Effects Of Insecticides Research Articles

Predaceous and Phytophagous Pentatomidae Insects Exhibit Contrasting Susceptibilities to Imidacloprid

Imidacloprid, a widely used neonicotinoid insecticide, targets insect pests but also affects natural enemies. However, the effects of neonicotinoid insecticides on closely related insects remain unclear. We evaluated the harmful effects of imidacloprid on the phytophagous Halyomorpha halys and predaceous Arma chinensis. Bioassays revealed that imidacloprid was more toxic to H. halys than to A. chinensis and more harmful to the males than to the females of the two insects. A. chinensis adults recovered from imidacloprid-induced knockdown, as evidenced by restored respiratory rates, metabolic rates, and locomotion. Surviving A. chinensis showed reduced fecundity, suggesting a trade-off between detoxification and reproduction. Bioinformatics analysis of nicotinic acetylcholine receptors (nAChRs) and molecular docking simulations indicated a lower diversity of the nAChR gene family in A. chinensis than in H. halys, with weaker binding to imidacloprid, consistent with the relatively low toxicity of the insecticide in this species. This might account for the susceptibility differences to imidacloprid between the species. These findings underscore the efficacy of imidacloprid against H. halys and provide insights into the toxicities of neonicotinoids to target and non-target insects.

Comparative efficacy of plant derived extracts with the insecticide mospilan on two whitefly species Bemisia tabaci biotype B and Trialeurodes ricini

The insecticidal, synergistic, and acetylcholinesterase (AChE) inhibitory effects of plant n-hexane extracts (HEs) were evaluated. The HEs from thyme (Thymus vulgaris L.) leaves, garlic (Allium sativum L.) bulbs, and weeping willow (Salix babylonica L.) leaves were used in comparison with the acetamiprid insecticide (mospilan) against two whitefly species, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype B and Trialeurodes ricini (Genn.) (Hemiptera: Aleyrodidae). Furthermore, using the choice test design, the repellent efficacy of three extracts was investigated against whitefly B. tabaci biotype B. The chemical compositions of HEs were identified using gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame-ionization detection (GC-FID) analysis. The main compounds of thyme HE were thymol and geranyl-α-terpinene; in garlic bulbs HE were diallyl sulfide and allyl tetrasulfide; and in weeping willow HE were 6-phenyltridecane, 6-phenyldodecane, and 5-phenyldodecane, while the methylated fatty acids were stearic and palmitic. The HEs of weeping willow and garlic showed the maximum toxicity against B. tabaci, while the HEs of thyme and garlic showed the highest toxicity against T. ricini. Mospilan with HEs resulted in a potentiating effect, with co-toxicity factors ranging between 21.47 for a mixture of garlic HE + mospilan against B. tabaci and 37.65 for weeping willow HE + mospilan against T. ricini. The mix of mospilan + weeping willow HE recorded the highest acetylcholinesterase (AChE) inhibitory effect 48 h after treatment. The highest expulsion effect was recorded by 2% thyme HE, with a repellency index (RI) of 88.22%. The HE of weeping willow at 1% exhibited the highest attractant effect with an RI value of -8.94%. The current research lays the groundwork for the integrated pest management (IPM) of B. tabaci biotype B and T. ricini by employing natural extracts and pesticides blends.

Comparing simulated aerial and chemigation insecticide applications to manage western bean cutworm (Lepidoptera: Noctuidae) in corn.

The efficacy of aerial application and chemigation of insecticides is not well explored for western bean cutworm, Striacosta albicosta (Smith), management in corn. In the short term, inadequate application of insecticides can lead to control failures when insect pests are not effectively targeted. In the longer term, exposure to sublethal insecticide concentrations can contribute to the evolution of insecticide resistance. The goal of this study was to compare aerial application and chemigation under simulated conditions to determine the most effective insecticide application method for managing S. albicosta. Three larval stages were exposed to the highest and lowest label rates of commercial formulations of bifenthrin (36.8 and 112.1g a.i. ha-1) and chlorantraniliprole (52.7 and 75.1g a.i. ha-1). Experiments were conducted in spray chambers, utilizing a carrier volume of 18.7L ha-1 for aerial application and 1.57cm ha-1 for chemigation. Mortality was recorded at 16, 24, and 41h after infestation. The simulated aerial application was more effective than simulated chemigation in controlling S. albicosta, resulting in 100% mortality 24h after infestation. Within the chemigation applications, chlorantraniliprole treatments were effective at both rates for all instars, while the high rate of bifenthrin exhibited greater efficacy than the lower rate. In conclusion, it was evidenced that the same insecticide active ingredients do not yield equivalent efficacy when applied via aerial application compared to chemigation. The present study highlights the importance of selecting appropriate insecticide application methods in controlling S. albicosta larvae.

