Spotted lanternfly adult activity update

Hello, everyone, Spotted lanternfly (SLF) development is about 2 weeks earlier than last year. INn 2023, first adults were seen on July 12, and in the grape-growing region of northern Virginia in 2024, June 29 (actually earlier farther east, June 12 in Richmond). Some vineyard high populations of fourth instars on Ailanthus trunks surrounding the vineyard. As adults appear in numbers, there will be immigration into vineyard blocks. There is a provisional action threshold of 5-10 adults given in the Pest Management Guide. This is likely to be conservative; unfortunately a multi-state proposal to provide a research-based action threshold was not funded this year.

A question has been asked of the advisability of removing tree of heaven (TOH) to help manage SLF. SLF is able to complete development in the absence of TOH, but does much better in its presence. It may be helpful to eliminate TOH from vineyard surroundings. However, in areas where SLF has been developing on TOH, this may not be the best time to remove those hosts, since it may hasten the movement of adult SLF into vineyard blocks.

Please let me know of any SLF-related questions.

Doug

2024 Fruit Pest Management Recommendations Posterd

Hello, everyone,

This year's revisions to our fruit pest management guides are now available.

The guides are available for free in PDF form. Hard copies may be purchased.

2024 Spray Bulletin for Commercial Tree Fruit Growers Click here for PDF.

2024 Pest Management Guides
2024 Commercial Horticultural and Forest Crops (including Commercial Small Fruit, Commercial Vineyards, Commercial Hops) Click here for pdf.
2024 Home Grounds and Animals (including HomeFruit). Click here for pdf.
2024 Field Crops Click here for pdf.

More later,
Doug

2024 Orchard Fruit Schools

Hello, everyone, 2024 Tree Fruit Schools This year's orchard fruit schools will be held the week of Feb 12-15. Please note there is a different arrangement of dates from the past. There is no fruit school scheduled this year for Botetourt-Roanoke. Details are provided below:

Mon, Feb 12, 8:30 AM - The Winchester Regional Fruit School, Alson H. Smith AREC, Winchester (contact Mark Sutphin, mark.sutphin@vt.edu). Click here for agenda.
Tues, Feb 13, 8:30 AM - The Rappahannock-Madison Fruit School, Graves Mt Lodge, Syria (contact Kenner Love, klove@vt.edu). Click here for agenda.
Wed, Feb 14, 8:30 AM - The Nelson-Albemarle (Central Virginia) Fruit School, Lovingston Fire Hall, Lovingston (contact Grace Monger, gimonger@vt.edu). Click here for agenda.
Thur, Feb 15, 8:15 AM - Carroll-Patrick Fruit School, Lambsburg Community Center, Lambsburg (contact Ashley Edwards, aledwards@vt.edu). Click here for agenda.

I hope to see you at the fruit schools!
Doug

A Double Brood of Periodical Cicadas in 2024?

Hello, everyone,

There has been discussion in the news and in social media this week of two broods of periodical cicada this year. Is this true, and how does that work? The answer to the first question is a qualified yes, but first I’ll give some background.

Cicadas are sucking insects that feed on xylem sap of various tree species. Annual cicadas emerge every year (though taking more than one year to develop feeding on tree roots). Periodical cicadas have a synchronized development, feeding on roots for 17 years (usually). A few broods have a 13-year cycle, mainly in more southern areas. When adults emerge, they do so in staggering numbers. They make remarkable “chorusing centers”, where males make a shrill singing sound, attracting both males and females. After mating, females use their sharp ovipositors to insert eggs into twigs of about pencil diameter. This is the source of economic injury – the area beyond the oviposition scar dies, creating a brown flagging of twigs. This is extremely damaging in a young orchard or vineyard.

There are about 12 17-year broods, and 3 13-year broods. These have different, but often overlapping geographical ranges. Some of these are widely spread, others sharply limited. The following map from the Forest Service, shows the distribution of periodical cicada broods, color coded. Because each county is assigned to only one brood, the degree of overlap of broods is sometimes vague, but there is some idea given of the range. Brood X is the most important to fruit producers in the mid-Atlantic region, but its range is somewhat obscured by coloration for other broods.

Fig. 1. Range of periodical cicada broods provided by US Forest Service. Brood XIII (the Northern Illinois Brood (17-year) is in brown; Brood XIX (the Great Southern Brood (13—year) is in light blue.

