Synthetic Chemical Insecticides Research Articles

PAPAYA LEAF POWDER EXTRACT (Carica papaya L.) TO CONTROL THE WHITEFLY (Bemisia tabaci Genn.) ON RED CHILI PLANTS (Capsicum annum L.)

Bemisia tabaci Genn. is a pest of red chili plants. Bemisia tabaci Genn pest control is usually carried out using synthetic chemical insecticides, but inappropriate use will have a negative impact on the environment, so another alternative that is safer and more environmentally friendly is the use of insecticide papaya leaf powder extract. This study aimed to obtain a concentration of papaya leaf powder extract (Carica papaya L.) which is effective in controlling whitefly pests (Bemisia tabaci Genn.) on red chili (Capsicum annum L.). The research was at the Experimental Garden and Plant Pest Laboratory, Faculty of Agriculture, Riau University from Juni to August 2021. The experiment using a completely randomized design (CRD) with 6 treatments and 4 replications so that 24 experimental units were obtained. The concentration of papaya leaf powder extract used as treatment was 0 g.l-1 water, 20 g.l-1 water, 40 g.l-1 water, 60 g.l-1 water, 80 g.l-1 water, dan 100 g.l-1 water. The results showed that the concentration of papaya leaf powder extract 60 g.l-1 water was an effective concentration in controlling B. tabaci pests because it was able to mortality B. tabaci pests by 85% with an initial time of death of 5.25 hours after application and a lethal time of 50 at 18.75 hours after application.Keywords: Bemisia tabaci Genn., Carica papaya L, and Capsicum annum L

The Efficacy of the Leaf Powders of Justicia Adhatoda L. and Leucas Aspera on the Management of the Pulse Beetle Callosobruchus Chinensis L. (Coleoptera: Bruchidae), in Cicer Arietinum L. (Chickpea)

Insects are a problem in stored grains throughout the world. In India, there are about 200 species of pest insects which cause damage to stored grains and grain products in storage. The stored chickpea seeds are affected by bruchids. The pulse beetle Callosobruchus chinensis is the most widespread and destructive insect pest of economically important leguminous chickpea. The pest control of C. chinensis is very important to protect the loss of nutritive and economic value of chickpea. The present study aimed to protect the stored chickpea seeds from C. chinensis infestation using leaf powders of Justicia adhatoda L. and Leucas aspera by analyzing the effect of these two leaf powders on the mortality rate. Through this study, it has been found that J. adhatoda showed more efficacy against C. chinensis and it can be considered as a safer alternative for synthetic chemical insecticides. The study was to investigate the phytochemicals, physico chemical parameters, FTIR spectrum, seed germination percentage and vigour index for their safety and efficacy. The use of natural medicinal plants like J. adhatoda and L. aspera develop a cheap, safe and easy method for the protection of stored grains against the insect pest C. chinensis. Keywords: Callosobruchus chinensis, Biopesticide, Justicia adhatoda, Leucas aspera, Insecticides

The Green Depression: American Ecoliterature in the 1930s and 1940s by Matthew M. Lambert

<i>The Green Depression: American Ecoliterature in the 1930s and 1940s</i> by Matthew M. Lambert

Repellent and toxic effects of Salvia rosmarinus oil against Liriomyza sativae

AbstractThe vegetable leafminer (VLM) Liriomyza sativae Blanchard is a troublesome pest of vegetable and ornamental plants worldwide. Resistance development and environmental pollution from the overuse of chemical insecticides have driven interest in alternative control strategies for this pest. Secondary metabolites derived from aromatic nonhost plants are recognised components of the plant defence system against herbivores. The essential oils derived from aromatic plants not only repel insects but also have toxic effects against various insect pests, yet little is known about their effects against leafminers. The major constituents of the essential oil extracted from rosemary leaves by hydrodistillation were identified by GC–MS. The behavioural responses of VLM adults to the rosemary essential oil (REO) were explored with Y‐tube olfactometer experiments, and the oviposition and feeding deterrent effects of REO against adults were studied using no‐choice cage tests. Dipping methods were used to determine the toxicity of REO and Matrine (a commercial botanical pesticide) against VLM eggs, larvae and pupae, while glass‐vial bioassays were used for adults. The identified major constituents of the cineoliferum chemotype of REO were 1,8‐cineole (23.53%), pinene (23.45%), (S)‐(−)‐verbenone (12.84%) and borneol (7.47%). REO repelled leafminer adults. Sublethal concentrations of REO deterred oviposition and feeding by adults. Adults were more susceptible than other developmental stages to toxicity of REO and Matrine. Female adults were more sensitive than males, based on EC50 values at 24 and 48 hr after treatment. Rosemary essential oil is a behaviour‐modifying stimulus potentially useful in a “push‐pull” strategy for L. sativae control, and as an alternative to synthetic chemical insecticides due to its low toxicity and high efficacy in the control of VLM.

