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ThesisItem Open Access Bioefficacy of natural products and biopesticides against Pieris brassicae L. infesting cauliflower(palampur, 2020-10-17) Shashni, Ishan; Sharma, Prem ChandThe present investigations entitled “Bioefficacy of natural products and biopesticides against Pieris brassicae L. infesting cauliflower” were undertaken during the year 2019-20 in Department of Entomology, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur. Intrinsic toxicity of Agniastra and Brahmastra, azadirachtin, Bacillus thuringiensis, Beauveria bassiana, diafenthiuron and spinosad was worked out against neonate larvae of P. brassicae by leaf dip method of bioassay. Based upon LC50 values, the LC50 values of spinosad was found to be minimum (0.034 ppm), followed by diafenthiuron (0.059 ppm), azadirachtin (1.031 ppm), Bt (5.214 ppm), B. bassiana (1.723 x 108 cfu g/lit.), Agniastra (3508.232 ppm) and Brahmastra (3720.866 ppm). Evaluation of natural products, biopesticides and insecticides against P. brassicae on cauliflower (var. Maharani F1 Hybrid) was carried out under field conditions. Prophylactic sprays of natural products and azadirachtin were started 30 days after transplanting whereas application of Bt, B. bassiana, diafenthiuron and spinosad was started with the appearance of pest and repeated at an interval of 10 days. On the basis of 4 sprays, minimum larval population per plant was observed in diafenthiuron (3.19), followed by spinosad (3.30), azadirachtin (7.20), Bt (7.60), Agniastra (10.61), B. bassiana (11.16) and Brahmastra (11.39). The highest per cent reduction in larval population over untreated check was observed in spinosad (69.16%), followed by diafenthiuron (68.31%), azadirachtin (49.83%), Bt (47.81%), Agniastra (37.19%), Brahmastra (35.95%) and B. bassiana (35.48%). Cauliflower curd samples were collected from diafenthiuron (0.05%) and spinosad (0.015%) treated plots at 0 (2 hrs), 1, 3, 5 and 7 days after 3rd spray. The residues were determined by HPLC. The average recovery of diafenthiuron was 84.61 per cent and it was 84.56 per cent for spinosad from fortified samples of cauliflower curds. Limits of quantification (LOQ) for diafenthiuron and spinosad were worked out to be 0.033 and 0.011 mg/kg, respectively. Initial residues of diafenthiuron were 0.5144 mg/kg which dissipated to 0.3418, 0.2331 and 0.0339 mg/kg after 1, 3, and 5 days of application, respectively. Initial residues of spinosad were 0.4669 mg/kg which reduced to 0.2504, 0.1207 and 0.0603 mg/kg after 1, 3, and 5 days of application, respectively. Half-life values of diafenthiuron and spinosad were calculated to be 1.94 and 2.23 days, respectively. Safety intervals of 2 days for diafenthiuron and 10 days for spinosad are suggested for safe consumption of cauliflowerThesisItem Open Access Efficacy of bioformulations against cutworm, Agrotis spp. (Lepidoptera: Noctuidae)(palampur, 2019-07-15) Joshi, Manish kumar; Verma, K. S.The present investigation entitled “Efficacy of bioformulations against cutworm, Agrotis spp. (Lepidoptera: Noctuidae)” was undertaken during 2018-2019 in the Department of Entomology, CSK HPKV, Palampur to assess the intrinsic toxicity of different bioformulations viz., Dashparni ark, Neemastra, Agniastra, Brahmastra and garlic+ ginger+ mint mixture at concentration ranges from 2.5 to 40 per cent against the first, second and third instar larvae of A. ipsilon by leaf dip methods of bioassay. Based on LC50 values, the order of toxicity of bioformulations against first, second and third instar was observed as: Dashparni ark (8.28, 9.82, 11.69%) > Brahmastra (10.38, 11.58, 15.08%) > Agniastra (11.19, 13.21, 17.32%) > Neemastra (14.53, 15.43, 20.40%) > garlic + ginger + mint mixture (16.66, 19.01, 23.04%, respectively). The feeding inhibition (FI) studies of different bioformulations concentration ranges from 1.5 to 24 per cent were evaluated against the fourth, fifth and sixth instar larvae of A. ipsilon. Based on FI50 values, the order of feeding inhibition of bioformulations tested against the fourth, fifth and sixth instar larvae was observed as: Dashparni ark (5.11, 5.53, 7.08%) > Brahmastra (5.54, 5.76, 7.29%) > Agniastra (5.76, 6.17, 7.46%) > Neemastra (6.29, 6.67, 7.85%) > garlic + ginger + mint mixture (6.90, 7.39, 8.89%, respectively). Laboratory studies revealed that at recommended concentration (10%) of different bioformulations used against fourth instar larvae impaired the normal development of A. ipsilon by prolonging the larval period of fourth, fifth and sixth instar i.e. 3.55, 5.50 and 8.65 days in Dashparni ark as compared to control 2.45, 4.50 and 7.65 days, respectively. In Dashparni ark, there was 7.84 per cent increase in pupal period over control, reducing male and female longeivity, shortening the oviposition period and reducing the fecundity by 13.3 per cent in Dashparni ark i.e. 1085 eggs as compared to 1250 eggs in control. Evaluation of bioformulations against A. ipsilon in pot experiment under laboratory conditions revealed that the application of bioformulations (10%) in the potato seedling tray reduced the plant cut by fourth instar larvae to 69.24 per cent in Dashparni ark followed by Brahmastra (61.53%), Agniastra (49.24%), Neemastra (41.53%) and garlic + ginger + mint mixture (29.24%) over control. Based on the outcome of the present study, it was concluded that organic products have potential in causing mortality in the early stages of larval development besides impairing growth and development of later instar larvae. Among five organic products, Dashparni ark was observed to be the most effective treatment against the test insect.ThesisItem Open Access Bioecology and management of rice leaf folder, Cnaphalocrocis medinalis (Guenee) infesting paddy in Himachal Pradesh(Palampur, 2017-06-27) Chhavi; Sharma, Pawan K.The present investigation entitled “Bioecology and management of rice leaf folder, Cnaphalocrocis medinalis (Guenee) infesting paddy in Himachal Pradesh” was undertaken in the Department of Entomology, CSKHPKV, Palampur and Rice and Wheat Research Centre, Malan during 2014-2016. Under laboratory conditions, C. medinalis completed three generations from August to mid-December. The life cycle of C. medinalis consisted of four distinct stages viz., egg, larva, pupa and adult, each having an average duration ranging between 3.70-4.50, 17.50-20.50, 7.00-7.50 and 6.40-7.40 (female); 2.50-3.30 (male), respectively, during different generations. The fertility parameters worked out for first, second and third generation resulted in the net reproductive rate (R0 ) of 29.16, 17.94 and 17.72 female eggs per female with the corresponding true generation time of 37.06, 37.99 and 39.38 days, respectively. The intrinsic rate of increase (rm) was maximum in the first generation (0.091) and minimum in the third generation (0.073). The field collected adults of last generation when reared under laboratory conditions to study the survival of pest, failed to lay eggs. However, a few individuals of C. medinalis larvae survived in winter till January on paddy plants and weeds and a limited feeding was observed during this period. Survey for the incidence of C. medinalis and its associated natural enemies in four locations viz., Sundernagar, Nurpur, Jogindernagar and Palampur of Himachal Pradesh was conducted during 2015 and 2016 at different time intervals. The pest appearance was noticed in the second fortnight of July at Nurpur, Palampur and Jogindernagar. Whereas, at Sundernagar, the pest activity initiated during first fortnight of July and population of adults was at its peak in the first fortnight of September in all the four locations. From the correlation studies between adult catch and abiotic factors, it was concluded that the temperature (maximum and minimum) favours the C. medinalis build-up. However, RH (maximum and minimum) and rainfall had a negative impact on C. medinalis abundance. During survey, Cotesia cypris (Nixon) was found to be the most dominating larval parasitoid associated with C. medinalis. Fifty natural enemies were encountered in paddy ecosystem of all the four locations, out of which twenty four were found associated with C. medinalis. Spiders viz., Araneus pseudosturmii (Yin et al.), Micropholcus fauroti (Simon) and Runcinia ghorpadei (Tikader) were recorded for the first time from India. Based upon the Shannon index, diversity