Plant-based Insecticides Research Articles

Bioassay of Plant-based and Synthetic Insecticides for the Management of Tomato Leaf Miner, Tuta absoluta (Meyrick) in Open-field Conditions in Salyan, Nepal

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most parts of Nepal and threatens tomato production. Their management primarily relies on insecticides in Nepal. Market-available and locally-madeplant-based pesticides are not equally effective in managingT. absoluta. Therefore, this study aimed to evaluate the effectiveness of such potential insecticides in managing T. absoluta in open-field conditions. This study was carried out in the Salyan district of Nepal in 2021 and treatments were designed in a randomized complete block design (RCBD)with seven treatments and three replications. All treatments were sprayed at12-dayintervalsfor two times. The treatments used were Emamect in benzoate 5% SC, Imidacloprid 17.8 SL, Jholmol (botanical mixture extract and urine mixture), Chlorantraniliprole 18.5 SC, Spinosad 45 SC, Azadirachtin 300ppm and Control. The results showed that the lowest percentage of leaves and fruit damage was recorded in Chlorantraniliprole 18.5 SC and Spinosad 45 SC sprayed plots. Insecticide efficiency was ranked as Chlorantraniliprole > Spinosad>Ema-mectin Benzoate > Azadirachtin >Imidaclroprid>Jholmol>Control. Marketable yield was obtained highest in Chlorantraniliprole (85.26 t/ha) treated plots followed by Spinosad (79.26 t/ha); both were not significantly different. This study provides an opportunity to select the most suitable and effective pesticides for the management of tomato leaf miners and can be used in integrated pest management strategies as a selective insecticides.

Efficacy of plant-based products and nonconventional pesticides for the management of tropical bed bug.

Insecticide resistance is widespread in global bed bug populations. Both common bed bugs and tropical bed bugs are pyrethroid-resistant among most field populations. Plant-based products and nonconventional pesticides offer minimal-risk strategies for managing bed bug resistance, but this strategy has yet to be formally evaluated in Cimex hemipterus (F.) (Hemiptera: Cimicidae). Here, several commercial plant-based formulations (Cedarcide, EcoRaider (also known as EcoVenger), EcoSMART, and Bio-D), a novel product, Provecta, and a pyrethroid insecticide, Pesguard FG161 were tested against pyrethroid-susceptible and resistant strains of C. hemipterus using direct spray, residual exposure, and egg dipping assays. Direct spray treatments outperform residual applications against all tested bed bug strains. Cedarcide exhibits the highest consistency in eliminating bed bugs, followed by EcoRaider, EcoSMART, and Provecta that outperform Bio-D and Pesguard FG161. In comparison to Pesguard FG161, all plant-based insecticide products and Provecta showed higher efficacy against pyrethroid-resistant strains. Although effective, product efficacy varies in terms of speed. Cedarcide kills all bed bugs within 1 min after spraying; however, other products can take up to 9 days to achieve 100% mortality. The efficacy of all products was reduced when evaluated on fabric surface (42%-65% mortality). Cedarcide and EcoRaider reduced egg hatchability by 37%-73% and 47%-70%, respectively. This study suggests that certain plant-based insecticides and an unconventional insecticide can serve as alternative direct spray treatments for managing tropical bed bugs, though their residual effects are limited.

Molecular identification and eco-friendly management of rice brown planthoppers in Bangladesh

