الفهرس 
Biochemical studies of tested tomato varietiesOnly 14 pages are availabe for public view
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Abstract
Tomato, Solanum lycopersicum is an important economic vegetable crop in Egypt. Tomato plants were infested numerous insect pests. For instance, tomato is liable to infestation by white fly, thrips, aphid, mite and Tuta absoluta. Tomato borer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is a main tomato crop pest in numerous countries and can cause up to 100% yield loss in tomato crops under both greenhouse and open-field conditions. Thus, the objective of the present study was undertaken to shed light on the following:
A) Ecological study of tomato borer
I.A. The population fluctuation of the tomato borer, Tuta absoluta stages on some tomato varieties during two successive seasons, 2018 and 2019
The abundance of T. absoluta eggs infesting T306, 130, Super Hagen, 586 and 585 varieties were 2.70, 2.37, 1.91, 1.76 and 1.20 eggs/ leaf, respectively. The occurrence of T. absoluta eggs was lower in the second season, 2019 than the first one, 2018. Data revealed that the population density of tomato borer, T. absoluta larvae was sharply recorded three peaks, the first one started in all tomato varieties in April, the second highest peak illustrated in whole varieties in May, whereas the third one appeared in all varieties in June during two successive summer season, 2018 and 2019. Moreover, tomato variety ”585”was harbored the lowest infestation by T. absoluta larvae during both investigated seasons. Data showed that the highest mean numbers of T. absoluta adults infestation was reported on super Hagen variety (198.11 adults/trap), but the slightly mean no. of adult infestation was observed on 130 variety being 158.37 adults/trap during the summer season, 2018. During 2019, the higher catching of T. absoluta was harbored on three first tomato varieties 130, 586 and T 306 (48.86, 38.00 and 44.42 adults/ trap) than the two last tomato varieties, super Hagen and 585 being 22.14 and 29.03 adults/ trap, respectively. The symptoms of mines were increased to reach the highest value in May during 2018 and 2019. In view to the obtained results, 585 variety was harbored a low number of the damaged caused by larvae during both two seasons.
I.B. Relationship between some abiotic factors and the population of T. absoluta stages on tomato plants:
The obtained data showed a positive relationship between both maximum and minimum temperatures and the population fluctuation of T. absoluta stages, eggs and larvae on all tested tomato varieties during the two investigated successive summer seasons, 2018 and 2019. That means, the increasing of temperatures increased the T. absoluta infestation on tomato crop. However, a negative relationship was recorded between relative humidity and the density of T. absoluta eggs and larvae on tomato crop during the investigated summer tomato plantation in Egypt.
The effect of three weather factors, maximum, minimum temperatures and relative humidity was a negative effective on the catching adults of T. absoluta per pheromone trap on the five investigated tomato varieties during seasons, 2018 and 2019 that means, the increasing of these factors decreased the T. absoluta infestations.
In the present work, both temperature and relative humidity were common factors affecting the development of various stages of T. absoluta. Accordingly, the temperature variations and temperature-humidity combination affected on the dynamics of T. absoluta stages and the plant infestations by the larval stages and the worm and humidity conditions prevailing during summer season are more suitable for increase in the tomato borer population.
I.C. population growth rate of the tomato borer, T. absoluta stages on five tomato varieties during two successive summer seasons 2018 and 2019
Regarding results, the highest rate of Nt (the highest count of stage / variety) was showed on 130 variety in both of eggs and larvae per leaf (12.60 & 8.67, respectively) but the highest number adults of Nt was in T306 variety (283.67). Whereas the lowest number of Nt was in 585 variety in eggs and larvae per leaf (4.35 & 4.82). While, in adults on 130 variety (192.00/ trap).
The present data indicated that the population growth rate was low with 585 and super Hagen varieties, mean that, the population size of T. absoluta stages was decreased on this variety, which, it may be help in IPM planning of tomato cultivations.
I.D. Susceptibility of different tomato varieties to the infestation of the tomato borer, Tuta absoluta
In the present work, three degrees of susceptibility in both tested seasons: susceptible (S) in tomato varieties, 130, T306 and Super Hagen, low resistance (LR) in 586 variety and moderately resistant (MR) in 585 variety. Data indicated that the mean numbers of T. absoluta larvae/leaf significantly differed between the five tomato varieties during seasons, 2018 and 2019. These degrees of susceptibility are therefore important to point out that insect infestation rates must refer to the degree of resistance of each variety.
II. Biochemical studies of tested tomato varieties
I.A. Effect of some plant enzymes of five tomato varieties on infestation rates of T. absoluta
II.A.1. levels of three tested plant enzymes in five tomato varieties
Regarding the present data illustrated that a significant difference between the tested tomato varieties and the content of three plant enzymes (phenoloxidase, peroxidase and GST) during the summer season 2019. The low level of enzyme was found in 586 variety (Phenoloxidase) and in 130 variety (peroxidase enzyme). Moreover, the 586 variety contained the highest amount of peroxidase and GST enzymes.
