Insecticide Applications Research Articles

Studies on the synthesis, crystal structures, biological activities and molecular docking of novel natural methylxanthine derivatives containing piperazine moiety.

A series of novel methylxanthine Mannich base derivatives containing substituted piperazine groups were synthesized through Mannich reaction. The structures of these new compounds were confirmed by NMR, HRMS or elemental analyses, and X-ray single crystal diffraction. Bioassay results showed that some of the compounds exhibit favorable fungicidal and insecticidal potentials. Particularly, compounds IIk, IIq, IIs and compounds If, IIk against Physalospora piricola and Rhizoctonia cerealis, respectively, were comparable with Azoxystrobin and Chlorothalonil; compound Ik exhibited higher potency than Triflumuron against Plutella xylostella L., suggesting its potential as a lead compound for further development in insecticidal applications. Despite possessing weak herbicidal activities, the target compounds, especially the methylxanthine S-Mannich base derivatives I displayed remarkable inhibitory activities toward ketol-acid reductoisomerase (KARI); compounds Ib, If, and Ik which had Ki values of 2.41-8.08 µmol/L can be novel potent KARI inhibitors for deeper exploration. The SARs were analyzed in detail. The molecular docking studies on the highly active inhibitors with KARI provided possible binding modes between inhibitor and the target enzyme. The physicochemical parameter predictions indicated that compounds Ik, IIk, IIq and IIs have "druglike structure" features. The research results in this article may bring a new inspiration to the extensive explorations on new methylxanthine derivatives in pesticide area.

Comparative analysis of active period and oxidative stress of DDVP and ginger (Zingiber officinale) oil on Indian meal moth (Plodia interpunctella Hübner) infesting maize grain

BackgroundIndian meal moth (Plodia interpunctella) is a significant pest infesting stored grains, particularly maize. Over time, synthetic insecticides have been employed to control insect. The residual effects posed on non-target organisms have called for replacement of synthetic insecticides with botanicals. This study therefore aimed at comparing the insecticidal consistency and oxidative stress invoked by dichlorvos (DDVP) and the oil extract of ginger (Zingiber officinale) on Indian meal moth infesting maize. Disinfested maize grains were treated with DDVP and ginger oil extract separately. Adults P. interpunctella were introduced to the treated grains daily using complete replacement method. The percentage mortality was calculated daily for 10 d. Furthermore, the oxidative stress caused by DDVP and ginger oil extract on the moth was evaluated by measuring the level of some oxidative stress biomarkers such as glutathione S-transferase, superoxide dismutase, glutathione peroxidase (GPx), and catalase (CAT) activity in the exposed insects.ResultsPreliminary results indicated that both DDVP and ginger oil extract exhibited insecticidal properties against Indian meal moth infesting maize. However, the insecticidal (active) period of ginger oil extract was found to be longer than that of DDVP. Nevertheless, DDVP provoked greater oxidative stress in the exposed moth.ConclusionsGinger oil extract and DDVP show potential for controlling Indian meal moth infestations in stored maize. Yet, ginger oil offers a longer-lasting effect on pest suppression and control. Consequently, it could be a replacement or synergistic insecticide with DDVP to provide ecofriendly insecticide application.

Yeast encapsulation of photosensitive insecticides increases toxicity against mosquito larvae while protecting microorganisms

An important defense against the deadly diseases that mosquitoes transmit is the application of insecticides that reduce mosquito populations. Unfortunately, the evolution and subsequent spread of insecticide resistance has decreased their efficacy. Therefore, new mosquito control strategies are needed. One class of larvicides, known as photosensitive insecticides, or PSIs, kills larvae via light-activated oxidative damage. PSIs are promising larvicides because of their high larvicidal efficacy, rapid photodegradation, inexpensive cost, and mechanism that is dissimilar to other insecticide classes. We explored a novel delivery strategy for increasing both the larvicidal efficiency and environmental biocompatibility of PSIs, known as yeast encapsulation. Using the PSIs, curcumin and methylene blue, we measured the survival of Anopheles gambiae larvae and Escherichia coli following exposure to either non-encapsulated or yeast-encapsulated PSIs and a photoperiod. Yeast encapsulation increased the phototoxicity of both curcumin and methylene blue against mosquito larvae, likely by increasing ingestion. Furthermore, yeast encapsulation protected E. coli from the phototoxicity of yeast-encapsulated curcumin, but not yeast-encapsulated methylene blue. Yeast encapsulation increases the larvicidal efficacy of a PSI while also increasing biocompatibility. Therefore, yeast encapsulation of PSIs is a promising insecticide delivery strategy for mosquito control.