Infestation by various insect pests is the main constraint for growing rice where rice brown planthopper (Nilaparvata lugens Stål) can severely damage rice plants directly through feeding. Therefore, the study aims to detect rice brown planthoppers (BPH) and provide environment-friendly management tactics to mitigate the problem which caused by brown planthoppers. The BPH samples were collected from rice fields of different locations in the Patuakhali of Bangladesh for molecular identification. A molecularly single species of rice brown planthopper, Nilaparavata lugens was identified using mitochondrial cytochrome oxidase subunit I (mtCOI) universal marker. The nucleotide sequences of collected samples were compared with other nucleotide sequences from the GenBank database of NCBI, which make single clades in the phylogenetic tree at an insignificant distance. Moreover, brown planthopper management observations were recorded in laboratory conditions after providing an artificial diet with different treatments of plant-based insecticides Neem oil (1 %, 5 %, and 10 %), Castor oil (1 %, 5 %, and 10 %) where only 20 % sucrose solution was used as negative control and Abamectin (1 %, 5 % and 10 %) were also used as a positive control for comparing the efficacy of plant-based insecticides on rice brown planthoppers. The results showed the highest mortality (100 %) of rice brown planthoppers was recorded by Abamectin 10 %, followed by Abamectin 5 %. Neem 10 % performed better than Abamectin 1 % during 1st hour. Initial after exposure of 2nd hour for Abamectin 1 % revealed greater mortality (59 %) than Neem 10 %. Neem 5 % showed less effect on mortality in brown planthopper than Neem 10 % but was higher than Neem 1 % during 6 h of observation. The Castor oil of 10 % caused higher mortality than the Castor of 5 % but not up to the marks of Abamectin and different concentrations of Neem oil. Castor oil of 1 % and control have shown no mortality of brown planthopper for 6 h of observation.

Insecticidal Activities of Securidaca longepedunculata Fresen Extracts and Feeding Behavior of Schizaphis graminum Rondani: Electropenetrography Approach.

The aphid, Schizaphis graminum Rondani (Hemiptera: Aphididae), is one of the most destructive pests of wheat. It is responsible for significant economic losses in the agricultural sector, with an estimated 45% of wheat fields affected. Plant-based insecticides have seen a rapid increase in popularity in recent years due to their efficacy, cost-effectiveness, biodegradability, and lower toxicity compared to synthetic pesticides. The study aimed to evaluate the toxic potential of S. longipedunculata extracts against S. graminum and investigate the insect's feeding behavior on wheat. Initially macerated in methanol, the different extracts of S. longipedunculata organs were fractionated using n-hexane, chloroform, ethyl acetate, and butanol. The feeding behavior was analyzed by comparing the waveforms generated by the EPG with the control. After 72 h of treatment, the ethyl acetate fraction extracted from root had the highest toxicity against aphids, with mean 26 mortality of S. graminum at LC50 of 330 ppm; 25 mortality S. graminum at LC50 of 400 ppm for leaves; and mean 24.5 mortality S. graminum at LC50 of 540 ppm in stem bark. EPG analysis indicated that the extract fractions enhanced plant tissue resistance by significantly preventing aphid access to the phloem. The toxic effect of the botanical extracts significantly enhanced the chemical composition of the leaf medium, resulting in a drastic reduction in the number of tissue attacks by S. graminum. In summary, besides their toxicity to S. graminum, extracts of S. longipedunculata reinforce the plant's defense mechanisms, significantly reducing the S. graminum population. They also reinforce wheat's defense mechanisms. S. longipedunculata can, therefore, be used as a promising agent in the biological control of S. graminum.

Moringa Leaf Powder as Environmentally Friendly Repellent Agent for Controlling the Warehouse Insect Pest for Black Soybean Grain

Black soybean grain (Glycine max L. Merril.) storage is susceptible to insect pests such as Callosobruchus analis (F.), which feeds on soybeans. Steroids/triterpenoids, phenolics, alkaloids, tannins, and terpenoids found in moringa leaf powder can be employed as insect repellents in black soybean grain warehouses. The purpose of this study was to ascertain how applying plant-based insecticides made from powdered moringa leaf will affect the amount of C. analis (F.) that died, the severity of the damage, and the weight loss of black soybean seeds of the Detam 4 Prida varieties. The study took place from August to October 2019 at an elevation of 878 meters above sea level in the Biology Laboratorium of the Agriculture Faculty, University of Winaya Mukti. An experimental design including five treatments and five replications was employed as the research methodology. A was not given any moringa leaf powder; B, C, D, and E each received 0.25, 0.75, and 1 grams of moringa leaf powder, fine powder, and so on. 10 pairs of C. analis (F) per jar were used in each treatment, which involved 100 g of black soybean grain. In the storage of black soybean grain, the percentage of seed damage, weight loss, the number of eggs, larvae, pupae, and images, and mortality of C. analis (F) were all impacted by 0.75 g of moringa leaf powder, according to the findings. According to this research, C. analysis, a warehouse insect pest, is effectively repelled by powdered moringa leaf (F.).

