Natural Insecticides Research Articles

INSECTICIDAL AND REPELLENT ACTIVITIES OF FOUR PLANT EXTRACTS AGAINST COTTON APHID APHIS GOSSYPII GLOVER (HOMOPTERA: APHIDIDAE) UNDER LABORATORY CONDITIONS

In this study, four chosen wildlife plants (Caralluma tuberculata, Capparis spinosa, Marrubium vulares, and Argemone ochroleuca) were extracted by ethanol and tested for their biological and toxicological properties against the cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae), in a lab setting. The outcomes showed that the toxicities of different plant extracts against the cotton aphid A. gossypii varied. After 24 hours, the cotton aphid A. gossipyii displayed the highest mortality rate (91.67%) when treated with at 500 ppm concentration of Caralluma extract. These results were followed by 88.33, 83.33, and 75.83% mortalities when aphids were treated with the extracts of Capparis, Marrubium, and Argemone, respectively at the same concentration and observed time. When Caralluma (66.46 and 53.35 ppm) and Capparis (97.18 and 69.28 ppm) were treated after 24 and 48 hours, respectively, the LC50 values of cotton aphid A. gossipyii were significantly reduced. Also, the plant extract from Argemone demonstrated moderate repellent activity, as evidenced by the repellency rate of 73.33 at 500 ppm, while the plant extract from Caralluma had the highest repellent percentage of 97.78% at 500 ppm, followed by Capparis (93.33%) and Marrubium (86.67%) at the same concentration. In conclusion, the ethanolic extracts of C. tuberculate and C. spinosa demonstrate their potential uses as promising natural insecticides for aphid control.

Cocktail effect and synergistic mechanism of two components of Perilla frutescens essential oil, perillaldehyde and carvone, against Tribolium castaneum

Tribolium castaneum (Herbst) is one of the most harmful insects in stored products. The objective of the current study was to search for active constituents of Perilla frutescens (L.) Britt. essential oils from three localities against T. castaneum, as well as to investigate the optimal formula of active constituents and their synergistic mechanism. A total of 38 constituents were identified from the three essential oils by gas chromatography-mass spectrometry (GC-MS) according to the mass spectra and retention index values, and the relative contents of the individual components were determined by the peak normalization method. The following major compounds were identified: perillaldehyde, (R)-(-)-carvone, 2-furyl methyl ketone, d-limonene, and β-caryophyllene. Contact toxicity was assessed by topical application under room temperature, and the insects were reared in a dark incubator for 24 h at approximately 30 °C and 75 % humidity. Of these compounds, perillaldehyde (LD50 =7.71 μg/adult) and R-(-)-carvone (LD50 =10.93 μg/adult) displayed the most significant contact activities against T. castaneum. Synergistic interactions between perillaldehyde and R-(-)-carvone were evaluated using Wadley's model. All nine tested formulas displayed synergistic effects against T. castaneum, and a 1:4 (v:v) mixture exhibited an intense cocktail effect by dramatically reducing the LD50 to 2.73 μg/adult. The results of the RNA-Seq and qRT-PCR analyses suggested that the synergistic effect could be attributed to a reduced capacity for detoxification and elimination of xenobiotics. Three cytochrome P450 genes (CYP6BQ11, CYP6BQ7, and CYP6BK5) in phase I and two multidrug resistance protein genes (MRP4a and MRPX4) in phase III of the detoxification process may play essential roles. These findings provide a basis for the development of novel natural insecticides for the control of storage pests.

Evaluation of essential oils and diluents against Chrysomya megacephala, an important mechanical vector

Chrysomya megacephala represents a major threat to public health. It is a mechanical vector of various pathogens, such as viruses, bacteria, and protozoan cysts, while their larvae may cause myiasis. The alternative to synthetic insecticides, which are harmful to the environment and man`s health, is to use natural insecticides that are safe for both. Plant derivatives have gained prominence in this field, but little is known about how the diluents used in the formulations can influence the insecticidal activity, and the physiology of insects. In this work, among the diluents tested, ethanol, DMSO and miglyol did not affect the viability and the development of C. megacephala, while propylene glycol and mixtures containing Tween® 20 or Tween® 80 caused mortality and increased the total development time from newly hatched larvae to adult. Furthermore, essential oils and their compounds were solubilized in selected diluents to evaluate their insecticidal activities against C. megacephala. Lippia sidoides essential oil, which contained 96.14% thymol, caused mortality of 90%, while Laurus nobilis essential oil caused mortality of 63.7%. The monoterpenoids 1,8-cineole at 125 μg/μL and linalool at 30 μg/μL, that are the main constituents of L. nobilis essential oil, caused mortality of 67.6% and 100% respectively. These effects were confirmed by scanning electronic microscopy. The present study also showed that linalool and the thymol-enriched fraction of L. sidoides essential oil were as active as the synthetic insecticide used as positive control.

