Enhanced Mitigation and Rapid Response to Reduce Spread and Impact of Spotted Lanternfly in the United States
The spotted lanternfly (SLF; Lycorma delicatula, Hemiptera: Fulgoridae) is a phloem-feeding insect from China that was first detected in Berks County, PA in 2014 and has recently been confirmed in Virginia, New Jersey and Delaware.. In Pennsylvania, the range of this invasive species has expanded nearly 138-fold to more than 11,000 km2 in just 4 years. The host range of this invasive species is still poorly understood and there may be many forest and cultivated fruit tree species likely at risk. Also, the role of tree of heaven, Ailanthus altissima, an apparent favored host in its life cycle, is uncertain. There are no established methods for detecting spread of SLF populations besides tree banding, no phenology models to predict stage-specific development, and no established laboratory rearing methods. Therefore, Penn State University, Rutgers University, USDA Forest Service (Hamden, CT) and USDA-Agricultural Research Service (ARS) (Kearneysville, WV) are working on a collaborative Farm Bill-funded project to address some of these key knowledge gaps.
Penn State will lead field-based projects aimed at:
- developing rapid detection and monitoring methods using remote sensing technology;
- determining host tree preference and performance of SLF among life stages and the role of Ailanthus altissima as a purportedly required host plant under field conditions;
- tracking SLF movement season-long across the landscape using mark-release-recapture studies in contiguous forest; and
- assessing SLF impacts on forest tree health.
USDA-ARS will lead complementary projects in a quarantine greenhouse at Fort Detrick, MD to:
- identify risk posed by SLF feeding to key forest and cultivated fruit tree species;
- establish suitability of single and mixed host plant diets of SLF development and survivorship; and
- develop SLF rearing methods.
USDA-ARS will also initiate a project to have key Asian SLF publications translated for the SLF research/Extension/stakeholder community.
USDA Forest Service and Rutgers University will jointly:
- develop information for a stage specific phenology model
- identify conditions necessary to break egg diapause.
By addressing the key knowledge gaps identified here, new knowledge will enable Federal regulatory agencies, State Departments of Agriculture and researchers to develop enhanced mitigation and rapid response to spreading SLF populations and reduce the spread and impact of SLF in the United States.
Good phenology models based on the responses of SLF to a broad range of temperatures are needed for predicting when monitoring for SLF needs to occur, when the right stage is present for application of control methods, and what regions of the United States are likely to support SLF populations. This information is also needed to develop protocols for rearing large numbers of spotted lanternfly for use in bioassays or biological control rearing. Without an efficient laboratory rearing methodology for SLF, mass rearing of any discovered natural enemies needed for field testing or release will be limited, especially outside the infested zone. Efforts to screen pesticides are equally restricted by the resources needed to obtain the large numbers of even aged individuals from natural populations. Year-round mass rearing would allow rapid screening of many pesticides and other monitoring or control methods.
SLF has one generation per year in Korea, with nymphs emerging in May and adults appearing in July. Similar occurrence of life stages is observed in Pennsylvania, where it is also assumed univoltine. Little is known about SLF responses to temperature and the only modeling on potential range was done for Korea using CLIMEX and the current range information for populations in Korea.
Egg survival of SLF is associated with winter temperature and in laboratory rearing experiments egg hatch occurs at 56, 27, and 22 days at 15, 20, and 25 degrees Celsius, respectively. Degree day requirements for egg hatch is 355 degree days using a lower developmental temperature threshold of 8.14 Celsius but no information on biofix is included. Thus, it is currently unknown if egg hatch can occur outside of this narrow range of temperature threshold or if SLF uses specific environmental cues to hatch, such as photoperiod or chilling days. For example, SLF egg hatch was observed in Winchester, VA by D. Pfeiffer on May 9, 2018, which is 266 degree days using the parameters from available studies. This suggests that evaluation of egg hatch and nymphal development of the U.S. population is needed to develop precise phenological models and predict seasonality. The timing of egg hatch is the biofix needed to start the phenology model and the conditions needed could potentially restrict the range of this insect.
- Develop information on SLF stage-specific temperature responses needed to produce a SLF phenology model.
- Determine the abiotic conditions needed for eggs to break diapause and hatch.
- Melody A. Keena , Research Entomologist, USDA Forest Service Northern Research Station
- Anne Nielsen, Assistant Extension Specialist, Rutgers Agricultural Research and Extension Center, Rutgers University
- Last modified: April 2, 2019