Evaluation of the Efficacy of Several Plant-Based Insecticides and Aqueous Nano-Silica Formulations Against the Rust-Red Flour Tribolium castaneum (Herbst.) Under Laboratory Conditions

Laboratory studies were conducted to evaluate the effects of plant-based insecticides such as Tandexir and Balizin, hydrophilic nanosilica compounds in addition to biopesticides synergistic with nanocompounds to estimate the effects of rust-red flour beetle Tribolium castaneum the mortality percentage Efficacy was evaluated. The results showed the effectiveness of tundexir insecticide with a statistically significant difference of up to 75% in obtaining higher mortality rate, compared to Balizin which obtained a rate of 63.61%. Furthermore, the results showed that 4 ml liter-1 dose of Tandexir was more effective than Balizin with a statistical difference after 5 days of treatment, resulting in mortality rates of 93.33% and 83.33%, respectively. For both formulations, a dose of 4 ml litre-1 was the most effective in obtaining mortality, and 100% was recorded after 7 days of treatment The results of the efficacy study of the nanosilica formulations showed that the 0.4 g liter-1 dose showed high mortality at 100% after 7 days of treatment, when mortality time was obtained comparing dosages of 0.2 and 0.3 g liter-1 in at the same time 76 .66% and 83.33%. The results showed that using plant-based insecticides at a concentration of 2 ml per liter of water, together with 0.2 grams per liter of a water-friendly nanosilica compound, worked really well together. Tundexir exhibited superior performance in achieving higher mortality rates, reaching 100% after 7 days of treatment, with a mortality rate of 84.16%, compared to Balizin, which achieved a mortality rate of 96.66% at a concentration of 77.50%.

Adulticidal Activities and Synergistic Effects of Citrus Aurantiifolia Peels and Hyptis spicigera Leaves Essential Oils against Anopheles gambiae s.l. (Diptera: Culicidae)

Research on new plant-based insecticides meets the need for an alternative to address mosquito resistance to synthetic insecticides. This study assessed the adulticidal activity and synergistic effects of essential oils (EOs) from Citrus aurantiifolia peels and Hyptis spicigera leaves on female adults of Anopheles gambiae s.l. The extraction yields were on the order of 0.17 and 0.11%, respectively, for C. aurantiifolia and H. Spicigera EOs obtained by hydrodistillation. The phytochemical composition of the EOs was analysed by Gas Chromatography coupled with Mass Spectrometry (GC-MS). GC-MS revealed that the essential oils of C. aurantiifolia and H. spicigera contained high amounts of monoterpene compounds (100% and 77.45%, respectively). Adulticidal activity was assessed using WHO and CDC bottle bioassays at concentrations of 2.5, 5, 7.5 and 10 mg/ml/btl. The EOs of both plants caused significant concentration-dependent Knock down and adulticidal activities. Individually, H. spicigera EOs had more adulticidal effects (LC50 = 4.42 mg/ml/btl) than did C. aurantiifolia EOs (LC50 = 6.79 mg/ml/btl). An EO mixture 25%Ca + 75%Hs from C. aurantiifolia and H. spicigera had synergistic effects (CI = 142.84; SF = 1.42) on female Anopheles gambiae adults. Combinations of the two plant EOs considerably optimize their insecticidal effectiveness.