The Potency of Essential Oils in Combating Stored-Product Pests: From Nature to Nemesis

Sitophilus oryzae, Tribolium castaneum, Tribolium confusum, Oryzaephilus surinamensis, Rhyzopertha dominica, Tenebrio molitor, Trogoderma granarium, Acarus siro, and Alphitobius diaperinus represent significant arthropod stored-product pests worldwide. To combat these noxious arthropods, the current study examines the pesticidal effect of essential oils (EOs) derived from four aromatic plants, i.e., Illicium verum Hook. F., Citrus reticulata Blanco, Monodora myristica (Gaertn.) Dunal, and Xylopia aethiopica (Dunal) A. Rich. Considering the challenge of pesticide resistance, the current study focuses on assessing the efficacy of these EOs as an eco-friendly alternative to traditional synthetic insecticides. Two EO concentrations (500 and 1000 µL/kg wheat) were applied to different life stages of these pests in the bioassays. Mortality rates were monitored over several days under controlled environmental conditions. The findings demonstrated that C. reticulata and I. verum EOs had elevated insecticidal effects, especially against larval stages, resulting in 100% mortality in several species. On the contrary, M. myristica and X. aethiopica EOs showed less overall efficacy despite their potency against some pests. Both I. verum and C. reticulata EOs outperformed the positive control, pirimiphos-methyl, in several assays. The results of the current study highlight the potential of several EOs as effective alternatives in reducing synthetic pesticide use for integrated pest control management.

INTEGRATION OF GENOTYPES OF MAIZE (Zea mays L.) AND PLANT POWDERS AGAINST Sitophilus zeamais Motschulsky (COLEOPTERA: CURCULIONIDAE)

The objective of this study was to determine the combined effect of maize (Zea mays L.) genotypes with the application of epazote (Dysphania ambrosioides L.), castor oil plant (Ricinus communis L.), Mexican pepperleaf (Piper auritum Kunth), moringa (Moringa oleifera Lam.), neem (Azadirachta indica A. Juss.), and Pacific Coast mahogany (Swietenia humilis Zucc.) as an alternative to control the maize weevil (Sitophilus zeamais Motschulsky). It was hypothesized that combining certain maize genotypes with specific plant powders would significantly reduce S. zeamais damage without affecting germination. Three bioassays were conducted. In the first, the biological activity of six plant powders to control weevil populations and their impact on seed germination was evaluated; in the second, the effect of the hardness of three maize hybrids and the “Ancho Pozolero” variety on weevil was determined; and in the third, the interaction between genotypes and the most effective powders was explored. With five replicates per treatment and a control without application, 100 g of maize and 1 % plant powder were placed in 250 mL glass containers using a fully randomized design. Mortality, emergence, insect damage, and maize germination were assessed. In the evaluation of plant powders, D. ambrosioides and S. humilis stood out for their insecticidal and insectistatic effects and protection of maize, although they affected germination by 6.5 and 7.2 %, respectively. P. auritum showed good insecticidal and insectistatic effects without affecting germination. The hybrid “Tlaoli Puma,” classified as hard, reduced the damage caused by S. zeamais by one third. The combination of the hybrid “Tlaoli Puma” with 1 % plant powder of D. ambrosioides or S. humilis reduced the chances of attack and damage by S. zeamais, contributing to reducing post-harvest losses of stored maize and thus validating the hypothesis.

