Phytoplasma Sub-Groups infecting Insects Collected in Damaged Strawberry Fields.

To study 16Sr I-C phytoplasma (clover phyllody subgroup) transmission in cultivated areas where symptomatic strawberry plants show autumnal flowers with sepals instead of petals (virescence), and produce fruits with leaf-like tissues instead of seeds (phyllody), samples from 71 plants and from 2811 individuals of Trialeurodes vaporariorum (Westw.) and Empoasca spp. insects were analysed, using molecular tools. Four symptomatic strawberry plantlets collected in the autumn of 2002, and one Trialeurodes vaporariorum (Westw.) sample collected in June 2003, tested positive for 16SrI-C subgroup phytoplasmas. The plant and insect samples collected after autumn 2003 in the same two fields where the new strawberry plants showed absence of virescence and phyllody symptoms, tested negative for 16Sr I-C phytoplasmas using molecular analyses.