Evaluation of drench treatments against cotton seed bug infesting hibiscus, 2025

Authors: Zilnik, Gabriel; MIDDLETON, ERIC - University Of California Agriculture And Natural Resources (UCANR)

Submitted to: Arthropod Management Tests
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2026
Publication Date: 7/11/2026
Citation: Zilnik, G.L., Middleton, E.G. 2026. Evaluation of drench treatments against cotton seed bug infesting hibiscus, 2025. Arthropod Management Tests. 51(1). Article 80. https://doi.org/10.1093/amt/tsag080.
DOI: https://doi.org/10.1093/amt/tsag080

Interpretive Summary: A researcher from USDA-ARS Pest Management and Biocontrol unit in collaboration with a researcher from the University of California Agriculture and Natural Resources conducted a trial testing soil drench insecticides against cotton seed bug on potted hibiscus by placing insects on bagged plants, treating the soil with Acephate, Safari, Altus, or water, and counting live and dead insects over time. Acephate caused the most dead insects right after treatment and showed higher dead counts later, but it was only statistically better than the untreated plants at 3 days after treatment; by 15 days Safari and Acephate were similar. Altus performed worst, with the most live insects and lowest mortality during the first month. When plants were re-infested at 32 days, Safari behaved like the untreated plants and was dropped, while Acephate continued to show more dead insects through 69 days, though overall long-term control was limited.

Technical Abstract: We evaluated the performance of drench insecticides against cotton seed bug (CSB) on hibiscus at the Center for Applied Horticultural Research (Vista, San Diego County, CA). One-gallon potted hibiscus plants with at least one flower were enclosed in fine mesh bags and infested with 10 CSB collected from the Palomar College campus (San Marcos, San Diego County, CA). After 24 h, each plant received a soil drench of Acephate 97UP, Safari 20 SG, Altus, or water as an untreated check. Treatments were applied through the mesh using a plastic syringe (Model 301035; NDC, Nashville, TN) delivering 60 mL of solution mixed at maximum field rates. Each treatment was replicated across ten plants. Plants were irrigated to saturation before treatments were applied and once per week afterwards. We counted live and dead CSB at 3, 7, 15, and 32 days after treatment (DAT). To evaluate efficacy against reinfestation, at 32 DAT we reinfested the plants treated with Acephate, Safari, or water. Each plant received 15 CSB, and each treatment was replicated six times. We checked plants for live and dead CSB at 35 DAT. We continued to evaluate Acephate and the untreated check through 69 DAT. Data were analyzed with a Kruskal–Wallis test. Mean separation at a = 0.05 was evaluated with Dunn tests using a Benjamini–Hochberg correction. We observed no differences in live CSB counts between the untreated check and Acephate through 32 DAT (Table 1). At 3 DAT, Acephate produced the highest number of dead CSB, and this pattern continued through 32 DAT; however, mortality was only statistically higher than the untreated check at 3 DAT. By 15 DAT, there were no statistical differences between Safari and Acephate for either live or dead CSB. Altus consistently produced the lowest mortality and the highest live counts throughout the first month of evaluation. At 35 DAT, there was no difference between Safari and the untreated check, so we discontinued measurements for that treatment (Table 2). Acephate had the highest number of dead CSB at 35 DAT, and this pattern continued through 69 DAT.