Reporte Anual Duraznillo de Agua 2016

HERNÁNDEZ, M. CRISTINA; FALTLHAUSER, ANA C.

2015-07-01/2016-07-01

Biológica

Rec.Nat.Renov.-Conservacion y preservacion

Invasive species that established successfully in a new environment are released of natural controls that exist in its native range and this effect was named by Keane and Crawley (2002) as enemy release hypothesis. Based on this concept, the biological control utilizes specific herbivorous insects to control exotic weeds, restoring the natural association plant-insect that they have in the native range. In aquatic environments the biological control method has advantages over other control methods giving that control agents can disperse and find the target host in spite of the land difficulties. An important aquatic weed in the US and many countries in Europe is the waterprimrose, Ludwigia grandiflora subsp. hexapetala; it is a South American plant species that in Argentina has 19 species of herbivorous insects associated (Hernández & Cabrera, 2014). From them, Liothrips ludwigi Zamar (Thysanoptera: Phlaeothripidae) was described as a new species and selected for further studies (Zamar & Hernández, 2013). Nymphs of L. ludwigi significantly reduced the biomass, the stems length, and the number of leaves produced by killing the apical and axilar meristems (See previous Ann. Rep.). They only developed on L. grandiflora, L. peploides and its evaluated subspecies. Damage tests showed that 8 and 15 nymphs per stem significantly affected the development of the plants producing shortened stems and fewer leaves; in addition, 15 nymphs per stem diminished the aerial biomass and killed all the buds. These studies were complemented with the following trials presented here, designed to obtain the field host range of L. ludwigi and to discriminate its preferences between to Ludwigia species as hosts.