The Spotted Lantern Fly (SLF) is an invasive planthopper native to Asia, which was first detected in the US (Pennsylvania) in 2014. Its highly invasive nature warrants education and outreach to protect vulnerable crops, but given current information, cranberries are not topping the ‘risk list’.

• SLF is known to feed on over 100 different types of plants, but cranberries are not currently included on these lists.  Blueberries are listed in host-plant papers (see Worldwide Feeding Host Plants of Spotted Lanternfly, With Significant Additions From North America linked below), but not cranberries.  We can be cautiously optimistic that it could be good news for cranberry growers, but folks should still keep a close eye out as it’s possible that SLF simply hasn’t been reported from cranberry yet.  However, with the heavy SLF presence out east, I’d suspect that if there were any problems in cranberries in states like New Jersey, we would have heard reports by now.  
• Some more good news for cranberry growers: given the location of cranberry production in Wisconsin, overall SLF risk may be low.  Based on the modeling study  The Establishment Risk of Lycorma delicatula (Hemiptera: Fulgoridae) in the United States and Globally, central and northern Wisconsin were deemed to have low suitability for SLF or were unsuitable.  Things could always change over time, but Wisconsin doesn’t appear to be great SLF habitat compared to other Midwestern states.

Potential distribution of L. delicatula in the United States. Areas shaded in red, yellow, and green indicate high, medium, and low suitability, respectively. Unshaded/blank areas indicate areas that are unsuitable for L. delicatula establishment. Color figures area available in the online version only. Wakie, 2000.

Appearance:

Adult SLFs are approximately 1 inch long and ½ inch wide when resting. The insects’ forewings are light brown to grey with black spots at the base and have a grey net-like pattern at the tips. The hindwings are red with black spots at the base, have white bands near the center, and have a black net-like pattern at the tips. The heads and legs of SLF adults are black, while their abdomens are yellow with broad black bands. When resting, adults fold their wings over their bodies and appear light brown to grey with black spots. Adult female SLFs have a red spot at the tip of their abdomens. SLF egg masses are 1 to 1½ inches long and ½ to ¾ inches wide, greyish-brown, covered with a grey, waxy coating, and contain 30 to 50 eggs. First stage immature SLFs (i.e., nymphs) are wingless and black with white spots. As nymphs mature, they eventually develop red patches, but retain their white spots.

Host Range:

SLF has a wide host range and nymphs appear to feed on leaves and branches of virtually any plant they encounter, often gathering in large numbers. In the fall, adult SLFs gather in large numbers on tree of heaven/paradise tree, willow, maple, birch, poplar, tulip poplar, ash, oak, grape, apple and stone fruit trees (e.g., cherries and plums). Tree of heaven/paradise tree (Ailanthus altissima) is a preferred fall feeding host for SLF adults, as well as a preferred mating and egg laying site. This plant is an invasive species native to China that grows in disturbed sites and along roadsides. SLF damage on grape, apple and stone fruit trees is of particular concern because these plants are important agricultural crops.

Symptoms and Effects:

SLF adults and nymphs feed on a plant’s phloem (i.e., food conducting tissue), sucking the sap from young stems and leaves, and reducing the plant’s ability to photosynthesize. Affected plants often have weeping/oozing wounds on their trunks that eventually result in greyish-black discolorations. Damage can lead to weakened, withered plants, and potentially even plant death. In addition, SLFs excrete large amounts of honeydew (i.e., sugar-rich feces) which can cover stems and leaves and build up on the ground at the base of plants. Honeydew can become colonized by sooty mold fungi (see University of WisconsinExtension bulletin A2637, “Sooty Mold”, available at http://learningstore.uwex.edu) giving leaves and branches a blackish coating that can further reduce photosynthesis and contribute to plant decline and death. Oozing sap and honeydew also attract other insects such as wasps, hornets, bees, and ants.

Life Cycle:

SLF has only one generation per year and overwinters as eggs in egg masses. In the spring and early summer, eggs hatch and SLFs go through four nymphal stages (called instars). Adults begin to appear in July and August. Males and females mate multiple times and females can produce one or two egg masses University of Wisconsin Pest Alert XHT1236 Provided to you by: Revised Oct. 20, 2016 between September through November (or until they die from the onset of winter). Female SLFs lay egg masses on smooth-barked trunks, branches, and limb bases of medium to large-sized trees, as well as on smooth stone and other natural surfaces, and on man-made items such as yard furniture, cars, trucks, and farm equipment.

Scouting Suggestions:

SLF adults are poor fliers, but strong jumpers, and prefer to walk. Nymphs and adults gather in large numbers on host plants and are easy to find at dusk or at night when they migrate up and down tree trunks. SLFs are harder to find during the day as they tend to stay near the base of the host plants. Beginning in late April to mid-May, watch for nymphs on smaller plants and vines, and on any new growth on trees and shrubs. Watch for adult SLFs in late August through September, when they can be found in large numbers. Sticky tree bands can be helpful for monitoring for young SLFs, but less useful in detecting later stage immature and adult SLFs. From October through spring, watch for SLF egg masses (which can be very inconspicuous), particularly on tree of heaven.

Sources:

1. Spotted Lanternfly: XHT1236.  Christelle Guédot, UW-Madison Entomology
2. Worldwide Feeding Host Plants of Spotted Lanternfly, With Significant Additions From North America Lawrence Barringer1,3 and Claire M. Ciafré
3. Tewodros T Wakie, Lisa G Neven, Wee L Yee, Zhaozhi Lu, The Establishment Risk of Lycorma delicatula (Hemiptera: Fulgoridae) in the United States and Globally, Journal of Economic Entomology, Volume 113, Issue 1, February 2020, Pages 306–314, https://doi.org/10.1093/jee/toz259
4. https://insectlab.russell.wisc.edu/2021/08/31/spotted-lanternfly-wisconsin/

This article was posted in Cranberry, Insects and tagged Allison Jonjak, Christelle Guédot, Cranberries, insects, PJ Liesch, Spotted Wing Drosophila.