Assessing diversity and phylogeny of Indonesian breadfruit (Artocarpus spp.) using internal transcribed spacer (ITS) region and leaf morphology

BackgroundBreadfruit (Artocarpus spp.) is the main genus of Moraceae with multipurpose benefits, both ecologically and economically important, e.g., food ingredients, building materials, traditional medicine, and natural insecticides. However, most endemic Artocarpus have been threatened due to natural disasters and habitat degradation. The objective of our study was to determine the genetic diversity and relationships of endemic Artocarpus from South Borneo, Indonesia, using an internal transcribed spacer (ITS) region and leaf morphology. ResultsMorphologically, endemic Artocarpus endemic to South Borneo, Indonesia, has a different leaf shape, i.e., narrow-obovate to broad-elliptic, from simple to deeply dissected. Following the ITS region, this germplasm has a moderate level of nucleotide diversity (0.069). The phylogenetic analysis revealed Artocarpus into four (4) main clades, where the nearest is shown by the ‘Puyian’ (Artocarpus rigidus) and ‘Binturung’ (Artocarpus odoratissimus) at a coefficient divergence of 0.027, whereas the furthest by ‘Kulur’ (A. camansi) and ‘Tiwadak’ (A. integer) at a coefficient of 0.132. ConclusionIn brief, although an endemic Artocarpus of South Borneo, Indonesia, has a moderate level of nucleotide diversity, this germplasm also shows a unique phylogenetic relationship. Thus, this information is urgent in supporting the future Artocarpus breeding and preservation programs, mainly to save this germplasm from being threatened.

PENGARUH PEMANFAATAN DAUN PANDAN WANGI (Pandanus Amarillyfolius) DAN BATANG SERAI (Andropogon nardus) SEBAGAI INSEKTISIDA ALAMI PEMBASMI KUTU BERAS (Sitophylus oryzae)

This study aims to determine whether there is an effective effect of fragrant pandan leaf powder (Pandanus amarillyfolius) and lemongrass stems (Andropogon nardus) as natural insecticides on the optimal death of rice bugs (Sitophylus oryzae). This research is an experimental research conducted in the biology laboratory of Patompo University. The experiment was designed using a completely randomized design (CRD) with the concentration of pandan leaf powder (P.amarillifolius) and lemongrass stem (A.nardus) which were varied, namely P0 (0), P1 (60 gram fragrant pandan leaf powder), P2 (60gram lemongrass stem powder), P3 (60gr fragrant pandan leaf powder + 60gr lemongrass stem powder). Based on the results of the study for rice flea mortality, it can be seen that the average of each concentration is P0 (0%), P1 = 56.7%, P2=66.7%, and P3 = 73.3%. Of these concentrations, it can be seen that the best concentration as a natural insecticide for rice flea mortality is P3 with an average mortality of 73.3%. Based on the results of the analysis, it can be seen that the value of F count> F table (6.333> 5.14) or sig value <0.05 (0.033 <0.05), so it can be concluded that H0 is rejected, which means that there is a significant effect of utilizing fragrant pandanus leaves and lemongrass stems as a natural insecticide against rice fleas. So it can be said that fragrant pandanus leaf powder (P.amarillyfolius) and lemongrass stems (A.nardus) can have an effective effect and as a natural insecticide against the death of rice fleas (S.oryzae).Keywords: Pandanus amarillyfolius, Andropogon nardu, Sitophylus oryzae

Phytochemical screening and larvicidal effects of methanolic leave extract of Ocimum gratissimum on Anopheles species larva in Gombe, Gombe State Nigeria

