Phytochemical composition and insecticidal potentials of some plant aqueous extracts in suppressing Podagrica spp. (Coleoptera: Chrysomelidae) Infestation on Okra (Abelmoschus esculentus L. Moench)

Foliar application of 25% w/v crude aqueous extracts Calotrophus procera (Aiton) W.T. Aiton, Canarium schweinfurthii (Engl.) and Bryscocarpus coccineus (Schum. & Thonn.) were evaluated for their insecticidal activity in reducing Podagrica infestation on okra. Results showed that plants extracts significantly suppress Podagrica spp. infestation and protect okra plant from severe leaves defoliation, with C. schweinfurthii (21.67 and 20.14) and B. coccineus (23.07 and 24.55) showing promising insecticidal activity. The yield attributes from okra sprayed with Lambda cyhalothrin did not differ significantly compared to those sprayed with botanical insecticide despite having highest yield attributes. Qualitative phytochemical screening revealed the presence of Triterpenoids, Steroids, Flavonoids, Phlobatanins, Saponins, Tannins, Cardiac glycoside and Anthraquinones. Alkaloids and Anthraquinones were not detected in C. procera and C. schweinfurthii while Triterpenoids and Phlobatanins were absent C. schweinfurthii. The presence of these phytochemicals indicates that the plants possess insecticidal properties responsible for significant reduction in Podagrica spp. infestation, severity of leaves damaged and improved okra yields. Performance of the treatments is rated in the following order: Lambda cyhalothrin > B. coccineus > C. schweinfurthii > C. procera, with B. coccineus and C. schweinfurthii having similar treatment means in all the parameters evaluated. In light of the foregoing, crude extracts of B. coccineus and C. schweinfurthii could be utilized as suitable alternative to synthetic insecticide in sustainable okra productio

Botanicals as Grain Protectants

Prevention of food losses during postharvest storage is of paramount economic importance. Integrated pest management is now a widely accepted strategy in pest control including postharvest infestation control which involves the use of chemical (contact/residual) insecticides along with fumigants. The use of synthetic chemical insecticides is either not permitted or used restrictively because of the residue problem and health risks to consumers. In view of the above, there is a need for plants that may provide potential alternatives to the currently used insect control agents as they constitute a rich source of bioactive molecules. Available literature indicates that plant could be source for new insecticides. Therefore, there is a great potential for a plant-derived insecticidal compounds. This paper focuses on the current state of the botanical insecticides as grain protectants and its mode of action

Insecticidal Evaluation of Bridelia Micrantha and Dalbergia Lactea Aqueous Extracts for the Control of Podagrica Uniforma (Jacoby) and Nisotra Dilecta (Jacoby) (Coleoptera: Chysomelidae) Infestation on Okra

Insect pest infestation is a major factor militating against okra production and farmers generally adopt synthetic insecticides for its management. A field trial was undertaken to evaluate the insecticidal potency of Bridelia micrantha and Dalbergia lactea for the management of Podagrica uniforma (Jacoby) and Nisotra dilecta (Jacoby) insect pest of okra (Abelmoschus esculentus L. Moench). The treatments consisted of aqueous leaf extracts of Bridelia micrantha and Dalbergia lactea and Cypermethrin as check; laid out in Randomized Complete Block Design and repli-cated three times. Data was collected on insect population before treatment application and 3 days after spraying of insecticides at 28, 35, 42, 56 days after planting (DAP). Yield parameters data collected were number of fruits and fruit weight. Results obtained showed that the plant extracts exhibited effectiveness in reducing the insect population and improved okra fruit yield compared to Cypermethrin. The order of effectiveness in decreasing sequence was found to be Cypermethrin ˃ D. lacteal ˃ B. micrantha. D. lacteal and B. micrantha crude extracts could be explored as promising insecticidal agents to provide valuable alternatives to chemical control of insect infestation on okra. Further study is recommended to determine the chemical constituents responsible for the plant insecticidal activity

Time-course of <i>in vivo</i> inhibition of Na⁺, K⁺-ATPase in relation to knockdown of housefly treated with decalesides.

