VERMA, S CSHARMA, PRIYANKA2019-09-202019-09-202019-08http://krishikosh.egranth.ac.in/handle/1/5810128779ABSTARCT The present investigations entitled “Studies on spatial distribution and parasitisation potential of Aphelinus asychis Walker against green peach aphid, Myzus persicae (Sulzer) in Bell pepper” were conductedduring the year 2018-2019 at Dr. Y S Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh. During the study period, M. persicae and its parasitoid, A. asychis and A.matricariae populations followed negative binomial distribution throughout the season. Taylor’s power equation for M. persicae, A. asychis and A.matricariae were σ² = 6.97X1.531 (R2 = 0.931), σ² = 3.013X1.098 (R2 = 0.867) and σ² = 4.29X1.282 (R2 = 0.90) during 2018-2019, respectively. Iwao’s patchiness regression was X* = 45.12 + 1.333X (R2 = 0.853), X* = 1.485 + 1.375X (R2 =0.784) and X* = 5.406 + 1.195X (R2 =0.767) during 2018-2019, respectively. Optimum number of samples required for the green peach aphid, M. persicae, A. asychis and A.matricariae were 261.1, 332.5 and 474 during 2018-2019, respectively at 20 per cent precision level. The egg to adult emergence period, pre-oviposition period, oviposition period, post-oviposition period, fecundity, sex ratio (F:M) was 16.23±0.45, 1±0.00, 6.6±0.40, 1.6±0.40 days, 58.8 eggs/female, 1:0.97, respectively. The highest adult longeivity (male:16.5 and female:17.75 days) was observed with 70 per cent honey solution sand lowest with distilled water (male:8.75 and female:9.75 days). The true generation time (T), the true intrinsic rate of increase (rm), doubling time, finite rate of increase (λ) and the net reproductive rate of the parasitoid, A. asychis with second instar of M. persicae was 22.02 days, 0.16 females/female/day, 2.52 days, 1.174 feamles/day and 33.32 feamles/feamle, respectively. A. asychis parasitized 20.29 per cent during 2018-2019. A hyperparasitoid, Alloxysta victrix parasitizing A. asychis between 20.00 to 27.27 per cent was recorded during 2018-2019. A. asychis was able to parasitize all the nymphal instars of M. persicae with preference to the second instar (53%) followed by first instar (46%), third instar (44%) and fourth instar (33%). A. asychis exhibited a Type-II functional response to the second instar nymph of M. persicae with attack rate and handling time was 0.034 ± 0.004 h-1 and 1.32 ± 0.23 h, respectively for the Holling disc equation. Hence, A. asychis can be utilized as one of the components in the integrated pest management programme of green peach aphid, under protected condition in Himachal Pradesh. Signature of Major Advisor SennullThesis