Reporte Anual Duraznillo de Agua 2020

HERNÁNDEZ, M. CRISTINA; FALTLHAUSER, ANA C.; SOSA, ALEJANDRO J.

2019-07-01/2020-07-01

Biológica

Rec.Nat.Renov.-Conservacion y preservacion

The studies on the very damaging flea beetle (Lysathia sp.) are devoted to clarifying the identity of the species. The possibility that there is more than one species involved is being considered, for which we are working on obtaining more biological, genetic and morphological information (Fig. a). This will also contribute to the knowledge of the genus that has a control agent Lysathia sp. for Myriophyllum aquaticum already released. Basic studies were started with the sap feeder plant hopper Pissonotus paraguayensis (identified by Dr. Ana M. Remes Lenicov, La Plata Museum, Argentina) (Fig. b). There is no biological information on this species, therefore a rearing method was obtained to then perform first host plants screening. In a new survey trip in Buenos Aires province, the following species of the stem miner weevil, Tyloderma, were collected: T. natator, T. elongatum, and T. obrieni (Fig. c, d and e). Identification of the specimens were carried out by the specialist G. Wibmer and A. Marvaldi (La Plata Museum, Argentina) (Fig. f). Because there is a large diversity of weevil species on water primrose, correct identification was key before proceeding to testings. The flea beetle and weevils are considered promising candidates since they?ve been collected on the south region of Buenos Aires, making them candidates more likely to resist wider temperature ranges. This trade has still to be evaluated. Samples of the water primrose rust have been sent to a specialist for identification and its potentiality to be reproduced. This rust damages leaves and stems that due to the consumption of nutrients, drastically reducing the quantity and quality of the plant (Fig. g). This type of pathogen is usually highly specific and are known to be successful control agents.The diversity of Ludwigia in rice fields of Argentina has been evaluated recording eight species, some of them, never reported in that specific environment. One species is L. decurrens, also described as a rice weed in California, U.S. The coverage that this weed represents in rice fields and therefore crop loss is being analysed.