10/10/2025
I have 500 grapevines and have plf with no damage
Spotted lanternflies are certainly a nuisance, but research suggests they rarely kill plants--with two major exceptions: cultivated grapes and Ailanthus altissima, known as tree of heaven (an invasive w**d).
What does that mean for Virginia's vineyards?
Heavy, uncontrolled feeding can result in death of grape vines, with surviving vines failing to set fruit. It is not hard to prevent that level of loss, however, but at the cost of increased insecticide use.
In Pennsylvania, insecticidal applications in affected vineyards increased from 4.2 applications in 2016 to 14.0 in 2018 (insecticide costs increasing from $54.63/acre in 2016, to $147.85/acre in 2018). Each of these vineyards reported spraying an insecticide every 3-5 days during peak SLF activity.
Nymphal populations are not as problematic as adults when present. Insecticides directed against other pests may suffice for nymphs. Be vigilant when adults are active from late August through October.
More about grape vines and SLF: https://www.pubs.ext.vt.edu/content/pubs_ext_vt_edu/en/ENTO/ENTO-323/ENTO-323.html
More about SLF myths (including the idea that they regularly kill trees): https://www.psu.edu/news/agricultural-sciences/story/spotted-lanternfly-lore-penn-state-experts-clear-falsehoods-about-pest
