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Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support and guide experimental efforts and for the prediction of atomistic and electronic properties. In this regard, electronic structure packages have played a special role by using first-principle-driven methodologies to model complex chemical and materials processes. Over the past few decades, the rapid development of computing technologies and the tremendous increase in computational power have offered a unique chance to study complex transformations using sophisticated and predictive many-body techniques that describe correlated behavior of electrons in molecular and condensed phase systems at different levels of theory. In enabling these simulations, novel parallel algorithms have been able to take advantage of computational resources to address the polynomial scaling of electronic structure methods. In this paper, we briefly review the NWChem computational chemistry suite, including its history, design principles, parallel tools, current capabilities, outreach, and outlook.

The most devastating pest besides bollworm in cotton is stem weevil, Pempherulus affinis which decreases the cotton productivity as it affects the plant survival, boll production and seed cotton yield. The purpose of the investigation was to understand the infestation stage of the crop prone to heavy yield loss. The field experiment was carried out at Bannari, Erode district, India during summer 2021 to assess the yield loss caused by P. affinis in protected condition namely IPM module 1, IPM module 2 farmers' practice and unprotected condition. The results revealed that among the infested plants the mean survival of plants, boll production and yield was maximum in IPM module 2 of 90.10%, 20.90 bolls/plant and 29.93 g/plant respectively followed by farmers' practice with 89.25%, 11.37 bolls/plant and 29.17 g/plant respectively and the unprotected condition recorded the least mean survival of plants (82.25%), boll production (9.34 bolls/plant) and yield (23.87 g/plant). There was no significant difference among the treatments pertaining to mean survival of plants in healthy plants which recorded 100% survival. The mean number of bolls produced from healthy plants (at harvest) were high in IPM module 2 (20.90 bolls/plant) followed by farmers' practice which registered 19.87 bolls/plant while untreated plot recorded only 15.60 bolls/plant. The mean yield recorded from the healthy plants (at harvest) was 57.64 g/plant followed by farmers' practice (55.88 g/plant). The minimum yield of 39.24 g/plant was obtained in unprotected condition from healthy plants. [ABSTRACT FROM AUTHOR]

Insecticidal interventions at critical stages of maize are an important strategy for managing invasive insect pest fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith). Conventional spraying systems cannot be used over larger areas, and the insecticide application using unmanned aerial vehicles is becoming popular among peasants. As the FAW resides inside the maize whorls, targeted insecticide application is necessary for effective management. The efficacy of (UAV) spray with different types of nozzles was compared with the conventional spray system, namely high-volume spray and Control droplet applicator. The other spray systems' droplet density, efficacy, and residues of insecticides in plants, soil and water were studied. The UAV droplet density up to 5 m swath recorded no significant variation for both nozzles. A UAV with an atomizer nozzle was as effective as a high-volume spray in reducing the FAW infestation. The residue analysis of leaf samples from the study area revealed more residues in the control droplet applicator and UAV atomizer nozzle. The per cent reduction of initial deposits in the top, middle and bottom maize leaves was least in the UAV atomizer nozzle. The insecticide residues in the study sample area were also below the detectable limit. UAV usage in maize saves time and reduces FAW damage as that of high-volume sprayers. [ABSTRACT FROM AUTHOR]

Emamectin benzoate has been frequently used in the banana ecosystem to combat the damage of pseudostem weevil. Therefore, the present study was conducted to validate the method, to assess harvest time residues and monitor emamectin benzoate residues in mature banana peel and pulp samples through LC-MS/MS. The validated method was used to determine emamectin benzoate residue in market banana samples. The study used Waters Alliance LC and Acquity TQD with an electrospray ionization interface in the positive ion mode. An isocratic flow of 0.1% formic acid (HCOOH) in water and 0.1% HCOOH in acetonitrile (CH3CN) was utilised for separation. CH3CN was utilised to extract emamectin benzoate residue from the samples, and a dispersive solid-phase extraction technique was used for subsequent cleanup. Linearity tests were performed with standard solutions containing 0.01 to 0.1 g mL-1, with three replicates for each concentration. For mature banana peel & pulp and mature banana pulp matrices, satisfactory recoveries of 79.85 to 95.09% and 89.20 to 100.94%, respectively and high precision relative standard deviations of 0.56 to 2.34% and 2.33 to 6.88%, respectively were obtained. For mature banana (peel and pulp, pulp alone) fruits, the lower detection and quantification limits were (0.003, 0.008), and (0.002, 0.007). The validated approach was utilised to analyse mature banana fruit samples obtained from emamectin benzoate treated fields and banana samples purchased from the local market. Results showed satisfactory validation of parameters like linearity, the limit of detection and quantification, and recovery for determining emamectin benzoate residues in banana fruit. [ABSTRACT FROM AUTHOR]

In recent years, an invasive cassava mealybug Phenacoccus manihoti has been threatening cassava cultivation alongside another invasive papaya mealybug Paracoccus marginatus which invaded the country more than a decade ago. In order to evaluate their responses against the commonly used neonicotinoid insecticides: thiamethoxam 25 WG and imidacloprid 17.8 SL, acute toxicity experiments to determine the susceptibility baselines in populations of two invasive mealybugs in the cassava agro-ecosystem, namely, cassava mealybug P. manihoti and papaya mealybug P. marginatus were performed upto 15 generations. A systemic uptake method was used for the bioassay. The LC50 values of thiamethoxam for F1 generation were 3.298 ppm whereas it was 1.066 ppm for F15 in cassava mealybug. The LC50 values of F1 generation were 2.014 ppm and that of F15 generation was 1.384 ppm when tested with imidacloprid. In the case of papaya mealybug, the LC50 values ranged from 6.138 ppm (F1) to 2.503 ppm (F15) for thiamethoxam and 7.457 ppm (F1) to 3.231 ppm (F15) for imidacloprid. All the susceptibility indices calculated were less than threefold. The rate of resistance development was negative in all cases showing that none of the tested populations harboured any resistance without insecticidal selection pressure. Tentative discriminating doses were fixed for both chemicals with the help of LC95 values obtained from the bioassay experiments, namely five ppm for both thiamethoxam and imidacloprid in the case of cassava mealybug and 10 ppm and 15 ppm, respectively, for thiamethoxam and imidacloprid in the case of papaya mealybug. [ABSTRACT FROM AUTHOR]