Chemical composition and insecticidal activity of Mentha rotundifolia and Chrysanthemum coronarium essential oils against the tomato leaf miner, Tuta absoluta

Tuta absoluta is one of the most destructive pests of tomatoes. Chemical insecticides used to control this leafminer harm all organisms, increasing the risk to public health and the environment. Developing natural alternatives, such as bioinsecticides formulated from essential plant oils, is a key strategy to address this problem. These volatile compounds, derived from the secondary metabolic pathways of plants, exhibit targeted activity against specific pest species. Their use is consistent with an environmentally responsible framework that reduces adverse impacts on ecosystems, protects non-target organisms, safeguards human health, and enhances the efficacy of integrated crop management systems. This study aims to determine the chemical composition of the essential oils (EOs) of from round leaf mint (Mentha rotundifolia) and crown chrysanthemum (Chrysanthemum coronarium) and to evaluate their toxicity to T. absoluta larvae in-vitro. The chemical composition of EOs obtained by steam distillation from the leaves of the plants was analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Indeed, 77 volatile compounds representing 98.19% of the total oil of M. rotundifolia, including cyclobutane acetonitrile, 1-methyl-2-(1-methyl ethenyl)-, terpinene-4-ol, p-menthane, germacrene D, caryophyllene and myrcene, were the main compounds. However, farnesene, myrcene, eugenol, germacrene D, phytol, and pinene were significant components among 69 compounds representing 95.39% of the total oil of C. coronarium. Results showed that the EOs were toxic to the different larval stages. According to the Finney method, concentrations 2.88 and 1.07% are the LC50 of M. rotundifolia and C. coronarium oils, which induce 50% mortality of T. absoluta within 7 days of exposure. Statistical analysis of in-vitro tests showed that both EOs had a similar level of insecticidal efficacy by contact. The overall results showed that the oils used have been shown to have an important insecticidal effect and can be used as a source of biological and natural treatment against tomato leafminer (TLM).

An Assessment of the Cyto-Genotoxicity Effects of Green-Synthesized Silver Nanoparticles and ATCBRA Insecticide on the Root System of Vicia faba.

We aimed to synthesize silver nanoparticles (AgNPs) using Elettaria cardamomum (cardamom) extracts and assess the cytotoxicity and genotoxicity of the cardamom extract, cardamom-AgNPs, and the insecticide ATCBRA-commonly used for pest control-on the root system of Vicia faba (broad bean). The chemical composition of the aqueous cardamom extract was identified and quantified using GC-MS, revealing a variety of bioactive compounds also present in cardamom essential oil. These included α-terpinyl acetate (21.3-44.3%), 1,8-cineole (10.7-28.4%), and linalool (6.4-8.6%). The successful green synthesis of AgNPs was confirmed through various micro-spectroscopic techniques, including UV-Vis spectroscopy, transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS). UV-Vis analysis showed a strong peak between 420 and 430 nm, indicating the presence of AgNPs. TEM imaging revealed that the synthesized cardamom-AgNPs were monodispersed, primarily spherical, and semi-uniform in shape, with minimal aggregation. EDS analysis further confirmed the composition of the nanoparticles, with cardamom-AgNPs comprising around 60.5% by weight. Cytotoxicity was evaluated by measuring the mitotic index (MI), and genotoxicity was assessed by observing chromosomal aberrations (CAs). The roots of Vicia faba were treated for 24 and 48 h with varying concentrations of ATCBRA pesticide (0.1%, 0.3%, 0.5%, and 0.7%), aqueous cardamom extract (3%, 4%, 5%, and 6%), and green-synthesized cardamom-AgNPs (12, 25, and 60 mg). The cytogenetic analysis of MI and CA in the meristematic root tips indicated an improvement in the evaluated parameters with the cardamom extract. However, a marked reduction in mitotic activity was observed with both ATCBRA and cardamom-AgNP treatments across both time points, highlighting potential cytotoxic and genotoxic effects.

