Insecticide Treatments Research Articles

Population Dynamic of Aphis gossypii, and Their Parasitoids, and Effect of Some Insecticides on Aphids, Chlorophyll Content, Non-Enzymatic and Antioxidant Enzymes Activity in Cantaloupe Leaves in Greenhouses

Under green house, the Population density of Aphis gossypii on cantaloupe plants recorded two peaks on May 9th and 23th with 1409 and 1561 individuals/ 10 leaves in season 2022, while one highest peak, on 16th May with 1650 individuals/ 10 leaves in season 2023. Parasitism status of Aphidius colemani and Lysiphlebus fabarum varied from 1.49% on 25 April to 35.79% on 9th of May with seasonal parasitism 2023 in 2022 and ranged between 0.73% on 25th of April and 30.06% on 16th of May with seasonal parasitism 16.57% in 2023. Acetamiprid, imidacloprid, imidacloprid + abamectin, jojoba oil, orange oil and thiamethoxam + abamectin compounds were tested to control aphids during two seasons. Imidacloprid recorded the highest reduction with all average 97.88 ±1.15 and 97.39 ±1.15 in the first and second season respectively. the highest mean reduction of emergence of the two-parasites caused by thiamethoxam + abamectin by 16.92% followed by Imidacloprid with 16.87%. While the least toxicity to emergence of the parasitoids recorded with jojoba oil 0.0% followed by orange oil 1.93% in season 2022, while in season 2023, the higher parasitoid reduction caused by acetamiprid 18.05% followed by Imidacloprid 17.69% and thiamethoxam + abamectin 17.53%. Chlorophyll content increased with treatment jojoba oil followed by Imidacloprid by 47.91 and 44.73 unit in the first season and Thiamethoxam with abamectin lead to the highest content by 44.05 unit in the leaves followed by jojoba oil with 43.65 unit. The least treatment was Imidacloprid + abamectin with 39.55 unit compared with control treatment 40.43 unit. Treatment Thiamethoxam + abamectin recorded the highest content of carbohydrates (48.43) compared with control (47.71). Treatments of insecticides led to increase of protein, fats and total lipid compared with control. Also, Antioxidant enzymes activity in cantaloupe leaves were found to be increased in the treatment of insecticides compared with control.

Incremental Cost Benefit Ratio (ICBR) of Poly House and Open Field Conditions in Cabbage (Brassica oleracea var. capitata) after Chemical Intervention

This study evaluates the Incremental Cost Benefit Ratio (ICBR) between Poly house and Open field conditions in cabbage cultivation chemical intervention. The research aimed to compare the economic feasibility of adopting poly house technology over traditional open field methods, considering costs and benefits associated with chemical inputs. A comparative cost analysis was conducted to assess production expenses like costs for insecticidal treatments and labor charges. Yield data from both environments were collected to determine output differences and subsequent economic returns. Results indicate that Incremental cost benefit ratio of cabbage heads yields to the cost of treatments in poly house and open field presented as there was a significant superior difference in ICBR ratio of poly house with 1: 0.946 as compared to open field with 1: 0.639 of cabbage heads. The economic analysis revealed that the higher yields and quality achieved in poly house conditions due to less dissipation and undisturbed environmental factors on insecticide applied. Resulting in a favorable incremental Cost benefit ratio compared to open field cultivation.

Enhancing pest management - Utilizing supplementary food spray to harness predatory insects against fall armyworm in maize crop of Vinh Phuc Province, Vietnam

The effect of supplementary food spray on the fall armyworm (Spodoptera frugiperda) and beneficial insects (predominantly predatory insects) was studied in commercial maize field experiments from 2020 to 2022. The food spray formulation was developed from local ingredients in Vietnam, both with and without neem extract. The sugar-based rice dough product attracted and sustained beneficial insects, significantly reducing fall armyworm populations. Compared to conventional insecticide treatments, the net margin achieved in plots treated with food spray was higher ($3,467) to $3,394 in the conventional insecticide-treated plots demonstrating its economic viability (1 AUD=17.28 VND). Our study observed an average predator-to-prey ratio of 9.2:1 per plant in the food-spray-treated plots, and that was effective in managing the fall armyworm throughout the season. We propose that this ratio can serve as a valuable parameter and decisionmaking tool in food spray-based Integrated Pest Management (IPM) programs against fall armyworm in maize fields. Therefore, we suggest that food sprays can be incorporated into IPM strategies to successfully manage fall armyworm infestation in maize crop.