In Vitro Insecticidal Effect of Commercial Fatty Acids, β-Sitosterol, and Rutin against the Sugarcane Aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae)

The sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), is the main pest of sorghum, Sorghum bicolor L. Moench (Poaceae), in Mexico. To control this insect, farmers currently use synthetic chemical insecticides, which are toxic to humans and biodiversity. However, natural products are a promising potential source of safer alternative means to control different agricultural pests. The main objective of this study was to evaluate the insecticidal effect of contact by fumigation of pure molecules of four commercial fatty acids (palmitic, stearic, pentadecanoic, and linoleic acids), the phytosterol β-sitosterol, and the flavonoid rutin. The results showed that fatty acids were the most effective against M. sacchari; the highest mortality rate (85%) was produced by linoleic acid and the mean lethal concentration was 1,181 ppm, followed by stearic and palmitic acids with 74 and 63% mortality, respectively, at a concentration of 2,500 ppm at 72 h. The positive control, imidacloprid, had 100% mortality in 24 h and the Tween 20, negative control, exhibited 4% mortality in 72 h. Our results show that commercial fatty acids are effective against adults of M. sacchari and can be considered an environmentally friendly alternative to the frequent use of synthetic chemical insecticides.

Efficacy of the extract from pongam (Pongamia pinnata) leaves against the cassava pink mealybug (Phenacoccus manihoti Matile-Ferrero) under laboratory conditions

The cassava pink mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae), a native of South America, have been one of the most serious pests of cassava (Manihot esculenta Crantz) in the world. Conventional control of this pest is dependent on synthetic chemical insecticides. This study was carried out at Entomology Laboratory, Faculty of Agronomy, University of Agriculture and Forestry, Hue University, Vietnam during 2020 - 2021 to determine the efficacy of leaf extract from Progamia pinnata against the cassava pink mealybug. The efficacy of pongam leaf extract was more efficacious against the first instar than the second instar of P. manihoti, and was according to the evaluation time. After ten days treatment, the efficacy of the leaf extract against first and second instars of P. manihoti was 100% and 50.0, 73.3, 66.7% at concentrations of 2.0, 1.8 and 1.4%, respectively. Therefore, pongam leaf extract can be recommended for protection of the cassava pink mealybug.

Contact Toxicity and Ovideterrent Activity of Three Essential Oil-Based Nano-Emulsions against the Olive Fruit Fly Bactrocera oleae

The control strategies for the olive crop key pest, Bactrocera oleae, involve synthetic chemical insecticides and few eco-sustainable alternatives, such as ovideterrents and lures. In the last few decades, the interest concerning the formulation of botanical based biopesticides increased, but little research investigated the suitability of these approaches for B. oleae control. This research aimed to investigate the residual contact toxicity and the oviposition deterrence of three essential oil (EO)-based nano-emulsions (Pimpinella anisum, Foeniculum vulgare, Mentha × piperita) against B. oleae adult flies. All the nano-emulsions possessed optimal physical characteristics, with droplets dimensions ranging from 115 to 152 nm and low PDI values (&lt;0.2), even after 1 year of storage. Although no notable residual contact toxicity was noted, all the tested formulations reduced the number of oviposition puncture in no-choice tests (percent repellence: mint &lt; fennel &lt; anise). In choice trials, olives treated with fennel and anise EO-formulations at the highest concentration (7.5%, 75 g of EO/L) were less attractive respect to control fruits and a significant reduction of olive punctures was recorded. Nano-biopesticides are promising eco-friendly tools to integrate B. oleae pest management programs and to reduce the use of harmful conventional active ingredients.