Side effects of insecticides used for management of Tuta absoluta Meyrick (Lepidoptera: Gelechidae) on the biocontrol agent Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae)

Trichogramma brassicae is one of the most important egg parasitoids of many pests including South American tomato pinworm, Tuta absoluta (Lepidoptera: Gelechiidae). In agrosystems, the function of parasitoids can be affected by the application of insecticides. To use biological control agents and pesticides simultaneously in pest management, it is necessary to know the potential effect of pesticides on biological control agents. In this study, the lethal and sublethal effects of four insecticides (flubendiamide, emamectin benzoate + lufenuron, thiocyclam, and spinosad) frequently used to control T. absoluta, were investigated on its parasitoid Trichogramma Brassicae Bezdenko (Hymenoptera: Trichogrammatidae), under controlled laboratory conditions. The results showed that spinosad with an LC50 value of 0.73 mg a.i./ L was highly toxic against adults of T. brassicae in comparison to flubendiamide (4.09 mg a.i./ L), emamectin benzoate + lufenuron (4.17 mg a.i./ L), and thiocyclam (9.59 mg a.i./ L). Furthermore, key demographic parameters such as net reproductive rate (R0), intrinsic rate of increase (rm), mean generation time (T), and doubling time (DT) were significantly decreased after exposure of T. brassicae to the LC30s of spinosad, thiocyclam, flubendiamide, and emamectin benzoate + lufenuron compared to the control. In the light of our results, the four insecticides should be used cautiously in T. absoluta integrated management programs. While the thiocyclam can be combined with the T. brassicae, the flubendiamide and emamectin benzoate + lufenuron are not recommended in the presence of this parasitoid. The use of spinosad should be avoided concomitantly with the release of T. brassicae.

White rot fungi to decompose organophosphorus insecticides and their relation to soil microbial load and ligninolytic enzymes

The functional and structural features of microbial load in soil are influenced by the presence of insecticides. This study examined the impact of two organophosphorus insecticides, dimethoate and parathion on the microbial load of soil. The colony count of fungi, actinomycetes, bacteria, and nitrogen fixing bacteria was reduced after insecticides application at 7 and 14 days, but at 28 days the colony count began to increase. The growth of two white rot fungi including Pleurotus sajor-caju and Phanerochaete chrysosporium was affected by parathion, which was reflected by a decrease in colony radius to 1.85±0.05 and 0.75±0.06 cm, respectively, and by dimethoate, reflected by a decrease in colony radius to 3.33±0.12 and 1.85±0.05 cm, respectively at 40 mg/L compared to colony radius at control 7.90±0.12 and 7.50±0.06 cm, respectively. The applied low concentration (10 mg/L) encouraged P. sajor-caju and P. chrysosporium to remove up to 87.7% and 81.8% of dimethoate, respectively, and 69.20 and 68.30% of parathion, respectively compared with the decomposition at high dose (40 mg/L) at 28 days. The presence of insecticides induced the production of ligninolytic enzymes lignin peroxidase, laccase, and manganase peroxidase.

Multi-year evaluation of an attract-and-kill strategy for apple maggot fly (Diptera: Tephritidae) in New England commercial apple orchards.

