Reporte Anual Duraznillo de Agua 2015

HERNÁNDEZ, M. CRISTINA; FALTLHAUSER, ANA C.

2014-07-01/2015-07-01

Biológica

Rec.Nat.Renov.-Conservacion y preservacion

MethodsThe identity of Argentine populations of Ludwigia grandiflora, L.g.subsp.hexapetala, L.peploides subsp. montevidensis, L.p. subsp. glabrescens and two new subspp. were assessed in the laboratory. We carried out several collections trips in the East of Argentina, roughly between 25º43?S and 38º41?S. Morphological and cytological traits were compared to characterize and describe the taxa. The phenology of L.g.subsp. hexapetala throughout the year was described by mean the greenhouse rearings. (Hernández, Cuello, Faltlhauser, in preparation).A variety of insect guilds feeding on L. g. subsp. hexapetala, have been described. Five stem miner weevils were selected to be studied because of the damage produced by their larvae. A promising biological control agent, the thrips Liothrips ludwigi, was studied (Hernandez, Cuello, Faltlhauser, unpublished).ResultsField studies in Argentina have identified a large guild of insects, with 17 species that feed on this host. Five stem miner weevils were selected to be studied because of the damage produced by their larvae. A promising biological control agent, the thrips Liothrips ludwigi, was studied and is ready for quarantine work in the US. Exhaustive morphological and cytological studies were carried out on Perennial water primrose and Creeping water primrose, and their subspecies, in search of reliable characters to distinguish them for field and laboratory work.Exhaustive morphological and cytological studies were carried out with L.grandiflora, L.peploides and subsp. to obtain reliable characters to distinguish among them.A new agreement has been signed with our cooperators in Albany to bolster research on this weed, looking to introduce natural enemies into quarantine facilities. Also, a 5-year research proposal is at present being negotiated with cooperators in the UK and France, where water primrose is considered one of the worst environmental weeds.Water primroses are an aggressive and invasive group of aquatic species, forming extensive mats that impair water flow and shoreline activity. They are perennial forbs with creeping stems that root freely at the nodes, growing in mud or shallow waters. They have floating and erect aerial stems, connected by running stems on or under the ground. They reproduce by seeds and vegetatively.These species have the potential to dominate the shoreline vegetation if introduced to lakes, river, ponds, ditches or streams. This species is very difficult to control once established.The main invasive taxa, Ludwigia grandiflora, L.g. ssp hexapetala, and L. peploides, are distributed in many states of East Coast, around the Gulf of Mexico, and in all the West Coast states (USDA, NRCS. 2009).The cell-content feeder Liothrips ludwigi (Thysanoptera), was described as new species (Zamar and Hernández 2013). A rearing method was developed; the biology, specificity and damage were studied concluding that it is a good candidate for further studies in California (Hernández, Cuello, Faltlhauser, in preparation).