family Vineyards. For more information, contact Grace Monger, gimonger@vt.edu (free with pre-registration, $10 at the gate). I will announce other sessions as I learn of dates.

One of the conditions of the quarantine is that at least one person within each company (vineyard, winery, orchard, hops yard, etc.) be certified to inspect and approve vehicles or shipments leaving the quarantine zone. The current certification program is linked here. Cost for a certification is $6.00.

The quarantine zone is being expanded because SLF continues to spread in Virginia. Different maps are prepared reflecting this spread. There are understandable differences in details among maps depending on the nature of programs - approvals that are needed for a quarantine, official identification of SLF samples, etc. Here are two current maps. The first has been developed within the Department of Entomology at Virginia Tech, by Eric Day and Theresa Dellinger. The second is maintained in a SLF site by the New York State IPM program at Cornell University.

These two maps reflect two infested counties not yet included in the quarantine: Campbell and Loudoun. An important point of the Cornell map is that it includes the whole range of SLF. A significant point here is that SLF has turned up in North Carolina, the first infestation for this state, in Forsythe County, Close to I-44. More information on the NC infestation can be seen here.

Summary: Important take-away points here are that SLF has continued its spread, now including the whole Shenandoah Valley, further incursions in the Piedmont of Virginia, and a significant jump into southern Virginia, almost certainly assisted by human transportation, at the junction of two major highways. There has been an expansion into North Carolina, close to (though not adjacent) to Carroll and Wythe Counties. VDACS is set to announce a significant expansion of the SLF quarantine zone in Virginia. Watch for annoucements of informational meetings in affected counties.

You can contact me for information on spotted lanternfly biology or management. For questions on the quarantine program itself, contact VDACS at spottedlanternfly@vdacs.virginia.gov, or 804-786-3515.

More later, Doug

Update and repost of Giant Asian Hornet article

See Asian Giant Hornet Fact Guide by James Mason in Virginia Tech’s Department of Entomology for a summary of risk, and an excellent pairing of photos of this species with species likely to be confused.

Fig. 1a, b. Asian giant hornet, Vespa mandarinia, courtesy of USDA-APHIS

Fig. 2. European hornet, Vespa crabro, attacking a blackberry (Pfeiffer)

Hello, everyone, Recently a nest of the Asian giant hornet was found in Washington State, using a new approach to nest detection. Workers are captured and fitted with tracking devices, leading investigators to the nest. I've had some questions about this hornet, and so I'm reposting an article from May 2020. Follow below!

I’d like to say a few words about another invasive insect that has been in the news lately, and is generating questions (I promised myself I would not say generating a lot of buzz, and I’m going to hold to that!). This is the Asian giant hornet, Vespa mandarinia. A recent newspaper article (Baker 2020) used a nickname for this insect – murder hornet - that is a literal translation of a Japanese nickname. One needs to be careful about common names and nicknames of insects. Velvet ants are neither velvet nor ants, but a family of wasps that have been referred to as “cow-killers”, even though they are no threat to cattle. The Asian giant hornet was referred to as a murder hornet to elicit interest in readers, but people have really latched onto it, going beyond mere “elicited interest”! This is the world’s largest hornet, about 45 mm long, about 1.8 inches (queens are larger, about 50 mm, or 2 inches. Their main food consists mainly of insects, e.g. other wasps, beetles and mantises.

Several points need to be made about this wasp: 1) It is nowhere close to Virginia or anywhere else in our region. The discovery was made last December in northwestern Washington State, after being found earlier in the fall in adjacent British Columbia. 2) The known infestation in the US currently consists of two dead wasps found. There was likely a nest that gave rise to these individuals, but it has not been common even where discovered. 3) The US discoveries were across the water from a hive that was discovered in Nanaimo, on Vancouver Island in British Columbia in September. That hive was found and destroyed (Bérubé 2020). A genetic analysis has shown that the wasps from the BC and WA sites were not from the same hive. 4) In Japan about 40-50 people die from stings from this species. In the US from 2014-2017, annual deaths from bee and wasp stings ranged from 43-89 (CDC 2019). 5) The main threat is to honey bees. The wasp workers will attack honey bee hives in order to steal brood. Beekeepers and entomologists in Washington State will be working to find and destroy nests while it is still in a restricted geographical range.