Previously developed behavioral approaches for controlling the apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), include attract-and-kill (AK) systems such as perimeter trapping using either, odor-baited red sticky spheres or odor-baited, sticky-free attracticidal spheres with contoured tops that ensure the sustained release of both insecticide and feeding stimulant. Here, over a 3-year span in 26 commercial apple orchards across Massachusetts, New Hampshire, and Maine, we evaluated the effectiveness of a novel AK strategy for R. pomonella management. Synthetic apple blend lures were deployed on perimeter-row trees to attract the pest, while perimeter-row insecticide sprays blended with 2% sugar, a known phagostimulant, served as the lethal component. Comparatively, grower standard (GS) blocks received full-block insecticide sprays devoid of sugar and lures. Monitoring revealed that red sticky spheres in AK blocks captured significantly more R. pomonella adults than unbaited monitoring spheres in GS blocks. Penetration of R. pomonella into block interiors remained consistently low and statistically similar for both AK and GS blocks. Whole-block infestation levels showed no significant difference between the 2 management approaches. Notably, insecticide application in AK blocks was reduced by 75%, 64.7%, and 64.2% in 2019, 2020, and 2021, respectively, compared with GS blocks. This grower-friendly AK approach could be integral to a reduced insecticide spray-based strategy for apple cultivation in the northeastern United States.

Evaluation of the toxicity of translaminar insecticides against the soybean tentiform leafminer (Lepidoptera: Gracillariidae), a potential new pest of soybean.

Macrosaccus morrisella (Fitch) (Lepidoptera: Gracillariidae) is a leaf-mining microlepidopteran native to North America recently reported feeding on soybean in the United States and Canada. Control methods for the management of this pest remain unknown. The insecticides Agri-Mek SC (abamectin) and Endigo ZXC (lambda-cyhalothrin + thiamethoxam) were evaluated for: (i) effects against immature stages of M. morrisella in potted soybean plants; (ii) effects against adults of M. morrisella through different routes of exposure; and (iii) efficacy of field applications against M. morrisella. In the experiment with immature stages, when either insecticide was applied to potted plants with M. morrisella in serpentine or blotch mines, significantly fewer adults emerged compared to the untreated plants. In contrast, adult emergence from potted plants treated with either insecticide when M. morrisella was in tentiform mines did not differ from untreated plants. In the experiment with adults, the survival of M. morrisella exposed to either insecticide through oral exposure or residual contact + oral exposure was significantly lower than that for residual contact exposure alone, which in turn was lower than the untreated control. Within each exposure route, the response to the 2 insecticides did not differ. In the field experiment, at 21 days after insecticide application, the mean percentage of leaf area mined was significantly lower in plots treated with Endigo ZCX compared to plots treated with Agri-Mek SC or those left untreated. These results suggest that Endigo ZXC and to a lesser extent Agri-Mek SC may have potential for management of M. morrisella.

Effects of GroMore® Program on Rice Yield and GHG Emissions in a Korean Paddy Rice

The agronomic benefits of pesticides combined with amino acid application to increase rice production have been recognized, but they are still not well-known for greenhouse gas (GHG) emissions and mitigation in irrigated paddy fields. Thus, this study was conducted to investigate the combined effects of pesticide and amino acid application on rice yield and methane (CH4) emissions in a Korean rice paddy. A field experiment was conducted with five levels: none (no pesticide application, T1), different conventional practices (combined application of insecticides and fungicide, T2 and T3), and GroMore® programs (combined application of insecticides, fungicides, and amino acids, T4 and T5). Rice grain yield and yield components were obtained using agronomic measurements. To determine the greenhouse gas intensity (GHGI) of each treatment, CH4 emissions were measured throughout the rice growing period. Results showed that the chemical applications in combination with amino acids in T4 obtained a higher grain yield and number of panicles per plant compared to T1, T2, and T3, while T4 and T5 showed no difference on filled spikelets except for T2. T3 and T5 showed lower respective cumulative CH4 emissions by 30% and 32% during the entire rice growing season, compared to no chemical application (T1). Meanwhile, N2O emissions were negligible in all treatments because the paddy field was flooded most of the growing season. The results of the impact of GroMore® programs on relatively higher grain yield and lower GHG emissions are presented. In conclusion, the application of pesticides combined with amino acids obtained lower GHGI values.

