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.

Integrating Trissolcus japonicus (Ashmead, 1904) (Hymenoptera: Scelionidae) into Management Programs for Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae) in Apple Orchards: Impact of Insecticide Applications and Spray Patterns.

Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae) is an invasive species in the United States, where it has caused significant damage to specialty crops, including apples. While integrated pest management techniques have been developed for H. halys in apple, including spray application techniques, it is unknown how these techniques affect foraging, adventive Trissolcus japonicus (Ashmead, 1904) (Hymenoptera: Scelionidae), and its offspring. In this study, egg masses (unparasitized and 2 and 7 day parasitized pre-treatment) were placed in apple orchards in treated and untreated locations that received full block insecticide applications or reduced application techniques, including border row or alternate row middle applications. Bifenthrin, thiamethoxam + λ-cyhalothrin, clothianidin, and methomyl were evaluated. Egg masses were retrieved 24 h after spray applications. For 2 and 7 day parasitized pre-treatment, adult T. japonicus emergence was recorded from each egg mass. For unparasitized egg masses, T. japonicus females were given 24 h to forage and oviposit on post-treatment egg masses with female survivorship, and adult emergence from egg masses was recorded. Female survivorship was significantly lower on post-treatment egg masses retrieved from areas receiving bifenthrin applications. Emergence from post-treatment egg masses was affected by thiamethoxam + λ-cyhalothrin, bifenthrin, and methomyl in some treated areas, whereas less impact was observed on 2 and 7 day pre-treatment parasitized egg masses in general. These data provide further insights into H. halys management and the potential impact of T. japonicus in sprayed orchard agroecosystems.