of natural enemies was maximum at Palampur (2.58-2.65) and minimum at Nurpur (1.52-1.89). The leaf damage and losses inflicted to paddy due to different release levels of C. medinalis viz., 2, 4, 6, 8, and 10 larvae per hill released at panicle initiation stage revealed that maximum leaf infestation was 24.48 per cent at highest release level (10 larvae/ hill) and lowest (6.94%) at release level of 2 larvae per hill and per cent avoidable losses varied from 0.94-28.93 per cent. Among forty three genotypes evaluated against C. medinalis, thirty three genotypes were found moderately resistant, nine as moderatey susceptible and one as susceptible. None of the genotypes was found to be free from leaf folder damage. Among the six treatments of Trichogramma chilonis, maximum control was achieved when 1,50,000 parasitized eggs per hectare were released. However, this treatment was found to be at par with 1,00,000 and 1,25,000 parasitized eggs per hectare. Out of six insecticides and one biopesticides evaluated against C. medinalis, flubendiamide (24 g a.i./ ha), indoxacarb (30 g a.i./ ha) and lambda-cyhalothrin (12.5 g a.i./ ha) were found to be efficacious. However, biopesticide, Bt (1.5 kg/ ha) was found to be least effective for the control of pest. Incremental output input ratio was highest in case of lamba-cyhalothrin and lowest in BtThesisItem Open Access Seasonal Abundance and Management of Insect-Pests in Garden Pea(CSKHPKV Palampur, 2020-10-13) PATHANIA, SHILPI; Kumar, SurjeetStudies were conducted at CSKHPKV, Palampur, Himachal Pradesh (India) during 2018-19 and 2019-20 to record seasonal incidence of insect-pests of garden pea and to evaluate bioefficacy of various organic products, indigenously prepared from the byproducts of Indian cow and locally available plant leaves, and a commercial formulation of azadirachtin (Neembaan) against them. Pea leaf miner, Chromatomyia horticola (Goureau) (Family: Agromyzidae) and pea aphid, Acyrthosiphon pisum (Harris) (Family: Aphididae) were found to infest garden pea (variety PB-89) grown under different farming practices viz., Organic, Natural-1, Natural-2, Integrated and Conventional, which mainly differed on the basis of agro-inputs used for maintaining soil fertility. Different farming practices significantly influenced the seasonal incidence of the insect-pests. Overall average extent of pea leaf miner infestation was lowest in Integrated (7.47%) followed by Natural-1 (8.77%), Organic (10.34%), Conventional (11.56%) and Natural -2 (14.96%). The population counts of the pest also differed significantly on the crop raised under different farming practices. Aphid population (no./5 plants) was lowest in Organic (5.44) followed by Conventional (7.31), Natural-1(8.83), Integrated (9.23) and Natural-2 (11.01). Incidence of pea leaf miner showed significant positive correlation with temperature (max and min) whereas aphid population had significant positive correlation with sunshine. Different organic products viz., Agniastra, cow urine, Darekastra, Dashparni, Lantana extract, Tamarlassi and azadirachtin when applied after establishment of pea leaf miner infestation, as curative measures, resulted into significantly low levels of pea leafminer infestation compared to those in untreated control. After three sprays, average reduction in the extent of pea leaf miner infestation in different treatments varied from 9.71 to 40.57 per cent over control. Maximum reduction over control was recorded in Agniastra (40.57%), followed by azadirachtin (39.59%) and Dashparni (27.27%). Average reduction in the extent of infestation over control after seven sprays varied from 12.60 to 50.99 per cent among different treatments when their application was started just on the appearance of the pest, as prophylactic measures. Maximum reduction over control was observed in azadirachtin (50.99%) followed by Agniastra (39.05%) and Tamarlassi (37.77%). Agniastra, azadirachtin and Dashparni also resulted into significantly low population of the aphid compared to control; however, different treatments did not show any significant influence on parasitization of the aphid by different parasitoids. Per cent increase in yield of green pods obtained in