Evaluation of foliar insecticide treatments for thrips control in onion, 2025

Thrips are a significant problem for vidalia onion growers during spring in southern Georgia. Thrips can damage leaves, which can impact the development of bulbs and reduce yields. They can also spread bacterial diseases to healthy onions, and favor the development of center rot, which is a common disease in Georgia onions. In 2025, an insecticide efficacy trial was conducted to evaluate various chemicals for the control of thrips in onions at the Onion and Vegetable Research Center, Tattnall County, Georgia. Onions, hyb. ‘Plethora’, ‘1014’, ‘1011’, ‘369’, ‘Sweet’, ‘Superex’ were transplanted on 9th December 2024 into 4 rows per bed at approximately 4–6 inches between plants and maintained with standard cultural practices. Four applications of insecticide were made on 3rd, 12th and 27th March and 9th April respectively. Foliar insecticide treatments were applied with a CO2 hand sprayer delivering 32 gallons/ acre at 30 psi with 4 TX-18 hollow cone tips per bed. Products used included: Spinetoram (Radiant SC, Corteva), Bifenthrin (Brigade 2EC, FMC), a pyrethroid (IRAC Group 3A); Exirel (Cyazypyr active, FMC, IRAC Group 28, anthranilic diamide); Torac (Nichino America, Inc, Tolefenpyrad) and an unsprayed check. All spray treatments included the adjuvant MSO 0.5% v/v at 10 ml per 2-L spray. Each treatment was replicated 4 times, in a completely randomized block design. For each plot, the total numbers of thrips per 10 plants were counted and preserved in 70% ethanol. The preserved samples were later identified as species using a stereoscopic microscope (Olympus SZH10, max. magnification: 140×).