Effect of hexane, acetone and methanol extracts of Plectranthus glandulosus on the mortality of the adults of Callosobruchus maculatus and Sitophilus zeamais

Plants extracted substances can constitute the best alternative to synthetic chemical insecticides and a good preservation of the environment because they are biodegradables. The leaves of Plectranthus glandulosus were extracted with hexane, acetone and methanol, then fractionated and tested on adults of Sitophilus zeamais and Callosobruchus maculatus. Corn and cowpea seeds were each administered three (3) different doses (1, 5 and 10 g/kg) of these extracts to assess adult mortality of S. zeamais and C. maculatus. The other percentage of mortality obtained was collected and analyzed. In all cases, the hexane fraction was more effective than that of acetone and methanol because it induced more mortality and it appears that S. zeamais is more vulnerable than C. maculatus to the different extracts. The hexane extracts induced mortality of 98.08% against adults of S. zeamais and 70.00% against adults of C. maculatus in one day of exposure with the dose of 10g/Kg. P. glandulosus extracts can be used as a natural solution against insect plant damage.

Chemical Composition, Antioxidant Activity, Cholinesterase Inhibitor and in Vitro Insecticidal Potentiality of Essential Oils of Lippia multiflora Moldenke and Eucalyptus globulus Labill. on the Main Carpophagous Pests of Cotton Plant in Ivory Coast.

The abusive and repeated use of synthetic chemical insecticides has proven to be harmful to human health and the viability of the cotton production system in Ivory Coast, so it is imperative to find alternatives. . Thus, the objective of this study was to study the chemical composition and biological activity of essential oils of Lippia multiflora (Verbenaceae) and Eucalyptus globulus (Myrtaceae) and to evaluate their insecticidal potential in the laboratory on three main pests of cotton. After essential oils extraction, their chemical composition was determined. Also, antioxidant activity and cholinesterase inhibitor of essential oils were evaluated. After that, different concentrations of the two essential oils were prepared and applied by contact on groups of insects constituted by ten. The essential oil of L. multiflora was the most toxic for the three pests tested. Indeed, the lethal concentrations (LC50 ) were 1.74 %, 1.39 and 7.20 %, respectively, on Pectinophora gossypiella, Thaumatotibia leucotreta and Helicoverpa armigera. In contrast, the values obtained with E. globulus essential oil were nine to two times greater (16.05 %, 10.23 % and 16.32 %, respectively on these pests). With respect to the chemical composition of the essential oils, E. globulus essential oil was the richest in oxygenated monoterpenes (65 %) with 1,8-cineole or eucalyptol as the majority compound (61.6 %). The essential oil of L. multiflora was distinguished by a lower proportion of oxygenated monoterpenes (44.3 %), but it contained more terpene elements (24 vs. 15 for the essential oil of E. globulus). The essential oils of L. multiflora and E. globulus also showed significant inhibition of acetyl (2.13 and 2.16 mg galantamine equivalent (GALAE)/g, respectively) and butyryl cholinesterase (4.03 and 3.61 mg GALAE, respectively). L. multiflora was differentiated by its good inactivation of tyrosinases (163.46 versus 58.95 mg kojic acid equivalent (KAE)/g in E. globulus). Better antioxidant activity was observed with L. multiflora essential oil relative to DPPH (7.05±0.34 mg trolox equivalent (TE)/g). Biopesticides based on L. multiflora essential oil could be developed for the phytosanitary protection of cotton plant.

Mosquitoes Larvicidal Activity of Ocimum kilimandscharicum Oil Formulation under Laboratory and Field-Simulated Conditions.