Studies on the mechanism of the contact toxicity of carvone against Tribolium castaneum

Carvone exhibits significant insecticidal activity against Tribolium castaneum. Whereas, the precise underlying mechanism of carvone's toxicity remains elusive. In this study, we aimed to investigate the contact toxicity mechanism of carvone on T. castaneum through a comprehensive set of experiments. These experiments included observation of poisoning symptoms in T. castaneum, a time-mortality test, analysis of weight measurement and respiration activities, histological assessment, enzymatic assays, and molecular simulation studies. Physiological analyses show that carvone induces excitement, spasms, and a comatose state in T. castaneum, accompanied by darkening of the body surface. Survival rates significantly dropped by 44% after 8–12 h of carvone treatment. Carvone also affects metabolism, increasing CO2 release and body weight loss. Histopathological examination reveals changes in the body wall structure, including wax particle shape alterations, increased gaps, and damaged hair bases. Abdominal tissue examination shows impacts on muscle and fat tissues, leading to dehydration and impaired physiological functions. Key enzymatic assays demonstrate sustained inhibition of acetylcholinesterase and succinate dehydrogenase activity by carvone, with peak inhibition rates reaching 65.15% and 39.90%, respectively. Carvone exhibits a biphasic effect on ATPases and activates glutathione S-transferase while inhibiting carboxylesterase activity. Molecular docking analysis reveals direct interactions between carvone and acetylcholinesterase in T. castaneum, suggesting its inhibition mechanism. This study provides insights into the insecticidal mechanism of carvone on T. castaneum and contributes to the development of plant-based insecticides.

Development and characterization of potential larvicidal nanoemulsions against Aedes aegypti.

Plant-based insecticides offer advantages such as negligible residual effects, reduced risks to both humans and the environment, and immunity to resistance issues that plague conventional chemicals. However, the practical use of monoterpenes in insect control has been hampered by challenges including their poor solubility and stability in aqueous environments. In recent years, the application of nanotechnology-based formulations, specifically nanoemulsions, has emerged as a prospective strategy to surmount these obstacles. In this study, we developed and characterized nanoemulsions based on cymene and myrcene and assessed their toxicity both in vitro using human keratinocytes (HaCAT) cells and in an in vivo model involving Galleria mellonella larvae. Additionally, we investigated the insecticidal efficacy of monoterpenes against the mosquito Aedes aegypti, the primary dengue vector, via larval bioassay. Employing a low-energy approach, we successfully generated nanoemulsions. The cymene-based nanoemulsion exhibited a hydrodynamic diameter of approximately 98 nm and a zeta potential of -25 mV. The myrcene-based nanoemulsion displayed a hydrodynamic diameter of 118 nm and a zeta potential of -20 mV. Notably, both nanoemulsions demonstrated stability over 60 days, accompanied by controlled release properties and low toxicity towards HaCAT cells and Galleria mellonella larvae. Moreover, the nanoemulsions exhibited significant lethality against third-instar Aedes aegypti larvae at a concentration of 50 mg/L. In conclusion, the utilization of nanoemulsions encapsulating cymene and myrcene presents a promising avenue for overcoming the limitations associated with poor solubility and stability of monoterpenes. This study sheds light on the potential of the nanoemulsions as effective and environmentally friendly insecticides in the ongoing battle against mosquito-borne diseases.

Chemical analysis and hydroalcoholic extract activity of ferns on the mutualist fungus of leafcutter ants

Abstract Leafcutter ants are among the most important agricultural and forest pests in the Neotropical region, given that they use plant matter as substrate for the growth of their mutualist fungus Leucoagaricus gongylophorus. Plant-based insecticides and fungicides have shown potential for controlling these ants. The present study assessed the hydroalcoholic extract activity of four fern fronds (dry and rainy periods) on the mutualist fungus of leafcutter ants. Fungal mycelium suspensions were seeded on the surface of tubes containing fern extracts at a concentration of 5 mg/mL and 100 μg/mL. The chemical profile of the extracts was analyzed by thin layer chromatography (TLC). Extracts (dry period) at a concentration of 5 mg/mL inhibited the growth of the fungus: Macrothelypteris torresiana and Dicksonia sellowiana (less than 20%), Niphidium crassifolium (approximately 40%), Parapolystichum effusum extract (100%). None of the extracts (dry and rainy periods) inhibited fungal growth at a concentration of 100 μg/mL. The chemical profile analysis of the extracts indicated the presence of beta-sitosterol, friedelinol, rutin, and kaempferol. The crude extracts of P. effusum and N. crassifolium were the most promising in future formulations of antifungal products. Thus, ferns are potential plants in the search for environmentally-friendly substances for sustainable agriculture.