The first person known to have figured out the 17-year cycle of periodical cicada was Benjamin Banneker, a free African American living in Maryland. After observing outbreaks on his land in 1749, 1766 and 1783, he predicted an outbreak in 1800 (McGreevy 2021). That reference refers to Banneker working with Brood X of periodical cicada. He would not have known that term, because the recognition of the different geographical broods in different years, and the codifying these with Roman numerals was made by Charles Marlatt (Marlatt 1907), chief entomologist at USDA, and who also began some of the first regulations protecting the US from invasive pests.

In 2024, we can expect emergence of Brood XIX in Virginia (light blue in Fig. 1). But while Broods IX and X are the major broods affecting Virginia’s fruit production, the range of Brood XIX is limited here. It is nicknamed the Great Southern Brood because of the broad swath through the Deep South. But Virginia it is limited mainly to Southside (Hanover, Charles City, Prince George, Brunswick, Halifax and Wise Counties). In our Commercial Spray Bulletin for Commercial Tree Fruit Growers (VCE 2023), we have a map of expected emergence years of adult periodical cicadas, by county, for Virginia and West Virginia (see map). That map uses circles to indicate 13-year broods; all others are years for 17-year emergence.

Fig. 2. Periodical cicada map from VCE Publ. 456-419. Brood XIX denoted by encircled 24 counties.

Now for the explanation of the “qualified yes” regarding the double emergence of cicadas – emergence of more than one brood at a time. This can only happen rarely, when 17 year and 13 year cycles eventually meet in time. This year, 2024, we expect emergence of the 17-year XIII and the 13-year XIX. However, Brood XIII is nicknamed the Northern Illinois Brood for a reason (see Fig. 1). It will occur nowhere near Virginia! So this year, Virginians in Southside (and perhaps extreme southwestern Virginia) can expect to see periodical cicadas. Ecologically, this dual occurrence poses an interesting possibility – the chance for genetic exchange between broods that see each other only every few hundred years!

References

Marlatt, C. L. 1907. The periodical cicada. U. S. Dept. Agric. Bur. Entomol. Bull. 71: 1-181.

McGreevy, N. 2021. Meet Benjamin Banneker, the Black scientist who documented Brood X cicadas in the late 1700s, Smithsonian Magazine. (https://www.smithsonianmag.com/smart-news/meet-benjamin-banneker-black-scientist-who-documented-brood-x-cicadas-late-1700s-180977676/)

VCE. 2023. 2023 Spray Bulletin for Commercial Tree Fruit Growers. Va. Coop. Ext. Publ. 456-419. 180 p.

Appearance of Spotted Lanternfly Adults

Hello, everyone,

This week, spotted lanternfly (SLF) adults began their appearance. There was an appearance of an adult in a vineyard in Bedford County on July 19. There is a possible appearance a day or so earlier that is being follow up on.

This map includes the most recent updates in geographic spread of SLF in Virginia, generated in the Insect Identification Lab in the Department of Entomology. Red counties are included in the VDACS quarantine; counties in orange have established populations but are not yet in quarantine.

The adult stage poses the greatest risk of immigration into vineyards, because of its mobility and attraction to grapevines. If adults are just showing up in an area, there is no need to overreact. In areas where SLF has been present in an area for a season or two, the pest pressure is likely to be higher. In the coming weeks, play close attention, looking for adults on cordons and canes. A provisional action threshold in vineyards is 5-10 adults per vine. I emphasize the term provisional. This may go up or down as we gain further experience with this insect in our vineyards. There is often a strong edge effect with this insect, and border sprays may be able to handle the problem, without spraying the whole block.

The Pest Management Guide chapters for Commercial Vineyards, Small Fruits and Hops can be found at this link (https://www.pubs.ext.vt.edu/456/456-017/456-017.html). There are several materials listed for this time of the season, when adults are the target. Once sprays start, reassess frequently. Pay close attention to the maximum applications or amounts applied per season, and watch preharvest intervals. I would very much like to hear more about this as it unfolds at your sites.

Here is a link to my SLF page (https://www.virginiafruit.ento.vt.edu/SLF.html). There is a table linked there listing SLF materials, with PHI and seasonal max levels. There are fact sheets post for SLF for general information, management in vineyards and in residential areas.

Let me know if you would like to discuss SLF at your location.
More later,
Doug

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.