~ 1836 ~ Journal of Entomology and Zoology Studies 2018; 6(2): 1836-1839 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2018; 6(2): 1836-1839 © 2018 JEZS Received: 19-01-2018 Accepted: 20-02-2018 Roomi Rawal Department of Entomology, CCS Haryana Agricultural University, Hisar, Haryana, India KK Dahiya Department of Entomology, CCS Haryana Agricultural University, Hisar, Haryana, India Adesh Kumar Krishi Vigyan Kendra, Jhansi (U.P.), India Correspondence Roomi Rawal Department of Entomology, CCS Haryana Agricultural University, Hisar, Haryana, India Bollworms infestation in cotton genotypes on the bolls and locule basis under unsprayed condition Roomi Rawal, KK Dahiya and Adesh Kumar Abstract The present experiment was carried out on seven varieties of cotton under unsprayed condition. Experiment was carried out at research farm of cotton section, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar. Bollworms infestation was recorded at 90, 120 and 140 days after sowing and finally at harvest. At 90, 120 and 140 days after sowing significantly higher boll damage was observed on non-Bt variety H-1236 and minimum was recorded in BIOSEED- 6588 and it was superior over all other genotypes. And at harvest time damage was recorded in open bolls and locule basis. Highest infestation in open bolls and locule basis was recorded in non-Bt genotype H-1236 and lowest was found in Bt genotype Bioseed-6588 that was (28.63%), (6.70%), (1.27%) and (0.40%) respectively. Yield was recorded highest in Bt genotypes as compared to non-Bt genotypes. Keywords: Bollworms, Bt, Non-Bt genotype, infestation and yield Introduction Cotton is one of the most important cash crops of India due to agricultural as well as industrial importance. Cotton hampered by 1326 species of insects-pest from sowing to maturity in different cotton growing areas of the world and 162 species have been reported on the cotton crop in India, out of which 24 species have attained pest status [3] . Among these, the bollworm complex American bollworm; Helicoverpa armigera (Hubner), spotted bollworm; Earias insulana (Boisduval) and pink bollworm; Pectinophora gossypiella (Saunders) are the most important pests of cotton crop. Cotton yield is highly reduced due to attack of these bollworms. For controlling these pests a large number of insecticidal sprays were applied, which is harmful for environment and human health. The unseen residue of chemicals is continuously degraded the health of human, animals and plants. Bt (Bacillus thuringiensis) cotton is the best option to manage these bollworms and reduce the number of insecticides sprays. In Bt cotton toxins from a soil bacterium, Bacillus thuringiensis (Bt) are widely used for control of these insect pests from decades. Transgenic cotton, expressing the delta- endotoxin gene from the bacterium B. thuringiensis is a compelling answer to control cotton bollworms [11] . Although BG I cotton expressing Cry1Ac provided good control of bollworms but its replacement with BG II expressing dual genes Cry 1Ac and Cry 2Ab proteins has given the improved efficacy against bollworm complex and enhanced spectrum of activity against bollworms. Therefore the present experiment was carried out to study the effect of Bt and non- Bt cotton genotypes on bollworms infestation. Material and Methods The present experiment was carried out at Chaudhary Charan Singh, Haryana Agricultural University, Hisar, during the crop season 2014-2015 in order to study the bollworms damage in cotton crop. The study was carried out under unsprayed conditions on seven genotypes of cotton which were procured from Department of Genetics & Plant Breeding and Private Sector. Out of these seven genotypes, five were Bt with different gene construct (BIOSEED- 6588, NECH-6, JK-1947, SP-7007 and RCH-134) and two were non Bt (HHH-223 and H- 1236). Sowing was done on May, 2014 using standard package of practices [1] with randomized block design (RBD). Observations on bollworms infestation were recorded from the bolls and locules of five plants from each genotype per plot. Bolls were plucked from randomly selected five plants per replication per treatment and infestation of bollworms was recorded.