Abstract

ARAYA, JAIME E.; MERINO, CARLOS; SANTIBANEZ, FELIPE  and  SAZO, LUIS. Ring spots by feeding of Frankliniella occidentalis (Thysanoptera: Thripidae) on white table grapes. Rev. Colomb. Entomol. [online]. 2014, vol.40, n.1, pp.1-6. ISSN 0120-0488.

Seven trials were conducted during 2006-2008 in the Central Valley of Chile to verify that Frankliniella occidentalis feeding after flowering induce ring spots on white table grapes shortly before harvest, resulting in economic losses up to 50% in some areas. Treatment of spinosad at 5.76 g ai/hL were applied by dipping grape bunches or by spraying, across a range of fruit growth stages including bunch closure and veraison, and were stopped at early harvest. Ring spot incidence in bunches at harvest reached 70-99% in the untreated control compared to 1-6% in treatments where bunch closure was treated and protected from thrips. Applications starting at veraison resulted in 22- 55% incidence in bunches, while those started at early harvest time were equal in damage to the control. In all trials, results achieved by protecting against thrips feeding only at bunch closure were equal to multiple applications at all fruit growth stages. Damage levels in another trial during 2007-2008 for thrips control during bunch closure found that a single application at this stage can provide commercial ring spot russet reduction. However, of the six sites selected in 2006 due to ring spot russet damage previously, only three had significant damage in the untreated control. The variable appearance of ring spot russet should prompt growers to monitor thrip populations in bunches at early bunch closure or to do calendar sprays during this stage to avoid damage.

Keywords : Spinosad; Thrips feeding damage; Western flower thrips; White table grapes.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )