Efficacy Of Insecticides Research Articles

Field evaluation of Yorkool ®, a long-lasting insecticidal net after 12 months of use in Seme, Kisumu County, Kenya

Background: Physical integrity and insecticidal efficacy of long-lasting insecticide-treated nets (LLINs) is influenced by the handling practices during use. This was an evaluation of Yorkool® pyrethroid-based LLINs after 12 months of use to determine the washing and drying practices, physical conditions and bio-efficacy. Methods: This was a cross-sectional household survey in an area where rectangular Yorkool® a pyrethroid LLINs were distributed during national mass net distribution campaign in 2021. Questionnaires were used for data collection and bioassay tests were done from thirty randomly selected nets. Results: 262 household heads were interviewed with their mean age being 46.9 years (SD 17.4 years) and level of education was mainly primary (70.2%). Most households (71.8%) had 1 to 2 sleeping spaces. The households had a total 468 LLINs with 95.1% having been washed at least once. About three-quarters (74.4%) of the LLINs had been washed using local bar soap, with 99.6 % having not been scrubbed on hard surface during washing and 72.1% were dried under a shade. Those evaluated for physical integrity and had at least one hole made up 77.8% of the nets and 57.2% were too torn and requiring replacement. Bio-efficacy test recorded a mean KD of 92% after 1 hour, and mean mortality of 86% after 24 hours. The nets that passed the WHO efficacy cut off for mortality (≥80%) after 24 hours were 83.3% and 70% passed the KD (≥95%) cut off after 1 hour. Conclusions: While more than a half of the Yorkool® LLINs needed replacement due to poor physical integrity after one year of use in the households, the bio-efficacy of the LLINs was relatively high with the mortality on vectors meeting the WHO threshold

Biological efficacy of selected insecticides for the control of the green apple aphid Aphis pomi (de Geer, 1773) on apple in Bulgaria

The aim of this study was to evaluate the biological efficacy of chemical insecticides, from different chemical classes, recommended for the control of the apple aphid Aphis pomi in apple orchards in Bulgaria. The experiment was carried out in 2023 in the experimental field of Agricultural University-Plovdiv. The insecticides tested were spirotetramat (Movento 100 SC), flonikamid (Teppeki) and acetamiprid (Mospilan 20 SG). The insecticides were applied at the concentrations recommended for the control of this and other pests. All the tested chemical insecticides showed very high biological efficacy, therefore they can be recommended as suitable for efficient control of Aphis pomi on apple. Keywords: Chemical insecticides, Movento, Teppeki, Mospilan, Aphis pomi, Аpple, Bulgaria

Possibility for control with botanical insecticides against the mealy plum aphid Hyalopterus pruni Geoffroy, 1762 (Hemiptera: Aphididae) on the plum in Southern Bulgaria

The aim of this study was to evaluate the efficacy of botanical insecticides recommended for control of the mealy plum aphid Hyalopterus pruni (Hemiptera: Aphididae). The experiment was carried out in 2024 in the experimental field of the Fruit Growing Institute-Plovdiv, Bulgaria. The tested insecticides were orange oil (Limocid), liquid extract of Urtica spp. (Basictec) and pyrethrins (Abanto). The insecticides were applied at the recommended concentrations for control of aphids, whiteflies, thrips and other pests. All tested botanical insecticides showed high biological efficacy and can be used to control the mealy plum aphid. Keywords: mealy plum aphid, biological control, botanical insecticides, Limocid, Basictec, Abanto, Hyalopterus pruni

Chemical Composition and Insecticidal Potential of Essential Oil from Murraya koenigii (L.) Obtained by Natural Deep Eutectic Solvents.