Comparative Study of the Efficacy of Two Biological Insecticides (Azadirachta indica and Bacillus thuringiensis) and a Chemical insecticide (Diflubenzuron WP) against Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) in Maize Crop, Western Bur

Aims: This study aimed at comparing the biological efficacy of Diflubenzuron WP, a chemical insecticide, and two biopesticides, one based on neem oil (Azadirachta indica) and an entomopathogen (Bacillus thuringiensis) against the fall armyworm on maize. Place and Duration of Study: The work was carried out on the irrigated scheme of Bama, western Burkina Faso during the 2022 and 2023 wet seasons. Methodology: The experimental design was a Fisher block with 4 treatments: T0: untreated or control; T1: Bacillus thuringiensis; T2: neem oil; T3: Diflubenzuron WP, in 4 replications. Entomological observations focused on the score and severity of attacks, as well as the pest's infestations rate. Results: The results showed that the different insecticides tested over the two wet seasons of 2022 and 2023 induced better control of S. frugiperda populations, with larval density being kept lower with the treatment of Diflubenzuron WP (4.25±1.2%), neem oil (14.28±1.6%) and Bacillus thuringiensis (24.5±3.2%). The insect damage severity rates and scores of damaged ears were also low for the three treatments respectively (1.09±0.2, 0.9±0.26 and 0.27±0.71) over the two cropping seasons. Diflubenzuron WP insecticide treatment not only reduced pest pressure, but also significantly improved maize yield. No surprisingly the highest yield (5.14 t/ha) was recorded with Diflubenzuron WP, followed by neem oil (4.62kg/ha) and finally Bacillus thuringiensis (3.92kg/ha). Conclusion: Further studies are needed to determine the optimal doses of neem oil and Bt for the control of Fall Armyworm. Neem oil can be considered as a good alternative to a chemical insecticide like Diflubenzuron WP.

Efficacy of selected insecticide sprays against Indian meal moth (Lepidoptera: Pyralidae) wandering larvae on various surfaces

The Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is a worldwide pest found in food product warehouses. Presence of P. interpunctella wandering larvae causes customer complaints and product rejection from customers. Its prepupal stage is susceptible to insecticide treatment due to their wandering behavior. We evaluated the efficacy of three insecticide sprays, ExciteR (0.017% pyrethrins, 0.174% piperonyl butoxide), Suspend SC (0.053% deltamethrin), and Transport Mikron (0.047% acetamiprid, 0.056% bifenthrin) against P. interpunctella wandering larvae by forced exposure to porous (vinyl tile, unpainted pinewood, concrete, and paper) and non-porous (steel, glazed ceramic) surfaces, and exposure to treated harborages made of two pieces of vinyl tiles, unpainted pinewood, and concrete. Under continuous exposure conditions, both ExciteR and Suspend SC caused significantly higher mortality (90–96%) than Transport Mikron (73–75%) on non-porous surfaces after 4 days (P < 0.05). But on porous surfaces, the three insecticides caused ≤63% mortality with Suspend SC being the most effective. When using 2× amount of insecticides as that in the previous test (2.1 gallon/1000 ft2, which is 4.33, 1.20, and 2.33 mg a.i./m2 of ExciteR, Suspend SC, and Transport Mikron, respectively), Suspend SC was the only insecticide causing high mortality (≥99%) through both forced exposure to concrete surface and exposure to treated concrete harborage. Whereas other treatments caused <12% mortality. Among the porous surfaces, residual efficacy of Suspend SC on concrete was significantly higher than that on vinyl tiles. Application of an effective liquid insecticide (such as 0.053% deltamethrin) into harborages or directly to the possible pupation sites, such as corners, cracks, and crevices could be an effective strategy for managing P. interpunctella wandering larvae in warehouse environment.

Impact of triflumezopyrim (insecticide) on blood and serum biochemistry of freshwater fish, subadult Labeo rohita (Hamilton, 1822)

The impact of insecticides on water bodies can be evaluated by studying the physiology and health of fish. These chemicals pose a significant and direct risk to aquatic ecosystems and hence aquatic animals like fish. Therefore, this study was designed to investigate the toxic effects of sub-lethal concentrations of triflumezopyrim, a novel synthetic insecticide commonly used in crop protection, on the biochemical and hematological parameters of freshwater sub-adult Labeo rohita L. Here, fish were subjected to sub-lethal doses of triflumezopyrim at various concentrations (1.41 ppm, 3.27 ppm, and 4.97 ppm) for 21 days. In addition, fish were grown in an insecticide-free control group to determine the toxic effects of the insecticides. The obtained data on various biochemical and hematological parameters of the fish were analyzed using state-of-the-art statistics. Our findings suggest that triflumezopyrim exposure has a significant effect on blood variables. However, variable response, such as mean corpuscular volume, hemoglobin concentration, neutrophils, and eosinophils were unaffected by insecticide treatment, regardless of the dose. Our interhematological parameter analysis revealed varying interrelationships at various insecticide doses. Similarly, triflumezopyrim exposure significantly affected the response of serum biomarker profiles i.e., the difference in mean treatment pairs (control and three doses of triflumezopyrim) had a significant effect on the response of most serum profile parameters.

Impact of insecticides on natural enemies of planthoppers in direct seeded rice

In the kharif season of 2020, a field experiment was conducted at the Agricultural College Farm, Bapatla to evaluate the impact of some insecticides in combination with the neem products on natural enemies of planthoppers such as green miridbug, Cyrtorhinus lividipennis (Reuter) and spider Lycosa pseudoannulata (Boesenberg and Strand) and Tetragnatha maxillosa (Thorell) in direct seeded rice (DSR). The results concerning the influence of insecticidal treatments, on natural predators such as miridbugs and spiders revealed that neem formulation 1500ppm @ 5ml l-1 with 6.13 miridbugs/hill and 8.83 spiders/10 hills h were at par with the untreated control showing no adverse effects on the predators of rice planthoppers. Among the other treatments, dinotefuran 20SG @ 40g a.i. ha-1 has recorded lowest number of natural predators with 2.77 miridbugs/hill and 5.17 spiders/10 hills, followed by triflumezopyrim 10.6SC @ 25g a.i. ha-1 with 2.93 miridbugs/hill and 5.27 spiders/10 hills; Pymetrozine 50WG @ 150g a.i. ha-1 with 3.07 miridbugs/hill and 5.50 spiders/10 hills which differed significantly from the untreated control.

Multigenerational hormetic effects of different insecticides on Spodoptera frugiperda (J.E. smith) (Lepidoptera: Noctuidae)

To protect crops from pest insects, farmers continuously use insecticides, which eventually degrade into residue due to abiotic or biotic factors. These residual effects of pesticides may cause low lethal and/or sublethal impacts on the exposed pest insect populations, leading to the induction of pest resurgence through hormesis and ultimately the development of resistance. Hormesis is a beneficial bi-phasic effect generally characterized by low-dose reproductive stimulation and high-dose inhibition. In the present study, we investigated the impact of low lethal and sublethal concentrations (LC10, LC20, and LC30) of spinetoram, chlorantraniliprole, and thiodicarb on the F0 generation as well as their multigenerational hormesis effects on the F1 and F2 generations of Fall Armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). The study focused on reproductive parameters, fecundity, fertility, and life index parameters such as net reproductive rate (R0), intrinsic rate of increase (rm), finite rate of increase (λ), mean length of generation (Tc), and gross reproductive rate (GRR). Fecundity of S. frugiperda increased by 4.82%, 4.63% and 4.58%, while eggs fertility improved by 7.77%, 6.78% and 6.52% at LC10 of thiodicarb, chlorantraniliprole and spinetoram, respectively, from the F1 to F2 generation. Further, interaction analysis (Concentration × Insecticidal treatments) revealed that important vital parameters like pre-oviposition period (POP), oviposition period (OP), post-oviposition period (PtOP), R0,rm,λ, Tc and GRR of F0 were negatively impacted by LC30 of all the tested insecticides and LC20 of only spinetoram. However, LC10 of any of the tested insecticides did not affect these parameters when compared with control. Furthermore, interactive analysis in multigenerational exposure experiments (Concentration × Insecticidal treatments × Generation(s)) showed hermetic effects of LC10 of all tested insecticides which is more positive in F2 as compared to F1 generation. These unwanted positive hermetic effects of low lethal concentrations (LC10) of tested insecticides in offspring of exposed parental population of S. frugiperda indicated its resistance and/or resurgence. Furthernore, present study emphasizes the necessity for additional research to elucidate the underlying mechanisms responsible for these effects.

