الفهرس 
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Abstract
Tomato is classified as one of the most important table crops in all countries of the world. Peopledaily eat tomatoes in fresh or packaged form. Tomato crop is infected withseveral insect pests, due to its high economic values, producers usually prevent the damages caused by these pests depending on chemical pesticides that sprayed for pest control in the open fields or in the green houses. Thus, many of these insect pests, such as the leaf miner, have become resistant to these pesticides. Therefore, the evaluation of new insecticides such as neonicotinoid should be done in addition to the development of these bulk formulation into nanoparticles for controlling the tomato leaf miner. In this study, some neonicotinoid insecticides and their nanoparticles were evaluated which were processed by laboratory as well as the evaluation of some bioinsecticides in the laboratory and under field conditions on tomato leaf miner. In addition, the residues of some neonicotinoid pesticides and their nanoparticles were estimated on tomato fruits to find out the curves of the disappearance. It has also been monitored and tracked some organo chlorine residues known for its high environmental stability and organo phosphorus pesticides known for widespread use in samples from some markets in Upper Egypt to find out if the residue exceeded the allowable rate without causing damage to human health.
Laboratory assessment and analysis were carried out in the Plant Protection Department laboratories- Faculty of Agriculture - Assiut University and Central Laboratory of Pesticides at the Ministry of Agriculture - Egypt - in addition to the seasonal monitoring of the population fluctuation and field assessment of pesticides tested in the research farm at the Plant Protection Department - Assiut University - 2017/2018 and 2018/2019 seasones.
The following are the summarized results:
1. Study the seasonal fluctuations of the tomato leaf miner, L. trifolii on tomato
This study was conducted in two successive seasons 2017-2018 / 2018-2019 on the variety 765 of the tomato grown in the experimental plant protection farm, Faculty of Agriculture, Assiut University.The number of miners on tomato leaves was recorded from the first of November to the first February in two seasons, the tomato leaf miner mines were first observed on November 29, 2017 at a rate of 21.83 mine / plant. The miner’s ratio was 28.34 mine / plant on 13 December 2018.At the beginning of the second season, the mines were 25.5 mine / plant, while the highest mines were 41.8 mine / plant on 1 January 2019.The analysis of climatic factors during the two seasons showed that relative humidity was the most efficient factor (52.49% of 91.46%).While the temperature was the least effective (8.67% of 91.46%).The population of the tomato leaf mine was found to be highly positive correlated with relative humidity minimum (r=0.662) and maximum (r=0.315), and negatively correlated with the temperature minimum (r = -0.569) and the maximum (r = -0.753).
2. Toxicological studies
2.1. Studies of toxicity under laboratory conditions
The LT50 (the lethal time of half dead percentage) values were used for comparing the eight insecticide toxicity. For every tested insecticide, the recommended dose for bulk and nano insecticide. pupae were prepared as same stage and same weight. Five pupae were dipped for 10 seconds in diluted insecticide solution. The treated pupae were put in 7cm Petri dishes. The Petri dishes were incubated at 26 ± 2°C and relative humidity of 60 ± 5 all the tested day. Mortality was recorded at 1, 3, 5,7, 10, and 15 days after the pupa exposure, and the pupa were considered dead when the body of pupal become the black and they did not move when touched with a brush.the results showed that The LT50 values were 11.5, 8.5, 12.2, 8.5, 9.3, 6.0, 6.7 and 11.1 for 1x imidacloprid, 1x nano-imidacloprid, 1x thiamethoxam,1x nano-thiamethoxam, 1x acetamiprid,1x nano-acetamiprid, emamectin benzoate and Spinetoram treatments, respectively, the highest LT50 value recorded 12.2 days with 1x thiamethoxam while the lowest value was 6.0 days with 1x nano- acetamiprid against L. trifolii.
