Insecticide Active Ingredient Research Articles

Developing agricultural pest management strategies with reduced-risks to surface water: An economic case study of California's Central Coast region

Pesticides are critical for protecting agricultural crops, but the off-site transport of these materials via spray drift and runoff poses risks to surface waters and aquatic life. California's Central Coast region is a major agricultural hub in the United States characterized by year-round production and intensive use of pesticides and other chemical inputs. As a result, the quality of many waterbodies in the region has been degraded. A recent regulatory program enacted by the Central Coast Regional Water Quality Control Board set new pesticide limits for waterways and imposed enhanced enforcement mechanisms to help ensure that water quality targets are met by specific dates. This regulatory program, however, does not mandate specific changes to pest management programs. In this study, we evaluate the economic, environmental, and pest management impacts of adopting two alternative pest management programs with reduced risks to surface water: 1) replacing currently used insecticide active ingredients (AIs) that pose the greatest risk to surface water with lower-risk alternatives and 2) converting conventional arthropod pest management programs to organic ones. We utilize pesticide use and toxicity data from California's Department of Pesticide Regulation to develop our baseline and two alternative scenarios. We focus on three crop groups (cole crops, lettuce and strawberry) due to their economic importance to the Central Coast and use of high-risk AIs. For Scenario 1, we estimate that implementing the alternative program in the years 2017–2019 would have reduced annual net returns on average by $90.26 – $190.54/ha, depending on the crop. Increased material costs accounted for the greatest share of this effect (71.9%–95.6%). In contrast, Scenario 2 would have reduced annual net returns on average by $5,628.12 – $18,708.28/ha during the study period, with yield loss accounting for the greatest share (92.8–97.9%). Both alternative programs would have reduced the associated toxic units by at least 98.1% compared to the baseline scenario. Our analysis provides important guidance for policymakers and agricultural producers looking to achieve environmental protection goals while minimizing economic impacts.

The effectiveness of various insecticide active ingredients against the intensity of armyworm (Spodoptera exigua) attacks on onion plants (Allium ascalonicum L.) Varieties of Bima Brebes

Shallots (Allium ascalonicum L.) are one of the leading commodities in agriculture. Shallots are commonly used as a seasoning for cooking, besides that shallots are also useful as traditional medicine because they have antiseptic substances contained in them. The productivity of onion plants often decreases as a result of pest attacks. Armyworm (Spodoptera exigua) is one of the obstacles in the cultivation of onion plants (Allium ascalonicum L.), high caterpillar attack rates can reduce onion productivity, even causing crop failure. One way to control this pest is to control by using insecticides with certain active ingredients. This study aims to determine the effectiveness of various insecticide active ingredients to control armyworm pests (Spodoptera exigua) on onion plants (Allium ascalonicum L.). The design in this study was a Group Randomized Design (RAK) with 4 treatments of insecticide active ingredients and controls, namely A (Profenofos), B (Emamectin benzoate), C (Metomil), D (Cipermethrin) and E (control). Each treatment was repeated 5 times so that there were 25 experimental units. The research was conducted in Gagasari Village, Gebang District, Cirebon Regency, West Java. The trial research time starts from June - September 2023. The results showed that the application of insecticides active ingredients Profenofos, Emamectin benzoate, Metomil and Sipermethrin did not cause phytotoxicity to onion plants. Insecticide, Profenofos has a relatively gentle attack and low when compared to other active ingredients. In general, it is seen that all active ingredients of insecticides tested are able to play a role in controlling pests well. Insecticide treatment has a significant effect on the yield of dry weight of shallots per plot when compared to treatment without insecticide control (control). Profenofos active ingredient insecticide treatment was seen to produce a higher dry tuber weight than other treatments even when compared to all insecticide active ingredients tested, reaching 24.92 kg or equivalent to 24.9 tons per hectare

The Effect of Various Insecticide Active Ingredients on the Intensity of Pest Attacks on Red Pepper Plants (Capsicum annuum L.)

