Spirotetramat causes an arrest of nematode juvenile development

Abstract

Spirotetramat (Movento™, Bayer CropScience) (SPT), an effective insecticide, has also demonstrated potential activity as a nematicide. No significant effects on hatching rates of Caenorhabditis elegans, Meloidogyne incognita or Heterodera glycines were observed when eggs were soaked in a maximum concentration of 105 ppm of technical grade spirotetramat-enol (SPT-enol), the active form in plants. Synchronised first-stage juveniles of C. elegans soaked in SPT-enol concentrations as low as 30 ppm demonstrated arrested juvenile development with calculated EC95 of 44-48 ppm. Single applications of formulated SPT (Movento 240SC) were applied to plant foliage at the labelled insecticidal rate of 87.6 g a.s. ha−1 at 1-week intervals on soybean plants inoculated with H. glycines or tomato plants inoculated with M. incognita in glasshouse tests. SPT consistently inhibited nematode development to reproductive maturity when applied at 1-2 weeks after inoculation. Optimal SPT application timings coincide with early stages of root infection, when nematodes are still in vulnerable juvenile stages.