Laboratory bioassay was conducted to find out the impact of a green muscardine fungus, Metarhizium anisopliae (Metsch.), Sorokin (Deuteromycotina: Hyphomycetes) on an economically important cotton pest, red cotton bug Dysdercus cingulatus (Fab.) (Hemiptera: Pyrrhocoridae) under laboratory condition using cotton saplings, Gossypium hirsutum Linn. (Malvaceae). Two fungal isolates of M. anisopliae (CPRC 16 and CPRC 18) and also a standard M. anisopliae MTCC 892 were used for the present study. The present experimental results revealed that the tested strains were effective against the red cotton bug on the cotton saplings. Highest mortality (86.67 %) was observed in CPRC 18 at 1.9 x 108 spores/ml, followed by CPRC 16 (80.64 %) at 2.8 x 108 spores/ml.

Subsequently, the LC50 values were also lower (2.27 x 105) and higher 2.83 x 106) for CPRC 18 and CPRC 16 respectively. Percentage of insect infected with M. anisopliae of the former category was highest among live and dead cadavers at 80.00 and 92.30 respectively. The infected dead cadavers were attached on the upper surface of the cotton leaves, which grew very healthy. In future M. anisopliae CPRC 18 can be used to manage this sucking pest in cotton field.