Insecticide and low food quality treatments reduce health and pollination services of two key pollinator taxa

Abstract Pesticides and the lack of floral resources are key drivers of insect decline in agricultural areas. Both land‐use stressors can have a variety of synergistic and sublethal effects on pollinators, affecting their health and foraging behaviour. Pollinating insects include species with vastly different life histories, giving them potentially different vulnerability and resilience to stressors. However, most research has generally focused on bees. Here, we contrast synergistic effects of nutritional stress and pesticide use on social bumblebees and solitary hoverflies. We experimentally tested the effects of the neonicotinoid acetamiprid and low‐quality food on health traits of Bombus terrestris workers and Episyrphus balteatus adults (ovarian development, body size and colony development or survival). The foraging behaviour of treated pollinators was recorded in a semi‐field setup and, for B. terrestris, we measured the pollen amount on the body surface and the pollen deposited on stigmata after a single floral visit. Both stressors affected bumblebee health. Additionally, insecticide‐treated workers showed increased flower handling times and flight durations, while low‐quality food reduced the amount of pollen on the surface of bumblebees and the pollen deposited on stigmata. Syrphids were mostly affected by low‐quality food, which decreased their survival probability and changed their foraging behaviour. Furthermore, we found an interactive effect between the two stressors, reducing E. balteatus ovary development. Synthesis and applications. Insecticide and food stress affected fitness traits of both bumblebees and syrphid flies, possibly reducing pollinator populations under natural conditions. Especially for bumblebees, long‐term exposure led to a reduction in the provision of pollination services, both by changing their behaviour and reducing pollen transfer. We found differences between the two pollinator groups, showing that results gained from single groups like bees should not be extrapolated to all pollinators. Interactive effects indicate potential buffering effects of high‐quality food against other stressors and highlight the importance of considering synergies between multiple stressors in risk assessments. This further emphasizes the relevance of floral resources such as wild flower strips in agricultural areas to conserve pollinators and pollination services.

Flupyradifurone application: A promising approach to curtail tomato leaf curl New Delhi virus (ToLCNDV) transmission vectored by Bemisia tabaci in potato farming

The whitefly, Bemisia tabaci, serves as a carrier and transmitter of the tomato leaf curl New Delhi virus (ToLCNDV) in potatoes, leading to the emergence of potato apical leaf curl disease. Among the six insecticides tested against B. tabaci, flupyradifurone resulted in the highest mortality of nymphs and adults. Three effective insecticides were then further evaluated for their ability to prevent the acquisition and transmission of ToLCNDV by B. tabaci. Utilizing qPCR techniques, we determined the amount of virus acquired by B. tabaci from virus-positive plants that had undergone prior insecticide treatment. The results revealed a significant reduction in virus levels in the whitefly's body, flupyradifurone was found to be most effective among the tested insecticides in reducing ToLCNDV acquisition. Flupyradifurone also exhibited the highest efficacy in reducing ToLCNDV transmission by B. tabaci. Experiments conducted in the glasshouse 24 h post insecticide application demonstrated the complete prevention of ToLCNDV transmission in all plants treated with flupyradifurone. In the field experiment also, flupyradifurone effectively suppressed whitefly-mediated ToLCNDV transmission for up to 14 days following insecticide application. The findings indicate that the use of flupyradifurone has the potential to manage the vector population and control associated viral disease, which is known to cause significant losses in potato crops.

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.