Red Chili (Capsicum annuum L.) is an annuals of the eggplant family (Solanaceae). This plant comes from the American continent, precisely in the Peruvian area, and extends to other areas on the continent. The average consumption of red chili per capita of Indonesian people is 500 grams/year, 118,800 tons per year. Chili production in Indonesia has increased from year to year, in 2021 chili production reached 2,747,108 tons. Fruit caterpillars (helicoverpa armigera) are pests that often attack important plants in Indonesia. This pest usually attacks young fruits by making holes and eating them. An effort that farmers often make to control this pest is to use insecticides. Insecticides are chemicals that function to eradicate annoying insects. Common active ingredients applied for fruit caterpillar control are Chlorpyrifos, Chlorantraniliprol, Cipermethrin, Deltamethrin. This research was conducted in Ambit Village, Waled District, Cirebon Regency, West Java Province. The implementation time lasts for 3 months (July to September 2023). The method used in this study was Randomized Group Design (RGD) consisting of 5 treatments of various insecticide active ingredients and control (without treatment) repeated 5 times so that there were 25 experimental plots with treatment A (Chlorpyrifos), B (Chlorantraniliprol), C (Cipermethrin), D (Deltamethrin), and E (Control). The concentration of insecticide used is 2 ml / liter. The experimental results showed that the treatment of insecticide active ingredients had a real influence on the intensity of fruit caterpillar pest attacks (Helicoverpa amigera) and on other pests such as whitefly (Bemisia tabaci). Insecticides have no real effect on the intensity of chili plant disease attacks such as anthracnose disease (Colletotrichum gleosporioides). The insecticide applied also does not cause phytotoxicity to the growth of chili plants. The active ingredients of insecticides Chlorpyrifos, Chlorantraniliprol and Sipermethrin gave better results when compared to Deltrametrin and control insecticides. Thehighest harvest result was obtained from the treatment of the insecticide Chlorantraniliprol, as much as 10.31 kg/plot, or equivalent to 10.31 tons/ hectare.

Rapid assessments of the rice brown planthopper (Nilaparvata lugens Stal) outbreak in Semarang District, Central Java: Effects of farmers’ low KAP

Rapid assessments on the outbreak of rice brown planthoppers (BPH) (Nilaparvata lugens Stål) were conducted to investigate the status of BPH populations and the causative factors behind the outbreak. These assessments served as the basis for developing a proper action program. The assessments took place in Banyubiru Sub-District, Semarang District covering four villages (Kebondowo, Rowoboni, Tegaron, Kebumen) in December 2013. We analyzed BPH data, along with information about farmers’ practices in managing pests collected through interviews conducted in January 2018 in Indramayu. Additionally, we examined data on the number of BPH-infested areas in Java from 2010 to 2020 and the stock of insecticides in Java in 2021. Simple statistical analyses were carried out. The BPH population had spread throughout Banyubiru and was present in all sampled plots. The average number of BPH eggs ranged from 115.25 to 379.65 per rice hill, while the BPH nymphs and imagoes ranged from 3.42 to 11.87 per rice hill. The relatively low nymphs to imagoes ratio might be influenced by the high BPH predator populations, which ranged from three to six individuals per rice hill. Suspected causes of BPH resistance and resurgence included the application of banned and improper insecticides, as well as the repeated use of the same insecticide active ingredients for an extended period. It is recommended to discontinue the mass spraying of insecticides to prevent further plant damage. In 2022, the Pest Control Movement has suggested replacing chemical insecticides with biological or natural pesticides. Intensive extension programs are strongly needed.