different treatments over control varied from 3.12 to 42.01, maximum was in azadirachtin (42.01%) followed by cow urine (30.53%) and Agniastra (29.48%).ThesisItem Open Access STUDIES ON NATURAL ENEMY COMPLEX OF APHIDS INFESTING OILSEED BRASSICAS(CSKHPKV. Palampur, 2020-01-30) SONI, SAURBH; Surjeet, KumarStudies on natural enemy complex of aphids infesting oilseed Brassicas were carried out to find the distribution and abundance of aphid species and associated natural enemies in different parts of the state. The field experiments were undertaken during the rabi season of 2015-16, 2016-17 and 2017-18 at the Experimental Farm of the Department of Entomology, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur on mustard variety RCC-4 and the data on the population build-up of aphids and their associated natural enemies were recorded at weekly interval. At other locations of the state, the observations were recorded at fortnightly interval during rabi 2016-17 and 2017-18. The crop was found to be infested with all the three aphid species viz. mustard aphid, Lipaphis erysimi (Kaltenbach), cabbage aphid, Brevicoryne brassicae (Linnaeus) and green peach aphid, Myzus persicae (Sulzer). L. erysimi appeared early in the season and remained active for a longer duration. B. brassicae activity started late in the season and reached the peak towards the maturity of the crop. M. persicae appeared for a shorter duration and its population was scarce at all the locations. Three natural enemies i.e. coccinellids, syrphids and one parasitoid, Diaeretiella rapae M‟Intosh were found to be associated with the aphid species. They appeared late in the season and their peak population did not synchronize with peaks of aphid population and thus were unable to check the aphid population. Correlation coefficients indicated that the temperature favoured the build-up of aphid population and their natural enemies while rainfall exerted negative impact. The population of coccinellids was negatively correlated with the population of L. erysimi and M. persicae while, positive correlation with B. brassicae was observed. On the other hand, population of syrphids was found to be positively correlated with aphid population. Regression analysis revealed that none of the weather parameter alone was responsible for the population build-up of aphids and associated natural enemies. In order to know the biological control potential of the aphid parasitoid D. rapae, biological and behavioural characteristics were studied in the laboratory using M. persicae, B. brassicae and L. erysimi as host. The parasitoid successfully completed its life cycle on different instars in all the aphid hosts. It was longer in early instars compared to that in later instars. Oviposition period, post-oviposition period, fecundity (number of eggs laid/female/day) and total fecundity (total number of eggs laid/female) of D. rapae parasitizing nymphs of different age groups (1-2 days and 4-5 days old) of M. persicae, B. brassicae and L. erysimi were studied and the results showed that age of the host at the time of oviposition by the parasitoid significantly affected the duration of oviposition and fecundity of the parasitoid. Older nymphs (4-5 days old) of the aphids were able to defend themselves against ovipositing females of the parasitoid more effectively than the younger nymphs (1-2 days old). Immature survival of the parasitoid, D. rapae was found to be highestxii in the third instar (85.81+10.31%) of M. persicae, B. brassicae (83.70+5.62) and fourth instar (87.67+14.48) of L. erysimi. Highest survival was observed in older instars than in younger instars. A female-biased sex ratio was found for the parasitoid with mean values of 79.99, 73.38 and 79.32 per cent for M. persicae, B. brassicae and L. erysimi, respectively. Adult longevity of D. rapae was found to be significantly longer for females in comparison to that of males in all the aphid hosts. Mean longevity of adult females of D. rapae was significantly longer while parasitizing nymphs of younger age groups (1-2 days) in comparison to older age groups (4-5 days). Among different host plants tested, M. persicae reared on capsicum, B. brassicae reared on cabbage and