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2020 - 20213
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Subject: Agricultural Entomology × Start date: 1980 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Pollination potential of Apis species on guava and litchi
    (palampur, 2020-11-09) Akash; Sharma, Surender Kumar
    Guava and litchi are the two commercially important fruit crops grown in Shivalik Hills of Himachal Pradesh. Owing to their pollination, the present study holds potential for improving their reproductive success by utilizing most suited honeybee pollinators. The prime aim of the present investigation was to study the foraging traits of honeybees in guava and litchi ecosystems, ensuring effective pollination services. Healthy and bearing trees of guava (var. Allahabad Safeda) and litchi (var. Culcuttia) were chosen as experimental material for study. Abundance and foraging traits; foraging rate, foraging speed, foraging mode and pollination efficiency index were determined. Visitor insects were observed in litchi and guava ecosystems of six different locations during morning and afternoon hours. Data were recorded by selecting four branches in different directions of the tree. Honeybees followed by syrphids were the predominant visitors of litchi both during early and peak blooming period. Out of the three predominant honeybee species, Apis cerana was most frequent (10.19 flowers/min.) in the morning hours and Apis mellifera visited maximum flowers (10.04 flowers/min.) during afternoon hours. Foraging speed as time spent per flower was recorded maximum for Apis dorsata (7.55 sec.) during morning and A. cerana (7.34 sec.) in afternoon hours. Foraging mode indicated the maximum top foragers of A. mellifera. Maximum number of loose pollen grains among Apis pollinators on body and hind legs was carried by A. dorsata. A. mellifera with highest pollination efficiency index was found as the most efficient pollinator in litchi ecosystem. In guava ecosystem, honeybees were again abundant during the early bloom while A. cerana was the most prevalent during peak bloom. Maximum foraging rate, both in morning and afternoon hours was observed for A. cerana. A. mellifera and A. cerana had the maximum foraging speeds i.e. 6.83 seconds and 9.56 seconds during morning and afternoon hours, respectively. Foraging mode of honeybees revealed that in guava crop, maximum top foragers were of A. dorsata and the least of A. cerana. Maximum number of loose pollen grains among honeybees on body and hind legs was recovered from A. dorsata. The pollination efficiency index of A. cerana in guava was highest as 6.54, hence, represented the most efficient pollinator in the surveyed locations of Shivalik Hills.
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    ThesisItemOpen Access
    Evaluation of management techniques for predatory wasps of honey bees
    (Palampur, 2021-09-01) MOTMAYEN, MOHAMMAD ILYAS; Sharma, Surender Kumar
    To manage bee wasp species, knowledge of wasp predaceous behavior and defense mechanism of honey bees are of utmost importance. It is an experiment oriented elaborated attempt to save incinerating honey bee world over, and to have an alternative to stringent wasp menace. The incidence of four species of honey bee predatory wasps viz Vespa auraria, V. basalis, V. tropica and V. mandarinia was recorded. Impact of wasp attack was assessed in colonies and had 30 per cent mortality of colonies as well as reduction in strength, brood and nectar. Wasp incidence fluctuation was observed in different months. V. auraria had the lowest population of 2.76 ± 0.92 wasp in June while it was highest 24.73 ± 1.88 wasps/week in August. V. basalis, and V. tropica had their lowest population of 0.29 ± 0.29 and 0.04±0.04 wasps/week in the month of June while they reached to maximum visits of 5.80 ± 0.55 and 0.51 ± 0.07 wasps/week in August, respectively. In predatory behavior V. auraria was found the most agile wasp species with highest attacks on colony as 3.68 ± 0.98/week, and it also spent least time of 7.47 ± 0.28s to catch a bee followed by V. tropica (25.58 ± 0.51s) and V. basalis (31.26 ± 0.73s). V. basalis had tendency to attack at ground level than at hive entrance. On an average 6.04 guard bees/colony significantly can resist wasp attack. In heat balling a wasp, after 45s maximum of 25.75 ±0.43 bees were seen engulfed and in the process a rise of 6.47º F temperature was recorded. Thermal exposure for 5 and 20 minutes for wasps was 49 and 48 whereas for bees it was 53 and 55 respectively. Bee wasp protector was the most suitable wasp management technique and it had the lowest successful catches 0.55 ± 0.07, 0.21 ± 0.01, 0.00 ± 0.00 bees by any of wasp, V. auraria, V. basalis and V. tropica, respectively. Among six bait materials acetic acid was found the best while tested four repellents were also found promising. A 750 ml capacity bottle trap containing fermented honey has been found to the most effective way to manage V. auraria, V. basalis and V. tropica in apiaries.
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    ThesisItemOpen Access
    Bioefficacy of natural products against cabbage aphid, Brevicoryne brassicae Linnaeus in rapeseed
    (Palampur, 2021-11-03) SHARMA, ARUSHI; Kumar, Surjeet
    Six natural products viz., Agniastra, Brahmastra, cow urine, Darekastra, Dashparni and Eupatorium extract in cow urine were evaluated for their biological activity against Brevicoryne brassicae and for their effect on the population build-up of the aphid on Gobhi Sarson var. GSC-7 under laboratory and field conditions, respectively. The biological activity of natural products was studied by determining their toxic and repellent activity against fourth instar nymphs of cabbage aphid by using standard leaf-dip method of bioassay and effects on its biology. The order of toxicity of natural products to fourth instar nymphs of B. brassicae based on LC50 values in decreasing order was Brahmastra (9.11 %) followed by Agniastra (12.79 %), Dashparni (18.14 %), Eupatorium extract in cow urine (19.04 %), cow urine (19.29 %) and Darekastra (20.87 %). All natural products exhibited moderate level of repellence against the aphid. The repellence index (RI) calculated for different natural products at 10 per cent concentration against fourth instar nymphs of B. brassicae varied from 0.57 to 0.77, minimum and maximum corresponding to Brahmastra and Agniastra. When these products were tested at 10 per cent concentration for their effect on developmental biology of the aphid, Brahmastra was recorded to prolong the total nymphal period (9.97 days) by 3.90 days as compared to untreated check (6.07 days). Among natural products, nymphal growth index varied from 4.44 to 9.19 and highest growth index was recorded in untreated check (14.28). An increase in pre- and post-oviposition periods was recorded whereas oviposition period was found to decrease. All natural products were found to significantly reduce the fecundity of the aphid as compared to untreated check. The adult longevity was reduced but the results were found to be non-significant. Under field conditions, five sprays at regular intervals (10 days) of all natural products @ 10 per cent checked the population build-up of cabbage aphid, however, the extent of reduction over that of untreated check was low. Maximum per cent reduction over untreated check (29.31 %) was recorded in plots treated with Brahmastra followed by Agniastra (28.19 %). Darekastra was found to record minimum per cent reduction (21.62 %) followed by Eupatorium extract in cow urine (21.87 %). Overall, it can be concluded from the present study that all natural products, particularly Brahmastra, exhibited significant biological activity against cabbage aphid both under laboratory and field conditions and therefore, can further be investigated for inclusion in integrated pest management strategy against the aphid on rapeseed.