Aphis craccivora Koch and Planococcus lilacinus Cockerell are phloem feeders and act as vectors for transmitting plant viruses to agricultural and horticultural crops thereby damaging them. The persistent and widespread use of synthetic, wide-spectrum pesticides has resulted in resistance development that is detrimental to the environment, human health, and natural enemies of pests. The present investigation uses various extraction mediums to examine the insecticidal efficacy of essential oils (EOs) isolated from Murraya koenigii (L.) leaves. Increase in yield was observed in the EO extracted using NADES-AHD [0.16% (obtained with hydro-distillation)] to 0.30% [obtained with N-1 (glycerol:lactic acid)]. EO obtained with water was found more effective against A. craccivora (LD50 = 0.89 µL/insect) and followed by N-1 (glycerol:lactic acid), and N-3 (choline chloride:citric acid) (LD50 = 1.29-1.38 µL/insect). Similarly, EO isolated by water and N-4 (choline chloride:oxalic acid) was effective against P. lilacinus (LD50 = 2.63-3.06 µL/insect). Additionally, the EO prepared by water substantially reduced glutathione S-transferase (GST) and acetylcholinesterase (AChE) in target pests, suggesting that these enzymes may be the EOs' site of action. NADES-AHD has enhanced the EO yield as compared to the conventional method. The EO obtained with water showed promising toxicity against target pests and target site of action. Therefore, based on field and greenhouse bio-efficacy experiments, EOs/biopesticides/botanicals can be proposed for controlling the spread of mealy bugs and aphids.

Insecticidal activity of silver nanoparticles synthesised from aqueous leaf extract of Eucalyptus tereticornis on horn flies

An insecticidal efficacy of silver nanoparticles (AgNps) synthesised from aqueous leaf extract of Eucalyptus tereticornis, was carried out against adults, larval and pupal stages of Haematobia flies. In in vitro adulticidal and larvicidal assays the mortality ranged between 30.0 to 67.0 and 5.0 to 75.0 per cent in treated groups after 24 hours at different concentrations, respectively. The inhibition of pupation ranged between 5.0 to 30.0 per cent after 24 hours by dipping method. The lethal concentration values were calculated for all the assays. The probit analysis revealed the significant (p<0.05) effect at different concentrations of AgNPs synthesised from aqueous leaf extract of E. tereticornis on adults, larvae and pupal mortality Keywords: Haematobia flies, silver nanoparticles, in vitro assays

Insecticidal efficacy of local diatomaceous earth compositions with different particle sizes against stored grain pests

In this study, the efficacy of a mixture of local diatomaceous earth (DE) with different diatomite compositions and particle sizes against stored-grain pests, Sitophilus oryzae L., 1763 (Coleoptera: Curculionidae), Tribolium confusum du Val, 1863 (Coleoptera: Tenebrionidae), and Rhyzopertha dominica (F., 1792) (Coleoptera: Bostrichidae) adults was investigated in 2023 in the Entomology Laboratory of the Department of Plant Protection, Faculty of Agriculture, KSU. In biological tests, 500 and 1000 ppm concentrations (mg DE/kg wheat) of different particle sizes (≤ 20, 20-75, 75-150, and ≥ 150 µm) of DE mixture and original DE (≤ 250 µm) were applied to wheat. The highest mortality rate for all insect species tested at 500 ppm was obtained from DE treatments of ≤20 µm. At 1000 ppm, 100% mortality was observed for T. confusum and S. oryzae in almost all particle size DE-treatments, whereas no local DE treatments resulted in 100% mortality for R. dominica adults. Moreover, the greatest reduction in the number of F1 generation adults for S. oryzae and R. dominica was obtained in the DE treatment of ≤20 µm at 500 and 1000 ppm. In conclusion, local DE mixture treatments with ≤ 20 µm particle size were found to be highly effective in the control of stored-grain pests.

Regional changes of maximum dose insecticide responses in diamondback moth (Lepidoptera: Plutellidae) populations from Georgia and Florida, USA.

Maximum dose bioassays were conducted to assess the efficacy of multiple registered active ingredients for diamondback moth (DBM), Plutella xylostella (L.), control in Georgia and Florida from 2021 to 2023 as a follow-up to an earlier study. Low efficacy (<40% mortality) was recorded for the highest labeled rate of Bacillus thuringiensis var. kurstaki strain ATBS-351 in Georgia, as well as chlorantraniliprole, cyantraniliprole, and cyclaniliprole in Georgia and Florida. The active ingredients with the highest efficacy (>80% mortality) in both states were naled, emamectin benzoate, and spinetoram. Independent analysis of data by state indicated that the efficacy of bifenthrin, chlorantraniliprole, cyantraniliprole, tolfenpyrad, and methomyl was higher in Florida populations than in Georgia populations. In addition, a comparison of these data to a recent DBM maximum dose survey in the same region suggested that these DBM populations have rapidly developed high levels of resistance to cyantraniliprole and cyclaniliprole. This work provides growers in the region with a recent ranking of insecticide efficacy that documents the loss of control for certain active ingredients, which assists pest managers in the planning of ongoing insecticide rotations for DBM resistance management.