L. erysimi reared on mustard was found to be the best host for D. rapae on the basis of high mean fecundity, high parasitization (%), female biased sex ratio and the shortest time required by the parasitoid for completion of total developmental period. Host and parasitoid sizes were determined based on the length of their hind tibia and it was longest in M. persicae, followed by B. brassicae and L. erysimi. The adults of D. rapae emerged from M. persicae were the largest (males= 0.626 mm and females= 0.689 mm), followed by adults emerged from B. brassicae (males= 0.539 mm and females= 0.565 mm) and L. erysimi (males= 0.516 mm and females= 0.521 mm), respectively. Host stage preference of D. rapae on different instars of three aphids was studied in choice and nochoice preference tests. Second instar of M. persicae was the most preferred in both choice and no-choice tests. The parasitoid showed higher preference towards third instar nymphs of B. brassicae and second instar of L. erysimi in both choice and no-choice tests, respectively. D. rapae exhibited type II functional response to all the three aphids. The per capita parasitization and search efficiency of the parasitoid were observed to decrease with increase in parasitoid density. Similarly, the search efficiency of the parasitoid gradually decreased with the increase in the parasitoid density. It was concluded from the study that D. rapae is effective biological control agent which can be mass produced on aphids infesting oilseed Brassicas for utilization in augmentative biological control. The study can be helpful in further standardizing the protocols for mass rearing of the parasitoid.ThesisItem Open Access Evaluation of natural products and biopesticides against Helicoverpa armigera (Hubner) on tomato(CSKHPKV. Palampur, 2020-08-28) Jamalli, Omid; Verma, K. S.The present investigation entitled “Evaluation of natural products and biopesticides against Helicoverpa armigera (Hubner) on tomato” was undertaken during 2019-2020 in the Department of Entomology, CSK HPKV, Palampur to assess the intrinsic toxicity of different natural products and biopesticides viz. Brahmastra, Neemastra, Agniastra and Neem (azadirachtin), Beauveria bassiana, Metarhizium anisopliae, Bacillus thuringiensis var. kurstaki (Btk) and nuclear polyhedrosis virus of H. armigera (HaNPV) against the first and second instar larvae of H. armigera under laboratory conditions by the leaf dip method of bioassay. Based on LC50 values, the order of toxicity of natural products against first and second instar was observed as: Brahmastra (8.75, 11.62%) > Agniastra (9.61, 11.99%) > Neemastra (13.24, 16.21%) respectively). The LC50 values of azadirachtin (7.59, 9.85 ppm respectively) were observed against first and second instar. The feeding inhibition (FI) studies of different natural products concentration ranges from 1.25 to 20 per cent were evaluated against the third, fourth, fifth and sixth instar larvae of H. armigera. Based on FI50 values, the order of feeding inhibition of natural products tested against the third, fourth, fifth and sixth instar larvae was observed as: Brahmastra (2.92, 3.80, 4.20, 6.61%) > Agniastra (3.72, 4.55, 5.11, 7.76%) > Neemastra (3.46, 4.46, 5.28, 7.01%), respectively. While the FI50 values of azadirachtin against these instars was calculated to be 6.70, 8.83, 20.54, 27.21 ppm, respectively. Based on LC50 values, B. bassiana was found more effective against first and second instar larvae with LC50 values of 1.8x104 and 3.1x104 conidia/ ml, respectively as compared to M. anisopliae (3.0x104 and 5.8x104 conidia/ ml, respectively. Among biopesticides, the mortality was highest 66.67 and 53.33 percent, respectively to third and fourth instar larvae in case of HaNPV at concentration 3.0x106 PIBs/ ml after 120 h of treatment. The mortality to third and fourth instar larvae was recorded 63.33 and 56.66 per cent, respectively with B. thuringiensis var. kurstaki at concentration 7.5x106 spores/ ml after 120 h of treatment. Interaction effect of Brahmastra with different biopesticides was studied against third instar larvae of H. armigera and maximum additive effect was observed between Brahmastra and B. bassiana with 2.61 χ2 value.ThesisItem Open Access Bioecology and Management of Maladera insanabilis (Brenske) in Himachal Pradesh.