Rana, V KKumar, Mukesh2023-03-172023-03-172021-11-24https://krishikosh.egranth.ac.in/handle/1/5810195334The present investigations entitiled “Studies on biology and severity of Bactrocera scutellaris on cucumber in the low hills of Himachal Pradesh” The length and breadth of eggs ranged from 0.95 to 1.25 mm with an average of 1.03 ± 0.02 and 0.20 to 0.35 mm with an average of 0.29 ± 0.01 mm, respectively. The incubation period of eggs were varied from 0.70 to 1 day long with an average of 0.84 ± 0.03 days. The length of first, second and third instar larvae were 1.20 - 1.98 mm (1.59 ± 0.09 mm), 4.50 - 7.75 mm, (6.31 ± 0.27 mm) and 7.25 to 10.75 mm (8.98 ± 0.31 mm) whereas the width was 0.15 to 0.4 mm (0.27 ± 0.02 mm), 0.90 to 1.40 mm (1.25 ± 0.05 mm), 1.25 to 2.80 mm (2.10 ± 0.15 mm). The duration of respective instars were 1.15 ± 0.09, 1.6 ± 0.10 and 3.5 ± 0.12 days. The average larval period was 7.05 ± 0.25 days, with range of 6 to 8 days. The pupa measured 5.97 ± 0.13 mm in length and 2.34 ± 0.03 mm in width. The pupal stage lasted anywhere from 7 to 9 days, with an average of 7.8 ± 0.34 days. The pupa measured 5.97 ± 0.13 mm in length and 2.34 ± 0.03 mm in width. The pupal stage lasted anywhere from 7 to 9 days, with an average of 7.8 ± 0.34 days. The pre- oviposition, oviposition and post oviposition period were 11.52 ± 0.51, 7.05 ± 0.41 and 4.47 ± 0.50 days. The sex ratio was 1.18 ± 0.06 (male: female). The total life cycle ranged from 13 to 19 days with an average duration of 15.5 ± 1.07 days. The mean fruit infestation was positively and significantly correlated with average maximum temperature (0.9261) and negatively significantly correlated with minimum average temperature (-0.1016), while rainfall was negatively and non-significantly correlated (-0.3763) with mean fruit infestation of fruit fly and average relative humidity was negatively and significantly correlated (-0.0573), with mean fruit infestation of fruit fly. Mean fruit infestation severity was positively and significantly correlated with average maximum temperature (0.8270) and average maximum temperature, was positively and non- significantly correlated with minimum average temperature (0.1260). Rainfall was negatively and non- significantly correlated (-0.1922) with Mean fruit infestation severity of fruit fly and average relative humidity was positively and significantly correlated (0.6260) while minimum relative humidity was positively and significantly correlated (0.1583) with mean fruit infestation severity of fruit fly.EnglishThesis