Thrips species (Thysanoptera) on strawberry, persimmon and grape in the Ga¨²cho Highlands, Rio Grande do Sul State, southern Brazil
Pinent SMJ1,2, da C Pinent CE3, Botton M2, Redaelli LR1
1 Departmento Fitossanidade, Universidade Fed Rio Grande Sul, Porto Alegre, RS, Brazil.
2 Departmento Entomologia, Empresa Brasileira de Pesquisa Agropecu¨¢ria Uva e Vinho, Bento Gonçalves, RS, Brazil.
3 Departmento Estat¨ªstica, Pontificia Universidade Catolica do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Correspondence: silviapi@portoweb.com.br
A survey of thysanopterans occurring on persimmon, grape and strawberry in orchards of the Ga¨²cho Highlands region (Serra Ga¨²cha) (24¡ã09¡¯S 51¡ã31¡¯W), north-western Rio Grande do Sul, southern Brazil, was carried out to study thrips incidence, specially pest species. Seasonal samples were collected on persimmon and grape, and monthly from September/2004 to February/2005 on strawberry, which showed higher incidence of thrips. In each orchard, 10 plants, flowers, shoots and fruits were manually collected on a randomised way. In the lab, thrips were separated from the plants, preserved in AGA solution, mounted on microscopy slides and identified. From a total of 794 individuals, 365 adults and 429 immatures, ten thrips species were identified. From those, only the Frankliniella occidentalis (n = 45) occurred on the three crops, showing a higher degree of polyphagy and causing damage on grape. Frankliniella schultzei was the most abundant (n = 147) and was found causing damage by feed only on strawberry, followed by Frankliniella gemina (n = 106). Of the species considered as crop pests we found F. occidentalis, F. schultzei and Thrips tabaci (n = 9) on strawberry and Heliothrips haemorrhoidalis (n = 5) on grape. However, according to Mound (2005), T. tabaci has been losing this condition and some of the damage attributed to thrips by the farmers may be caused by other insects as aphids or mites and also by a deficit of bee pollination or virus incidence. Overall 75,3% occurred inside the flowers, being 16,2% on leaves and 8,5% on fruits. On fruit, they were observed on the bottom, under the sepals, and on leaves under the surface. The knowledge of the species associated to different crops is fundamental for the implementation of integrated pest management with emphasis on natural biological control. (Mound LA. 2005. Annual Review of Entomology 50: 247¨C69).