Variations of Gadung Tuber Extract (Discorea hispida) and Boric Acid in Gel Form as Cockroach Bait (Blatella germanica)

Cockroaches are disease vectors that pose health and aesthetic problems. Traditional control methods use insecticides, which are becoming ineffective and environmentally harmful due to residue. An alternative method involves gel bait with plant-based insecticides, such as grading tubers, which are toxic to insects. This research aims to determine the optimal combination of grading tuber extract and boric acid in gel bait by calculating LC50 and LT50. Conducted at the Yogyakarta Health Polytechnic Vector and Animal Control Laboratory in February-March 2023, the study used a proper experimental design with a post-test-only control group. Five treatments were tested with five repetitions each, using 125 female cockroaches (Blatella germanica) selected via purposive sampling. Mortality data were analyzed using One Way Anova, LSD tests (p-value < 0.05), and probit regression. Results showed significant differences in mortality rates among treatments (p-value = 0.000). Variation C had the highest mortality rate, while variation B was the most effective, with an LC50 of 7.227 g. LT50 values were 99.237 hours for 5 g, 93.797 hours for 10 g, and 73.463 hours for 15 g. This study concludes that gel bait with grading tuber extract and boric acid is a promising alternative for cockroach control.

Comparative Study of Cat’s Whiskers Leaves (Orthosiphon stamineus) and Mint Leaves (Mentha arvensis) as Repellent For Houseflies

House flies (Musca domestica) are one of the challenging pests that are difficult to overcome and control. Common control methods usually involve the use of chemical insecticides, but a more environmentally friendly alternative is to use plant-based insecticides with repellent properties. Medicinal plants from the Lamiaceae family are famous for their distinctive aroma and are effective in treating pest problems. This research aims to evaluate the potential of cat's whisker leaves and mint leaves as housefly repellent. The repellency test used cotton impregnated with extract concentrations of 2,000 ppm, 4,000 ppm, 6,000 ppm, 8,000 ppm and 10,000 ppm. Exposure time was 30 minutes and carried out 3 times. The repellency percentage is then calculated. The results of the research showed that at concentrations of 2,000 ppm and 4,000 ppm there were still some flies landing, but at concentrations of 6,000 ppm, 8,000 ppm and 10,000 ppm no flies landed. Strong repulsion was observed at concentrations of 2,000 ppm (86.7% for cat's whisker leaf extract and 82.7% for mint leaf extract) and 4,000 ppm (96% for cat's whisker leaf extract and 88% for mint leaf extract). Both extracts showed very strong repulsion (100%) at concentrations of 6,000, 8,000 and 10,000 ppm. These results show that the higher the concentration, the stronger the repellent effect produced. In conclusion, cat's whiskers and mint leaves have potential as active mosquito repellent ingredients, and this research can be the basis for further development as a pest control method, especially against houseflies.

The Effect of Plant-based Insecticides Contains Active Eugenol and Azadirachtin on Immune System of Common Carp (Cyprinus carpio L.)

This study aims to investigate the toxicity effects of plant-based insecticides containing eugenol and azadirachtin on the immune system of Common Carp (Cyprinus carpio L.). Several immunological parameters, including white blood cell count, red blood cell count, stress response, and macroscopic clinical symptoms, were examined [1]. The study was conducted from September to October 2022 at the Ciparanje Inland Fisheries Hatchery, Faculty of Fisheries and Marine Sciences, Universitas Padjadjaran. This study employed a completely randomized design with six treatments and three replications. The observation period encompassed the measurement of red and white blood cell counts, stress response, and macroscopic clinical symptoms for the initial 14 days. Leukocyte and erythrocyte counts were assessed before and after insecticide exposure on days 3, 7, 10, and 14. Data analysis involved the utilization of quantitative descriptive analysis for red and white blood cell counts. Exposure to plant-based insecticides containing eugenol and azadirachtin resulted in a suppression of the immune system in common carp fry. However, the insecticide treatment with a concentration of 64 ppm (Treatment F) remained safe for common carp. The highest count of white blood cells was observed in Treatment F (64 ppm) on day 3, while the lowest count was recorded in Treatment A (control). Treatment A (control) also exhibited the highest count of red blood cells, whereas Treatment F (64 ppm) displayed the lowest count. Thus, plant-based insecticides with a concentration of 64 ppm can still be safely utilized in common carp.

