Medicinal plants and plant oils as growth regulators against Bombyx mori (Linn.) and Spodoptera litura (Fab.) and bioefficacy of some insecticides against pest species
| dc.contributor.advisor | Srivastava, R.P. | |
| dc.contributor.author | Basera, Anju | |
| dc.date.accessioned | 2016-09-07T09:06:46Z | |
| dc.date.available | 2016-09-07T09:06:46Z | |
| dc.date.issued | 2009-08 | |
| dc.description.abstract | Present investigation was undertaken to determine the growth regulating activity of medicinal plants and plant oils against Bombyx mori (Linn.) and Spodoptera litura (Fab.) and bioefficacy of some insecticides against S. litura. All the experiments were conducted in Bioactive Plant Natural Product (BPNP) Lab. of the Department at room temperature. The culture of the test species were maintained in the lab on fresh mulberry (garden maintaiend) and castor leaves. Two of the nine medicinal plant extracts viz., S. media and P. ovata (aq. 1% conc. dry wt. basis) showed growth promoting activity as reflected by a significant increase in feeding, growth and developmental parameters againt B. mori. However at this conc. these extracts could not significantly increase the economic parameters. Seven plant oils (1% acetone solution) viz., neem, castor, karanja, eucalyptus, jatropha, camphor and thyme oil adversely affected the growth, development and economic parameters of B. mori. They prolonged the larval development and reflected the different levels of toxicity (70-86%) against full grown worms of B. mori with non- significant effect on economic parameters. Amongst the nine plant oils viz., neem, castor, karanja, eucalyptus, jatropha, camphor, citronella, lemongrass and turmeric tested against S. litura all the plant oils except E. citrodora and C. camphora at 1% conc in acetone exhibited the antifeedant activity. These oils also extended the larval period. At 1% conc. some of the oils viz., C. flexuosus and C. Longa caused 16.6 and 13.3% mortality, respectively which was significantly higher than control. All the four medicinal plant extracts viz., Jatropha curcas, Artemisia annua, Cnicus benedictus and Syzygium cumuni significantly reduced the feeding at both conc. (5 and 10% aq.). The maximum antifeedant activity was observed in S. cumuni (92.18%). In addition, these plant extracts also showed IGR activity which resulted in terminal larval mortality to the tune of 23.3% in S. cumuni at 5% conc. Two plant oils viz., karanja and jatropha when added to the synthetic pyrethroids viz., cypermethrin, lambdacyhalotrhin and alphametrhin synergized their insecticidal activity and increased their speed of action (LT value). The plant oils have potenital to potentiate the toxicity of three synthetic pyrethroids against S. litura. For example at 24 hours after exposure synergistic effect of karanja oil with cypermethrin, lambdacyhalothrin and alphamethrin was 8.8, 4.0 and 1.9 times, respectively and with jatropha oil it was 5.3, 10.5 and 2.0 times, respectively. In the present investigation the sublethal doses of synthetic pyrethoids viz., cypermethrin, lambdacyhalothrin and alphamethrin influenced growth and dvelopment of S. litura adversely. Addition of plant oils (karanja and jatropha at 1%, emulsified with teepol 1%) to synthetic pyrethroids further intensified its effect on growth, development and toxicity viz., cypermethrin, lambdacyhalothrin and alphamethrin caused terminal larval mortality of 40,40 and 35 %, respectively. When these insecticides were mixed with karanja and jatropha oil mortality ranged from 45-55%. A chronic feeding experiment conducted against 8d old larvae of S. litura wit LC30 four insecticides viz., indoxacarb (0.0001%), methomyl (0.017%), imidacloprid (0.2%) and thiamethoxam (0.1%) revealed that the larvae consumed less food when leaves treated with tested insecticides were offered as food as compared to untreated. the consumption was reduced by 20.90, 19.23, 17.60 and 14.53% at LC30 of indoxacarb, methomyl, imidacloprid and thiamethoxam, respectively over control. Sublethal dose of these insecticides were effective in delaying the development of S. litura and extended the developmental parameters significantly. For example larval period was extended by 1.85d over control (13.45d) by indoxacarb. Another experiment conducted on the effect of food plant viz., soybean, brinjal and castor on susceptibility of 6d old larvae of S. litura to three neonicotinoids (indoxacarb, imidacloprid, thiamethoxam) and one carbamate (methomyl) insecticide reflected that the larval mortality was significantly associated with host plants on which larvae were reared. The larvae of S. litura reared on soybean and castor became more susceptible (hihger RT, lower LT values at LC50) to the tested insecticides and those reared on brinjal were relatively tolerant (higher LT value and lower RT value at LC50). For example the RT values on soybean for different insecticies were 2.9, 1.8, 1.3 and 2.7 when the larvae were exposed to the LC50 doses of indoxacarb, imidacloprid, thiamethoxam and methomyl respectively; on castor the RT values were 2.5, 1.8, 1.6 and 2.2; and on brinjal the values were 1.9, 1.3, 1.0 and 1.8 against the respective insecticide. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/75769 | |
| dc.language.iso | en | en_US |
| dc.publisher | G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand) | en_US |
| dc.sub | Entomology | |
| dc.subject | medicinal plants, plant oils, growth regulators, Bombyx mori, Spodoptera litura, biological control, insecticides, insect pests, species diversity, silkworms | en_US |
| dc.these.type | Ph.D | |
| dc.title | Medicinal plants and plant oils as growth regulators against Bombyx mori (Linn.) and Spodoptera litura (Fab.) and bioefficacy of some insecticides against pest species | en_US |
| dc.type | Thesis | en_US |