Effect of insecticides and intercropping systems on fall armyworm (Spodoptera frugiperda (J.E. Smith)) infestations and damage in maize in northern Ghana

Field studies were conducted over two successive seasons to test the effects of maize-legume intercropping system on fall armyworm (FAW) (Spodoptera frugiperda (J.E. Smith)) and if insecticide use was necessary in intercropping systems. Three insecticide treatments [no spray, Emastar 112 EC (a.i. emamectin benzoate 48 g/L + acetamiprid 64 g/L), Neem seed oil (NSO) (a.i. 3% azadirachtin)] and three intercropping systems [sole maize (Zea mays L.), maize + soybean (Glycine max (L.) Merr.) and maize + groundnut (Arachis hypogaea L.)] were arranged as a 3 × 3 factorial experiment in a randomized complete block design. Data were collected on FAW larval infestations, parasitism rates, damage, grain yield and gross financial returns. Results from combined-years analyses showed that larval infestation was significantly affected by intercropping (p = 0.034) only, with maize + soybean recording the lowest infestation while sole maize was highest. Damage to crop and cobs were significantly affected by years and insecticide treatments. Cob damage was also significantly affected by intercropping system with maize + soybean being lowest and sole maize recording the highest damage. Parasitoids recorded were Coccygidium luteum, Chelonus bifoveolatus, and Charops sp. Grain yield was significantly affected by the intercropping systems only (p = 0.004), with no significant year (p = 0.152), insecticide (p = 0.726) and insecticide × intercropping system (p = 0.660) effects. Sole maize (1.6 t/ha) had the lowest yield while maize + groundnut (2.2 t/ha) was highest. In terms of income, an economic analysis showed that spraying intercropped maize with NSO resulted in the highest marginal rate of return. Thus, the use of NSO and intercropping is an effective FAW management strategy.

Dissipation kinetics and decontamination of chlorantraniliprole and thiamethoxam residues in curry leaves

ABSTRACT Herein, using liquid chromatography – tandem mass spectrometry, we validated a modified QuEChERS method to analyse thiamethoxam and chlorantraniliprole residues in curry leaves. These insecticides are part of a pest management module against the major curry leaf insect pests, psyllid and leaf roller. Based on the SANTE guideline, the method exhibited satisfactory recovery and precision. For both insecticides, the R2 value was 0.99. Furthermore, the determined limit of detection and limit of quantification were 0.008 and 0.025 mg/kg, respectively. The field persistence of both insecticides was longer, and below quantification limit was achieved within 30 and 40 days for chlorantraniliprole and 35 and 40 days for thiamethoxam. Residue degradation followed first-order kinetics, with longer half-lives of 5.08 and 5.28 days for chlorantraniliprole and 3.50 and 3.96 days for thiamethoxam at single (x) and double (2×) doses, respectively. For both insecticides, the hazard index (HI), calculated based on the highest residue on the day of insecticide treatment in the field study, was less than 1 at x and 2× doses, indicating an acceptable level of risk. Seasoning or quick frying of curry leaves in oil reduced maximum of thiamethoxam and chlorantraniliprole residues followed by treatment with NaCl (2%)/tamarind water (2%)/lemon water (2%) solutions. Analysis of 85 farm-gate samples revealed detectable residues of thiamethoxam in 25 samples (0.03–0.49 mg kg−1) and chlorantraniliprole in 1 sample (0.18 mg kg−1). The HI for the maximum quantity of insecticide residues detected in monitoring study was <1. Therefore, the research backs the idea of ensuring safe harvested produce, considering the field persistence of chlorantraniliprole and thiamethoxam in curry leaf and simple decontamination methods to satisfy consumer need for clean food commodity, if properly adopted.

Intervention portfolios analysis of Plasmodium vivax control in central China

BackgroundThe effects of a diverse spectrum of malaria interventions were evaluated through a deterministic Plasmodium vivax transmission model. This approach aimed to provide theoretical evidence of the performance of these interventions once implemented for achieving malaria elimination.MethodsAn integrated intervention portfolio, including mass drug administration, insecticide treatment, and untreated bed nets, was analyzed through modeling. Additionally, data-driven calibration was implemented to infer coverages that effectively reproduced historical malaria patterns in China from 1971 to 1983.ResultsMDA utilizing primaquine emerged as the most effective single intervention, achieving a 70% reduction in malaria incidence when implemented at full coverage. Furthermore, a strategic combination of MDA with primaquine, chloroquine, untreated bed nets, and seasonal insecticide treatments effectively eradicated malaria, attaining elimination at a coverage level of 70%. It was conclusively demonstrated that an integrated approach combining MDA and vector control measures is essential for the successful elimination of malaria.ConclusionHigh coverage of mass drug administration with primaquine and chloroquine before transmission was the key driver of the malaria decline in China from 1971 to 1983. The best-fit intervention coverage combinations derived from calibration are provided as a reference for malaria control in other countries.