Comparative Analysis of Five Moroccan Thyme Species: Insights into Chemical Composition, Antioxidant Potential, Anti-Enzymatic Properties, and Insecticidal Effects

This study aimed to investigate the chemical composition and bioactivities of essential oils (EOs) from five Moroccan thyme species: Thymus broussonetii subsp. broussonetii, T. maroccanus, T. willdenowii, T. zygis subsp. gracilis, and T. satureioides, collected from various geographical regions. Gas chromatography–mass spectrometry (GC-MS) identified thymol, p-cymene, borneol, γ-terpinene, carvacrol, α-pinene, and camphene as major constituents, with variations across species. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) revealed important levels of calcium (450.6–712.2 mg/kg), potassium (255.4–420.7 mg/kg), magnesium (97.3–150.7 mg/kg), and iron (1.95–15.1 mg/kg). The EOs demonstrated strong antioxidant activity in DPPH, FRAP, and β-carotene bleaching assays. Insecticidal activity against Aphis gossypii revealed the highest efficacy with T. willdenowii EO (LC50 = 6.2 µL/mL), followed by T. maroccanus and T. zygis subsp. gracilis. Additionally, the EOs exhibited potent enzyme inhibitory effects at 1 mg/mL on acetylcholinesterase (83.1–96.4%), tyrosinase (77.5–89.6%), and α-glucosidase (79.4–89.5%). These findings suggest that thyme EOs, particularly from T. willdenowii, T. zygis, and T. maroccanus, are promising candidates for integrated pest management and natural enzyme inhibitors. Their potential applications in medicinal and pharmaceutical fields underscore the need for further research to optimize their use under specific conditions and dosages.

Cellulose nanocrystals-based Pickering emulsion with enhanced foliar adhesion and pH responsiveness for intelligent delivery of pesticides

Pickering emulsions stabilized by functionalized natural macromolecules have emerged with promising responsiveness for pesticide encapsulation and release. This study developed Pickering emulsions using amine-modified cellulose nanocrystals (ACNCs) as stabilizers. The resultant O/W ACNCs-Pickering emulsions (ACNCs-Pickering) exhibited long-term storage stability and showed increasing emulsion stability depending on the concentration of ACNCs. Imidacloprid (IMI) was subsequently loaded onto the ACNCs-Pickering to form the IMI@ACNCs-Pickering via the in-situ loading route. The release rate of IMI demonstrated a notable pH responsiveness. Moreover, the IMI@ACNCs-Pickering prepared with an ACNCs concentration of 3 wt% showed optimal performances. Its foliar adhesion on Chinese cabbage (Brassica rapa L.ssp.pekinensis) was significantly higher than that of the commercial IMI formulation (70 WS, Bayer®, LS200032) (DG). In detail, the pesticide residue for the IMI@ACNCs-Pickering was 3.8 folds to that for DG after spraying and washing for 10 min. Also, the green peach aphid mortality rate was 98.33 %, which was 1.1 folds higher than that of the DG group. The present work developed a Pickering emulsion-based fat-soluble pesticide formulation with excellent foliar adhesion, resistance to rainfall washout, and insecticidal effect. It provided a new option to ensure the sustainable development of green agriculture.

Field Bioefficacy and Residue Dynamics of Most Effective Insecticides Against Aphids in Taro (Colocasia esculenta (L) Scott, 1832)

Field Bioefficacy and Residue Dynamics of Most Effective Insecticides Against Aphids in Taro (Colocasia esculenta (L) Scott, 1832)

Differential effects of pharmaceuticals and insecticides on swimming behaviour and survival in Gammarus pulex.

Many freshwater systems are continuously exposed to waste streams like municipal wastewater and agricultural runoff, leading to exposure to chemicals that can cause mortality and behavioural changes in aquatic organisms. While research has advanced our understanding of pesticide effects on behaviour of aquatic organisms, the impacts of pharmaceuticals are less understood. Psychopharmaceuticals are particularly interesting because they can act on nervous systems, potentially affecting the behaviour of aquatic organisms. Sublethal behavioural effects can be crucial in ecotoxicological research for environmental pharmaceuticals and are often detected below lethal concentrations. Gammarids, especially Gammarus pulex, are widely used in ecotoxicological studies due to their ecological role and sensitivity to pollutants. This study aims to evaluate the sensitivity of six swimming behaviour endpoints in G. pulex compared to the conventional endpoints immobility and mortality, using different chemicals with distinct modes of action: insecticides imidacloprid and chlorpyrifos and the pharmaceuticals carbamazepine and citalopram. After a 2-hour exposure, the mobile organisms were assessed for their swimming speed, acceleration, curvature, thigmotaxis and startle response (magnitude and duration). Our study reveals that G. pulex exhibits varied behavioural responses to different chemical pollutants. While behavioural endpoints can indicate harmful effects on aquatic organisms, they are not consistently more sensitive than traditional endpoints, such as immobility and mortality. The insecticides imidacloprid and chlorpyrifos show development of immobility and mortality without prior sublethal behavioural effects, suggesting a limited utility of behavioural endpoints as early warning indicators. In contrast, the pharmaceuticals carbamazepine and citalopram demonstrate adverse effects through behavioural changes before immobility and mortality occur. Further research is essential to understand the mechanisms underlying these varying sensitivities of behavioural endpoints to different compounds, emphasising the importance of considering both chemical type and endpoint relevance in toxicity testing protocols.

