An effective trap for spotted lanternfly egg masses

Abstract

Spotted lanternfly (SLF) (Lycorma delicatula (White)), an invasive planthopper discovered in Pennsylvania, USA in 2014, continues to spread and is now present in 14 states with substantial infestations present in seven states. Population projections using adult SLF trapping or visual counts are not reliable due to the transient, migratory behavior of the adults which make population forecasts difficult. Another approach to population monitoring is utilization of the stationary egg mass stage, but counting small cryptic egg masses throughout the canopy of large trees in dense woodlots is arduous and prone to error. After several field seasons testing various trapping configurations and materials, we have identified an efficient, simple, low-cost trap termed a 'lamp shade trap' that is attached to the lower trunk area of an SLF host tree. SLF females readily enter the trap and lay eggs on the thin, flexible trap surface. A vertical trap orientation was superior, and the most productive woodlots yielded an average of 47 and 54 egg masses per trap, and several traps had over 100 egg masses. There were 1,943 egg masses tallied from 105 traps placed at six locations in two states. Egg mass counts in the area above and below the traps and on nearby control trees yielded very few egg masses in comparison. Selection of trees 15 to 20 cm in diameter for trap placement is most efficient, yielding good egg mass abundance while minimizing the amount of trap material used. The lamp shade trap has potential as an effective tool to identify SLF in new areas, gauge SLF population levels in woodlots and can also be used to collect and monitor egg masses for research purposes.

Keywords: Ailanthus altissima; Lycorma delicatula; egg masses; spotted lanternfly; trapping.

Figure 1

Study sites where lamp shade egg mass traps were deployed. Map used by permission from www.amaps.com.

Figure 2

Fabric pieces arranged on a TOH as indicated by arrows, (A) camo fabric wrapped around the trunk at 1.4 m and burlap fabric wrapped around the base of the tree, (B) hanging burlap fabric stapled along the top edge.

Figure 3

Tube hotels placed at ground level next to the base of a TOH, (A) cardboard tubes, (B) metal duct tubes.

Figure 4

Set of cellulose traps, (A) without burlap, (B) with burlap, (C) rusty metal without burlap, (D) rusty metal with burlap, (E) metal with Rust-Oleum^® spray, (F) metal sandwich wrapped with landscaping fabric with spacers in between.

Figure 5

Half pipe rusty metal traps, (A) with burlap, (B) without burlap, (C) starfish formation around the trunk of the tree.

Figure 6

Triangle traps, (A) covered and uncovered with roofing, (B) covered and uncovered with gaffing tape, (C) covered and uncovered with cork. Each trap had one side with slightly overlapping strips of material and another side with a single smooth surface.

Figure 7

Hexagonal trap with roofing material and cork as egg laying substrates attached to A. altissima.

Figure 8

Lamp shade egg mass trap constructed on A. altissima.

Figure 9

Average SLF egg masses laid in lamp shade traps oriented vertically and horizontally, by site. Vertically oriented traps were statistically different at each study site (range P < 0.027 to P < 0.001; Wilcoxon Rank Sum Test) except at the Easton site where no horizontal traps were set up.

Figure 10

Average SLF egg masses (± SE) laid per m² of trapping area on all vertically oriented traps, grouped by tree diameter. DBH classes were not statistically different (P = 0.66; Kruskal-Wallis ANOVA).