Simple SummaryMosquitoes are vectors of many severe diseases, notably malaria, yellow as well as dengue fever, and lymphatic filariasis. Vector control with synthetic chemical insecticides has been associated with resistance development and undesirable human and ecological effects. Ocimum kilimandscharicum oil formulation was evaluated for larvicidal activity against third instar mosquito larvae in the laboratory. The formulation was then compared with Bacillus thuringiensis subsp. israelensis (Bti) granules on An. gambiae larvae under field-simulated field trials. The LC50 for O. kilimandscharicum oil after 24 h against third instar larvae of An. gambiae was 0.74 ppm while for the emulsified O. kilimandscharicum oil formulation against third instar larvae of An. gambiae and An. arabiensis was 0.07 and 0.31 ppm, respectively. The high bioactivity and sublethal toxic effects to offspring of treated mosquito larvae in terms of the disruption of larval morphological aspects suggest its high potential as a botanical larvicide for the control of disease vectors. The bioactive formulation had the advantage of high solubility in aqueous media; it is also easily produced, ecofriendly, and low-cost. Moreover, because O. kilimandscharicum can easily be widely cultivated and has high EO yields, it may provide a valuable alternative for the effective and eco-friendly control of disease vectors among developing and developed communities.Mosquitoes are vectors of many severe diseases, including malaria, yellow as well as dengue fever, and lymphatic filariasis. The use of synthetic chemical insecticides for mosquito control has been associated with resistance development and detrimental human, and ecological effects. For a safer alternative, the emulsified Ocimum kilimandscharicum oil formulation was evaluated for its larvicidal activity. The oil was analyzed by GC and GC/MS. The formulations were evaluated against third instar mosquito larvae in the laboratory and later compared with Bacillus thuringiensis subsp. israelensis against An. gambiae under field-simulated conditions. Thirty-nine compounds were identified in the oil, the main ones being D-camphor (36.6%) and limonene (18.6%). The formulation showed significant larval mortalities against An. gambiae and An. arabiensis larvae with LC50 of 0.07 and 0.31 ppm, respectively, at 24 h. Under the field-simulated trial, within 24 h, the formulation showed 98% mortality while Bti had achieved 54%. On day three, it caused 100% mortality while Bti achieved 76.5%. The high bioactivity and sublethal toxic effects to offspring of treated mosquito larvae, in terms of disruption of larval morphological aspects, suggest the high potential of the formulation as a botanical larvicide. The formulation, thus, may provide a valuable alternative for the effective and eco-friendly control of disease vectors.

Influence of Allium Sativum (Garlic), Zingiber officinale (Ginger) and Syzygium aromaticum (Clove) Extract against Larvae of Aedes mosquitoes (Culicidae: Diptera)

Mosquito control has become more difficult due to the unsystematic use of synthetic chemical insecticides which have inauspicious effect on the environment. Botanical phyto-chemicals with mosquitocidal potential are now recognized as potent alternative insecticides to replace synthetic insecticides in mosquito control programs due to their excellent larvacidal activities. The present study assessed the influence of A. sativum (garlic), Z. officinale (ginger) and S. aromatic (clove) extracts against Aedes mosquitoes. Larvacidal activities of three indigenous plant extracts were studied in the range 5.0 to 30.0mg/l in the laboratory bioassay against fourth instar larvae of Aedes sp. The mortality were subjected to probit analysis to determine the lethal concentration (LC50) to kill 50 percent of treated larvae of Aedes sp. Data obtained were analyzed by Comparing experimental groups and control groups with significance level established at p&lt;0.05. All plants tasted showed effects after 24hrs of exposure at different concentration (mg/l). However the highest mortality was found in A. Sativum (garlic) and Z. officinale (ginger) against larvae of Aedes mosquitoes with LC50 = 42.50% (2.685) and LC50 = 30.01% (4.461) mg/l, while S. aromatic(clove) was found to have lowest mortality at LC50 = 24.50% (5.52) respectively. It is therefore recommended that A. sativum(Gallic), S. aromatic (Clove) has showed larvacidal effects against Aedes mosquitoes and could be served as alternative form of botanical control against mosquitoes .&#x0D; Keywords: A. sativum (garlic), Z. officinale (ginger) and S. aromatic (clove), Extracts, Aedes mosquitoes