(CSK HPKV, Palampur, 2019-09) Gupta, Ritesh Kumar; Chandel, R.S.The beetles of Maladera species were collected from host trees and on UV and VL light traps at Kullu and Palampur during 2018-19. The Sericini beetles accounted for 22.45 and 33.40 per cent during March–September, and leading species were M. insanabilis, Maladera thomsoni, and Maladera sinaeivi. At Palampur, M. insanabilis, M. thomsoni and M. sinaeivi comprised 46.62-49.51, 38.57-41.02 and 7.52-11.7 per cent on light traps, whereas at Kullu, these species accounted for 29.75-34.63, 50.65-58.36 and 6.23-9.09 per cent of total Sericini beetle catch, respectively. The catches of M. insanabilis and M. thomsoni were 25-31.25 and 31.25-76.07 per cent higher on UV traps as compared to VL traps. On host trees, M. insanabilis and M. thomsoni were most predominant species at Palampur, and Kullu, respectively. To study food preference of beetles, toon and peach were found to be the most preferred host for M. insanabilis and M. thomsoni beetles in multi-choice tests. The biology of M. insanabilis and M. thomsoni was studied in laboratory at Palampur. The average length x width of newly laid eggs of M. insanabilis and M. thomsoni was recorded to be 1.16 ± 0.01 x 0.83 ± 0.03 mm and 1.14 ± 0.02 x 0.73 ± 0.04 mm. There are three larval instars, and the body lengths of the fully fed I-III instar grubs of M. insanabilis measured 3.08-4.43, 7.73-7.98 and 11.29-13.03 mm and the average width of head capsule was 0.91±0.01, 1.68±0.03 and 2.65±0.05 mm. The width of head capsule ranged from 0.85-0.99 mm. The fully fed I-III instar grubs of M. thomsoni measured 2.98-4.21, 7.15-7.45 and 8.53- 9.15 mm, and width of head capsule averaged 0.89±0.01, 1.23±0.01 and 1.91±0.04 mm, respectively. Duration of the first, second and third instar grubs was 20-25, 23-28 and 180-190 days in M. insanabilis. In M. thomsoni, the first, second and third instar grubs occupied 18-20, 20-24 and 174-189 days, respectively. Total larval period was recorded to be of 225-243 and 212-233 days for M. insanabilis and M. thomsoni, respectively. The detailed description of the labrum, clypeus, mandibles, epipharynx, maxillae, legs, spiracles and rasters of the third instar grubs is given with the help of suitable diagrams. The rasters of M. insanabilis and M. thomsoni have a single, transverse row of spines arranged in a crescent shape. In M. insanabilis, the length x width of pupae was recorded to be 12.04 ± 0.39 x 6.81 ± mm, whereas in M. thomsoni, the length x width of pupa ranged from 10.81 ± 0.18 x 6.49 ± 0.07 mm. The pupal period was 13.20 ± 1.61 days and 11.60 ± 1.48 days. The adult formation occurred during May in M. insanabilis, and in April for M. thomsoni. The beetles of M. insanabilis are reddish-brown and in case of M. thomsoni, yellowish brown to light brown in colour. The females (8.32 x 5.38mm - 4.47 x 3.183 mm) were slightly larger than the males (7.32 x 4.47mm - 4.48 x 2.43 mm). The antennal clubs revealed significant differences in size among species and sexes. In males of M. insanabilis and M. thomsoni the length of lamellae was 0.456 and 0.294 mm, and the corresponding value was 0.398 and 0.269 mm in female beetles. In forelegs, the claws are clefted and bifid in females, and trifid in males. Male genitalia are trumpet shaped in M. thomsoni and more or less flask shaped in M. insanabilis. Female beetle survived for 30.20±2.65 days in M. insanabilis and 35.50±2.57 days in M. thomsoni. The mean longevity of male beetles was recorded to be 26.20±2.15 days and 26.30±3.11 days, respectively. Against M. insanabilis, four insecticides and three natural products were tested. The LC50 values of dimethoate, flubendiamide, chlorpyriphos and spinosad were calculated to be 7.08, 109.16, 128.62 and 153.62 ppm. In case of natural products, Agniastra, Brahmastra and Neemastra were evaluated, and FD50 values were calculated to be 5.62, 7.71 and 11.01 per cent, respectively.ThesisItem Open Access BIOEFFICACY OF NEWER INSECTICIDES AGAINST LEPIDOPTERAN PESTS AND THEIR RESIDUE DYNAMICS ON CABBAGE(CSK HPKV, Palampur, 2019-06-18) Chowdary, Namburi