Novel insecticide for green stink bug management in pomegranates, 2024 Open Access

Chinavia hilaris (green stink bug) is a common Hemipteran pest of pistachio and almond nuts. They use their piercing and sucking mouthparts to puncture into the nut flesh, leaving behind blackened spots and gummosis (a sap-like substance). In California, green stink bugs commonly overwinter as adults, have 2 generations per year, and are active in nut crops from Mar through nut harvest in early Oct. They then switch to feed on other plants, such as pomegranates, and overwinter from Nov through Jan. Without broad-spectrum dormant insecticide applications, overwintering populations can become active early in the next season (Feb-Mar), restarting the cycle of crop damage. Here, we compared the efficacy of isocycloseram (PLINAZOLIN technology) and bifenthrin (Brigade 97WSB) to untreated control for managing green stink bugs in a pomegranate orchard. Brigade 97WSB is currently used for management in pomegranate. PLINAZOLIN technology is not yet registered with the EPA, and this trial was conducted to assess whether the product is safe and effective for managing green stink bugs on pomegranate trees. This trial was conducted in a 0.4-acre plot of 16-yr-old single-tree “Wonderful cv” pomegranate trees with a row spacing of 18 × 18 feet at the Kearney Agricultural Research and Extension Center in Parlier, CA. PLINAZOLIN technology at 2.06 oz/acre and Brigade 97WSB at 32 oz/acre were mixed with a nonionic adjuvant (Dyne-Amic) at a rate of 0.5% V/V and applied at a rate of 100 gallons per acre using standard 2-gallon sprayers (Root-Lowell Manufacturing Co.) on 13 Sep. The experimental layout was a randomized complete block design with 3 replicate blocks (rows). Each row included each treatment (PLINAZOLIN technology, Brigade 97WSB, Control), with one treatment applied to one tree. Forty-eight hours after treatment application, one branch was enclosed in a 5-gallon organdy bag (3 branches per tree), and 2 stink bugs were placed in each bag. The trial duration was 66 days, bags were checked weekly for stink bug mortality and replaced only when mortality was recorded for all 3 bags on a single tree. The number of days stink bugs lived after exposure to the treatment was recorded as days after exposure (DAE).

At 7 DAE, stink bugs exposed to Brigade 97WSB had the lowest survival (6.98%) compared to PLINAZOLIN technology (21.30%) and the untreated check (65.00%). At 14 DAT, there was no difference in survival between Brigade 97WSB (7.50%) and PLINAZOLIN technology (11.11%). At 21 DAT, no stink bugs survived the PLINAZOLIN technology exposure, and only 6.25% survived exposure to Brigade 97WSB (Table 1). Mortality was recorded for all stink bugs exposed to Brigade 97WSB or PLINAZOLIN technology at 28 DAE. These results suggest no difference between Brigade 97WSB and PLINAZOLIN technology activity against stink bugs during the first 14 DAE, that total mortality occurs sooner on trees treated with PLINAZOLIN technology (21 DAE) compared to Brigade 97WSB (28 DAE).¹

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