Toxicological characterization of the insecticide metofluthrin and assessment of the carcinogenic risk to human health due to its chronic inhalation effect

The aim of the investigation is the toxicological characterization and analysis of the danger criteria of the insecticide metofluthrin with an assessment of the carcinogenic risk to health caused by chronic inhalation exposure to the substance at the level of the maximum possible concentrations in the air environment of human life. The analysis of scientific reports of the US Environmental Protection Agency (US EPA) and the European Chemicals Agency (ECHA) on the toxicological properties of metofluthrin was carried out. The assessment of the risk of the development of carcinogenic effects due to chronic inhalation exposure to metofluthrin was carried out taking into account the average daily dose of the substance that can enter the human body during the natural life span (LADD) and the carcinogenic potential factor (SF) in accordance with domestic guidelines. Classification of levels of carcinogenic risk was carried out using domestic and international approaches. It was established that the limiting criteria for the danger of metofluthrin are the average lethal concentration in air (LC50 =1080 mg/m³) and the size of the zone of chronic action (Zch=7.46), which characterizes the danger of occurrence of chronic intoxication due to long-term inhalation exposure. According to these indicators, metofluthrin is classified as a dangerous substance (hazard class 2). The key effects of the toxic action of metofluthrin are determined – neurotoxicity, hepatotoxicity and nephrotoxicity. The threshold non-genotoxic oncogenic potential of metofluthrin according to the phenobarbital type was established. Individual carcinogenic risk under different scenarios of chronic inhalation exposure to metofluthrin was calculated. The substance concentration of 3.54 mg/m³ leads to a high level of risk (1.5×10-3), which is considered unacceptable for production conditions and the population. At concentrations of 0.28 mg/m³ and 1.0 mg/m³, the risk is estimated as average and acceptable for production conditions (1.1-4.1×10-4). The risk of exposure to a concentration of 0.14 mg/m³ is classified as low and acceptable for the population (5.7×10-5). Thus, the results obtained in the study indicate that such concentrations of metofluthrin in the air as 0.14 – 0.28 – 1.0 mg/m³ are safe for human health, subject to compliance with medical and sanitary regulations at the stage of production and application of insecticides based on metofluthrin as prescribed.

Toxicity and deterrence of pyroligneous extracts on Liriomyza sativae (Diptera: Agromyzidae)

Liriomyza sativa is a cosmopolitan and polyphagous insect, a key pest of crops such as tomato and melon. The inadequacy of insecticide application techniques has developed resistant populations. The objective of this research was to evaluate the toxicity, insecticidal activity and deterrence of pyroligneous extracts on the leafminer fly. The experiments were carried out under laboratory conditions of 25 ± 2°C and humidity of 60 ± 10%. For the toxicity test, solutions were prepared in different concentrations by diluting them in distilled water. Leaf discs containing L. sativae larvae were immersed in the solutions. For insecticidal activity and deterrence tests, jack bean plants were subjected to application of treatments using an airbrush, spraying 6 mL of the solutions on each plant. All extracts showed significant mortality for the larvae, with emphasis on the pyroligneous extract of coffee straw at 350ºC. The extracts did not interfere with the other developmental stages of the leafminer fly. The pyroligneous extract from the commercial company Agttec and the coffee straw extract at 600ºC were classified as attractive and the coffee straw extract at 350ºC as detergent. It is concluded that pyroligneous extracts can be used in the management of L. sativae.

Pink bollworm (Pectinophora gossypiella) movement with respect to rosette flowers in cotton: Novel insights for integrated pest management

Aim: This preliminary study aimed to investigate the movement patterns of Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) larvae in the rosette flowers. Methodology: Field experiments conducted on the migration behavior of pink bollworm larvae with respect to rosette flowers in cotton fields. Observations included monitoring infested flowers, larval stage duration within rosette flowers, and larval movement to soil for pupation, larval mortality post-drop, and larval migration to early bolls, all conducted without insecticide application to reflect natural conditions. Results: The movement of the larvae was tracked and recorded from the start of flowering to the boll formation stage. Nearly, 44.88% of the larvae present on the infested flowers had moved to the soil for pupation, while 14.29% had moved to newly formed bolls on the same rosette flower. Additionally, 30.90% of the larvae had moved to dry leaf debris on the soil, and the remaining 9.93% either escaped or died due to environmental factors such as damp soil. Notably, the study showed that dry soils or light debris accumulation were the most favorable environments for pink bollworm larvae. Interpretation: The present study has generated useful information regarding the movement of PBWs larvae from rosette flowers to bolls that contribute to infestation. Hence, by implementing integrated pest management strategies during the early crop periods between 60 and 100 DAS, green boll infestations can be avoided and economic yields improved. Key words: Larval movement, Pest carryover, Pest management, Rosette flower

Evaluation of transplant drench and foliar insecticide applications for wireworm (Coleoptera: Elateridae) management in sweetpotato.

