Use of prohydrojasmon to suppress Frankliniella occidentalis and tomato spotted wilt virus in chrysanthemums

We evaluated the suppressive effect of prohydrojasmon (PDJ) on Frankliniella occidentalis and tomato spotted wilt virus (TSWV) in chrysanthemums under semi-commercial conditions. Overhead sprinkling of plants with PDJ did not suppress initial colonization by released adult thrips. However, it significantly reduced subsequent feeding damage on leaves and reproduction of larval offspring. Rates of 1 and 2 L/m 2 0.8 mM PDJ equally suppressed F. occidentalis and feeding damage without phytotoxic effect on chrysanthemums, although 3 L/m 2 reduced plant growth. The PDJ had a residual effect of at least 8 days. Weekly applications suppressed the occurrence of TSWV transmitted by viruliferous adults dispersed from infection-source plants to a degree consistent with that of feeding damage, so PDJ might inhibit primary infection via disruption of feeding behavior. All our findings suggest that PDJ may offer a powerful option for the control of F. occidentalis and Orthotospovirus diseases transmitted by it in chrysanthemum greenhouses.