Efficacy of Alternative Insecticides against Dusky Cotton Bug (Oxycarenus laetus) to Improve Yield Losses in Cotton Crops through Residue-based Bioassay

The study evaluates the efficacy of leufenuron, emamectin benzoate, and thiamethoxam against the Dusky Cotton Bug (Oxycarenus laetus Kirby) using residue-based bioassay methods. Key findings indicate that emamectin benzoate showed the highest efficacy with the lowest LC50 value, making it the most potent insecticide among those tested. Leufenuron and thiamethoxam followed, displaying moderate effectiveness. The results highlight the comparative advantages of emamectin benzoate in controlling Dusky Cotton Bug populations, suggesting its potential role in integrated pest management strategies. This study underscores the need for environmentally friendly alternatives to traditional insecticides in mitigating yield losses in cotton production.

Efficacy of Insecticides Against Yellow Stem Borer (Scirpophaga incertulas Walker) and Rice Leaf Folder (Cnaphaocrocis medinalis Guenee) and Their Impact on Natural Enemies in Rice Ecosystem

The experiment was conducted at AAU-Assam Rice Research Institute, Titabor to test the efficacy of some insecticides against yellow stem borer and rice leaf folder. Out of 8 tested insecticides, Chlorantraniliprole 18.5 SC showed the best result in minimizing yellow stem borer and rice leaf folder infestation. The lowest infestation percentage of yellow stem borer (2.10%) was observed on Chlorantraniliprole 18.5 SC treated plots followed by treatment with Chlorantraniliprole 10% + Lambda Cyhalothrin 5% ZC (2.33 %) at 7 DAT. Similarly, white ear head (0.33%) was also recorded as the lowest on Chlorantraniliprole 18.5 SC treated plots. Chlorantraniliprole 18.5 SC recorded the lowest infestation percentage of rice leaf folder at 7 DAT (3.40 %) and 14 DAT (3.53 %) followed by Chlorantraniliprole 10% + Lambda Cyhalothrin 5% ZC. While, the highest number of spiders and coccinellids were recorded in Chlorantraniliprole 0.4GR (2.43 spider/plant and 1.33 coccinellids/plant) followed by Thiamethoxam 25WG (2.13 spiders/plant and 1.10 coccinellids/plant). In terms of yield, Chlorantraniliprole 18.5 SC was found to be the best insecticide which provided the highest yield of 5.83t/ha among all the tested insecticides.

Enhancing the insecticidal efficacy of Allium sativum extracts through microencapsulation via complex coacervation

Garlic (Allium sativum L.) has been widely studied for its insecticidal properties. The primary bioactive molecule in garlic extracts include allicin, alliin, S-allylcysteine, diallyl disulfide, diallyl trisulfide, diallyl sulfide and ajoene. However, these compounds degrade under environmental conditions once extracted. This study aimed to enhance the effectiveness of garlic extracts in controlling Tenebrio molitor by optimizing microencapsulation techniques. The garlic extracts were encapsulated using the complex coacervation method, with independent variables including pH levels (3, 6 and 9), whey protein isolate (WPI) (4 %, 6 % and 8 % w/v) and pectin (0.50 %, 0.75 % and 1.00 % w/v). A Taguchi L9 (33) orthogonal array was employed to design 9 treatments, and T. molitor mortality was assessed 72 h after a 10 sec immersion of the insects in the treatments. Statistical analysis revealed that WPI had the most significant influence (24.52 %), followed by pH (18.82 %) and pectin (7.79 %). The interaction between pH and pectin had the greatest effect on the encapsulation process, accounting for 38.65 % of the influence. The optimal microencapsulation conditions were predicted by software to be pH 3, a pectin concentration of 0.75 % w/v and a WPI concentration of 4.00 % w/v, resulting in a signal-to-noise (S/N) ratio of 42.30. Experimental validation of these conditions produced an S/N ratio of 18.54, corresponding to a T. molitor mortality rate of 92 % ± 4.47 %. The resulting microcapsules had diameters ranging from 1–5 ?m. Complex coacervation is a highly promising method for microencapsulating garlic extracts and preserving their insecticidal properties.