2.2. Field evaluation of different newer insecticides against leaf miner damaging tomato
The different newer insecticide molecules viz. acetamiprid 20%SP at the rate of 25 g /100 L water, imidacloprid 25%WP at the rate of 75 g /100 L water, thiamethoxam 25%WG at the rate of 20 g /100 L water, emamectin benzoate 5.7%WDG at the rate of 60 g /200 L water, and spinetoram 12%SC at the rate of 100 cm /200 L water were evaluated for their efficacy against the serpentine leaf minerand untreated control. Pretreatment observations were recorded a day prior tothe treatment and after the first week and the second week of spraying.
2.2.1. Season 2017-2018
2.2.1.1. First spray
The results showed that the miner on tomato leaves that were monitored before treatment ranged from 18.75 to 28.50 per plant, and do not reveal the existence of statistically significant differences between different treatments. The data showed that after treatment with insecticides, repeaters treated with nano-thiamethoxam recorded the lowest number of tunnels (4.44 mines / plant). It was on par with nano-imidacloprid (6.44 mines / plant), but differed significantly from nano-imidacloprid 0.5 x (12.78 mines/plant) and has similarity with nano-acetamiprid 0.5 x (10.28). The reduction percentages ofwere 86.87, 81.19, 55.87, 64.92 for nano thiamethoxam (1x), nano-imidacloprid (1x), nano-imidacloprid 0.5 x, and nano- acetamiprid 0.5 x respectively in 2017-2018.
2.2.1.2.Second spray
The number of pretreatment mines one day before second spray was ranged from 21.17 to 25.67 per plant. The distribution of population was found almost uniform in all the treatments, as there were no significant differences observed among them. The most effective treatment against leaf-miner in tomato after treatment with insecticides was nano acetamiprid 1x (3.92 mines / plant), was equal with acetamiprid 1x (4.58 mines / plant). But differed significantly with nano-thiamethoxam 0.5 x (9.96 mines / plant) and was on par with nano-imidacloprid 0.5 x (9.44 mines / plant). The reduction percentages ofwere 83,18, 80.45.09, 62.75 and 65.92 for nano-acetamiprid (1x), acetamiprid 1 x, with nano-thiamethoxam 0.5 x and nano-imidacloprid 0.5 x, respectively in 2017-2018 of the second spray.
2.2.2. Season 2018-2019
2.2.2.1. First spray
Data showed that the number of mines before spraying with insecticides in the first spray ranged between 20.11 and 25.83 mines / plant. Recorded the treated with nano imidacloprid 1x had the lowest number of mines per plant (4.75 mines / plant), which was on par with nano-thiamethoxam 1x (4.88 mines / plant),But were different with nano-thiamethoxam 0.5 x (9.69 mines / plant) and acetamiprid 1 x (9.17 mines / plant). The reduction percentage ranged between 80,80, 84.23, 62.43 and 64.20 for nano-imidacloprid 1x, nano-thiamethoxam 0.5 x, and acetamiprid 1 x, respectively in 2018-2019 of first spray.
2.2.2.2.Second spray
The mines that were monitored before the treatment ranged between 20.78 and 35.77mines / plant, and did not reveal the existence of statistically significant differences between different treatments. The data showed that after treatment with insecticidesThe replicates treated with nano-thiamethoxam 1x, recorded the lowest number of tunnels (7.00 mines / plant). It was on par with nano-acetamiprid 1 x, (8.33 mines / plant),but differed significantly from nano-thiamethoxam 0.5 x (12.67 mine / plant) and had similarity with acetamiprid 0.5 x (12.50mine / plant).The reduction percentage were 72.95, 73.18, 59.31, 60.98 for nano thiamethoxam (1x), nano-acetamiprid 1x, nano thiamethoxam 0.5 x, acetamiprid 1x, respectively at 2018-2019 in the second spray.
Concerning the first and second season, results indicated that nano-thiamethoxam, and Nano- Acetamiprid were more toxic compounds against the tested pest. However, Nano imidacloprid 0.5 x, Nano thiamethoxam 0.5 x were the lowest.
