©JBiopest. 346 140 Bioefficacy of entomopathogens against red cotton stainer JBiopest. 5(2): 140-143 JBiopest 5(1): 1-6 Efficacy of fungal entomopathogens against red cotton stainer, Dysdercus cingulatus Fabricius (Hemiptera: Pyrrhocoridae) P.Vinayaga Moorthi 1* , C. Balasubramanian 1 , Pasco B. Avery 2 , A. Najitha Banu 1 and T.Kubendran 1 ABSTRACT The efficacy of entomopathogenic fungi [Beavueria bassiana (Bb08, Bb10) and Isaria fumosorosea (Ifr)] isolated from different regions of Southern Tamil Nadu, India was assessed against red cotton stainer, Dysdercus cingulatus. All the tested isolates showed 100% mortality. The B. bassiana isolates such as Bb08, Bb10 and an I. fumosorosea isolates exemplified the significant mortality among the isolates tested. LC 50 , LC 90 and correlation coefficient were calculated for mortality. Bb08, Bb10 and Ifr isolates unveiled the lowest LC 50 (5.9 x 10 5 , 6.6 x 10 5 and 2.6 x 10 5 ) and LC 90 (1 x 10 9 , 7.3 x 10 8 and 3.9 x 10 8 ) value compared to the isolates tested. Highly significant correlation co- efficient was observed in the isolates Bb08, Bb10 and Ifr Key words: Beauveria bassiana, Isaria fumosorosea, native isolates, mortality. INTRODUTION Cotton, Gossypium hirsutum (Linn.) is the most economically important natural fiber material in the world. It is widely known as “The King of Fibers”. The economy of many countries depends up on cotton production. Nearly 24% of the total cotton production in the world is cultured from India. In recent years, cotton production is declining due to the infestation of insect pests and diseases. Of these sucking pests are deleterious during the early stage of cotton growth. Pests such as stainer, jassids, aphids, whiteflies and thrips are constituted as important pests of cotton (Uthamasamy et al., 2004). One of the dreadful pests of cotton in southeast Asian countries is Dysdercus cingulatus (Fab.) (Hemiptera:Pyrrhocoridae) (Kohno and Bui Thi, 2004). It is distributed in all the cotton growing regions of India (Sahayaraj and Ilayaraja, 2008). It is commonly known as red cotton bug and is an important pest of lady’s finger, sambhal, hollyhock etc. If not managed properly, both nymph and adult insects damage the cotton bolls and leaves severely. Although it has been controlled by many synthetic insecticides because of the high residual effect of chemical insecticides, the immediate need for sustainable eco-friendly pest management has been felt very strongly providing an impetus to research and development of microbial pesticides. Entomopathogenic fungi are widely available biological control agents (BCAs) for controlling agricultural pests (Wraight et al., 2001). Nowadays, hundreds of fungi have been identified and are being developed as biological control agents for various insects. Species from the genera Beauveria, Metarhizium, Isaria and Lecanicillium and others have been registered and commercialized in the United States. (Environmental Protection Agency, 2009). Isaria fumosorosea (Wize) (=Paecilomyces fumosoroseus) is a fungal biocontrol agent with the potential for controlling several insect pests (Dunlap et al., 2005). The species Isaria fumosorosea and Isaria farinosa are well-known entomopathogenic fungi with a worldwide distribution in temporate and tropical zones and there is a relatively wide host range which makes them interesting agents for the development of biocontrol methods. Hence, the present study aims to evaluate the potential biocontrol agent I. fumosorosea against D. cingulatus. MATERIALS AND METHODS Entomopathogenic fungi, Beauveria bassiana [Bb08 (Accession No. HQ848783) and Bb10 (Accession.No. HQ416713)] and Isaria fumosorosea isolates used in this investigation were isolated from rhizosphere soil of different