Functionally Modified Graphene Oxide as an Alternative Nanovehicle for Enhanced dsRNA Delivery in Improving RNAi-Based Insect Pest Control.

RNA interference (RNAi) has shown substantial promise as a sustainable pest management solution. However, the efficacy of RNAi-based insecticides heavily relies on advanced nanocarrier-mediated delivery systems. In this study, we modified raw graphene oxide into positively charged nanocarriers (GONs) tailored to bind with double-stranded RNA (dsRNA). The resulting GONs@dsRNA complexes demonstrated a small particle size (106 nm) and maintained stability under various conditions, including insect gut extracts, extreme pH, and extreme temperature. Furthermore, GONs efficiently transported dsRNA molecules into Drosophila S2 cells and Lepidoptera Sf9 cells, leading to an enhanced target transcript knockdown. Targeting the vacuolar ATPase gene, vha26, induced significant mortality and target transcript knockdown in D. suzukii adults but not in S. exigua. Finally, GONs@dsRNA complexes exhibited negligible cytotoxicity at both the cellular and organismal levels. This study demonstrates the potential of GONs as a biosafe nanovehicle for efficient dsRNA delivery into insects, presenting an alternative strategy for advancing RNAi applications in fundamental studies and pest control.

Efficacy of Intercropping, Botanicals and Insecticides Against Okra Shoot and Fruit Borer (Earias vittella F.) on Okra in Uttar Pradesh, India

This study assesses the effectiveness of intercrops, insecticides and botanicals against the okra shoot and fruit borer Earias vittella. The okra + marigold (1:1) and okra + coriander (1:1) intercropping had the least shoot damage (4.35 percent, respectively), according to the data (4.70 per cent). Okra + maize (1:1) saw the most shoot damage (5.51%) when compared to monoculture (6.68 per cent). Spinosad 45 SC 75 g a.i./ha (2.49%) had the lowest rate of shoot damage among the insecticides, followed by Abamectin 1.8 EC 25 g a.i./ha (3.12%) and botanical NSKE 5 per cent, which found that the per cent shoot damage (3.25) compared to sole crop (okra) was higher (6.68 per cent). The data showed that the least fruit damage (9.25 percent, respectively) occurred in the intercropping of okra + marigold (1:1) and okra + coriander (1:1) (11.59 per cent) weight basis. The fruit damage in okra + maize (1:1) was highest (15.37%) compared to monoculture (18.08 per cent). Among the insecticides, Spinosad 45 SC 75 g a.i./ha (1.73%) had the lowest rate of shoot damage, followed by Abamectin 1.8 EC 25 g a.i./ha (2.02%) and botanical NSKE 5%, which discovered that the percentage of shoot damage (2.76) compared to lone crop (okra) was higher (18.08 per cent ). The highest yield was observed when intercropping coriander and okra (1:1), whereas the lowest yield was recorded when intercropping maize and okra (23.28 q/ha) (1:1).

Barley yellow dwarf virus in winter barley: Control in light of resistance issues and loss of neonicotinoid insecticides

AbstractBarley yellow dwarf virus (BYDV) is the most widespread viral disease of cereal crops vectored by aphids, causing stunting of the crop and significant yield loss. Management recommendations for autumn sown cereals has centred on the timely control of aphid vectors, particularly their management before the crop has reached Growth Stage 31 (stem elongation). In recent years two separate but related issues have emerged, (i) the detection of pyrethroid resistance in a single Sitobion avenae SA3 clone and (ii) the withdrawal of neonicotinoid insecticide seed dressing; widely used to manage aphids in the early development of cereal crops. A series of replicated field studies were conducted from 2016 to 2019 to ascertain if the pyrethroid insecticide is still effective in light of the SA3 clones' presence in aphid populations and if withdrawal of neonicotinoid seed dressings has negatively affected aphid management. Both disease levels and yields confirmed that the neonicotinoid, clothianidin, applied as a seed treatment significantly contributed to the management of BYDV in the different trials investigated. Results of this study demonstrate application of a foliar (lambda‐cyhalothrin or a sulfoxaflor) insecticide has a significant positive impact on yield. Foliar pyrethroid insecticides were as effective in protecting yield from BYDV as the neonicotinoid seed treatments. In the absence of neonicotinoid seed dressing, alternative insecticides still offer protection for winter barley crops against the aphid vectors of BYDV and associated yield loss. Furthermore, the presence of a pyrethroid resistant Sitobion avenae SA3 clone had no observable impact on field efficacy of the pyrethroid insecticide, lambda‐cyhalothrin in these trials. However, this needs continuous monitoring because of potential further increases in resistance levels or emergence of additional resistance mechanisms, which could render pyrethroid insecticides ineffective.