II.A.2. Correlation matrix between some plant enzymes of five tomato varieties and infestation rates of T. absoluta stages
A negative and significant relationship was found between peroxidase and Glutathione s-transferase (GST) enzymes and the deposited eggs of T. absoluta per leaf. Contrariwise, phenoloxidase enzyme indicated a positive correlation coefficient during the summer season 2019. Peroxidase enzyme was highly affected by the T. absoluta eggs than the other two tested enzymes. Phenoloxidase enzyme had a positive and significant with T. absoluta eggs deposited on tomato varieties.
A significant negative relationship was reported between the infestation of T. absoluta larvae / leaf and both of peroxidase and GST enzyme contents in leaves of five tomato varieties. Contrariwise, phenoloxidase enzyme evinced a positive relationship with the infestation of T. absoluta larvae / leaf. The Explained variance showed high values with both GST and peroxidase by 76.38 and 67.05%, showing that, increased enzymes levels, decreased the population densities of T. absoluta (larvae/ leaf).
In case of T. absoluta adults infestation per pheromone trap, data illustrated a negative and significant with the amount of the three tested enzymes in leaves of all tomato varieties (-0.57, -0.58 and -0.77 with phenoloxidase, peroxidase and GST, respectively). from the obtained data of adults, the increasing of the catching of T. absoluta adults/ trap will be decreased the three tested enzyme contents in tomato leaves during the tested two summer seasons.
II.B. Impact of some phytochemical components in leaves of five tomato varieties on the infestation rates of T. absoluta stages
II.B.1. Levels of some phytochemical components in leaves of five tested tomato varieties at fruiting stage during summer seasons 2019
The present study showed that the tomato variety, 585 had a moderate resistance against T. absoluta infestations and also it had a high level of total phenols and flavonoids. Moreover, this tomato variety had low levels of total proteins, carbohydrates, and free amino acids, mean that, the total phenols and flavonoids were increased the resistance and tolerance against T. absoluta infestations during summer cultivations.
II.B.2. Correlation matrix between five leaf phytochemical components of five tomato varieties and the infestation rates of T. absoluta stages
The obtained results clearly indicated that the deposited eggs of T. absoluta on the tested tomato varieties were negatively correlated with the amount of all five photochemical components during both investigated seasons (r values were extended between -0.45 to -0.87).
With larvae infestations, it was observed a negative correlation with the total proteins, free amino acids, phenols and total flavonoids whereas, the total carbohydrates were positive relation, means that, the increasing of these components will be increased T. absoluta larvae on the five tested tomato varieties. In view of results, the total phenols and flavonoids had a highly values of explained variance (E.V. %) being 63.80 and 76.23% in case of T. absoluta eggs, and 64.63 and 45.93% with larvae. Means that, the increasing of these factors will be decreased the T. absoluta larvae infestation.
The presented results illustrated a distinct negative relation between the population density of T. absoluta adults/ trap on five investigated tomato varieties during summer season 2019 with all examined five leaf phytochemical components except with total carbohydrates and total flavonoids, it was positive on the attractive of T. absoluta adults to pheromone traps on the five tested tomato varieties. In general, the catching of T. absoluta adults per trap on the five tested tomato varieties were depended on the ability of sexual pheromone traps for the attracting T. absoluta adults, so that, the correlation coefficient (r) was very low value. Finally, the factors of total phenols, flavonoids (phytochemical contents), peroxidase and glutathione s-transferase (GST) were highly affected on the infestation rates of T. absoluta stages on the five tested tomato varieties.
III. Impact of some morphological characters in leaves of five tested tomato varieties on the infestation rates of T. absoluta stages
III.A. Measurements of some morphological characters in leaves of the five tested tomato varieties during 2019
Tomato plants were infested by T. absoluta larvae which causes numerous injuries, the leaf structure might be the first plant defense against insect pest. The number and length of trichomes on the tomato leaf also might be considered characters for selected the egg deposition and development of this pest The average length of trichomes was ranged from 147.37 to 165.37 μm and it recorded the highest numbers and length of trichomes in leaves of 130 variety. However, the lowest one was stated on 585 variety. Also, the density of stoma decreased in leaves of 130 variety and increased in leaves of 585 variety. In addition, the length of stoma was the smallest in Super Hagen leaves; a maximum length of stoma was recorded in 586 leaves.
III.B. Correlation between some morphological characters of the five tested tomato varieties and the infestation rates of T. absoluta eggs and larvae
A negative relationship between both the numbers of glandular trichomes, stomatal length and T. absoluta infestations was recorded.
The correlation factor (r) was extended between -0.85 to 0.91 in the number of non-glandular trichomes, glandular trichomes, trichome length, stoma number and stomal length, respectively.
I.V. Control studies on tomato borer, T. absoluta
Results cleared that the spraying of Voliam flexi )Thiamethoxam + Chlorantraniliprole ( , Bio-sect (Beauveria bassiana(, Auekous (3.2% E.C Azadrachtin) and Pyrethrum (5% pyrethrins) were the most efficient pesticide for suppression of T. absoluta infestation on tomato cultivations in Egypt than other investigated bio-pesticides in this study in comparison with voliam flexi used as control.