DEPARTMENT OF ENTOMOLOGY (ENT) http://103.7.193.12:8080/xmlui/handle/123456789/13 2026-04-17T17:10:10Z 2026-04-17T17:10:10Z Sanjita http://103.7.193.12:8080/xmlui/handle/123456789/2006 2025-12-03T08:42:05Z 2024-06-01T00:00:00Z

ACARICIDAL AND REPELLENT ACTIVITY OF THREE ESSENTIAL OILS AGAINST TETRANYCHUS URTICAE KOCH (ACARI: TETRANYCHIDAE) Sanjita The contact toxicity and repellent effects of three essential plant oils viz., Swietenia macrophylla (Mahogany), Azadirachta indica (Neem) and Eucalyptus camaldulensis (Eucalyptus) were evaluated against female adults of Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions. The selected essential oils were tested at 0.5, 1.0, 1.5, 2.0 and 3% concentration. Mahogany oil (S. macrophylla) was the most toxic essential oil to T. urticae females and eggs, while eucalyptus (E. camaldulensis) was the least toxic one (LC50 = 0.887 and 2.146% for adults and 1.230 and 6.980 for eggs), respectively. Leaf discs treated with increasing concentrations of S. macrophylla and E. camaldulensis oils showed a high percentage of repellency (92-100%), respectively. The oviposition deterrent indexes (ODI) of eucalyptus and mahogany oils were ranged (24-100) for T. urticae at a concentration (0.5-3.0%), while this value was between (7-60) in the case of neem oil at the same above concentration. In the persistence test, the mites were exposed to 1, 24, 48 and 72 h old residue and it was found that the lethal concentration effects of the plant oils fade within two or three days. The results suggest that oils of mahogany, neem and eucalyptus can potentially be used to manage T. urticae. ACARICIDAL AND REPELLENT ACTIVITY OF THREE ESSENTIAL OILS AGAINST TETRANYCHUS URTICAE KOCH (ACARI: TETRANYCHIDAE); A THESIS BY Sanjita, Registration No: 1701180, Session: 2023-2024, Semester: January-June, 2024; MASTER OF SCIENCE (MS) IN ENTOMOLOGY, DEPARTMENT OF ENTOMOLOGY, HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY DINAJPUR-5200; JUNE, 2024.

2024-06-01T00:00:00Z Ferdousy, Mst. Jannatul http://103.7.193.12:8080/xmlui/handle/123456789/2005 2025-12-02T06:56:14Z 2024-06-01T00:00:00Z

SURVIVAL, DEVELOPMENT AND REPRODUCTION OF COCCINELLA SEPTEMPUNCTATA L. (COLEOPTERA: COCCINELLIDAE) UNDER EFFECTS OF INSECTICIDES USED IN BEAN PLANTS Ferdousy, Mst. Jannatul Coccinella septempunctata L. (Coleoptera: Coccinellidae), a prevalent ladybird species, feeds on aphids and other arthropods harmful to plants. Although insecticides are commonly used to control various insects, they can harm unintended organisms through lethal and sublethal effects. This study evaluated the physiological selectivity of registered insecticides to safeguard C. septempunctata in the bean field ecosystem. Spiromesifen, deltamethrin, lambda-cyhalothrin, abamectin, chlorfenapyr, and imidacloprid were tested on eggs, third-instar larvae, pupae, and adults, with water as a control. Spiromesifen exhibited overall safety across all stages, while chlorfenapyr had minimal impact on the predator's biological features, except during the egg and adult stages. On the other hand, deltamethrin emerged as the most harmful across all stages. Lambda-cyhalothrin displayed notable toxicity to larvae and adults, similar to deltamethrin, and also affected other stages. Abamectin exhibited considerable toxicity across all developmental stages, while imidacloprid posed significant toxicity to the egg and larval stages and moderate toxicity to the adult stage. In conclusion, spiromesifen and chlorfenapyr emerged as the least toxic options for C. septempunctata and should be prioritized in Integrated Pest Management (IPM) strategies. The severe effects of deltamethrin, lambda-cyhalothrin and abamectin require further verification in field and greenhouse settings. Further studies at different concentrations and routes of exposure are suggested. SURVIVAL, DEVELOPMENT AND REPRODUCTION OF COCCINELLA SEPTEMPUNCTATA L. (COLEOPTERA: COCCINELLIDAE) UNDER EFFECTS OF INSECTICIDES USED IN BEAN PLANTS; A THESIS BY Mst. Jannatul Ferdousy, Student No. 1601399, Session: 2022-2023, Thesis Semester: January-June, 2024; MASTER OF SCIENCE (MS) IN ENTOMOLOGY, DEPARTMENT OF ENTOMOLOGY, HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR-5200; June, 2024.