Uptake and Retention of Imidacloprid and Cyantraniliprole in Cotton for the Control of Bemisia tabaci (Hemiptera: Aleyrodidae)

Abstract Plant tissue bioassays are a standard approach for bioassaying insects such as the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), an insect that specializes in systemic feeding on the phloem in leaves by using a piercing-sucking mouthpart apparatus. Systemic insecticides remain the most effective approach to whitefly management; however, little work has been done to quantify the amount of insecticide active ingredient that a species is exposed to when feeding. This study was conducted to estimate the imidacloprid and cyantraniliprole concentrations present in cotton (Gossypium hirsutum L.) leaves 24 h after a root drench for systemic toxicological bioassays. Insecticide active-ingredient quantification involved liquid chromatography–tandem mass spectrometry. Comparable concentration responses also were conducted to indicate the mortality of the sweetpotato whitefly at the tested concentrations. The results indicated significant active-ingredient retention with higher concentrations of insecticide treatments, which corresponded with higher sweetpotato whitefly mortality. Specifically, for imidacloprid and cyantraniliprole, the average slopes and intercepts of the log parts per billion of leaf tissue concentration to milligrams of active ingredient per liter of treatment solution were y = 4.08 x + 0.83 and y = 6.22 x + 0.47, respectively. These formulae estimate leaf tissue concentrations that can be linked to insect insecticide exposure in the leaves, with 50–73% of the overall variability explained. Significant correlations also were observed between the root drench concentrations, leaf tissue concentrations, and sweetpotato whitefly mortality.

Toxicity of fipronil and 2,4-D pesticides in Daphnia similis: a multiple endpoint approach

In Brazil, among the pesticides widely applied simultaneously in sugarcane monocultures are the Regent® 800 WG insecticide (active ingredient (a.i.) fipronil) and the DMA® 806 BR herbicide (a.i. 2,4-D). Thus, this study aimed to investigate, through different endpoints, the effects of the fipronil and 2,4-D pesticides, isolated and as mixtures, on the cladoceran Daphnia similis. To do this, acute toxicity tests were carried out with the compounds acting in isolation and in mixture, where the survival of the organisms was evaluated, and chronic toxicity tests with the isolated compounds, where reproduction and maternal and neonatal body length were evaluated. In this study, the physiological endpoints of D. similis were also analyzed, through the analysis of feeding rates (filtration and ingestion) in exposure and post-exposure scenarios, in order to verify the cladoceran food recovery capacity. In addition, D. similis data were compared with other species when exposed to the studied pesticides, using species sensitivity distribution curves. Acute toxicity tests of the fipronil and 2,4-D showed an average EC50-48h of 66.68μg a.i./L and 327.07mg a.i./L, respectively. In both cases, D. similis showed lower sensitivity compared to other species. For the mixture test, the evaluation by the IA model (independent action) and deviation DR (dose ratio dependent) indicated the occurrence of mostly antagonistic effects. The chronic test with fipronil showed a decrease in the fecundity of the organism at a concentration of 16μg a.i./L, a concentration already found in aquatic environments. For 2,4-D, no significant differences were observed for reproduction at the concentrations tested. Regarding the maternal body length, there were no significant changes when D. similis were exposed to both fipronil and 2,4-D, but these differences were observed in the body length of the neonates only for 2,4-D. There were no significant changes in the feeding rates of the organisms when exposed to both pesticides.

Risk Assessment of Fluxametamide Resistance and Fitness Costs in Fall Armyworm (Spodoptera frugiperda).

The fall armyworm (FAW), Spodoptera frugiperda, is one of the most devastating invasive polyphagous pests, which has attracted recent global attention by developing resistance to various insecticidal active ingredients with independent mode of action. Fluxametamide, a newly commercialized isoxazoline insecticide, is exceptionally selective towards several lepidopteran pests. The present study aimed to evaluate resistance risk in FAW to fluxametamide and the fitness costs associated with fluxametamide resistance. A field-collected and genetically mixed population of FAW was artificially selected through continuous exposure to fluxametamide. After successive selection of 10 generations, there was no obvious increase in the LC50 (RF: 2.63-fold). The realized heritability (h2) of fluxametamide resistance was estimated as h2 = 0.084 using a quantitative genetic approach. Compared with the susceptible F0 strain, the Flux-SEL (F10) strain of FAW displayed no significant cross-resistance to broflanilide, chlorantraniliprole, fipronil, indoxacarb, lambda cyhalothrin, spinetoram, and tetraniliprole, except emamectin benzoate (RF: 2.08-fold). Increased activity of glutathione S-transferase (ratio 1.94) was observed in the Flux-SEL (F10) strain of FAW, while the cytochrome P450 and carboxylesterase activities were not altered. The fluxametamide-selection significantly affected the development and reproductive traits of FAW with a lower R0, T and relative fitness (Rf = 0.353). The results alluded that the risk of fluxametamide resistance evolution in FAW is relatively lower; however, proactive implementation of resistance management approaches should be done to maintain the field efficacy of fluxametamide against FAW.