INSECTICIDAL EVALUATION OF ANISALDEHYDE AGAINST Rhyzopertha dominica [COLEOPTERA: BOSTRYCHIDAE] INFESTING STORED WHEAT GRAINS (Triticum aestivum)

The study investigates the insecticidal potential of Anisaldehyde against the survival of R. dominica infesting wheat grain under laboratory condition. The study was conducted in the research laboratory of Crop, Soil and Pest Management, The Federal University of Technology Akure, Nigeria. The compound was tested at 10, 20, 30, 40 and 50 µl /20g of wheat with 3 replicate each. Adult mortality of the insect was recorded at 24 h for 4 days, adult emergence, % inhibition rate and weight loss was observed. The mode of action of Anisaldehyde using neurotransmitter and digestive enzymes were also observed. It was observed that 50 µl dosage was the most effective among the treatments as it recorded 93.33% insect mortality within 24 h post-treatment and the effect was significantly (p &lt; 0.05) different from other treatments. Only 40 and 50 µl of the compound were able to achieve 100% mortality but their effects were not significantly (p &gt; 0.05) different from 30 µl dosage that recorded 86.67% insect mortality. The result obtained showed that 1.14 and 5.27 µl dosages of the compound are respectively required to achieve 50 and 95 % mortality of the insect at 72 h post-treatment. Both 40 and 50 µl dosage were able to cause 0% adult emergence, 100% inhibition rate and lead to no weight-loss. The 50 µl dose totally inhibited the activity of Acetylcholinesterase while a significant difference exists between the activity of lipase and others. It was evident from all observations that Anisaldehyde compound was effective. The findings also suggested that having displayed a promising insecticidal potential, it can be used as alternatives to synthetic chemical insecticides for the control of stored product insects as a whole.

Application of Essential Oils of Ocimum gratissimum and Cymbopogon citratus as Bioinsecticides for the Management of Two Major Biting-Sucking Insects (Bemisia tabaci Gennadius and Jacobiella fascialis Jacobi) and the Improvement of Seed and Fiber Quality of Cotton Plants in Ivory Coast.

In recent years, in all cotton production areas in Ivory Coast, whitefly (Bemisia tabaci) and jassid (Jacobiella facialis), two biting sucker insects were causing depreciation of quality of the cottonseed and fiber obtained at harvest. However, the excessive use of synthetic chemical insecticides against these pests presents a danger for the sustainability of the production system. This study aims to evaluate the insecticidal efficacy of essential oils of Ocimum gratissimum and Cymbopogon citratus on B. tabaci and J. fascialis and on the technological parameters of the cottonseed and fiber. A field experiment was conducted in which essential oils of O. gratissimum and C. citratus were applied to cotton plants every two weeks from day 45 to 115 after emergence using a backpack sprayer. The effects of these extracts were compared to those of a synthetic chemical insecticide composed of acetamiprid and alphacypermethrin known under the trade name IBIS A 52 EC (positive control). After 160 days of cultivation where entomological data were collected, the seed cotton samples were harvested, ginned and submitted for analysis. O. gratissimum essential oil at concentrations of 1 and 5 % gave to the cotton plants better protection against whiteflies and jassids. In addition to the synthetic chemical, these cotton plants received a better proportion of healthy cottonseed, fat and a fiber with very good reflectivity. The essential oil of O. gratissimum could therefore be integrated into the phytosanitary protection programs of the cotton plant.

Termicidal activity of two agro wastes against two termite castes, subterranean termites, Macrotermes subhyalinus [Isoptera: Termitidae