Mosquito vectors are among the well-known group of insect that transmit a number of deleterious human diseases, which has pose a major public health challenges affecting development of poorest countries in the world. Vector control is therefore an essential requirement in the control of these diseases. The emergence of insecticide resistance and their effects on non-target population and the environment has necessitated an urgent search for development of new and improved vector control methods that are ecofriendly, economical and effective as well as safe for non-target organisms and the environment. The present study aims to access the larvicidal efficacy of Ocimum gratissimum extracts against Anopheles species larvae. The Ocimum (scent) leaf methanolic extract was obtained using a cold method of extraction, the phytochemical investigation was studied using a simple qualitative analysis and a biological test to determine it larvicidal properties as per the WHO standard protocol. The percent yield of the methanolic extract from leaves of Occimum gratissimum was 8.14%. Presence of alkaloids, flavonoids, tannins, steroids, saponins, antraquinones, phenolics and glycosides have been observed. The biological test revealed that the methanolic extract from Occimum gratissimum has remarkable larvicidal properties with an LC50 and LC90 values of 4.28 and 24.40 mg/ml after a period of 72 hours respectively. This may offer great prospective as new control agents against Anopheles spp which is considered a threat to human health in the World especially Nigeria. The Ocimum gratissimum plant extracts tested in our study showed potent larvicidal properties that have potential to be developed as a natural insecticides.

Plant Terpenoid Permeability through Biological Membranes Explored via Molecular Simulations.

Plants synthesize small molecule diterpenes composed of 20 carbons from precursor isopentenyl diphosphate and dimethylallyl disphosphate, manufacturing diverse compounds used for defense, signaling, and other functions. Industrially, diterpenes are used as natural aromas and flavoring, as pharmaceuticals, and as natural insecticides or repellents. Despite diterpene ubiquity in plant systems, it remains unknown how plants control diterpene localization and transport. For many other small molecules, plant cells maintain transport proteins that control compound compartmentalization. However, for most diterpene compounds, specific transport proteins have not been identified, and so it has been hypothesized that diterpenes may cross biological membranes passively. Through molecular simulation, we study membrane transport for three complex diterpenes from among the many made by members of the Lamiaceae family to determine their permeability coefficient across plasma membrane models. To facilitate accurate simulation, the intermolecular interactions for leubethanol, abietic acid, and sclareol were parametrized through the standard CHARMM methodology for incorporation into molecular simulations. To evaluate the effect of membrane composition on permeability, we simulate the three diterpenes in two membrane models derived from sorghum and yeast lipidomics data. We track permeation events within our unbiased simulations, and compare implied permeation coefficients with those calculated from Replica Exchange Umbrella Sampling calculations using the inhomogeneous solubility diffusion model. The diterpenes are observed to permeate freely through these membranes, indicating that a transport protein may not be needed to export these small molecules from plant cells. Moreover, the permeability is observed to be greater for plant-like membrane compositions when compared against animal-like membrane models. Increased permeability for diterpene molecules in plant membranes suggest that plants have tailored their membranes to facilitate low-energy transport processes for signaling molecules.

Edible Plant Extracts against Aedes aegypti and Validation of a Piper nigrum L. Ethanolic Extract as a Natural Insecticide.

The Aedes aegypti mosquito significantly impacts public health, with vector control remaining the most efficient means of reducing the number of arboviral disease cases. This study screened the larvicidal and pupicidal activity of common edible plant extracts. Piper nigrum L. (black pepper) extract production was optimized using accelerated solvent extraction (ASE) and validated following regulatory requirements using HPLC-PDA analytical methodology to quantify its major component-piperine. Larvicidal activity was determined for the standardized P. nigrum fruit ethanol extract (LC50 1.1 µg/mL) and piperine standard (LC50 19.0 µg/mL). Furthermore, 9-day residual activity was determined for the extract (4 µg/mL) and piperine (60 µg/mL), with daily piperine quantification. Semi-field trials of solid extract formulations demonstrated 24-day activity against Ae. aegypti larvae. Thus, the standardized P. nigrum extract emerges as a potential candidate for insecticide development to control the arboviral vector.

Qualitative Behavioral Analysis in Mosquito Dynamics Model with Wolbachia

The Aedes Aegypti mosquito is the primary vector that can transmit diseases to humans such as zika, dengue fever, chikungunya, and yellow fever. This mosquito species is controlled to reduce the frequency of its bites on humans. Several methods have been developed to control mosquito populations, ranging from natural insecticides to artificial ones. However, the impact of these insecticides leads to resistance. Wolbachiabacteria as a promising alternative in reducing the spread of viruses on humans due to free resistance. This work constructs a genetic population model in the form of differential equation system that describes mosquitopopulation dynamics by involving random mating between mosquito populations with and without Wolbachia bacteria. The stability of the equilibrium was analyzed locally here. Numerical simulations and sensitivity analyzes are presented to confirm the analytical results and investigate the effect of the parameters involved on the model. The results show that the success of the expansion of Wolbachia-infected mosquitoes depends on the fitness level of the mosquito species. The more Wolbachia mosquitoes are released into nature, the more possibility this mosquito expansion will be successful.