Insecticide discovery–“Chance favors the prepared mind”

New options for pest insect control, including new insecticides, are needed to ensure a plentiful food supply for an expanding global population. Any new insecticides must meet the increasingly stringent regulatory requirements for mammalian and environmental safety, and also address the need for new chemistries and modes of action to deal with resistance to available insecticides. As underscored by a paraphrase of a quote from Louis Pasteur “Chance favors the prepared mind”, the agrochemical industry uses a variety of approaches that attempt to improve on “chance” for the discovery of new insecticides. Although there are a number of approaches to the discovery of new insecticidal active ingredients (AIs), historically most insecticides are based on a pre-existing molecule or product either from a competitor or from an internal company source. As such the first examples of a new insecticide representing a new type or class of AI (First-in-Class: FIC) are important as prototypes for other AIs stimulating further spectrum, efficacy, physicochemical, and environmental safety refinements. FIC insecticides also represent a measure of innovation. Understanding the origins of these FIC compounds and the approaches used in their discovery can provide insights into successful strategies for future new classes of insecticides. This perspective will focus on an analysis of the approaches that have been used for discovery of FIC insecticides highlighting those approaches that have been the most successful and providing a reference point for current and future directions.

Laboratory evaluations of biodegradable boric acid hydrogel baits for the control of Argentine ant (Hymenoptera: Formicidae).

Due to their mutualistic relationship with plant pests, the Argentine ant is considered a major pest in subtropical fruit orchards and vineyards. Besides insecticide sprays, liquid baiting has been demonstrated as an effective method to suppress the Argentine ant populations. To improve the economic feasibility of liquid baiting, hydrogel materials have been recently tested as a carrier for liquid baits containing various insecticidal active ingredients. Here, we tested boric acid as a toxicant in the aqueous sugar bait delivered in a biodegradable calcium alginate hydrogel. Laboratory tests demonstrated that boric acid (1%) liquid bait incorporated in the calcium alginate hydrogel effectively killed Argentine ant workers. Potassium sorbate (0.25%) added to the liquid bait as a preservative did not impact the efficacy of boric acid even though it significantly reduced the degree of swelling of the hydrogel beads in the bait solution. Testing with 2-month-old bait suggested that long-term storage might impact bait efficacy even with potassium sorbate preservative.

Опыт практического применения многофункциональной станции для дезинфекции в целях дополнительных мер при проведении истребительных дезинсекционных мероприятий на примере постельных клопов

Today, disinfection institutions, having a small selection of insecticide active ingredients and a huge selection of mix insecticide preparations to combat bed bugs, face the problem of ensuring effective processing of objects of different categories. Keywords: preventive disinfection, fighter disinsection measures, disinsection, chamber disinfection (disinsection), bed bugs, tropical bed bugs, disinsection equipment.

Field applications of zein as a precise nanoscale delivery system for methoxyfenozide.