2024-06-01T00:00:00Z ROY, KHOKON http://103.7.193.12:8080/xmlui/handle/123456789/2004 2025-12-02T06:20:06Z 2024-06-01T00:00:00Z

FIELD EFFICACY OF SOME SELECTED INSECTICIDES AND BIOPESTICIDE AGAINST SUCKING PESTS ON OKRA ROY, KHOKON Okra, Abelmoschus esculentus (L.) Moench is a popular vegetable grown in Bangladesh and throughout the cropping season, the crop is vulnerable to many types of sucking pests. A field experiment was conducted in the research field of the Department of Entomology, HSTU, Dinajpur, to evaluate the field efficacy of five selected insecticides and biopesticide against sucking pests on okra during February to June, 2023. The selected insecticides and biopesticide namely imidacloprid (Imitaf 20 SL), acetamiprid (Tundra 20 SP), emamectin benzoate (Emacto 5 WDG), spinosad (Trace 45 SC), lamda-cyhalothrin (Fighter 2.5 EC) were applied at 10 days intervals in the field. The experiment were done with RCB design with three replications and data were recorded on the number of whiteflies, jassids, curled or infested leaves /3 leaves at one day before 3, 7 and 10 days after each spray. The marketable fruits were harvested at 3 days interval and weight of fruits was also recorded. The results showed that the lowest cumulative mean number of whiteflies was found (2.67, 1.33 & 0.77/ 3 leaves) in the treatment of imidacloprid (Imitaf 20SL) after 1st, 2nd and 3rd sprays, respectively. On the other hand, the highest cumulative mean number of whiteflies was found (5.00, 7.56 and 12.88 / 3 leaves) in the control. The highest percent decreased of whiteflies over control was 46.60, 82.41 and 94.02 % observed in the treatment of imidacloprid (Imitaf 20SL) after 1st, 2nd & 3rd sprays. In case of jassid population, the lowest cumulative mean number (1.44, 1.11 and 0.77/3 leaves) of jassids was recorded from the treatment of imidacloprid (Imitaf 20SL), contrarily the highest cumulative mean number (4.11, 7.11 and 5.55 / 3 leaves) of jassids was recorded from the control. Consequently, the highest percent decreased of jassids over control was found 65.00, 84.39 and 86.13 after 1st, 2nd & 3rd sprays when applied imidacloprid (Imitaf 20SL). The cumulative yield was the highest (2.22 kg/ plot) with the highest benefit cost ratio (1.50) was recorded in the treatment of imidacloprid (Imitaf 20 SL). Based on the experiment, it may suggest that okra field can be treated with imidacloprid (Imitaf 20 SL) to reduce the number of population of sucking pests like jassids and whiteflies for better yield. FIELD EFFICACY OF SOME SELECTED INSECTICIDES AND BIOPESTICIDE AGAINST SUCKING PESTS ON OKRA; A THESIS BY KHOKON ROY, Student No.: 1701159, Session: 2022-2023, Semester: January-June 2024; MASTER OF SCIENCE (MS) IN ENTOMOLOGY, DEPARTMENT OF ENTOMOLOGY, HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR-5200, BANGLADESH; JUNE 2024.

2024-06-01T00:00:00Z MORSHED, MUSTAKIM http://103.7.193.12:8080/xmlui/handle/123456789/2002 2025-11-30T08:40:14Z 2024-06-01T00:00:00Z

SUBLETHAL EFFECTS OF THREE DIFFERENT INSECTICIDES ON Hadronotus pubescens (HYMENOPTERA: SCELIONIDAE), AN EGG PARATISITOID OF Riptortus pedestris (HEMIPTERA: ALYDIDAE) MORSHED, MUSTAKIM Riptortus pedestris (Hemiptera: Alydidae) is one of the most damaging insects of leguminous crops in Eastern Asia and has become a new pest in Bangladesh. Hadronotus pubescens (Hymenoptera: Scelionidae) is one of the active egg parasitoids of R. pedestris available in Bangladesh. Spinosad, pyriproxyfen and pymetrozine+ nitenpyram are commonly used to manage the stink bug populations. In this study, sublethal effects of spinosad, pyriproxyfen and pymetrozine+ nitenpyram were investigated on the parasitized host eggs by H. pubescens at different days after parasitization. At 1, 7 and 15 days after parasitization by H. pubescens, the parasitized eggs were diped in spinosad, pyriproxyfen and pymetrozine+ nitenpyram solution. All of the three insecticides reduced the number of emerged parasitoids, emergence rate, sex ratio and increased the mortality rate as well as development time of both male and female. The maximum number of emerged parasitoids was reduced by spinosad. On the other hand, it reduced the emergence rate by 41.72% and increased the mortality rate by 41.72% at 15 days after parasitization. Pyriproxyfen showed the lowest reduction in emergence rate and lowest increase in mortality rate at 1 day after parasitization. Spinosad reduced the sex ratio of H. pubescens by 0.09 compared to control at 1 day after parasitization. The least reduction was showed by pymetrozine+ nitenpyram in both 1 day and 15 days after parasitization. However, pymetrozine+ nitenpyram showed the maximum increase in development time of both male and female parasitoids at 1 day after parasitization, whereas the minimum increase was also caused by pymetrozine+ nitenpyram at 7 days after parasitization. Therefore, it can be said that, spinosad showed the strongest toxicity and most potential sublethal effect on the H. pubescens egg parasitoid. The sublethal effect of pyriproxyfen was the weakest of all insecticides applied. So, pyriproxyfen can be suggested to use in mung bean and soybean fields as it showed less toxicity and sublethal effect on the host eggs parasitized by H. pubescens. SUBLETHAL EFFECTS OF THREE DIFFERENT INSECTICIDES ON Hadronotus pubescens (HYMENOPTERA: SCELIONIDAE), AN EGG PARATISITOID OF Riptortus pedestris (HEMIPTERA: ALYDIDAE); A THESIS BY MUSTAKIM MORSHED, Student No. 1601388, Session: 2022-23, Thesis Semester: January-June, 2024; MASTER OF SCIENCE (MS) IN ENTOMOLOGY, DEPARTMENT OF ENTOMOLOGY, HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR; JUNE, 2024.

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