Food Safety Evaluation of Imidacloprid Residues in Grape Berries at a Different Dose of Spraying

Background & Aims of the Study: Grape, a crucial agriculture crop of Malayer city, is affected by Vine cicada, Psalmocharias alhageos.  Imidacloprid, a neonicotinoid insecticide, provides a good management of this insect. The aim of this research is residue persistence study of imidacloprid on grapes, to estimate its residue deposit, the half-life of degradation and safe pre-harvest consumption time. Materials & Methods: Residues of imidacloprid were estimated in grape following two recommended types of spraying (80.0 g a.i. ha-1) and duplicates the application rate (160.0 g a.i. ha-1). Samples were collected at 1 h to 21 days after spraying of imidacloprid. The analyses were done by the QuECHERS technique, using HPLC-UV. Results: The average initial concentration of imidacloprid on grapes found to be 10.58 and 17.56 mg kg-1 at single and double dosages, respectively. These residues of imidacloprid decreased to 97.8% and 98.0%, respectively, at single and double dosages in 15 days, with a half-life period of 2.21 and 2.94 days. Residues of imidacloprid on grapes were less than its MRL value after 7 and 10 days of recommended and double dosage of spraying. Residues of imidacloprid in grape berries at harvest were discovered to below the determination limit. Conclusions: Consequently, a waiting time of 7 and 10 days is usually recommended for safe consumption of grapes once imidacloprid spraying. Acceptable daily intake (ADI) of imidacloprid is 0.06 mg kg-1 body weight day-1. According to the results of this study, the employment of imidacloprid on the grape looks to be toxicologically acceptable

Evaluation of Pseudomonas and Bacillus Bacterial Antagonists for Biological Control of Cotton Verticillium Wilt Disease

Verticillium wilt is considered the most important disease of cotton in the world, including Iran. Cultural practices and the use of resistant varieties are the most common strategies used to control Verticillium wilt of cotton. These strategies are not always available or effective. In recent years, biological control using fungal and bacterial antagonists, has been applied to control some cotton diseases including damping-off. In this study, we investigated the possibility of biological control of Verticillium wilt of cotton using bacterial antagonists. Suspension of eight bacterial strains of Pseudomonas fluorescens and Bacillus spp. isolated from different rhizospheric soils and plant roots in the Iranian cotton fields, were prepared with a concentration of 108 cfu/ml. Ten cotton seeds (cv Varamin) were then coated with each bacterial suspension and were planted in soil pre-inoculated with Verticillium dahliae microsclerotia. The efficacy of bacterial antagonists in reducing wilt disease was evaluated by determination of the disease index in different treatments. The results indicated that most isolates were effective in reducing disease (compared to the untreated control) 90 days after sowing. Isolates B5, B6, B2, B7, and B3 were the most effective, respectively, in reducing wilt index. In contrast, isolates B1, B4, and B8 did not significantly reduce the disease. In general, P. fluorescens isolates were more effective than Bacillus isolates. This study suggests that bacterial antagonists might be potential biological control agents of cotton

A NUMERICAL SIMULATION OF THE EFFECT OF INLET GAS TEMPERATURE ON THE ENERGY SEPARATION IN A VORTEX TUBE

The main objective of this paper is to study the effect of inlet gas temperature change on the fluid flow characteristics and energy separation phenomenon within a counter-flow vortex tube. The computational fluid dynamics (CFD) model is a three-dimensional steady compressible model that utilizes the k-ɛ turbulence model in order to analyse the high rotating flow. In this numerical research, different inlet gas temperatures have been used in the modeling in order to analyse the operation of the vortex tube. The results showed that increasing the inlet gas temperature leads to greater temperature separation, as well as greater hot and cold temperature separation. Moreover, it was found that increasing the inlet temperature does not have any significant effect on the stagnation point and maximum wall temperature position. Since this research concerns increased inlet gas temperatures, an implication of this study can be for vortex tubes to be used in procedures where heating or preheating is required