Mixture of neonicotinoid and fungicide affects foraging activity of honeybees.

The use of plant protection products (PPPs) is a major factor contributing to global insect decline. We here use the honeybee (Apis mellifera) as a model to study combined effects of the last neonicotinoid in the EU (acetamiprid) and different fungicides on live-long foraging flights using radio frequency identification. The mixture of the sterol-biosynthesis-inhibiting fungicide difenoconazole and the insecticide acetamiprid significantly reduced the number of foraging trips per day compared to the control and each PPP alone, while a mixture of the insecticide with the non-sterol-biosynthesis inhibiting fungicide boscalid/dimoxystrobin did not affect behaviour. This potential synergistic effect of the fungicide/insecticide mixture supports the notion that some fungicides can enhance the effect of insecticides, which did not lead to significant changes in behaviour when applied on their own. Our results emphasize the need for more studies on the interaction of different PPP.

An environmentally friendly, rainfall-resistant suspension prepared based on halloysite nanotubes for the delivery of hydrophobic pesticides

The application of nanomaterials in pesticide system shows many advantages such as enhanced dispersion stability, high foliar affinity, improved insecticidal effect, and reduced environmental risks. In the study, a simple wet grinding method was used to decrease the particles size of the pesticides chlorobenzuron and indoxacarb (CI) in presence of halloysite nanotubes (HNTs). The irregularly shaped suspension pesticide system (CI@HNTs) in size of ∼ 2 μ m is obtained via HNTs and xanthan gum (XG) encapsulation of the hydrophobic pesticides. Attributed to the small size and interfacial interactions of HNTs, CI@HNTs have excellent stability, dispersion and slow release behavior. CI@HNTs exhibit enhanced foliar wettability, spreading and topological effect on plant leaves compare to commercial suspension concentrate (SC) product and CI (without HNTs), which results in high resistance to rainfall washout. In the crop model treated by fall armyworm, the mortality rate is 53.3 % in CI group, while the mortality is 75.0 % in CI@HNTs-8 which is 1.41 times that of CI. In addition, the safety of CI@HNTs is systematically evaluated, and the results show that the toxicity of CI@HNTs to the wheat and the aquatic organism zebrafish is lower than that of the SC. This study develops an economical, efficient and environmentally friendly pesticide system based on natural clay nanotubes, which shows promising applications in sustainable agricultural production.

Effect of peppermint leaf extract and peppermint oil on the flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae)

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is among the global storage pests that lead to the deterioration of grains and stored products. A series of laboratory experiments were conducted to evaluate the efficiency of different concentrations of Mentha piperita L. (Lamiaceae) oil and leaf methanol extracts against the rust-red flour beetle in the different instars. The results of the present study showed that the mint, M. piperita, oil treatments at all concentrations used (8%, 10%, or 12%) were significantly effective, resulting in remarkable individual mortality of T. castaneum third instar larvae and adult mortality compared to the treatment of the peppermint methanol leaf extract at the highest concentration. Peppermint oil showed insecticidal effect against the third instar larvae of the red flour beetle, especially where sprayed at the highest concentration of 12%. The post-treatment results after seventh days showed 94% adult mortality and 82% mortality in the third instar of larvae. This study confirmed the possibility of using mint essential oil at relatively low concentrations as environmentally friendly product in controlling the rust-red flour beetle T. castaneum.