Adulticidal activity of essential oils of Ageratum conyzoides L., Hyptis suaveolens L., Ocimum basilicum L. and their synergistic effects against anopheles mosquitoes

This study investigated the insecticidal efficacy of essential oils (EOs) extracted from Ageratum conyzoides, Hyptis suaveolens, and Ocimum basilicum against female Anopheles mosquitoes, aiming to explore their potential as alternatives to synthetic insecticides amidst rising resistance issues. EOs were obtained through steam distillation from freshly harvested plant aerial parts, and their chemical compositions were analyzed using gas chromatography-mass spectrometry. The results revealed significant variations in chemical profiles among the oils, with precocene I dominating in A. Conyzoides, eucalyptol in H. suaveolens, and estragole in O. basilicum. Thin layer chromatography analyses revealed various components with rf values ranging from 0.25 – 0.93. Mosquito bioassay demonstrated varying knockdown effects across the oils, with H. suavolens achieving 77.5% knockdown within six minutes of the observation period. None of the oils or their combinations reached susceptibility status (98–100% mortality), indicating prevalent resistance among the mosquito population in the study area. The combination of A. conyzoides and H. suavolens essential oil gave the highest percentage mortality (70%) at the least time (9 minutes), this is a suggestion of synergistic activity. Despite resistance challenges, this study highlights the promise of botanical insecticides in sustainable mosquito control and underscores the ongoing need for innovation and adaptation in vector management strategies.

Efficacy of Botanicals and Insecticides against Whitefly, Bemisia tabaci Gennadius (Homoptera; Aleyrodidae) in Mungbean

Background: Mungbean is the major pulse crop of India. Pulse constitute the major source of dietary protein; therefore, it has ability to fulfil required protein recommended dietary allowance for vegetarian population of India. Pulse crop attack more than 200 insect pests. Methods: Efficacy test of Botanicals and Insecticides viz., Kaner powder, Garlic extract, Azadirectin 1500 ppm, Dasparni Ark, flonicamid, thiamethoxam, Imidacloprid and Dimethoate against B. tabaci was conducted in mungbean during Kharif 2022-2023 at Students’ Instructional Farm, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya (UP), India under field conditions with nine treatements including control in three replication. Result: The results demonstrated that Thiamethoxam 25 WG (50 g a.i./ha) was the most effective insecticide among all treatments, with a significant population reduction above control, followed by Imidacloprid 70 WG (5ml/l). Among the botanicals, Azadirectin 1500 ppm (5 ml/l) was the most effective against whitefly infestation in mungbean and could be applied as an eco-friendly alternative to conventional pesticides for whitefly management.

Facet-Dependent Lethality of a Contact Insecticide Crystal.

The activity of crystalline contact insecticides relies on the extraction of surface molecules by insect tarsi upon contact. Most crystals are inherently anisotropic, and surface molecules on symmetry independent faces are expected to have different free energies. The facet-dependent bioavailability and associated efficacy of insect lethality have not been investigated, however. We discriminate the bioactivity of various facets of single crystals of DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane), a well-known contact insecticide. Our findings reveal facet-dependent lethality differences of nearly 75% among four crystallographically unique facets. Furthermore, computations reveal that the respective lethalities of the facets are strongly correlated with the detachment energies of molecules from the crystal surfaces. This facet-dependent lethality suggests a pathway to enhance the efficacy of known contact insecticides through crystal habit control.

Chirality in Insecticide Design and Efficacy.