The threat to honey bees: This wasp feeds on a wide range of insects, but in late summer and into the fall will attack honey bee hives. There are several phases of wasp attack against the hive (Matsuura and Sakagami 1973). Early in the cycle, there is a hunting phase, where wasps will wait near hives and attack individual bees as they leave the nest. Later this will progress to a slaughter phase, where groups of wasps will attack worker bees, biting and killing the bees until there is no more defense. This leads to the occupation phase, where bees enter and remove bee pupae to serve as food for the wasp brood. Honey is not taken. During this occupation phase, the wasps become more aggressively defensive and will attack perceived intruders. European honey bees (Apis mellifera) are much more vulnerable than Japanese honey bees (Apis cerana).

You may have read about a response of Japanese honey bees when their hive is threatened by the wasp. I’ll expand on this by including links I have been using in my course on Insect Structure and Function, showing how the insects’ circulatory system is coopted for another use. First – the threat posed to our main honey bee, the European A. mellifera. This bee did not evolve with Asian giant hornet, and so has no effective defense. A scout wasp finds and marks a bee hive, and her nestmates soon arrive to attack the hive. After eliminating the workers, the brood is taken to feed the wasp brood back in their nest. Here is the video depicting the threat to European bees:

http://www.youtube.com/watch?v=EZ1eAM8CChc

The Asian honey bee, A. cerana, has evolved with the hornet, and has evolved a defense – think of this as an evolutionary arms race. When the scout wasp finds the nest, the bees swarm over the invader, vibrate their wing muscles, and generate a heat that heat the blood. This heat is dissipated through the cuticle, or exoskeleton, of the bees. While the temperature generated is tolerable to the bees, it is lethal to the wasp, killing the intruder before her nestmates learn of the hive. Here is the link to a video on that response by A. cerana:

https://www.youtube.com/watch?v=K6m40W1s0Wc

How can Asian giant hornet be managed?: In Japan, several types of approaches to managing Asian giant hornet in bee yards were discussed and summarized by Matsuura and Sakagami (1973) as falling into six categories: 1) Beating to death, 2) Removal of hornet nests, 3) Bait trapping, 4) Mass poisoning, 5) trapping at hive entrances, 6) Protective screens. Many of these were developed on an ad hoc basis by beekeepers and need to be further tested.

Telling Asian giant hornet from wasps that are already here: Because of the widespread public concern over Asian giant hornet, it will be very useful to be able to differentiate that species from insects that may be confused. In addition to size, note the shape of the yellow to yellow-orange head, the yellow stripes on the abdomen (Figs. 1a,b), the dark antennae with yellow-orange scape (first or basal segment), and a wide gena (the area behind the eye). Here is a link to a graphic that compares the Asian giant hornet to several other wasps:

https://cms.agr.wa.gov/WSDAKentico/Documents/Pubs/846-SizingUpAsianGiantHornet.pdf

This graphic was developed in Washington State, where the Asian giant hornet was found. Some of the species shown are western species, but we have similar ones here in the east. For example, the yellowjacket shown is Vespula pensylvanica, which, despite its scientific name, is mainly a western species. However, it is similar in size to our eastern species, Vespula vulgaris among others.

Another big wasp, likely to be confused: Because of its large size, the wasp that will most likely be mistaken to be the Asian giant hornet is the European hornet, Vespa crabro. That species was introduced into the US in the middle 1800s, and is now present in much of the east (Akre et al. 1981). It usually not very aggressive, and does not cause the problems that yellowjackets do. This wasp is commonly seen. Note the projections of dark area that cut into the leading edge of yellow striping, a dark area that is somewhat doorknob shaped. This can be seen in the photo (Fig. 2) at the beginning of the post and in the illustration below (Fig. 3).