ZnFe2O4 substituted with Cu atoms for ultra-efficient formation of sulfate radicals: Extremely low catalyst dosage for thiamethoxam degradation

Neonicotinoids as one of the newest major class of insecticides is a kind of persistent pollutants. Herein, copper-substituted zinc ferrites (Cu0.75Zn0.25Fe2O4) prepared in subcritical aqueous solution has a nanosize of ∼2 nm with high crystallinity and strong magnetic property. At low catalyst dosage of 0.05 g L−1, peroxymonosulfate (PMS) can be effectively converted into sulfate radicals in Cu0.75Zn0.25Fe2O4/PMS system. Thiamethoxam (THIA) degradation rate is in the order of Cu0.75Zn0.25Fe2O4 > CuFe2O4 > ZnFe2O4 (124, 84, 21 × 10−3 min−1, respectively). At pH ∼7.0, THIA degradation efficiency can be over 99 % in 40 min. The radical species (e.g., HO•, SO4•− and 1O2) were demonstrated by EPR spectra using probe molecules. The majority effects in Cu0.75Zn0.25Fe2O4/PMS system with kinetics modelling were comprehensively investigated as well. This work provides that multi-metal coupling, i.e., Cu(Ⅰ)/Cu(Ⅱ) & Fe(Ⅱ)/Fe(Ⅲ), in spinel structure by polyhedral design is an effective strategy for enhancing the catalytic activity. The Cu0.75Zn0.25Fe2O4/PMS system has promising for water treatment of neonicotinoid insecticide with ease of recycling catalysts by magnetic separation.

Efficacy of Biopesticides and Insecticides against Lepidopteran Pests in Rainfed Castor

Field experiments were conducted during kharif 2022 to evaluate the bio-efficacy of biopesticides and insecticides against tobacco caterpillar, Spodoptera litura (F.);semilooper, Achaea janata L. and shoot and capsule borer, Conogethes punctiferalis Guenee on castor. The results revealed that, all the insecticide treatments were significantly superior over untreated control. The highest% reduction of lepidopteran pest complex over the control after three sprays was recorded with spinetoram 11.7 SC followed by cyantraniliprole 10.26 OD, Bacillus thuringiensis var. kurstaki (Btk) SC, profenophos 50 EC, lambda cyhalothrin 5 EC and B. thuringiensis var. kurstaki (Btk) WP 1.5, Beauveria bassiana SC and Neemazal 10000 PPM. Highest seed yield was recorded with spinetoram (1434 kg/ ha) followed by cyantraniliprole (1338 kg/ ha) as against 940 kg/ ha in untreated control. The maximum incremental cost-benefit ratio of 1:3.13 was obtained with application of spinetoram followed by lambda-cyhalothrin (1:3.00) and Btk SC (1:2.73).

The neonicotinoid acetamiprid reduces larval and adult survival in honeybees (Apis mellifera) and interacts with a fungicide mixture

Plant protection products (PPPs), which are frequently used in agriculture, can be major stressors for honeybees. They have been found abundantly in the beehive, particularly in pollen. Few studies have analysed effects on honeybee larvae, and little is known about effects of insecticide-fungicide-mixtures, although this is a highly realistic exposure scenario. We asked whether the combination of a frequently used insecticide and fungicides would affect developing bees. Honeybee larvae (Apis mellifera carnica) were reared in vitro on larval diets containing different PPPs at two concentrations, derived from residues found in pollen. We used the neonicotinoid acetamiprid, the combined fungicides boscalid/dimoxystrobin and the mixture of all three substances. Mortality was assessed at larval, pupal, and adult stages, and the size and weight of newly emerged bees were measured. The insecticide treatment in higher concentrations significantly reduced larval and adult survival. Interestingly, survival was not affected by the high concentrated insecticide-fungicides-mixture. However, negative synergistic effects on adult survival were caused by the low concentrated insecticide-fungicides-mixture, which had no effect when applied alone. The lower concentrated combined fungicides led to significantly lighter adult bees, although the survival was unaffected. Our results suggest that environmental relevant concentrations can be harmful to honeybees. To fully understand the interaction of different PPPs, more combinations and concentrations should be studied in social and solitary bees with possibly different sensitivities.