Toxicity activities of two agricultural wastes, cowpea pod and groundnut shell against worker and soldier termites were investigated under appropriate laboratory conditions (temperature 28±2 °C; 75 ± 5% relative humidity). The agricultural wastes powders were admixed separately at 1 g, 3 g, 6 g, 9 g and 12 g/40 g of wood shaving while wastes extracts was tested at concentrations 1%, 3%, 6%, 9% and 12%/40 g of wood shaving in a 500 ml plastic container. The termiticidal effects of the agricultural waste powders and extracts against worker and soldier termites were examined for 12 and 24 h. Cowpea pod powder caused 100% mortality of workers termite at 12 g after 24 h of exposure. Cowpea pod powder compared to groundnut shell powder was the most toxic to workers and soldiers of termites causing high % mortality at all tested concentrations. Groundnut shell powders also caused 97.5% mortality of soldier termites at concentration 12 g after 24 h of treatment. There were no significant differences (p > 0.05) among the agricultural wastes tested (cowpea pod and groundnut shell extracts) after 24 h of treatment. Cowpea pod extract evoked 100% mortality of workers termite at concentration 9% after 24 h of treatment. Groundnut pod extract was the least toxic to workers and soldiers of termites compared to the effect of cowpea pod extract with higher lethal concentration. The use of agricultural wastes such as cowpea pod and groundnut shell as termiticides will reduce pollution of these wastes in our environment and decrease use of synthetic chemical insecticide.

Assessment of Bacillus thuringiensis var. kurstaki (Bt-127) SC formulation as a component of IPM in soybean through farmer's participatory approach

Insect pests are major biotic constraints limiting soybean production and quality. Soybean growers rely heavily on synthetic chemical insecticides to combat insect pests. Increasing concern for environmental awareness about the use of chemical insecticides has sparked interest in eco-friendly pest management alternatives. An experiment was conducted to assess Bt-127 suspension concentrate (SC) formulation as a component of IPM under real farm situation in Hegdoli village of Kotgiri Mandal, Nizamabad District, Telangana during kharif 2017-18. Incidence of semiloopers (Chrysodeixis acuta and Mocis undata) and tobacco caterpillar (Spodoptera litura) was lowered by 99.5% and 92.9% with the first spray of Bt-127 SC formulation while their incidence was lowered by 99.6% and 97.3%, respectively in farmer's practice with spray of emamectin benzoate. After second spray of Bt-127 SC formulation, incidence of S. litura was lowered by 91.3% and found on par with 91.5% lowering from spray of chlorantraniliprole in farmer's practice. Incidence of natural enemies in IPM field after first and second spray was higher at 0.84 and 0.72 per meter row length in comparison to 0.12 and 0.40, respectively in farmer's practice. The IPM module resulted in higher cost-benefit ratio (1: 2.36) as compared with farmer's practice (1: 1.61).

Evaluation of the insecticidal activity of the methanol extracts of Calotropis procera (Asclepiadaceae) and Albizia lebbeck (Mimosaceae) on larvae of Culex quinquefasciatus Say, 1823

BackgroundVector-borne diseases are mostly transmitted by mosquitoes. Therefore, these mosquitoes constitute a socio-economic scourge. Due to the resistance of mosquitoes to synthetic chemical insecticides and the pollution they generate, this study was conducted to assess the larvicidal activity of plant crude extracts on larvae of Culex quinquefasciatus.ResultsBioassays performed on larvae shown that the extract of Calotropis procera at 0.6 mg/mL recorded the highest mortality rate of 100% for L1, L2 and L3. However, the extract of Albizia lebbeck at 0.7 mg/mL recorded the highest mortality rate of 100% for all the four stages of larvae. Negative and positive controls recorded 16% and 100% mortalities, respectively, after 24 h of exposure. The extract of Calotropis procera recorded LC50 values as follows: 0.194, 0.251, 0.258 and 0.284 mg/mL for L1, L2, L3 and L4, respectively. The LC90 of Calotropis procera were: 0.340, 0.433, 0.444 and 0.502 mg/mL for L1, L2, L3 and L4, respectively. In contrast, the extract of Albizia lebbeck recorded the following LC50: 0.238, 0.264, 0.290 and 0.316 mg/mL for L1, L2, L3 and L4, respectively. Also, its LC90 were: 0.456, 0.498, 0.531 and 0.580 mg/mL, respectively, to L1, L2, L3 and L4.ConclusionThe larvicidal bioassays performed revealed that these plant extracts have significant larvicidal properties. In the framework of fighting against vector-borne diseases, these two plants constitute alternative products to control mosquitoes.

