Biocidal activity of two marine green algal extracts against third instar nymph of Dysdercus cingulatus (Fab.) (Hemiptera: Pyrrhocoridae)

Abstract

Seaweeds are the extraordinary sustainable resources in marine ecosystem which have been used traditionally as source of food, feed and medicine. The biological effects of thallium Hexane (HE), Chloroform (CH), Methanol (ME) and Water (AQ) extract of Ulva fasciata Delile (UF) and Ulva lactuca Linnaeus (UL) were tested against Dysdercus cingulatus (Fab.) third instar nymphs at different concentrations (100, 200, 400, 600 and 800 ppm). Tested green algae caused dose dependent mortality. The ME of UF (LC50= 313.59 ppm) and UL (LC50= 399.27 ppm) shows more nymphicidal activity at 96 hrs. It is concluded that methanol extract of both UF and UL possesses nymphicidal, antiovipositional activity, reduced fecundity, hatchability, adult longevity and relative growth rate. However, more detailed studies are essential before recommending them for pest management programme. © JBiopest.