The revocation of chlorpyrifos tolerances in 2022 left sweetpotato growers without their most important tool to combat a complex of soil-borne root pests that includes wireworms (Coleoptera: Elateridae). Since then, growers have reported increased root damage despite a rapid pivot to pyrethroid-based management systems to replace mechanically incorporated preplant chlorpyrifos broadcast sprays. Our goal was to evaluate the efficacy of alternative insecticide chemistries and application methods to expand the portfolio of management options for wireworms, specifically Conoderus spp. and Melanotus communis (Gyllenhal). We tested (i) insecticidal transplant water drenches and (ii) a foliar spray program targeting adult elaterids. We found that incorporating insecticides into transplant water reduced wireworm damage when compared to untreated transplant water. Our treatments included a recently registered meta-diamide, broflanilide, which represents a promising path to diversify active ingredients and shift away from an overreliance on preplant and post-directed pyrethroid soil sprays. Foliar spray plots had less damage than plots that did not receive foliar sprays. One benefit of adult-focused management is the availability of effective monitoring tools such as sex pheromones and blacklight trapping. Developing a robust adult monitoring program would enable more precise applications of foliar insecticides versus season-long prophylactic soil sprays targeting larvae. Our results demonstrated a significant benefit to both alternative delivery methods. These management alternatives could expand treatment options beyond traditional preplant and post-directed pyrethroid sprays.

Assessing the multifaceted repercussions of chemical insecticides on vegetable yield and human population: A modeling study

Vegetables stand out as invaluable reservoirs of essential vitamins, minerals, antioxidants, and vital dietary elements, yet their production faces a considerable threat due to insects. To tackle this challenge, farmers spray chemical insecticides to enhance vegetable yields by controlling the insect population. Nevertheless, the presence of insecticide residues in vegetables stands as a primary contributor to acute illnesses and chronic health conditions in humans. In the present research work, we formulate a novel nonlinear mathematical model meticulously designed to scrutinize the multifaceted repercussions of chemical insecticides on vegetable yield and the human population. In our model formulation, we adopt a dynamic approach where insecticide application on vegetables in agricultural fields correlates with the insect population. However, we acknowledge the consequential impact of insecticide usage on human health, which in turn reduces the growth rate of the human population. This study determines the critical value of the spraying rate of insecticide at which the human population reaches its maximum, ensuring that human needs for vegetables are met while minimizing the adverse effects of insecticide. Since various species of insects attack vegetables in the field and different insect species have different natural mortality rates, therefore we also identify the range of natural mortality rates of insects for which vegetable yield is minimal and fluctuates with time. Further, our research reveals that if the natural mortality rate of insects in a certain crop field lies within this identified range, then farmers should increase the insecticide spraying rate to avoid this upheaval situation and stabilize vegetable yield at a higher level.

Application timing affects the efficacy of Bacillus thuringiensis subsp. kurstaki against Tortrix viridana in deciduous oak forests