Behavioral, Electrophysiological, and Toxicological Responses of Plutella xylostella to Extracts from Angelica pubescens.

Plutella xylostella L. is a destructive pest affecting cruciferous vegetables, causing massive economic losses worldwide. Plant-based insecticides are considered promising insect control agents. The Angelica pubescens extract inhibited female oviposition, with an oviposition deterrence index (ODI) of 61.65% at 12.5 mg/mL. We aimed to identify the bioactive compounds in A. pubescens extract. The compounds from A. pubescens extract were analyzed using LC-MS techniques. The toxicity and behavioral responses of larvae and adults of P. xylostella to ten compounds were investigated. We found that the caryophyllene oxide and 3,4-dimethoxycinnamic acid inhibited female oviposition; the ODIs were 98.31% and 97.59% at 1.25 mg/mL, respectively. The A. pubescens extract, caryophyllene oxide, and 3,4-dimethoxycinnamic acid caused larval mortality, with LC50 values of 21.31, 4.56, and 5.52 mg/mL, respectively. The EAG response of females was higher than that of males under A. pubescens extract conditions, while the EAG response of males was higher than that of females in caryophyllene oxide and 3,4-dimethoxycinnamic acid conditions. The A. pubescens extract and caryophyllene oxide showed repellent activity against both female and male adults, while the 3,4-dimethoxycinnamic acid did not elicit any notable behavioral responses from P. xylostella adults. A. pubescens extract and caryophyllene oxide are potential insecticides, oviposition deterrents, and behavioral regulators against P. xylostella, and they could be potential candidates for the development of biological insecticides to control P. xylostella.

Wood Vinegar as an Alternative Insecticide in Controlling Rice Weevil, Sitophylus oryzae (Coleoptera: Curculionidae)

Rice production faces many challenges including damages due to pest infestation in storage after harvest. Stored rice grains are often under threat and damage from pests such as rice weevil which resulted in reduction of the quality and quantity. Application of chemical insecticides helps to control this pest, however, it gives negative impacts to the environment and human health. Application of plant-based insecticides including the use of wood vinegar can become an alternative to the conventional method. This work describes the effectiveness of wood vinegar as bioinsecticide to inhibit the rice weevil’s activity by assessing the repellency, mortality and antifeedant activity at different concentration of 50, 100, 150 and 200 rpm. Wood vinegar showed high repellency of 98.3% towards rice weevils at 200 ppm after 5 hours of exposure times. Increased in concentration affects in increased mortality with highest number of 97% recorded at 200 ppm. The lethal concentration (LC) of wood vinegar was calculated to be 77.62 ppm. Antifeedant activity resulted in reduction of weight loss in stored rice with lowest reduction of 2% at 200 ppm. This promising result reflects the ability of wood vinegar as insecticidal agents in management and control of stored-grain pest.

Activity of enzyme Esterase, Glutathione S Transferase and Inorganic Substance of Dengue vector Aedes aegypti larvae against Lansium domesticum leave extract and fractionation

