Symphylan control in grass grown for seed, 2022

Authors: BATEMAN, CHRISTOPHER - Oregon State University; WILLETTE, ALISON - Oregon State University; KAUR, NAVNEET - Oregon State University; Dorman, Seth; BUCKLAND, KRISTINE - Oregon State University; ANDERSON, NICOLE - Oregon State University

Submitted to: Arthropod Management Tests
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2023
Publication Date: 2/23/2023
Citation: Bateman, C., Willette, A., Kaur, N., Dorman, S.J., Buckland, K., Anderson, N.P. 2023. Symphylan control in grass grown for seed, 2022. Arthropod Management Tests. 48(1). Article tsad013. https://doi.org/10.1093/amt/tsad013.
DOI: https://doi.org/10.1093/amt/tsad013

Interpretive Summary: The garden symphylan, Scutigerella immaculata Newport, is a serious soil arthropod pest whose root-feeding limits yield potential and survival of several high-value crops in Western Oregon during crop establishment. The broad host range includes grass for seed, vegetable seed crops, and other specialty crops such as peppermint and strawberries. Previously, symphylans were primarily managed using Lorsban (chlorpyrifos) incorporated in the soil before planting (PPI). Now that chlorpyrifos is being phased out, growers have limited chemical control options (pyrethroids only) as no clear path for registration exists for alternate chemistries. In this study, we evaluated the efficacy of new and existing insecticides and identified potential candidates to support the product registration process. One pre-existing symphylan-infested area was identified at Oregon State University’s Hyslop Research Farm to conduct an efficacy trial in tall fescue grown for seed. Five insecticide treatments and an untreated control were assessed. Upon soil application, treatments were incorporated with tillage in the topsoil, and tall fescue was planted the same day. Data were recorded on symphylan abundance using the potato bait method by deploying two bait stations per plot at 10, 14, and 25 days after treatment (DAT). Plant density was measured in each plot at 45 DAT by counting the number of plants per 3.2 linear ft of a single row. Overall, Capture LFR was a promising candidate for symphylan suppression; however, no statistical differences were detected in plant density among treatments.

Technical Abstract: The garden symphylan, Scutigerella immaculata Newport, is a serious soil arthropod pest whose root-feeding limits yield potential and survival of several high-value crops in Western Oregon during crop establishment. The broad host range includes grass for seed, vegetable seed crops, and other specialty crops such as peppermint and strawberries. Previously, symphylans were primarily managed using Lorsban (chlorpyrifos) as pre-plant incorporation (PPI). Now that chlorpyrifos is being phased out, growers have limited chemical control options (pyrethroids only) as no clear path for registration exists for alternate chemistries (e.g., Mocap and Ethoprop). In this study, we evaluated the efficacy of new and existing insecticides and identified potential candidates to support the product registration process. One pre-existing symphylan-infested area was identified at Oregon State University’s Hyslop Research Farm to conduct an efficacy trial in tall fescue grown for seed. Five insecticide treatments and an untreated control were arranged in a randomized complete block design with four replicates. Upon soil application, treatments were incorporated with tillage in the topsoil using a tractor-mounted rototiller, and tall fescue (var. ‘Titanium G-LS’) was planted the same day. Data were recorded on symphylan abundance using the potato bait method by deploying two bait stations per plot at 10, 14, and 25 days after treatment (DAT). Plant density was measured in each plot at 45 DAT by counting the number of plants per 3.2 linear ft of a single row. Overall, Capture LFR was a promising candidate for symphylan suppression; however, no statistical differences were detected in plant density among treatments.