Sugarcane Wax Metabolites and Their Toxicity to Silkworms

Sugarcane wax has the potential to be utilized as a novel natural insecticide, which could help to reduce the large yield losses caused by agricultural pests. By employing the gas chromatography-mass spectrometry (GC-MS) approach, we conducted a study to analyze the composition of epicuticular wax from the rind of the sugarcane variety YT71210. A total of 157 metabolites, categorized into 15 classes, were identified, with naphthalene, a metabolite with insect-resistant properties, being the most prevalent. The feeding trial experiment suggested that sugarcane wax is toxic to silkworms by impacting the internal organs. Intestinal microbial diversity analysis suggested that the abundance of Enterococcus genus was significantly increased in both ordure and gut of silkworm after wax treatment. The results indicated that the feeding of wax has an adverse effect on the gut microbial composition of silkworms. Our findings lay a foundation for the efficacy of sugarcane waxes as a valuable natural insecticide and for the prediction of promising sugarcane varieties with insect resistance.

Identifikasi Senyawa Bioaktif Ekstrak Daun Semak Bunga Putih (Chromolaena odorata) Asal Kota Kupang, Nusa Tenggara Timur

Chromolaena odorata, a member of Asteraceae, is a tropical shrub that grows throughout the year and can dominate pastures. The tropical weed is known as a medicinal plant and has the potential as a natural insecticide. For local people in NTT, the crude extract of the leaves is used to treat myasis on the livestock. C. odorata is also used as silage or food alternative for livestock. This study aims to determine the content of bioactive compounds in C. odorata leaves and determine the extract yield value, as scientific validation of local wisdom in NTT. This research began with the collection of fresh C. odorata leaves, extraction by maceration using 70% ethanol as solvent, solvent evaporation, and phytochemical screening. Phytochemical screening showed that the leaf extract of C. odorata from Kupang City contained high amounts of flavonoids, tannins, alkaloids, triterpenes and steroids and were tested negative for saponins. The extract yield value is 6.09%, means that the extract contains bioactive compunds in high concentration. Further research needs to be done to find out in more detail the content of secondary metabolites from C. odorata leaves and its activity in promote wound healing on livestock in NTT.

Isolation of steroids from n-hexane extract of the stems of Miliusa velutina Dun Hook. f. et. Thoms

Miliusa velutina (Dun) Hook. f. et. Thoms belongs to the Na family (Annonaceae). In folklore, M.velutina is widely used as a traditional medicine to treat inflammation, scabies, antiseptic, hemostatic, and antibacterial, in addition to being used to kill parasites and as a natural insecticide. Some research on its chemical constituents showed that there are groups of phenols, alkaloids, flavonoids, steroids, acetogenin, sesquiterpenoids, and lactones along with diverse biological activities that help cure cancer, antifungal, antibacterial, antimalarial, antioxidant, antidiabetic. However, in Vietnam, there have not been many studies on M. velutina, so this study was conducted with the aim of investigating the chemical constituents of the M. velutina, somehow providing more data related to the plant. By column chromatography method with thin layer chromatography with different solvent systems from n-hexane extract, five steroids were isolated. The chemical structure of the compounds was elucidated from 1D and 2D-NMR spectroscopic data combined with literature data showing that five steroids were obtusifolione (1), β-sitosterol (2), stigmasterol (3), stigmastan-3-one (4), stigmast-4-en-3-one (5). Among them, three compounds (1), (4) and (5) are first known to exist in the M. velutina.

The impact of wheat resistance and bio-rational insecticides toxicity against cherry-oat aphid, Rhopalosiphum padi L. (Hemiptera: Aphididae)