When insecticides are applied in the environment, much of the product does not reach the target pest. Biopolymeric nanoparticles as nanocarriers have the potential to improve insecticide efficacy by improving absorption, coverage, and permeability while protecting the insecticide active ingredient from abiotic conditions and extending efficacy through controlled release. We conducted a series of experiments using a biopolymeric nanoparticle synthesized from zein, a biodegradable maize protein, to compare efficacy of a nanodelivered hydrophobic insect growth regulator (methoxyfenozide) against a commercial formulation. Positively charged zein nanoparticles (empty and loaded with methoxyfenozide) were compared to the formulated product, Intrepid 2F, as a foliar spray in-field on soybean. Chrysodeixis includens (Walker) was used as a model and was fed sprayed soybean leaves to evaluate efficacy of the tested foliar products over time. A separate set of leaves was sampled to measure residue levels of methoxyfenozide (MFZ) over time following foliar application using QuEChERS extraction and high-resolution liquid chromatography-mass spectrometry. Regression analysis found no differences in mortality slopes between positively charged zein nanoparticles loaded with methoxyfenozide [(+)ZNP(MFZ)] and Intrepid 2F, suggesting comparable efficacy of the synthesized nanoparticles to a commercial product. Higher concentrations of MFZ were present in (+)ZNP(MFZ)-treated in leaf tissue at 3 d following spray when compared to Intrepid 2F. The multiyear study results demonstrate that nanoparticles loaded with MFZ are comparable to Intrepid 2F under field conditions, with potential short-term benefits.

Impacts of Bioassay Type on Insecticide Resistance Assessment in the German Cockroach (Blattodea: Ectobiidae).

The German cockroach, Blattella germanica (L.), is one of the most critical urban pests globally due to the health risks it imposes on people, such as asthma. Insecticides are known to manage large cockroach population sizes, but the rapid rate at which they develop resistance is a continuing problem. Dealing with insecticide resistance can be expensive and time-consuming for both the consumer and the pest management professional (PMP) applying the treatment. Each cockroach population is unique because different strains have different insecticide susceptibilities, so resistance profiles must be considered. This study addressed the above issue in a controlled laboratory setting. Cockroach strains from Indianapolis, Indiana, Danville, Illinois, and Baltimore, Maryland, USA were used. Four insecticide active ingredients (AIs) most used by consumers and PMPs were selected for testing in vial bioassays to establish resistance profiles. Next, no-choice and choice feeding assays with four currently registered bait products were performed to assess the impacts of competing food and circadian rhythms on bait resistance levels. The results indicate that emamectin benzoate (Optigard) was the most effective AI in causing the highest mortality in all strains in vial and no-choice bioassays; whereas, the other AIs and products were more impacted by resistance. The results acquired from these studies can help develop rapid tests for use by PMPs based on the no-choice feeding assay while also adding more information supporting current resistance and cross-resistance evolution theories.

Quality of corn seed industrial seed treatment (IST) and on-farm treatment (OFT) in Brazilian agribusiness

Abstract: Seed treatment is important for protecting seed and seedling from pests and/or pathogens. Seed treatment can be performed generally in two ways: industrial seed treatment (IST), performed by seed companies, or on-farm treatment (OFT). These treatment technologies will affect the final quality of the process. Therefore, the objective of this study was to characterize the seed quality profile of ISTs and OFTs in Brazilian agribusiness in terms of functional quality and dose application effectiveness (DAE). Seed samples treated by both processes were collected in 6 producing states of Brazil, Mato Grosso, Goiás, Paraná, Minas Gerais, São Paulo, and Santa Catarina. To evaluate the functional quality of the treatments, the coating percentage was determined by high-resolution image analysis with GroundEye® equipment, and the insecticide active ingredient DAE amount was determined with high-performance liquid chromatography (HPLC). Image analysis proved to be a promising technique to evaluate seed coating, in addition, samples treated with “on farm” technology had greater variation and heterogeneity in coating and active ingredient dose, while samples treated industrially showed greater homogeneity, uniformity, effectiveness of applied products. There was a strong positive correlation between coating with phytosanitary products and DAE in treated corn seeds, important parameters in the evaluation of the quality of the treatment.

