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Increased efficacy and extended shelf life of spinosad formulated in phagostimulant granules against Spodoptera frugiperda

Author:
Tamez‐Guerra, Patricia, Tamayo‐Mejía, Fernando, Gomez‐Flores, Ricardo, Rodríguez‐Padilla, Cristina, Damas, Gabriela, Tamez‐Guerra, Reyes S, Ek‐Ramos, Maria J, Williams, Trevor
Source:
Pest management science 2018 v.74 no.1 pp. 100-110
ISSN:
1526-498X
Subject:
Bacillus thuringiensis, Spodoptera frugiperda, active ingredients, application rate, bioassays, chemical treatment, corn, corn flour, field experimentation, grain yield, granules, larvae, mortality, pest control, phagostimulants, shelf life, spinosad, temperature
Abstract:
BACKGROUND: Spinosad is recommended for control of Spodoptera frugiperda (J.E. Smith) larvae; its application with phagostimulants may reduce the quantity of active ingredient required for effective pest control. Spinosad (Tracer®) was formulated in maize flour matrix granules and three field tests compared 10–100 ppm a.i. granules (equivalent to 0.24–2.4 g a.i. ha–¹) with Tracer as an aqueous spray (200 ppm a.i.; 60 g a.i. ha–¹), and the recommended application rates of Bacillus thuringiensis, a chemical and an untreated controls were performed. RESULTS: The 100 ppm spinosad granules resulted in similar S. frugiperda mortality compared with the chemical treatments in all three field trials, and resulted in a significantly higher maize grain yield compared with unformulated and control treatments (4141 vs. 2857 and 2407 kg ha–¹, respectively) that was similar to the chemical treatment (3778 kg ha–¹). Bioassays of granules stored at room and cold temperatures showed that after 5 years, ∼ 70% of the original activity remained (OAR) of spinosad when formulated as granules. Nevertheless, after 9 years, efficacy was reduced (26.2% and 48.5% OAR) at both room (25 °C) and refrigerated temperatures (4 °C). CONCLUSION: Spinosad, in the granular phagostimulant formulations evaluated in this study, had advantages measured as high efficacy and long shelf life. © 2017 Society of Chemical Industry
Agid:
5873179