Backgound: Dengue vector control using chemical insecticides for a long time on the same target encourages the rapid development of a resistant dengue vector population of Aedes aegypti. Therefore, an alternative method is needed in the form of the use of plant-based insecticides, Lansium domesticum or duku has been proven to contain secondary metabolites that have the potential as insecticides. This study was conducted to measure the activity of enzyme esterase and glutathione S-transferase, as well as to observe the concentration of inorganic substances such as Fe, Mg, Na, and K in Ae. aegypti larvae exposed to L. domesticum extract using methanol as the solvent and fractionation using hexane, butanol, and ethyl acetate as the solvents. Methods: This study used Ae. aegypti larvae and L. domesticum leaves extract and fraction. Esterase activity was measured using a spectrophotometer at λ = 490 nm and obtained as light absorption per minute per mg protein. GST activity was measured using a spectrophotometer at λ = 340 nm and expressed as light absorption per minute per mg protein. Inorganic substance level was evaluated by the absorbance of the atoms using an atomic absorption spectrophotometer which was analyzed at certain wavelengths of each atom according to Beer's law equation Results: The results showed LD50 and LD90 of the crude extract of L. domesticum were 2200ppm and 3200ppm after 24 hours of observation. Crude extract and the fraction of L. domesticum leaf influenced the development of Ae. Aegypti. It reduced the activity of the esterase enzyme. Meanwhile, it increased the GST enzyme activity of Ae. aegypti larvae as well as affects the levels of inorganic substances in Ae. aegypti larvae. Conclusion: Thus, L. domesticum as a plant-based insecticide is an alternative to control the vector whose target is more selective and safe.

UJI BEBERAPA KONSENTRASI EKSTRAK TEPUNG DAUN PAITAN (Tithonia diversifolia A. Gray) TERHADAP MORTALITAS LARVA PENGGEREK TONGKOL JAGUNG Helicoverpa armigera Hubner

Borer pest of corn cobs (Helicovepa armigera Hubner) is a major pest of corn. Pest control can be done using plant-based insecticides from paitan leaf extract (Tithonia diversifolia A. Gray). This study aims to obtain the best concentration of paitan leaf extract in controlling corn cob borer Helicoverpa armigera. The study was conducted at the Plant Pest Laboratory of the Faculty of Agriculture, University of Riau. The research was carried out using a completely randomized design (CRD), consisting of 5 treatments and 4 replications. The treatments used were several concentrations of paitan leaf extract, namely 0 gl-1, 25 gl-1, 50 gl-1, 75 gl-1and 100 gl-1. Parameters observed were initial death, lethal time 50, lethal concentration (LC50 and LC95), daily mortality, and total mortality. data. Data were collected from daily mortality and then descriptively analyzed and displayed graphically. Data lethal concentration (LC50 and LC95) were analyzed probit using the POLO-PC program, while other data such as initial death, total mortality, and lethal time (LT50) were analyzed with analysis of variance. Data from the variance analysis with significant effect will be continued using the smallest significant difference (LSD) test at the 5% level. Results showed that the application of paitan leaf extract with a concentration of 100 gl-1 water was able to control H. armigera with mortality of 55.00%. The proper concentration to lead mortality of 50% of larvae H. armigera was 10.3% or equal to 103 gl-1 of water of paitan leaf extract. Meanwhile, the proper concentration to lead mortality of 95% of larvae population H. armigera was 44.7% or equivalent to 447 gl-1 water of paitan leaf extract.

The potentials of Pangi leaf extract for Aedes spp. mosquito control

Aedes spp. are the primary vectors of arboviruses such as dengue, Zika, and chikungunya. To date neither an approved vaccine nor a drug that can definitively prevent or treat these diseases, vector control continues to be an essential method of disease prevention. Plant-based insecticides are an alternative to chemical insecticides because they are less toxic to non-target insects and degrade more quickly. The Papuan people have used Pangi leaves for generations as a potent natural chemical against head lice and mosquito larvae. This study aimed to evaluate the potential of pangi (Pangium edule) leaf extract as a biolarvicide and mosquito repellent. Fresh pangi leaves were extracted with water by using a blender to pulverize the leaves. One-way ANOVA was used to examine the variance in mortality rates, and the LC50 value was calculated for probit analysis. Dead larvae were identified and counted. In addition to testing the effectiveness of the extracts as biolarvicide, the extract was also tested as potential insect repellents. The findings demonstrated that pangi leaf extract can kill mosquito larvae. The concentration of the extract affected larval mortality. Furthermore, the extract demonstrated its effectiveness as an insect repellent. Pangi leaf extract contains alkaloids, flavonoids, tannins, saponins, phenolic compounds, and cyanide compounds, with alkaloids being the most abundant. The study found that there was a direct correlation between the concentration of the insecticide and the number of dead Aedes spp. larvae. The LC50 probit test revealed that pangi leaf extract belongs to the category of toxic substances. Several compounds, including alkaloids, flavonoids, tannins, saponins, and cyanide, may be responsible for the toxicity of pangi leaf extract. Thus, pangi leaf extract might be established as a means of overcoming numerous health issues caused by mosquito vectors.