Study of spinetoram nano suspension for environmentally friendly control of Plutella xylostella L. (Lepidoptera: Plutellidae)

Diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) is the main pest for brassicas and can potentially cause 90% yield losses. Currently the most effective control method is the use of insecticides, with spinetoram Suspension Concentrate (SC) formulation as one of the newest insecticide generations against this pest. However, there are some limitations in current SC formulations, including run-off issues owing to poor wettability, which may cause low efficacy and severe environmental contamination. Nano formulations that involve very small particles of an insecticide active ingredient could be promising candidates to solve this issue. Therefore, this study aims to prepare spinetoram nano suspension formulations using two modifications milling techniques NS1 and NS2, with various sized ZrO2 beads and evaluated their toxicity against 3rd larvae instars of P. xylostella. The PSA and SEM confirmed that NS1 and NS2 produced nano-sized particles pre-milled (2299.44 nm) to smaller than 100 nm. NS1 and NS2 improved the attachment and penetration of spinetoram into the leaf surface as provided a lower contact angle NS1 (56.98°), NS2 (55.82°), SC (80.03°). The LC50 of NS1 and NS2 with the wetting agent test improved the toxicity by 33% (NS1: 0.0061) and 7% (NS2: 0.0085) compared with SC (0.0091). Without the inclusion of the wetting agent, the spinetoram samples were 46% (NS1: 0.0138) and 41% (NS2: 0.0181) more toxic than SC (0.0256). This result was concluded that spinetoram nano suspension formulations can be administered at low doses as indicating their greater safety, and environmental friendliness than basic SC.

Environmental Safety Assessments of Lipid Nanoparticles Loaded with Lambda-Cyhalothrin.

Lipid nanoparticles (LN) composed of biodegradable lipids and produced by green methods are candidates for the encapsulation of pesticides, potentially contributing to decreasing their release in the environment. From a safety-by-design concept, this work proposes LN for the encapsulation of insecticide active ingredients (AI). However, given the complexity of nanoparticles, ecotoxicological studies are often controversial, and a detailed investigation of their effects on the environment is required. Accordingly, this work aimed to produce and characterize LN containing the insecticide lambda-cyhalothrin (LC) and evaluate their safety to crops (Solanum lycopersicum and Zea mays), soil invertebrates (Folsomia candida and Eisenia fetida), and soil microbial parameters. The average particle size for LN-loaded with LC (LN–LC) was 165.4 ± 2.34 nm, with narrow size distribution and negative charge (−38.7 ± 0.954 mV). LN were able to encapsulate LC with an entrapment efficacy of 98.44 ± 0.04%, maintaining the stability for at least 4 months. The LN–LC showed no risk to the growth of crops and reproduction of the invertebrates. The effect on microbial parameters showed that the activity of certain soil microbial parameters can be inhibited or stimulated by the presence of LN at highest concentrations, probably by changing the pH of soil or by the intrinsic properties of LN.

Cross effects of heat stress and three insecticides on the survival of the codling moth Cydia pomonella (L.): Investigating the molecular and biochemical mechanisms

As temperature is expected to strongly increase in the future, understanding temperature-mediated toxicity of insecticides is determinant to assess pest management efficiency in a warming world. Investigating molecular and biochemical mechanisms associated with cross mechanisms of temperature and insecticides on pests' tolerance would also be useful in this context. This study aimed to investigate cross effects between temperature and insecticides on the survival of a major pest, the codling moth Cydia pomonella, and their underlying mechanisms. The effect of three insecticidal active ingredients, i.e. chlorantraniliprole, emamectin and spinosad, was assessed at different temperatures on: (i) C. pomonella larval survival; (ii) detoxification enzymes activities (cytochrome P450 multi-function oxygenases, carboxylesterases and glutathione S-transferases) and (iii) genes expression of some detoxification enzymes, heat shock proteins and receptors targeted by the insecticides.We observed a decreased efficiency of emamectin and spinosad at high temperature to control the codling moth while no influence of temperature on chlorantraniliprole efficacy was observed. Detoxification enzymes activities were improved by heat stress alone but not by double stress (temperature + insecticides). Moreover, two detoxification genes (Cyp9A61 and Gst1) were over-expressed by a single stress but not by two stresses while Hsp70 and Cyp6B2 genes may be involved in tolerance to two stresses in C. pomonella. These results confirmed the cross effects of temperature and insecticides on C. pomonella for emamectin and spinosad and provided clues to understand how temperature affects the susceptibility of C. pomonella to insecticides. They illustrate however the complexity of molecular and biochemical responses of individuals facing multiple stresses.