The green oak leaf roller moth, Tortrix viridana, is one of the main defoliators of deciduous oaks in the Mediterranean region. Although aerial applications of Btk-based insecticides represent the most effective method to control the larval populations of this pest at a large spatial scale, the optimal time window for sprayings has not yet been defined. Accordingly, experimental trials were conducted in a Quercus pubescens forest district in Sardinia (Italy) involving both large-scale aerial treatments and small-scale applications from the ground. The aim of our work was to study how different larval development stages and/or sprouting phenological phases of the host trees affect Btk efficacy. Aerial sprayings were conducted in 2003 and 2004 in two different areas of about 300 ha, selected according to altitude and exposure to simulate three different application timings against different larval instars and sprouting phenological phases. From-the-ground applications were carried out in 2021 in a Q. pubescens forest stand by applying Btk-based insecticides at different timings, and the overall Q. pubescens phenological stage and the distribution of T. viridana larval development stages were assessed accordingly. The effectiveness of Btk applications was evaluated by estimating larval mortality 7, and 14 days after aerial applications, and 7, 14 and 21 days after ground applications. Defoliation due to T. viridana was also evaluated at the end of larval development in all years. In both 2003 and 2004, the average larval mortality due to Btk exceeded 80 % two weeks after aerial applications across all application timings. Damage caused by T. viridana varied with Btk application timing, with the later applications showing a higher defoliation than other timings. In ground application experiments, larval mortality significantly increased when Btk was sprayed against a larval population primarily composed of IV instars, which were feeding on sprouts with leaves that were spread out and had not fully developed internodes, thus resulting in a significative reduction of insect damage. Our findings indicate that, in accordance with the strict synchrony between the larval development and the oak flushing, the optimal timing for Btk application against T. viridana can be defined based on the bud burst phenological phase. In particular, the prevalence of sprout with expanding leaf surface allowing insecticidal droplet interception and the simultaneous presence of susceptible larval instars (within the IV), resulted in an increased treatment efficacy.

A Comprehensive Review of Unmanned Aerial Vehicle (UAV) Sprayers Used in Modern Agriculture

Global demand for food is increasing daily due to increase in population growth. Hence to meet these food demands for the growing population crop productivity must be enhanced. Plant pests and diseases are major threats to crop productivity causing an annual reduction of 20 to 40% in global crop production. For management of these pest and diseases spraying using manual sprayers is quite laborious and also not precise. Further manual spraying is hazardous to farmer’s health, World Health Organization (WHO) reported one million incidences of illness as a result of manually application of insecticides to crop fields. As a result, new automated drone technology techniques were unveiled. This review examines the application of Unmanned Aerial Vehicle (UAV) sprayers in modern agriculture, highlighting their transformative role in enhancing crop management and increasing efficiency. UAV technology has emerged as a vital tool for precision agriculture, offering benefits such as targeted pesticide and fertilizer application, reduced labor costs, and minimized environmental impact. This paper discusses the various types of UAV sprayers, their operational mechanisms, and the advantages they provide over traditional methods. Additionally, we explore challenges associated with UAV adoption, including regulatory issues, technical limitations, and the need for operator training. The review emphasizes the future potential of UAV sprayers in sustainable agriculture, suggesting that continued advancements in technology and regulatory frameworks will further integrate UAVs into mainstream agricultural practices.

Comparative transcriptional analysis between susceptible and resistant populations of Aedes (Stegomyia) aegypti (Linnaeus, 1762) after malathion exposure.

Aedes aegypti is an important vector of arboviruses, including dengue, chikungunya and Zika. The application of synthetic insecticides is a frequently used strategy to control this insect. Malathion is an organophosphate insecticide that was widely used in Brazil in the 1980s and 1990s to control the adult form of A. aegypti. In situations where resistance to currently used insecticides is detected, the use of malathion may be resumed as a control measure. Many studies have confirmed resistance to malathion, however, comparative studies of differential gene expression of the entire transcriptome of resistant and susceptible insects are scarce. Therefore, understanding the molecular basis of resistance to this insecticide in this species is extremely important. In this paper, we present the first transcriptomic description of susceptible and resistant strains of A. aegypti challenged with malathion. Guided transcriptome assembly resulted in 39,904 transcripts, where 2133 differentially expressed transcripts were detected, and three were validated by RT-qPCR. Enrichment analysis for these identified transcripts resulted in 13 significant pathways (padj < 0.05), 8 associated with down-regulated and 5 with up-regulated transcripts in treated resistant insects. It was possible to divide the transcripts according to the mechanism of action into three main groups: (i) genes involved in detoxification metabolic pathways; (ii) genes of proteins located in the membrane/extracellular region; and (iii) genes related to DNA integration/function. These results are important in advancing knowledge of genes related to resistance mechanisms in this insect, enabling the development of effective technologies and strategies for managing insecticide resistance.

Spatial distribution and fixed-precision sequential sampling plans for Popillia japonica (Coleoptera: Scarabaeidae) adults in primocane raspberry: influence of foliar insecticides.

The Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), an invasive species from northern Japan, was first detected in Minnesota in 1968. According to fruit growers and the Minnesota Department of Agriculture, population size and feeding damage has been an increasing concern since 2010. Based on trap-catch data, populations have recently exceeded 4,000 beetles/trap/week during July-August near raspberry fields, and can increase by an order of magnitude within 7-10 days. The primary goals of this study were to assess the spatial distribution of P. japonica adults in raspberry, and to develop and validate a practical fixed-precision sequential sampling plan for grower use. Taylor's Power Law (TPL) regression was used to characterize the beetle's spatial pattern in research plots and commercial fields, either with or without insecticide applications. We then used Green's plan to develop an enumerative sequential sampling plan to estimate P. japonica density in primocane raspberry. Beetle population data were collected at two locations in southern Minnesota, including the Rosemount Research and Outreach Center, and a commercial field near Forest Lake. The TPL results, via slope comparisons, indicated no significant differences in P. japonica spatial pattern between insecticide treated plots versus untreated plots, or among 4 different insecticides (P>0.05). Utilizing all spatial pattern data, we characterized the distribution of P. japonica beetles to be highly aggregated in raspberry, with TPL slopes ranging from b = 1.38 to 1.55; all slopes were found to be >1.0. Although the slopes were not significantly different, we accounted for variability in spatial pattern by using 33 independent data sets, and the Resampling for Validation of Sampling Plans (RVSP) model to validate a sampling plan with a final average precision level of 0.25 (SEM/mean), recommended for integrated pest management (IPM) purposes. The final sampling plan required an average sample number of only 15, 1-m-row samples, while providing high relative net precision (RNP), and thus a cost-effective, efficient sample plan for growers.

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.

Improving Sphenophorus levis Adult Mortality Through Solid Insecticide Applications and Increased Insecticide Dose.

The sugarcane weevil (Sphenophorus levis Vaurie, 1978) is currently considered the most important sugarcane pest in Brazil, causing significant yield losses. Application methods of insecticides for S. levis control have not been effective, mostly due to the insect's cryptic behavior below the soil surface which suppresses the correct placement of insecticide active ingredients on target. Two experiments were conducted using an innovative bioassay methodology that simulates sugarcane field conditions to effectively evaluate S. levis adult mortality and insecticide residues in the soil under different treatments. The first experiment aimed to assess the efficacy of two liquid- and solid-applied insecticides, while the second aimed to examine the effect of increasing the dose of lambda-cyhalothrin + thiamethoxam on S. levis adult control. The novel bioassays simulated liquid and solid insecticide applications on sugarcane by exposing S. levis adults to chemical residuals on rhizomes and in soil after insecticide application. In the first experiment, low S. levis adult control was detected (< 53% mortality) across all treatments, where both solid and liquid applications of lambda-cyhalothrin + thiamethoxam provided greater efficacy levels than imidacloprid and control treatments, respectively. Solid applications maintained higher insecticide concentrations in the soil for longer periods than liquid insecticide applications, providing maximum insect control levels 7days after application. The second experiment revealed that solid applications at higher insecticide doses significantly improved control of S. levis adult (76.7% mortality) and resulted in greater insecticide concentrations in the soil compared to the recommended label rate (58.8% mortality).

Neonicotinoids Impact All Aspects of Bird Life: A Meta-Analysis.

Worldwide, bird populations are declining dramatically. This is especially the case in intensely used agricultural areas where the application of neonicotinoid insecticides is thought to-unintendedly-cause a cascade of negative impacts throughout food webs. Additionally, there could be direct (sub-) lethal impacts of neonicotinoids on birds, but to date there is no comprehensive quantitative assessment to confirm or rule out this possibility. Therefore, we use a meta-analytical approach synthesising 1612 effect sizes from 49 studies and show that neonicotinoids consistently harm bird health, behaviour, reproduction, and survival. Thus, in addition to reduced food availability, the negative direct effects of exposure to neonicotinoids likely contribute to bird population declines globally. Our outcomes are pivotal to consider in future risk assessments and pesticide policy: despite localised bans, the metabolites and residues of neonicotinoids remain present in the environment and in birds and will thus have long-lasting direct effects on both the individual and the population levels.