Aphids cause substantial damage to the wheat crop. In order to determine how host plant resistance and insecticides manage the Rhopalosiphum padi L. Current experiments were carried out to find the influence of host plant resistance and bio-rational insecticides against aphids in wheat (Triticum aestivum L.) crop. Field experiments were carried out for two growing years (2017/18 and 2018/19) to access the resistance of wheat against the aphids. The field resistance of wheat is highly expressed in Pirsabak-08 variety (infestation range = 1-2.5) while the most susceptible variety is Faisalabad-08 (infestation range > 10). The varietal preference experiment results revealed that 5.33 aphids were attracted towards Pirsabak-08 while Faisalabad-08 stood as the most susceptible variety as 25.0 aphids were found after 72 h. The linear correlation analysis revealed that the aphid attractiveness is negatively correlated to the trichome density. A stage-specific insect growth regulator (IGR) and natural insecticides were applied to a comparatively more resistant variety. The best results were achieved with pyriproxyfen and neem, as the population rapidly declined to 2.66 and 2.60 aphids/plant, respectively. Current findings lead to the conclusion that utilizing resistant hosts against aphids along with the use of safer insecticides can significantly reduce wheat damage.

Essential oils as environmentally friendly insecticides for controlling cotton mealybug, Phenacoccus solenopsis (Tinsley) (Hemiptera: Pseudococcidae)

Eight plant essential oils were extracted and tested for their efficiency as natural insecticides against the cotton mealybug, P. solenopsis (Tinsley). In-vitro bioassay, the contact toxicity of the tested oils to adult females and 2nd instar nymphs was determined. Also, repellence activity of the tested oils were tested. The most effective oil against adult female’s after 72 hrs of application was L. nobilis followed by Apium graveolens, M. longifolia, C. articulates, M. sativa, A. graveolens, O. vulgar, then F. vulgar. The 2nd instar nymphs showed more susceptibility for all tested essential. Regarding repellency, M. longifolia showed the highest repellency effect but unfortunately with high degradation rate. The most repellent essential oils with satisfactory stability were L. nobilis, F. vulgar and C. articulates. Also, the efficacy of the tested oils were tested against P. solenopsis in open field conditions. The most efficient oil at 72hrs after treatment was L. nobilis which showed great reduction percentage (89.3%) followed by Apium graveolens (88.6%), M. longifolia (88.6%), C. articulates (87.8%), M. sativa (87.7%), A. graveolens (86.9%), O. vulgar (85.9%) and F. vulgar (85.2%), respectively.

Toxicity and larvicidal activity on Aedes aegypti of citronella essential oil submitted to enzymatic esterification.

The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 μg mL-1 were obtained for the essential oil and 4.36 μg mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 μg mL-1 for the essential oil of citronella and 86.30 μg mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.

ENTOMOPATHOGENIC BACTERIUM Serratia marcescens ISOLATED FROM Episparis tortuosalis CAUSING A DAMAGE TO Chukrasia tabularis IN VIETNAM

Episparis tortuosalis Moore, 1867 is a serious pest of the Chukrasia tabularis A. Juss which is widely planted in plantations in Vietnam. A biocontrol option to manage this pest is a priority for the forest sector. The objective of this study was to evaluate whether there are potential biocontrol candidates within the E. tortuosalis population. Sixteen bacterial strains were isolated from E. tortuosalis larvae that were parasitized in a C. tabularis plantattion in Nghe An province. Four isolates (FPRC06, FPRC07, FPRC14 and FPRC16) had strongest pathogenicity on Galleria mellonella larvae at 1, 24 and 36 hours after the injection and 72, 96 and 120 hours after the spraying experiments. The mortality rate of G. mellonella resulted from these two experimental approaches at the end of experiments was 93.3–100% and 76.7–100%, respectively. In a greenhouse experiment, the four isolates caused 44.3–61.1%, 52.0–68.0%, 54.3–69.1% and 41.4–60.7% mortality of E. tortuosalis larvae after 3, 5 and 7 days of spraying, respectively. These results were similar to applying a commercial Bacillus thuringiensis. The two isolates (FPRC07, FPRC14) were identified as Serratia marcescens based on phylogenetic analysis of 16S rRNA. Thus, this finding reveals the potential opportunities for the development of a natural insecticide of E. tortuosalis in Vietnam.

Efficiency of essential oils in the control of the black bean aphid Aphis craccivora Koch (Hemiptera: Aphididae).