<p><b>A)</b> % Knockdown effect (n = 4, error bars, s.e.m.). <b>B)</b> Decaleside I (control activity: head = 61.6 μg Pi / mg protein; thorax = 38.6 μg Pi / mg protein) (n = 4, error bars, s.e.m.)<b>,</b> and <b>C)</b> Decaleside II (control activity: head = 74.02 μg Pi / mg protein; thorax = 47.82 μg Pi / mg protein) (n = 4, error bars, s.e.m.).</p

Botanicals as grain protectants

Prevention of food losses during postharvest storage is of paramount economic importance. Integrated pest management is now a widely accepted strategy in pest control including postharvest infestation control which involves the use of chemical (contact/residual) insecticides along with fumigants. The use of synthetic chemical insecticides is either not permitted or used restrictively because of the residue problem and health risks to consumers. In view of the above, there is a need for plants that may provide potential alternatives to the currently used insect control agents as they constitute a rich source of bioactive molecules. Available literature indicates that plant could be source for new insecticides. Therefore, there is a great potential for a plant-derived insecticidal compounds. This paper focuses on the current state of the botanical insecticides as grain protectants and its mode of action

Acetylcholinesterase inhibition by biofumigant (Coumaran) from leaves of Lantana camara in stored grain and household insect pests

Recent studies proved that the biofumigants could be an alternative to chemical fumigants against stored grain insect pests. For this reason, it is necessary to understand the mode of action of biofumigants. In the present study the prospectus of utilising Lantana camara as a potent fumigant insecticide is being discussed. Inhibition of acetylcholinesterase (AChE) by Coumaran, an active ingredient extracted from the plant L. camara, was studied. The biofumigant was used as an enzyme inhibitor and acetylthiocholine iodide as a substrate along with Ellman&apos;s reagent to carry out the reactions. The in vivo inhibition was observed in both dose dependent and time dependent in case of housefly, and the nervous tissue (ganglion) and the whole insect homogenate of stored grain insect exposed to Coumaran. The possible mode of action of Coumaran as an acetylcholinesterase inhibitor is discussed

Effect of hydrolysis of decaleside II on the knockdown and inhibition of Na⁺, K⁺ ATPase activity in the brain of <i>Blatella germanica</i> exposed to KD₅₀ (0.07 mg/cm²) of decaleside II by contact bioassay.

<p><b>A)</b> Knockdown, <b>B)</b> Inhibition of Na⁺, K⁺ ATPase of activity. <b>I)</b> Control (without hydrolysis), <b>II)</b> Acid hydrolysis, <b>III)</b> β-Galactosidase, <b>IV)</b> α-Glucosidase. (n = 4, error bars, s.e.m.) One-way ANOVA, ***<i>P</i> < 0.001.</p

<i>In vitro</i> inhibition of Na⁺, K⁺ ATPase by decaleside I and II in comparison with that of ouabain.

<p><b>A, B</b> : cockroach brain and thorax, respectively (control activity: head = 29.33 μg Pi / mg protein; thorax = 88.5 μg Pi / mg protein); <b>C, D</b> : house fly head and thorax, respectively (control activity: head = 73.6 μg Pi / mg protein; thorax = 97.42 μg Pi / mg protein ); <b>E:</b> Purified Na⁺, K⁺ ATPase (porcine cerebral cortex, sigma); <b>IC</b>_<b>50</b><b>:</b> Ouabain, 25.4 × 10^-5M; Decaleside I, 10.5 × 10^-5M; Decaleside II, 9.5 × 10^-5M.</p

Dose-dependent <i>in vivo</i> inhibition of Na⁺, K⁺-ATPase by decalesides in relation to insecticidal activity in the house fly.

<p><b>A)</b> % Knockdown effect (n = 4, error bars, s.e.m.). <b>B</b>) Decaleside I <i>(</i>control activity: head = 38.03 μg Pi / mg protein; thorax = 45.8 μg Pi / mg protein) (n = 4, error bars, s.e.m.).<b>C)</b> Decaleside II (control activity: head = 33.15 μg Pi / mg protein; thorax = 45.4 μg Pi / mg protein) (n = 4, error bars, s.e.m.).</p

Not Available

Not AvailableDue to environmental concerns, health hazards to man and the evolution of resistance in insect pests, there have been constant efforts to discover newer insecticides both from natural sources and by chemical synthesis. Natural sources for novel molecules hold promise in view of their eco-friendly nature, selectivity and mammalian safety. We have isolated one natural bioactive molecule from the leaves of Lantana camara named Coumaran, based on various physical–chemical and spectroscopic techniques (IR, 1H NMR, 13C NMR and MS). Coumaran is highly toxic and very low concentration is needed for control of stored product insects. This molecule has potent grain protectant potential and caused significant reduction in F1 progeny of all the three species in the treated grain and the progeny was completely suppressed at 30 μg/l. The differences in germination between the control and treated grains were not significant. The lack of any adverse effect of Coumaran on the seed germination is highly desirable for a grain protectant, becoming a potential source of biofumigant for economical and environmentally friendly pest control strategies against stored grain pests during storage of grains or pulses.Not Availabl