Survival and development of Lycorma delicatula (Hemiptera: Fulgoridae) on common secondary host plants differ by life stage under controlled conditions

Short- and long-term effects of season-long infestation of Lycorma delicatula (Hemiptera: Fulgoridae) on young apple (Malus domestica) and peach (Prunus persica) trees

Lycorma delicatula White, commonly called spotted lanternfly, is an invasive fulgorid that was first detected in the United States in Pennsylvania in 2014 and has spread across Eastern states. Lycorma delicatula is a phloem feeder, and feeding of persistent populations can cause wilt and dieback in host plants. Vineyards in infested regions have experienced vine loss, where damage has been attributed to L. delicatula. Nymphal and adult lifestages have been observed on cultivated apple and peach trees, but the feeding effects of this pest on these crops have not been quantified. Here, we caged young potted apple and peach trees and infested them with 50 nymphal or 25 adult L. delicatula per plant for 3 months and tracked plant health. Horticultural measurements including trunk diameter, height, leaf drop, and photosynthesis rates were recorded before, during, and after the infestation. To evaluate the long-term effects of infestation, all apple and peach trees were removed from pots and planted in an orchard block where their phenology, growth, and physiology could be evaluated the following growing season. Short- and long-term measurements showed no significant differences in apple tree health between infested and noninfested trees. There was a significant reduction in the growth of trunk diameter in peach trees during exposure to early-instar nymphs; infested peach trees also had significantly increased frost damage to buds the following spring. However, there were no long-term impacts on peach growth and physiology. These results indicate that L. delicatula likely will not be a major threat to these deciduous fruit crops.

Development and survivorship of Lycorma delicatula (Hemiptera: Fulgoridae) on cultivated and native Vitis spp. (Vitales: Vitaceae) of the Eastern United States

As Lycorma delicatula (White) continues to spread across the United States, more winegrapes are potentially susceptible to damage from this pest. Lycorma delicatula, spotted lanternfly, is primarily associated with Ailanthus altissima (Mill.) Swingle, a tree from its native range that is now globally distributed. While L. delicatula is a known pest of cultivated Vitis spp. in South Korea, its relationship with the specific grape species grown in the United States is unclear. This study assessed L. delicatula survivorship and development on 5 Vitis species, including 2 winegrape V. vinifera L. varieties, 'Pinot Noir' and 'Chardonnay', Concord grape, Vitis labrusca L., River grape, Vitis riparia Michx., and muscadine grape, Vitis rotundifolia Michx. var. 'Carlos'. A diet of A. altissima served as a positive control. Lycorma delicatula provided with a diet of V. riparia or V. vinifera 'Pinot Noir' yielded the highest survivorship and fastest rates of development among grape diets and were statistically equivalent to those provided with A. altissima. Vitis rotundifolia did not support L. delicatula growth past the third-instar life stage, indicating this species is a poor host for the early development of this pest. Our results indicate that both V. riparia and V. vinifera are favorable hosts for L. delicatula and may provide the means for this insect to invade and establish in new regions.

Assessing acceptability of wild and cultivated hosts of Lycorma delicatula (Hemiptera: Fulgoridae) under semifield conditions

Lycorma delicatula White (Hemiptera: Fulgoridae) is an invasive phloem feeder with a broad host range that includes both hardwood trees and cultivated temperate fruit crops. Here, we evaluated acceptability of wild hosts, A. altissima and Juglans nigra L. (Fagales: Juglandaceae) and cultivated hosts Vitis vinifera, Malus domestica (Rosales: Rosaceae), and Prunus persica L. Batsch (Rosales: Rosaceae) to L. delicatula under field conditions. Fluorescent-marked early instar nymphs, late instar nymphs, or adult L. delicatula were released at the base of single potted host plants and the number of individuals retained was recorded over 24 h. Paired choice trials with A. altissima and another host plant were conducted. Individuals retained on or moving between plants were recorded over 24 h. Sentinel A. altissima, J. nigra, V. vinifera, M. domestica, and P. persica potted plants were deployed at 5 sites and the number of L. delicatula present on each plant was recorded weekly. In single and paired host trials, early instars and adults were generally retained in higher numbers on A. altissima and V. vinifera, and late instars were retained on A. altissima and J. nigra. Significantly more L. delicatula were present on sentinel A. altissima compared with other host plants, except J. nigra during the period when late instars were the most prevalent lifestage in the field. These results indicate that wild hosts such as A. altissima and J. nigra are likely supporting establishment of L. delicatula populations, and that presence of cultivated V. vinifera may contribute to population establishment and growth.