Effects of Insecticides on Soil Arthropods in the Rice Crop Ecosystem

Effects of Insecticides on Soil Arthropods in the Rice Crop Ecosystem

Study on Applications of Hot Pepper and Quinoa’s Saponin Extract in Control of Barley Crop Cultivars Aphid Insects

Barley (Hordeum vulgare L.) is one of the most important food and feed crops in the world, which infested with several insect pests, the main economic pest is aphid which causes direct damage and indirect damage in barley production. The integrated pest management (IPM) programs are requirement to reduce aphids’ damages, by using chemical substances extracts obtained from plants as an alternative to synthetic chemical control for its satisfactory effectiveness in pest control. The insecticidal effect of the aqueous extract of hot pepper and quinoa’s saponin on aphids controlling were evaluated on ten Egyptian barley cultivars to determine their susptability and resistance to aphids’ infestation through studying their agro-phycological behavior for aphids’ infestation under Malawi station, during two growing seasons 2021/2022 and 2022/2023. The results showed that Egyptian barley cultivar Giza 137 was the lowest infested cultivars with aphids which had lowest No. of aphids (9.777insects/tiller) with lowest percentage infestation of aphids was 29.638%/plant, lowest cultivars in Chlorophyll content (ChLa &Chl b) with values (4.17 and 1.65 µg ml-1), with highest values for flavonoids and total phenolic with values were (2.37 and 79.82) and high grain yield was 19.17 ard fad1. However, the Egyptian barley cultivar Giza 136 was the highest cultivar that infested by high No. of aphids (33.167 insects/tiller) with highest percentage infestation with aphids which was 71.833%/plant, which displayed highest ChLa and ChL b with values (7.54 and 3.04 µg ml-1), and had lowest values for total flavonoids contents and total phenolic content with values (0.14 and 44.04 mg/g) and had grain yield was 18.47 ard fad1 . The low aphids’ infestation cultivars under Malawi station were Giza 123, Giza 133, Giza 134 and Giza 130 which were (35.027, 39.111, 39.388 and 40.834%/plant according their physiological behavior after infestation. The Pearson correlation coefficients showed that high aphid insect infestation had high positive and significantly correlated with cha and ChL b, while had had high negative and significantly correlated with T-phenol and flavonoids The results showed that the first and second principal components accounted 78.3% of the total changeability, which PCA2 clarified 15.3 % of the total variability influenced by T-phenol and flavonoids which placed in the left side (negative) of the horizontal axis according to its negative significant correlations with other characters. Treated barley plants by hot pepper and quinoa extract due to decreasing the aphid’s infestation percentage on all cultivars after spray, the results showed that Giza 136 which was recorded the highest infested percentage 71.87 % was reduce to 35% after treated and also had a significant increasing grain yield of the ten barley cultivars.

Transgenic tomato strategies targeting whitefly eggs from apoplastic or ovary-directed proteins

BackgroundTransgenic plants expressing proteins that target the eggs of the ubiquitous plant pest Bemisia tabaci (whitefly) could be an effective insecticide strategy. Two approaches for protein delivery are assessed using the mCherry reporter gene in transgenic tomato plants, while accommodating autofluorescence in both the plant, phloem-feeding whitefly and pedicle-attached eggs.ResultsBoth transgenic strategies were segregated to homozygous genotype using digital PCR. The first strategy uses a glycotransferase secretion signal peptide. Despite bright apoplastic accumulation, mCherry is not evident in the eggs. The second strategy targets in vivo whitefly eggs, where the mCherry transgene was fused to a protein transduction domain (PTD) to facilitate uptake into the whitefly hemolymph as well as a synthetic vitellogenin ovary-targeting sequence. Phloem-specific expression of the mCherry fusion is achieved from a Commelina viral promoter. Accumulation was not sufficient to be observed in females feeding on these ovary-targeting plants nor in their eggs subsequently laid on non-transgenic plants. Egg protection may be mediated by protease activity which is observed in macerated eggs.ConclusionsmCherry proved an effective reporter for the desired tissue-specific expression in tomato, but insufficiently sensitive to allow for localization in feeding whiteflies or their eggs. Segregated homozygous transgenic tomato lines were important for drawing these conclusions. The implications of these observations to possible pest-control strategies including preliminary expression of analogous chitinase constructs are discussed.