Fig. 3. Top of gaster (abdomen) of the European hornet, taken from Akre et al. (1981)

See our new fact guide for Asian giant hornet: To help address the public concern, the Entomology Department at Virginia Tech has published a fact guide to the Asian giant hornet (Mason 2020) (https://www.ento.vt.edu/News/Asian_Giant_Hornet.html). In this article, photos of the Asian giant hornet are paired with photos of several wasps that may cause confusion. Note the differences in size and color pattern. I’ve seen one news article that used the European hornet photo mis-labeled as the Asian giant hornet, creating the potential for further confusion.

In summary, two dead adults of Asian giant hornets were found in Washington State in December, shortly after a nest was found and destroyed in nearby British Columbia. The locality of the originating nest of the US finds is not known, but there is so far no definitive proof that Asian giant hornet is established in this country. The main threat from this wasp is to honey bee hives. Beekeepers are working with the Washington Department of Agriculture and Washington State University to find, and if necessary, work to eradicate this species. It is not expected in the eastern states in the foreseeable future. More important risk to honey bees continues to be parasitic mites and the viruses they transmit, loss of foraging diversity, lack of genetic diversity, pesticides, and overwork!

More later,

Doug

References for added enjoyment!

Akre, R. D., A. Greene, J. F. MacDonald, P. J. Landolt, and H. G. Davis. 1981. The Yellowjackets of America North of Mexico. U. S. Dept. Agric. Handbook 552: 102 p.

Baker, M. 2020. 'Murder hornets' in the U.S.: The rush to stop the Asian giant hornet. The New York TImes.

Bérubé, C. 2020. Giant alien insect invasion averted - Canadian beekeepers thwart apicultural disaster. Am. Bee J. 160: 209-214.

CDC. 2019. QuickStats: Number of deaths from hornet, wasp, and bee stings, among males and females — National Vital Statistics System, United States, 2000–2017. MMWR Morb. Mortal. Wkly. Rep. 68 649.

Mason, J. 2020. Asian giant hornet fact guide, Department of Entomology News.

Matsuura, M., and S. F. Sakagami. 1973. A bionomic sketch of the giant hornet, Vespa mandarinia, a serious pest for Japanese apiculture. J. Fac. Sci. Hokkaido Univ. Ser 6, Zool. 19: 125-162.

Update on spotted lanternfly - first adults

Hello, everyone,

We are at crucial stage of development for our population of spotted lanternfly, both in terms of range expansion and seasonal phenology. You may remember that at the end of last season, we had detected SLF at a commercial vineyard for the first time, in a vineyard north of Winchester (we had earlier detected it on a table grape planting in Winchester). This week we found fourth instar nymphs at two commercial vineyards southwest of Winchester. Dr. Johanna Elsensohn, a post doctoral researcher with USDA-ARS, found a single nymph on a vine. At both of these Frederick County vineyards we found nymphs on tree of heaven on both sides of the blocks – the vineyards are essentially surrounded!

Fig. 1-2. Spotted lanternfly fourth instar nymphs on tree of heaven surrounding a vineyard.

Yesterday, the first adults of SLF for this season were reported. This is an important time of the season, since the adult stage is the main dispersal stage. From now until fall, there will be a time of movement into vineyard blocks if SLF is established in the area. Growers in such areas should be watchful. Adults will form large feeding aggregations, and can impost a large drain on the vine.

Fig. 3-4. Spotted lanternfly fourth instar nymphs on tree of heaven surrounding a vineyard.

In both of these vineyards, there were stands of young tree of heaven that had grown from cut trees. It will be helpful to remove tree of heaven, but it is important to not simply cut the trees with out supplemental herbicide treatment, because of the way these trees regenerate. Figs. 2 and 3 show nymphs on such small trees (Figs. 1 and 4 contain nymphs on mature trees). We are fortunate in having only a single generation of SLF. If we start the season with a low population of young nymphs, it is unlikely that significant immigration will occur, and additional sprays may not be needed. This can change with the mobility of winged adults.

Fig. 5. Adult spotted lanternfly

This year is likely to be a year of additional commercial vineyards with populations of SLF. Apple and peach orchards may also see feeding aggregations, but these may be transient. Hops are also fed upon, but more information is needed on duration and severity, Please let me know of observations at your plantings.

More later,
Doug