Potential of neem oil extract® against Palmetto weevil larvae, <em>Rhynchophorus cruentatus </em>Fabricius (Coleoptera: Curculionidae) and its impact on some detoxification enzymes

Palmetto weevil, Rhynchophorus cruentatus (Fabricius) (Coleoptera: Curculionidae), is considered the giant weevil in North America (Weissling & Giblin-Davis, 1997). It is a severe pest of palm trees, especially cabbage palms (Sabal palmetto). Larval stages feed heavily on the internal palm soft tissues causing total palm loss (Hunsberger et al., 2000). We know that reports about controlling this pest are very scarce. This research project focuses, for the first time, on controlling Rhynchophorus cruentatus via plant-based insecticides. This study examined the potential of using neem oil extract®, a commercial product, against the third-instar larvae of palmetto weevil (R. cruentatus). Impacts of neem oil extract® on mortality, larval weight, the activity of detoxification enzymes, and thei gene expression levels were examined. Neem oil extract® manifested dose-dependent larvicidal activity against the third-instar larvae of R. cruentatus. Investigations revealed higher mortality and reduction in weight 24 hours post-treatment. LC50 and LC90 values were estimated 24 h post-treatment to be 12.04% and 26.48%, respectively. Biochemical analysis revealed increasing activities of three detoxification enzymes (Acetylcholinesterase, Glutathione S-transferase, and Superoxide dismutase) in the third-instar larvae after 8 h of treatment with LC50. A significant elevation in the expression levels of detoxification genes (Acetylcholinesterase, Glutathione S-transferase, Cytochrome P450, and Superoxide dismutase) was recorded in the treated larva. Our findings help to underline the detoxification mechanisms of R. cruentatus larva against neem oil extract® at both biochemical and molecular levels. Thus, neem oil extract® had a lethal potential against third-instar larvae of R. cruentatus and is suggested as a safe bioinsecticide that may be used in IPM of palm trees as an alternative to chemical insecticides.

Efektivitas Kombinasi Ekstrak Lidah Buaya dan Lidah Mertua Terhadap Mortalitas Larva Aedes aegypti

The Dengue Haemoragic Fever (DHF) vector control with synthetic larvicide has an impact on health and environmental problems, so alternative plant-based insecticides are needed. The study aims to determine the larvicidal effect of a combination with Aloe vera extract and Sansivieria trifasciata on the mortality of Aedes aegypti larvae. This study was conducted with experimental design by a post-test only with control groups design consisting of five groups. Two groups are positive control (1% temephos) and negative control (0% concentration). The other three groups served as a combination of Aloe vera extract and S. trifasciata Prain in ratio of 75%:25% (P1), 50%:50% (P2), and 25%:75% (P3). A total of 375 larvae were introduced in this study with three replications and with observation time of 30 minutes, 1 hour, 3 hours, 6 hours, 12 hours, 24 hours until totally died 100%. The mortality of Aedes aegypti larvae were analyzed by Kruskal Wallis and probit analysis to calculate LC50 and LC90. The larvae totally died 100% after 12 hours of exposure. There are significant differences in the mortality of Ae. aegypti larvae after administration of a combination with Aloe vera extract and S. trifasciata Prain. The P1 group (The combination with Aloe vera extract and S. trifasciata Prain with a ratio of 75%:25%) was the most effective in mortality of Ae. aegypti larvae. The LC50 value is 0.517% while the LC90 value is 2.121% within 6 hours. The combination group of Aloe vera extract and mother-in-law's tongue with a ratio of 75%:25% was the most effective in causing mortality of Ae. aegypti within 6 hours.