Phytochemical Profiling, Bioactivity, and Insecticidal Effectiveness of Mammea americana L. Leaf Extracts Against Ferrisia sp.

Plant botanical extracts are recognized for being a source of biologically active phytochemicals that potentially have diverse applications. The phytochemical composition, potential cytotoxicity, and insecticidal effectiveness of three leaf extracts from the folkloric medicinal plant Mammea americana L. (Calophyllaceae) were investigated. Micro-Soxhlet extraction with chloroform, dichloromethane, and methanol was used, and key phytochemicals were identified via Gas Chromatography-Mass Spectrometry (GC-MS). The extracts were mainly composed of sesquiterpenes, carboxylic acids, coumarins, esters, diterpenes, and other bioactive compounds. Potential cytotoxicity was assessed using brine shrimp lethality tests, where all extracts displayed high toxicity to Artemia salina. The dichloromethane extract (MAD) had the lowest LC50 value (8.39 μg/mL), followed by methanol extract (MAM, 11.66 μg/mL) and chloroform extract (MAC, 12.67 μg/mL). Insecticidal activity was tested against Ferrisia sp. (Hemiptera:Pseudococcidae), demonstrating the highest efficacy with the methanolic extract (LC50 = 5.90 mg/mL after 48 h). These findings provide a basis for further research into the bioactive components of Mammea americana leaves, particularly their antibacterial, anti-inflammatory, and anticancer properties. It also highlights the potential of Mammea americana L. leaf extracts as botanical insecticides due to their high bioactivity against agricultural pests of economic significance. This is the first study that evaluates the insecticidal activity of Mammea americana leaf extracts against Ferrisia sp. insects, offering valuable insights into using plant-based natural products in pest control.

Behavior and management of thrips population using biorational insecticides in avocado (Persea americana MILL.) trees

Objective: To evaluate the effectiveness of biorational insecticides to control thrips and to provide alternatives that reduce the negative environmental impact of chemical pesticides on the management of avocado tree. Design/Methodology/Approach: Using a randomized complete block design with four replicates, the following five treatments were evaluated: T1) control (water); T2) chicalote (Argemone mexicana L.) extract; T3) neem (Azadirachta indica) oil extract; T4) potassium soap (potassium salts); and T5) Spinosad (Spinosyn A and Spinosyn D). Each product was applied in its own row. Treatment rows were separated by a row of trees to which no treatment was applied. Samples were taken in different dates from plant and floral sprouts of four randomly selected avocado trees. Each tree was an experimental unit. Results: The data obtained did not comply with the normality test and the homogeneity of variance; consequently, the data were subjected to a General Additive Model (GAM). The most efficient treatments were neem oil extract and Spinosad. Study Limitations/Implications: Different orchards, with different initial pest populations, should be evaluated to determine the level of infestation in which the application of biorational products is still feasible for pest control. Findings/Conclusions: Plant extracts have high potential to control thrips in open-air avocado plantations; consequently, they could be an alternative to the application of synthetic insecticides for pest management.

Evaluating the Efficacy of Sea Cucumber (Stichopus horrens) as a Biocontrol Agent against Blattella germanica and Periplaneta americana

Background: Cockroaches, particularly Blattella germanica and Periplaneta americana, are major urban pests that pose significant public health risks and economic burdens. Traditional chemical control methods are increasingly challenged by the development of resistance and environmental concerns. Methods: This study investigates the potential of Stichopus horrens, a sea cucumber species, as a biocontrol agent against these cockroaches. The bioactive compounds of S. horrens were extracted and tested for toxicity and repellency. Result: Toxicity assays demonstrated a concentration-dependent increase in mortality, with 93.3% and 90% mortality observed for B. germanica and P. americana, respectively, at 1% concentration after 72 hours. However, repellency was moderate, with a maximum of 56.6% for B. germanica and 53.3% for P. americana at the same concentration. The findings suggest that S. horrens possesses strong insecticidal properties, making it a promising candidate for integrated pest management (IPM). Its moderate repellency indicates that its primary utility may lie in its insecticidal effects rather than as a repellent. Future research should focus on isolating the specific bioactive compounds and exploring their potential synergistic effects with other control methods to enhance efficacy and sustainability in pest management strategies.