Stephanitis pyrioides Scott, 1874 (Hemiptera: Tingidae) phenology in Oregon

Authors: Lee, Jana; FLORES, SALVADOR - Oregon State University; ROSETTA, ROBIN - Oregon State University; LABONTE, JAMES - Oregon State University

Submitted to: The Pan-Pacific Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2019
Publication Date: 7/1/2019
Citation: Lee, J.C., Flores, S.M., Rosetta, R., Labonte, J.R. 2019. Stephanitis pyrioides Scott, 1874 (Hemiptera: Tingidae) phenology in Oregon. Pan-Pacific Entomologist. 95(2):99-105. https://doi.org/10.3956/2019-95.2.99.
DOI: https://doi.org/10.3956/2019-95.2.99

Interpretive Summary: The azalea lace bug is a serious pest of rhododendrons and azaleas. While it has been present in the eastern U.S.A. since 1915, it was only detected in the Pacific Northwest in 2008-9. Pest control trials and pest biology has been examined in the eastern states, but little information is available about how to manage this pest in western states. Thus, we conducted a 2.3 year survey to document the life stages present at sites in the Willamette Valley of Oregon, and checked for the presence of natural enemies specializing on lace bugs. Similar to prior studies, eggs were the predominant overwintering stage in Oregon. Three generations of lace bugs were observed during monthly inspection of infested plants, and ~3.5 generations were estimated by developmental-temperature calculations. Egg hatch was observed as early as April. The egg parasitoid, Anagrus takeyanus, and predatory mirid, Stethoconus japonicus, were not detected when rearing out lace bug eggs or taking shake samples from infested leaves. These results suggest that early season management might be targeted in April – May as overwintered eggs hatch. Also, future biological control efforts should identify other effective local natural enemies or use augmentative programs.

Technical Abstract: The azalea lace bug, Stephanitis pyrioides Scott, 1874, is a serious pest of rhododendrons and azaleas. While it has been present in the eastern U.S.A. since 1915, it was only detected in the Pacific Northwest in 2008-9. While pest control trials and pest biology has been examined in the eastern states, little information is available about how to manage this pest in western states. Thus, we conducted a 2.3 year survey to document the life stages present at 3–8 sites in the Willamette Valley of Oregon, and checked for the presence of natural enemies specializing on lace bugs that are important in the East Coast. Similar to prior studies, eggs were the predominant overwintering stage in Oregon. Three generations of S. pyrioides were observed during monthly inspection of infested plants, and ~3.5 generations were estimated by degree-day (DD) calculations with 11.2°C and 33°C as the lower and upper thresholds. Egg hatch was observed as early as April at 156 DD based on a 10.2°C lower threshold. The egg parasitoid, Anagrus takeyanus Gordh, 1977, and predatory mirid, Stethoconus japonicus Schumacher, 1917, were not detected when rearing out S. pyrioides eggs or taking shake samples from infested leaves. These results suggest that early season management might be targeted in April – May as overwintered eggs hatch. Also, future biological control efforts should seek effective endemic natural enemies or augmentative programs.