~ 1516 ~ Journal of Entomology and Zoology Studies 2017; 5(4): 1516-1519 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2017; 5(4): 1516-1519 © 2017 JEZS Received: 23-05-2017 Accepted: 24-06-2017 Abhilisa Mudoi Assam Agricultural University, Jorhat, Assam, India Purnima Das Assam Agricultural University, Jorhat, Assam, India Lakshmi Kanta Hazarika Assam Agricultural University, Jorhat, Assam, India Correspondence Abhilisa Mudoi Assam Agricultural University, Jorhat, Assam, India Pathogenicity of Beauveria bassiana (Bals.) Vuill. (KR855715) against Periplaneta americana (L.) Abhilisa Mudoi, Purnima Das and Lakshmi Kanta Hazarika Abstract A laboratory experiment was conducted, to study the pathogenicity of Beauveria bassiana (KR855715) against different instars and adults of Periplaneta americana (L.) (Blattodea : Blattidae) in the Physiology Laboratory, Department of Entomology, Assam Agricultural University Jorhat-13 during 2014-2016. The study revealed its pathogenicity on both instars and adults of the insect. B. bassiana at 1x10 7 conidia per ml caused cent percent mortality in first and second instars at second and third days after treatment respectively. However, mortality varied from 64 -72 per cent, 52 - 68 per cent and 16 – 36 per cent mortality in 3 rd , 4 th and 5 th instars respectively between third and ninth days after treatment. In adults mortality varied from 12 – 26 per cent between third and ninth days after treatment. Keywords: adults, Beauveria bassiana, instars, pathogenicity, Periplaneta americana 1. Introduction Periplaneta americana (L.) (Blattodea : Blattidae) is the largest as well as ubiquitous and obnoxious grubby domestic pest that spread throughout the tropical countries of the world [1],[2] . They cause unappealing damage to household materials and stored products. They are highly damaging pests worldwide in terms of potential health problems and costs for pest control including their ability to move from sewers into homes and commercial establishment [2] . Managing P. americana with chemicals is easier but due to their close association with human beings managing the pest with mere application of pesticide is not an efficient method for its control. Beauveria bassiana (Bals.) Vuill., a naturally occurring entomopathogenic fungus has occupied an important place in pest management [3] . It is the most versatile parasite capable of attacking their host and penetrates the host in various developmental stages [4] . This entomopathogenic fungi has been effectively used in controlling several crop pests viz. Sweetpotato weevil, Cylas formicarius (F.); Whitefly, Bemisia tabaci (Genn.); Cotton leaf worm, Spodoptera littoralis (Boisd.); Cabbage butterfly, Pieris rapae (L.); Dicladispa armigera (Olivier) [5, 6, 7, 8] . They play an important role in biological control of insect pests population [9] . They constitute the largest group of insect pests control among the microorganisms [10] . Managing P. americana with chemicals is easier. But these are found in close association with human beings and chemicals may have fatal reactions on human beings. So managing the pest with mere application of pesticide is not an efficient method for controlling this pest. However there is scanty of literature on pathogenicity of B. bassiana on P. americana Keeping this in view, the present investigation was designed to study the pathogenicity of B. bassiana against P. americana. 2. Materials and Methods 2.1 Laboratory rearing of Periplaneta americana (L.) The present experiment was conducted in the Physiology laboratory, Department of Entomology, Assam Agricultural University, Jorhat-13 during 2014-2016.The mass rearing of P. americana was done in wooden rearing cages (90×60 cm) containing belljars (Borosil; 32 cm long, 22 cm dia.) inside which stacks of wooden plates (13.5cm×10.5 cm) were placed for rearing adults. Whereas rearing of nymphs were done inside plastic containers (8 cm length and 8.5 cm dia.). Crushed dog biscuits as food material and moist sponges as water source were provided separately in petriplates (9 cm dia.) inside the belljars for adults and in small plastic corks (1.5 cm length, 2.5 cm dia.) inside the plastic containers for nymphs.