Mounica; Sharma, Prem ChandField experiment was conducted at Experimental Research Farm of Department of Entomology, CSKHPKV, Palampur during the rabi season 2018-19 to determine the bioefficacy of insecticides against Plutella xylostella and their residue dynamics on cabbage, variety Pusa Cabbage-1. The bioefficacy of insecticides comprising chlorantraniliprole, cypermethrin, diafenthiuron, emamectin benzoate, indoxacarb, novaluron, azadirachtin, spinosad and Bacillus thuringiensis was determined. After two sprays, chlorantraniliprole @ 10g a.i./ha recorded minimum larval population with 1.21 larvae/plant followed by spinosad @ 15 g a.i./ha (1.43) and indoxacarb @ 40 g a.i./ha (1.6). The treatments with high larval population were azadirachtin (5.56 larvae/plant) followed by Bt (5.47). The per cent reduction of larval population over untreated check was highest in chlorantraniliprole (81.02%), followed by spinosad (78.13%) and indoxacarb (78.02%). The lowest per cent reduction was found in the plots treated with Bt (45.14%) and azadirachtin (45.52%). Incremental cost benefit ratio was maximum (1:18.44) in chlorantraniliprole followed by spinosad (1:16.33) and diafenthiuron (1:13.96). The lowest incremental cost benefit ratio was found with novaluron (1:2.48). The initial deposits of diafenthiuron, indoxacarb and novaluron on cabbage heads were found to be 0.604, 0.309 and 0.218 mg/kg, respectively which were below the quantification limits on 7th day after spray. The half-life values were calculated to be 1.05, 1.73 and 1.14 days, the safety intervals were found to be 0.77, 0.13 and 1.91 days, for diafenthiuron, indoxacarb and novaluron, respectively.ThesisItem Open Access MONITORING RESISTANCE TO ACARICIDES IN TETRANYCHUS URTICAE (KOCH) UNDER PROTECTED CULTIVATION.(CSKHPKV, Palampur, 2019-07-23) Titiksha; Sood, Ajay K.Investigations on “Monitoring resistance to acaricides in Tetranychus urticae (Koch) under protected cultivation” were carried out during 2018-19. The study was aimed to determine the level of resistance in field populations of T. urticae and to formulate a strategy for resistance management. Intrinsic toxicity of three chemical acaricides (fenazaquin, hexythiazox and propargite), one biopesticide (azadirachtin) and two natural products (Tamarlassi and Darekastra) against T. urticae was determined. For this, mite population was reared in laboratory for more than 25 generations without exposing it to any chemicals. The median lethal concentration for azadirachtin, Darekastra, fenazaquin, hexythiazox, propargite and Tamarlassi was 0.00013, 4.01176, 0.00125, 0.00056, 0.00681 and 2.49950 per cent, azadirachtin being most toxic and Darekastra the least. Field populations of T. urticae collected from six localities in Zone I and II of Himachal Pradesh revealed maximum resistance ratio to exhibit in Una population for all the chemical acaricides(3) followed by Kullu(3) > Solan(2) > Sundarnager(2) > Kangra(3) and least for Palampur(3). Among acaricides, T. urticae populations were found most resistant to propargite (3.47 to 5.63) followed by fenazaquin (3.62 to 4.26) and hexythiazox (1.88 to 2.45). Fenazaquin resistant strain was developed by giving selection pressure based on the LC50 values till the extremely high level of resistance was achieved after eight generations of selectivity and was designated as fenazaquin resistant strain (FR-strain) exhibiting extremely high level of resistance (216.74). Growth and development parameters studied for FR- and S-strain revealed the FR- strain to be bigger in size but their generation time, adult longevity and fecundity were reduced significantly when compared to S-strain. Resistance incorporated in FR-strain was not stable and declined by 26.7 per cent in three generation of non-selectivity. FR-strain exhibited low cross resistance to azadirachtin, Darekastra, hexythiazox, propargite and Tamarlassi, being non- significant. The results indicated that T. urticae can quickly develop resistance to fenazaquin. It also exhibited low level of cross resistance, being non-significant to acaricides belonging to different mode of action and natural products suggesting their incorporation in mite resistance management plan.