The black aphid Aphis craccivora Koch is one of the main pests of the caupi-bean crop Vigna unguiculata (L.) Walp. Due to the need to find effective and safe methods of control, there has been an increase in research seeking natural alternatives. Thus, the objective of this work was to evaluate the potential of essential oils from jatoba Hymenaea courbaril, copaiba Copaifera langsdorffii and aroeira Schinus terebinthifolius to control nymphs and adults of A. craccivora. The oils were extracted from the leaves by the hydrodistillation method, diluted to 0.1% in distilled water with 2% dimethyl sulfoxide (DMSO). Each treatment had four repetitions, plus a control with distilled water + 2% DMSO. The biotests were conducted in two stages: the first was conducted in the laboratory, under controlled conditions of temperature, relative humidity and photophase, and the second was conducted in the greenhouse, using only the treatment with the best laboratory test results. After 24, 48, 72, 96 and 120 hours of exposure, the insect mortalities were checked. In the first phase of the experiment, the aroeira oil showed 83.33% and 75.75% efficiency of mortality in nymphs and adults, respectively. In the greenhouse tests, this same oil showed 73.52% in nymphs and 62.85% in adults, opening new perspectives regarding its use as a natural insecticide for the control of the black aphid of the bean.

Camphorosma monspeliaca essential oil as a new potential eco-friendly biopesticides for control of Colorado potato beetle Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

Potato plant is an important agricultural and food product for our country and the world. As a result, it is widely cultivated. The most common problem in the cultivation of potato plants is pests, which damage the plant and cause a decrease in product quality and yield. Leptinotarsa decemlineata, is a pest on the Solanaceae family, and can cause great damage by eating the leaves of the living plant during the development period. Although the most effective control method against potato beetle is chemical control, researches on alternative methods are becoming more widespread. In this context, the current study aimed to develop a new biological control agent with the aim of reducing product loss by investigating the effect of Camphorosma monspeliaca plant essential oil on L. decemlineata species eggs, larvae and adults. As a result, C. monspeliaca essential oil application was found to have lethal effect on early larvae, late larvae and adults. Besides, it was determined that the eggs were seriously deformed morphologically with the application of essential oil and that no larvae hatched from these eggs, which proved that C. monspeliaca essential oil has a high potential to be used as an effective natural insecticide.

Effectiveness of n-hexane and ethanol extract of papaya (Carica papaya L.) leaves as shallot pest (Spodoptera exigua Hübner) natural insecticide

One of the agricultural commodities that has a high selling value and consumption level is shallot (Alium ascalonicum). However, the productivity of shallots is known to be susceptible to plant-destroying organisms, such as the shallot caterpillar (Spodoptera exigua). Currently, most shallot farmers control S. exigua using synthetic insecticides. Synthetic insecticides are poisonous and use for a long time period will cause resistance to pests and environmental pollution. One of the natural ingredients that has the potential as a botanical insecticide is papaya (Carica papaya). This study aimed to determine the effectiveness and concentration of n-hexane and ethanolic extracts of papaya leaves which are the most effective against toxicity and inhibition of the feeding power of S. exigua second instar larvae. The extract was obtained by gradual maceration of n-hexane (non polar) and ethanol (polar) solvents. Test the secondary metabolite content of papaya leaves using Thin Layer Chromatography (TLC). The results showed that the ethanol extract was the most effective extract in causing toxicity to larvae with the highest percentage of 96.67%. Meanwhile, n-hexane extract was more effective in inhibiting larval feeding than ethanol extract with the lowest feeding area of 2,27 mm. The most effective concentration of against toxicity and feeding inhibition of larvae is concentration 3%. The LC50 value of the ethanol extract was 0.0207% and the n-hexane extract was 0.0459%. Both extracts are known to contain compound groups, namely tannins, terpenoids, flavonoids, and alkaloids.

Effectiveness of Resam Fern Leaves Extract (Gleichenia linearis) as Bioinsecticide on Mortality of Black Ant (Dolichoderus thoracicus)

Insecticides are type of pesticide used to eradicate or control pests. Generally, there are two types of insecticides, namely natural and synthetic insecticides. Natural insecticides are scarce due to their inability to eradicate pests such as black ants. Meanwhile, the use of synthetic insecticides is very practical and fast but can cause pollution that is harmful to humans, animals and other living things. Thus, natural insecticides are needed that can eradicate black ants effectively and efficiently and do not pollute the environment or poison other organisms. The research method used is combination of experimental methods, observation, and literature studies. In determining the best insecticide variation for mortality, a black ant mortality rate was measured using timer for 50 black ants. After the data was obtained, it was analyzed descriptively to determine the value of the mortality rate for each experimental sample. Based on the data obtained, the best variation of natural insecticides was the control variation of fern leaf extract with 3.646 seconds per ant. This is because fern leaf extract in insecticides contains tannin compounds which have several benefits as active pesticide ingredients. Thus, fern insecticides are effective in exterminating black ants.