Reducing flea-beetle feeding wounds on canola seedlings with foliar insecticide failed to improve blackleg control

In earlier studies, it was found that Leptosphaeria maculans could readily infect canola via fresh wounds but would require extended leaf wetness to infect intact tissues. We hypothesized that flea beetle feeding wounds might facilitate L. maculans infection under field conditions. Multi-year plot trials were conducted in western Canada to assess the effect of reducing flea beetle feeding wounds on canola seedlings with in-crop insecticide on subsequent blackleg infection. The experiment encompassed susceptible and resistant cultivars seeded into canola stubble from the previous year, with pyrethroid insecticide applied weekly commencing at trace feeding (<5%) to mitigate the insect damage. Fluopyram seed treatment was used as an additional treatment against early blackleg infection. Results from eight station years showed moderate feeding damage by flea beetles and generally high blackleg pressure, with the average disease incidence > 80%. Despite reduced feeding damage due to in-crop insecticide treatment, significant blackleg reduction was not observed. A greenhouse study revealed no correlation between puncture wounds on cotyledons and successful stem infection under high-inoculum conditions, suggesting that reduced insect feeding might not effectively counteract the heavy inoculum pressure resulting from canola residue in field trials. Fluopyram seed treatment did not reduce blackleg substantially, while resistant cultivars consistently exhibited effectiveness. Furthermore, harvested seed from plots with lighter blackleg often displayed lower levels of L. maculans inoculum contamination.

Evaluating foliar insecticides and economic thresholds for Tychius picirostris (Coleoptera: Curculionidae) management in Oregon white clover seed production.

The clover seed weevil, Tychius picirostris Fabricius (Coleoptera: Curculionidae), is a major pest in Oregon white clover seed crops. Reliance on synthetic pyrethroid insecticides and limited availability of diverse modes of action (MoAs) has increased insecticide resistance selection in regional T. picirostris populations, emphasizing the need to evaluate novel chemistries and rotational strategies for effective insecticide resistance management (IRM). The efficacy of 8 foliar insecticide formulations for managing T. picirostris adult and larval life stages was determined in small and large-plot field trials across 2 crop years. In both years, bifenthrin (Brigade 2EC), the grower's standard, showed negligible adult and larval suppression. Insecticide formulations with isocycloseram and cyantraniliprole active ingredients reduced adult and larval populations when applied at BBCH 59-60 (prebloom) and BBCH 65-66 (full bloom) growth stages, respectively. While differences in T. picirostris abundance were observed among insecticide treatments, seed yield differences were not detected in large-plot trials. Larval abundance was correlated with reduced seed yield, and an economic threshold of ≥3 larvae per 30 inflorescences was determined as a conservative larval threshold to justify foliar applications of diamide insecticides. Additional commercial white clover seed fields were surveyed to compare larval scouting techniques, including a standard Berlese funnel and a grower's do-it-yourself funnel. Both larval extraction techniques were correlated and provided similar estimates of larval abundance. These findings demonstrate new MoAs, optimal insecticide application timing, and larval monitoring methods that can be incorporated into an effective T. picirostris IRM program in white clover seed crops.

Wheat seed quality assessment after thiamethoxam treatment: integrating optical techniques with standard methods

Insecticide treatment of seeds protects against early field pests. Therefore, studies on the physiological and biochemical responses of crops exposed to insecticides are required. Standard (non-optical) tests are used to evaluate the physiological quality of seeds. However, some tests may need to be more sensitive to observe possible differences between the control group and the groups of interest. Optical techniques such as ultra- weak photon emission and Fourier transform infrared spectroscopy have been discovered to aid standard tests. The effects of different doses of Thiamethoxam were evaluated on wheat seeds from the cultivar FPS Certero. Samples were divided into five groups: control and treated with 75, 150, 225, and 300 mL of Thiamethoxam for each 100 kg of seeds. The ultra-weak photon emission results showed that it was possible to classify the treatment doses through the intensity of photon emissions. The Fourier transform infrared spectroscopy analyses can be used for biological analysis but are unrelated to Thiamethoxam seed treatment. Considering the findings, optical techniques can be used as an additional tool for assessing the physiological quality of seeds.