Identification, Microhabitat, and Ecological Niche Prediction of Two Promising Native Parasitoids of Tuta absoluta in Kenya.

Simple SummarySince the arrival of Tuta absoluta, a multivoltine insect species whose larvae develop in leaves, fruits, flowers, buds, and stems of tomatoes, producers are facing one of its biggest production challenges. The pest continues to invade new areas, causing heavy losses in the tomato value chain. Sprays of synthetic insecticides have shown very low efficacy on this pest because of its inclination to develop resistance to various insecticide-active ingredients. Biological control is one of the most promising solutions for the management of this pest. In this work, we investigated the most efficient indigenous parasitoids associated with T. absoluta in Kenya and their preferable habitat and ecological niche suitability. We identified two species, Stenomesius sp. near japonicus and Bracon nigricans, with up to 17% and 21% parasitism respectively. Stenomesius sp. near japonicus was more abundant in greenhouses and non-insecticide-treated tomatoes while B. nigricans was more abundant in the field tomatoes with a low abundance of Nesidiocoris tenuis. The ecological niche of these two species showed that B. nigricans was suitable for establishment in sub-Saharan Africa, a big part of South America, and Australia in both current and future scenarios.Associations between the South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), and its native parasitoids need to be updated to increase the implementation of pest control strategies. In this study, T. absoluta-infested tomato plants were collected from three regions in Kenya. The emerged parasitoids were identified, and their abundance was correlated with agroecological parameters, viz. cropping systems, and the abundance of the predator Nesidiocoris tenuis Reuter (Hemiptera: Miridae). The study further conducted a habitat suitability prediction for the identified parasitoids. Two parasitoid species, Bracon nigricans (Szépligeti) (Hymenoptera: Braconidae) and Stenomesius sp. near japonicus (Ashmead) (Hymenoptera: Eulophidae) emerged from T. absoluta immature stages, with parasitism rates ranging from 0 to 21% and 0 to 17% respectively. Insecticide application and open field cropping negatively influenced the parasitism by S. sp. nr japonicus. Low occurrence of N. tenuis positively affected B. nigricans parasitism. The predicted occurrence of parasitoid species indicated vast suitable areas for B. nigricans in sub-Saharan Africa, Australia, and South America. Low suitability was observed for S. sp. nr japonicus in Africa. Therefore, native parasitoids, especially B. nigricans could be considered for implementation as a biocontrol agent in the Integrated Pest Management program of T. absoluta.

Innovation in insecticide discovery: Approaches to the discovery of new classes of insecticides.

The continuing demand for agrochemical insecticides that can meet increasing grower, environmental, consumer and regulatory requirements creates the need for the development of new solutions for managing crop pest insects. The development of resistance to the currently available insecticidal products adds another critical driver for new insecticidal active ingredients (AIs). One avenue to meeting these challenges is the creation of new classes of insecticidal molecules to act as starting points and prototypes stimulating further spectrum, efficacy and environmental impact refinements. A new class of insecticides is foreshadowed by the first molecule exemplifying that class (first-in-class, FIC) and offers one measure of innovation within the agrochemical industry. Most insecticides owe their discovery to competitor-inspired (i.e. competitor patents/products) or next-generation (follow-on to a company's pre-existing product) strategies. In contrast, FIC insecticides primarily emerge from a bioactive hypothesis approach, with the largest segment resulting from the exploration of new areas of chemistry/heterocycles and underexploited motifs. Natural products also play an important role in the discovery of FIC insecticides. Understanding the origins of these FIC compounds and the approaches used in their discovery can provide insights into successful strategies for future FIC insecticides. This review analyses information on historic and recently introduced FIC insecticides. Its main objective has been to identify the most successful discovery strategies for identifying new agrochemical solutions to meet the challenge of minimizing crop losses resulting from insects. © 2022 Society of Chemical Industry.