Chirality plays a crucial role in the design and efficacy of insecticides, significantly influencing their biological activity, selectivity, and environmental impact. Recent advancements in chiral insecticides have focused on enhancing their effectiveness, reducing toxicity to nontarget organisms, and improving environmental sustainability. This review provides a comprehensive overview of the current state of knowledge on chiral insecticides, including neonicotinoids, isoxazolines, and sulfiliminyls. We discuss the stereochemistry, synthetic development, mode of action, and environmental fate of these compounds. The review highlights the importance of chirality in optimizing insecticidal properties and underscores the need for continued research into novel chiral compounds and advanced synthesis technologies. By understanding the role of chirality, we can develop more effective and environmentally friendly insecticides for sustainable pest management.

Insecticidal and Anti-Feedant Activity of Clerodendrum Extracts on Growth and Development of Castor Spiny Caterpillar, Ariadne merione

The castor spiny caterpillar Ariadne merione (F.) is a major lepidopteran pest affecting castor (Ricinus communis) crops mainly by causing defoliation which in turn reduces the photosynthesis and yield. The conventional pest control methods have been based on chemical control which although has been effective, has its drawbacks of being hazardous to the environment and human health besides leading to resistance by the pests. The present work aims at investigating the possibility of using Clerodendrum inerme, a plant belonging to the Lamiaceae family, as an eco-friendly solution for pest management. Insecticidal and anti-feedant efficacy of C. inerme leaf extracts, which were prepared using solvents hexane, acetone, and petroleum ether, was tested against A. merione larvae using leaf dip bioassay under no-choice situation. The findings showed that the hexane extract had the highest insecticidal (73%) and anti-feedent (97%) action. The petroleum ether extract also showed moderate insecticidal (50%) and anti-feedant activity (48%) but not as potent as the acetone extract having insecticidal and anti-feedant action of 60 and 74 per cent respectively. The results imply that C. inerme extracts, especially the hexane extract, could be used as botanical insecticides in IPM programs as a natural replacement for chemical insecticides.

Susceptibility of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) Mediterranean Populations Found in São Paulo, Brazil to 11 Insecticides and Characterization of Their Endosymbionts.

The silverleaf whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), is a significant agricultural pest worldwide, impacting a variety of crop yields. Since the introduction of B. tabaci Mediterranean (MED) species in Brazil, limited research has measured the relative efficacy of the primary insecticides used in whitefly management. This study evaluated the susceptibility of three distinct B. tabaci MED populations to 11 insecticide active ingredients and characterized the bacterial endosymbionts within each population. The insecticides tested were acetamiprid, bifenthrin, cyantraniliprole, diafenthiuron, spiromesifen, imidacloprid, pymetrozine, pyriproxyfen, sulfoxaflor, and thiamethoxam. Results showed varying LC50 and LC90 values among tested insecticides and populations. Notably, populations varied in response to imidacloprid and thiamethoxam with some populations having a 6× higher tolerance. Sequencing data of endosymbionts revealed that individuals from the most susceptible B. tabaci population harbored Rickettsia and Arsenophonus, whereas these bacteria were not detected in the resistant populations. These findings highlight the need for frequent insecticide toxicity bioassays of distinct B. tabaci populations and the adoption of integrated pest management strategies to preserve the efficacy of insecticides for B. tabaci control. Additionally, the role of infection by endosymbionts to alter susceptibility should be further explored.

Field Efficacy of Insecticides for Management of Lepidopteran Pests in Cashew

Efficacy of different insecticides against lepidopteran pests of cashew were tested at Dr. YSRHU- Cashew Research Station, Bapatla, AICRP on Cashew during 2015-16 to 2021-22. Among the insecticides lamda-cyhalothrin 5 EC @ 0.6 ml/l was found effective in managing the foliage and floral pests such as, leaf and blossom webber, leaf miner, shoot tip caterpillar, apple and nut borer followed by Dr. YSR Horticultural University package of practices (POP) i.e. monocrotophos 36 SL @ 1.6 ml/l during the flushing stage, chlorpyrifos 20 EC @ 2.0 ml/l during the flowering stage and profenophos 50 EC @ 1.0 ml/l during the apple and nut development stage. Further, the spider population was observed to be highest in untreated check and Beauveria bassiana treatments compared to insecticidal treatments.