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!
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.
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