Molecular genotypic diversity of populations of brinjal shoot and fruit borer, Leucinodes orbonalis and development of SCAR marker for pesticide resistance.

The brinjal shoot and fruit borer, Leucinodes orbonalis is a destructive pest of Solanum melongena. The control of L. orbonalis with extensive application of synthetic chemical insecticides resulted in the development of resistance with known genetic heterogeneity among populations. Understanding the genetic diversity of their populations is important in developing strategies for their management. The present investigation was performed to characterize populations of L. orbonalis for their genetic diversity in the entire region of Tamil Nadu, South India using random amplified polymorphic DNA (RAPD) primers as a tool of the molecular marker. Among 60 random 10-mer primers, only ten primers generated reproducible and scorable banding profile. Among the ten different random primers, the primers namely OPG 7, OPG 8, OPS 2 and OPS 7 generated the highest genetic variation with over 80% genetic polymorphism. Phylogram analysis produced 18 clusters with eight major and ten minor clusters. Cluster analysis, statistical fitness, population structure and analysis of molecular variance confirmed the significant genetic variation among different populations. A trait specific marker obtained through RAPD was cloned, sequenced and used to develop a stable diagnostic SCAR marker for DNA fingerprinting to distinguish the populations. Amplification of this locus in the samples of 20 different populations indicated recognition of the trait for pesticide resistance in 12 populations. The results suggest that the biochemical nature of host plant varieties of this insect pest and variation in the application of different insecticides are essential contributing factors for the genotypic variations observed among populations of L. orbonalis.

A review of the management of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) with special reference to biological control using plant extracts

The tomato leaf miner Tuta absoluta is one of the most destructive pests of tomato plant Solanum lycopersicum L worldwide. Synthetic chemical insecticides are mainly used to manage T. absoluta. However, their excessive use has led to serious problems concerning human health, non-target organisms and environnement. Biological control, using bacteria, entomopathogenic fungi, animals and plants remain an eco-friendly alternative for controlling the tomato leaf miner. Here we review the use of biological management of T. absoluta with special reference to control using plant extracts.

Bioactivity of a Linoleic Acid–Rich Fraction of Ricinus communis L. (Euphorbiaceae) Leaves against the Yellow Sugarcane Aphid, Sipha flava (Hemiptera: Aphididae)

The insecticidal activity of a Ricinus communis leaf hexane extract and its fractions against adult yellow sugarcane aphids (Sipha flava) was evaluated using a contact bioassay after fumigation. The n-hexane extract at 10,000 ppm achieved the highest mortality (80%); the positive control had 100% mortality and the negative control had only 4% mortality over the 72-h experiment time. Chemical fractionation of the hexane extract of R. communis leaves produced multiple fractions, and 10,000 ppm of the F4 fraction resulted in 92% aphid mortality at 72 h. Gas chromatography-mass spectrometry of the F4 fraction revealed linoleic acid as the major compound (84.5%). The R. communis n-hexane extract and linoleic acid could be used for integrated pest control as an ecologically friendly alternative to synthetic chemical insecticides.

Insilico Molecular Docking Studies of Volatile Compounds Identified by GC-MS from Tagetes Species Against Mamestra brassicae (Linnaeus, 1758)

Plants evolved to be a potential source of pharmacologically active compounds that are being widely accepted as insect repellent compounds for generations. Products of natural origin are mostly preferred over synthetic compounds because of fewer side effects on human health and the environment, have the potential to be produced locally, cost-effective, and are proved to be more efficient. They are best suited in organic food production and can play a much greater role in developing countries as a new class of eco-friendly products for controlling pests. In turn, the development of repellents is desirable alternatives to synthetic chemical insecticides for controlling pests. In the process of continual search for insect-based repellents of natural origin, a wide number of Tagetes species have been archived and all parts of this plant from root to seed possess a range of phytochemicals that are responsible for the repellent activity. The present study concentrates on the identification of active volatile compounds from Tageteserecta leaves by Gas chromatography-mass spectrometry (GC-MS) analysis and further evaluation through molecular docking studies of identified compounds against Mamestra brassicae.