Degradation of Imidacloprid Residues on Unripe Tomatoes (Solanum lycopersicum) by AOPs and Its Analysis using Spectrophotometer and HPLC

Imidacloprid is an insecticide-active ingredient used by farmers to kill and control insects. Imidacloprid residue can be found in unripe tomatoes. Consuming unripe tomatoes contaminated with imidacloprid can cause human health problems such as cancer, chronic kidney disease, neurological disorders, and reproductive issues. In this study, imidacloprid pesticide residues on unripe tomatoes were degraded by the Advanced Oxidation Processes (AOPs) method, namely ozonolysis, sonolysis, and sonozolysis at various processing times (5, 10, 15, 20, and 25 minutes) in 50 g sample mass and 100 mL water volume. The changes in imidacloprid concentration before and after degradation were measured using a UV-Vis spectrophotometer and HPLC. The results of imidacloprid residue degradation by sonolysis was 66.99%, ozonolysis was 74.87%, and sonozolysis was 66.00%. The degradation kinetics of the imidacloprid residue was then studied. Kinetic study of all AOPs methods found that imidacloprid degradation followed a first-order kinetic model. The kinetics data showed that ozonolysis degradation is faster than sonolysis and sonozolysis, with a half-life (t1/2) of 16.90 minutes.

Integrated control of the mealybug Phenacoccus solenopsis (Hemiptera: Pseudococcidae) in Australian cotton with insecticides and naturally occurring beneficial arthropods

AbstractInsecticidal treatment options based on putative integrated pest management (IPM) compatible active ingredients spirotetramat, sulfoxaflor and buprofezin were evaluated for efficacy against first and second instar (small) and large (third instar and adult) cotton mealybugs, Phenacoccus solenopsis. Four field evaluations were conducted at the Department of Agriculture and Fisheries (Queensland) research station facilities at Kingaroy (KRS) and Emerald (ERS) in 2016 and 2017. Two ‘insecticide evaluations’ included treatment options with different rates of active ingredients and adjuvants, aimed at validating efficacy results obtained in previous glasshouse evaluations. The other two ‘IPM evaluations’ were designed to test the compatibility of selected insecticidal active ingredients with naturally occurring beneficial arthropods through differential exclusion by means of large field cages configured to be either partially open or fully closed to regulate access. Spirotetramat gave consistent and commercially acceptable (≥80%) control of large and small mealybugs at the highest rate of 96 g in these insecticide evaluations. The addition of crop oil to spirotetramat as a tank mix partner significantly enhanced efficacy, as documented previously in glasshouse evaluations. Sulfoxaflor provided equivalent control of large and small mealybugs but only at the ERS site. The overall control efficacy of buprofezin was equivalent to spirotetramat and sulfoxaflor at the ERS site but inferior to both at the KRS site. In the IPM evaluations, the abundance of predatory arthropods and their potential contribution to overall mortality was generally low. Parasitism contributed significantly to overall mortality among treatments over time and was independent of cage status (closed or open). Large mealybugs were equitably distributed between the upper (terminal) and lower sections of the cotton plant canopy in both ERS evaluations whereas in the KRS evaluations the distribution was biased towards the lower section. The importance of pest distribution within the crop canopy in the context of insecticide efficacy is discussed. The results of this study confirm the importance of spirotetramat, sulfoxaflor and buprofezin as key insecticidal platforms that will give growers and crop managers the flexibility and confidence to implement sustainable, multi‐pest IPM strategies in Australian cotton.