Effects of Freezing Lycorma delicatula Egg Masses on Nymph Emergence and Parasitization by Anastatus orientalis

Lifecycle of Anastatus orientalis (Hymenoptera: Eupelmidae) and synchrony with its host, the spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae)

Anastatus orientalis Yang & Choi (Hymenoptera: Eupelmidae), an egg parasitoid of spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae), has been documented emerging from host eggs in both autumn and spring, at the beginning and end of the period that spotted lanternfly eggs are present in the field, suggesting parasitoid-host specificity and synchrony. This study was designed to test whether, under conditions that simulate native and introduced ranges of spotted lanternfly, (a) A. orientalis has 2 and only 2 generations per year, (b) A. orientalis adults sometimes emerge when only nontarget species would be available for parasitization, and (c) emerging parasitoid adults can parasitize unhatched host eggs in the spring. Parasitized spotted lanternfly eggs were collected in 2019 and 2020 from Beijing, China and in 2020 and 2021 from Yantai, China. They were shipped for laboratory study in growth chambers programmed to simulate temperature and daylength for collection locations in China and in the invaded range in Pennsylvania, United States. Anastatus orientalis had a flexible lifecycle depending on environmental conditions and possibly genetic makeup, with 1-3 generations per year, and parasitoid emergence was not always synchronous with host egg availability. Additionally, given the cooler temperatures in Pennsylvania, autumn parasitoid emergence was often delayed until late October or November, no progeny were produced, and parasitoid populations died out. Anastatus orientalis does not exhibit host synchrony characteristics that would make it a good candidate for a classical biological control program.

Life history traits of spotted lanternfly (Hemiptera: Fulgoridae) when feeding on grapevines and tree of heaven

The invasive planthopper, spotted lanternfly (SLF), Lycorma delicatula (White) (Hemiptera: Fulgoridae), feeds on a broad range of plants including species of economic importance such as grape. Although SLF feeds on wild and cultivated grape, the effect of grapevines on the insect's life history traits is unknown. This study examined the effect of cultivated Concord grapevines (Vitis labrusca) and the insect's preferred host tree of heaven (TOH), Ailanthus altissima, on SLF development, survival, reproduction, and body mass. Newly emerged nymphs were allowed to feed on either TOH, Concord grapevines or a mixed diet of Concord grapevines plus TOH through adulthood until death. Development, mortality, and oviposition of paired adults were tracked daily to calculate the SLF rate of development, survival, and reproduction among treatments. When feeding exclusively on Concord grapevines, SLF was able to develop and reproduce but had higher mortality, slower development, and produced fewer eggs. SLF fed on the mixed diet of grapevines plus TOH exhibited faster nymphal development, laid more eggs, and had higher body mass compared with those fed only on grape or TOH. SLF had greater survival when fed on either the mixed diet or on TOH alone. We conclude that Concord grapevines are a poor-quality host for SLF, but when combined with TOH, SLF fitness increases above that of feeding on TOH alone. This study supports the elimination of TOH as a part of SLF vineyard management practices.