3. Insecticide residues on tomatoes
Fruit samples of tomato were analyzed separately for the residues of acetamiprid and thiamethoxam in tomato under open field conditions at different intervals after application. Marketable fruit samples were collected at 2houre 1, 3, 7,10, 14 and 21 days after application/spray and the residues were estimated by following the quechers methods by high performance liquid chromatography HPLC
3.1. Analysis of the thiamethoxam residue
Thiamethoxam, a neonicotinoid insecticide, has been widely accepted for use in various crops, including vegetables, owing to its high efficacy against various Caterpillars and sucking insect pests. The tested insecticides of thiamethoxam normal formulation and nano thiamethoxam were sprayed at recommended doses but the nano thiamethoxam was applied at half recommended dose on tomato crop. In this study, was examined the residue dynamics of this insecticide on tomato crops after 2 hours, 1, 3, 7, 10, 14, and 21 days of spraying. The half-life was 3.39, 3.19, 1.60 for thiamethoxam 1, nano thiamethoxam and nano thiamethoxam0.5 x, respectively. the pre harvest interval was calculated to be 9.8, 8.8 and 4.6 for thiamethoxam1x, nano thiamethoxam1x and nano thiamethoxam 0.5 x, respectively. Residues of nano thiamethoxam0.5 x was undetectable on tomato fruits 14 and 21 days after application.
3.2. Analysis of Acetamiprid Residue
Acetamiprid a new generation from neonicotinoid insecticides and highly active to protect the various vegetable crops, the present study was undertaken to determine the pre harvest interval (PHI) for acetamiprid in tomato. The rate of disappearance of acetamiprid 1x nano acetamiprid 1x and nano acetamiprid0.5 x residues from tomato fruits was investigated under field conditions, the half-life values were 2.64, 2.28 and 1.55 days on tomato, for acetamiprid 1x nano acetamiprid 1x and nano acetamiprid0.5 x, respectively. the residues of acetamiprid 1x nano acetamiprid 1x and nano acetamiprid 0.5 x reached to the acceptable maximum residue limits at 4.9, 4.5, and 2 days’ post treatment, respectively. so, that the tomato fruits could be used safely after that. so, that the tomato fruits could be used safely after that. Residues of nano acetamiprid 0.5 x was undetectable on tomato fruits 14 and 21 days after application, but residues of acetamiprid 1 x and nano acetamiprid 1 x was undetectable on tomato fruits 21 days after application.
4. Monitoring insecticides residues in tomato samples from different markets
This study was investigated that to monitoring the Organochlorine and Organophosphorus on tomato crops. A total of 16 samples (three kilograms each) were collected randomly from 4 local markets in four cities in EgyptSohag, New valley, El-Minia and Assuit. The samples collected were immediately covered and placed in an ice box and stored at -20 c in deep freezer until time for residue analysis. the residues were estimated by following the QuEChERS methods by gas chromatograph (GC).
4.1.Monitoring the organochlorine and organophosphorus on tomato crop.
Organochlorine and Organophosphorus insecticides are widely used in agriculture and animal production for the control of various insect pests.Toxic hazards of OP are therefore essentially short-term in contrast to that of the persistent organochlorine insecticides. Organophosphorus insecticides however have higher acute toxicities than chlorinated insecticides but they have an advantage of being more rapidly degraded in the environment. The results indicated that the heptachlor-epoxide, dieldrin, aldrin, p, p’-DDE and p, p’-DDT were the least frequently detected residues in all tomato samples, their occurrences were in (0.61, 0.93, 1.38, 1.7 and 1.74 µg/ kg), respectively of tomato samples for each pesticide residue.
While Heptachlor and Methoxychlor were the highest level of a pesticide residue (13.9 and 10.42 µg/ kg) respectively, also,all tomatoes collected from Sohag, New valley, El-Minia and Assuit were free from any detectable residu