الفهرس 
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Abstract
The field trial was conducted in faculty of Agriculture farm, Menoufia
University, Egypt. The trial was conducted in a randomized complete block
design with three replicates. The orange trees, tomato and cucumber plants at
the fruiting stage were spraying with Lambda-cyhalothrin, (imidacloprid and
fipronil) and abamectin at recommended rate according to Egyption Ministry
of Agriculture, respectively. Untreated control plot was sprayed with water
only.
Research objectives could be summarized as follow:
1. Study the persistence of (imidacloprid and fipronil) in /on tomato,
(abamectin) in /on cucumber and (Lambda-cyhalothrin) in /onorange fruits
to determine a safety period (time between pesticide application and
consumption of the fruits)
2. Investigate the side effect of the tested pesticides on the quality parameters
(ascorbic acid, total protein, acidity%, total soluble solid (TSS %),
moisture% and dry matter %) of fruits.
The following points provide a summary of such study:
I. The recovery percentages of tested pesticides ranged from 80-110.
II. Half–life time (t½) were 1.75, 1.60, 1.32 and 1.60 days in statistical
equation for (fipronil, imidacloprid ), abamectin and lambda-cyhalothrin on
tomato, cucumber and orange fruits, respectively.
III. The dissipation percentage of (fipronil, imidacloprid) in/on tomato,
(abamectin) in /on cucumber and (lambda-cyhalothrin) in /on orange fruits at
different time intervals, showed that after two weeks from treatments,the
residues were non detectable.
Persistance and dissipation of pesticides:
1. Residues of fipronil in/ on tomato at different time intervals were 1.902,
1.235, 0.637, 0.135, 0.099, 0.042 mg/kg after one hour, 1, 3, 5, 7 and 10
days, respectively.
2. Residues of imidacloprid in/on tomato at different time intervals were
1.35, 1.02, 0.71, 0.321, 0.075, 0.02 mg/kg after one hour, 1, 3, 5, 7 and 10
days respectively.
3. Residues of abamectin in/on cucumber at different time intervals were
0.621, 0.256, 0.092, 0.042 mg/kg after one hour, 1, 3, and 5 days,
respectively.
4. Residues of lambda-cyhalothrin in/on orange at different time intervals
were 1.02, 0.963, 0.521, 0.201, 0.064, 0.015 mg/kg after one hour, 1, 3, 5, 7
and 10 days, respectively.
It is very interested to suggest that the PHI of abamectin on cucumber and
that of lambda-cyhalothrin on orange fruits is 7 days. On tomato, the PHI of
imidacloprid is 5 days while that of fipronil is 14 days.
Effect of tested pesticide residues on internal quality parameters of
tomato, cucumber and orange
a. Effect of tested pesticide residues on quality parameters of tomatoes:
1. A slight change of ascorbic acid concentration was happened in treated
plant compared with treated tomatoes.However,chlorpyrifos, fipronil and
significantly increased the ascorbic acid concentration (in range 12.60-
12.63 mg/100g) imidacloprid compared to untreated plant (12.46
mg/100g).
2. Total protein contents of fruits was significantly higher in case of
chlorpyrifos (2.13 g/100g) than that in untreated plants and lower protein
was recorded with imidacloprid (1.49 g/100g) compared to untreated plant
(1.74 g/100g).
3. All tested pesticide significantly increased the acidity of tomato fruits
(RC% values werepositive). Mancozeb and fipronil treated tomatoes were
the highest in hancement on acidity contents (4.65% and 4.97% ,
respectively).
4. Fipronil significantly increased total soluble solid substances contents
(7.60%) while, imidacloprid significantly decreased it (7.00%) when
compared with untreated tomatoes (7.50%).
5. Fipronil increased moisture percentage of fruits significantly (88.49%).
Other tested pesticides increased the moisture percentage but not significant
except imidacloprid residues decreased the moisture significantly (84.8%)
compared with untreated plants (85.47%).
6. Dry matter of fruits was significantly reduced in all pesticide treatments
except in the case of imidacloprid insecticide treatment which significantly
increased the dry matter content compared to untreated plants (14.54%).
b. Effect of tested pesticide residues on quality parameters of cucumber:
1. Ascorbic acid concentration of fruits was lower than it in untreated
cucumber plants except in case of lambda-cyhalothrin (2.133 mg/100g)
Low ascorbic acid concentration was recorded in mancozeb (1.97
mg/100g), imidacloprid (2.02 mg/100g) and abamectin (2.093 mg/100g).
2. A negligible change of total protein content was happened in treated plants
compared with untreated plants, mancozeb and lambada-cyhalothrine had
the highest amount (0.526 g/100g) followed by imidacloprid (2.026
g/100g) .
3. No significant change of total soluble solid content (TSS) was happened
untreated plants compared with untreated cucumber fruits , low (TSS) was
happened in lambda-cyhalothrin treated plants (11.1%) followed by
imidacloprid and abamectin (11.2%).
4. Moisture percentage of fruits was lower than it in untreated plants.
Significant reduction of moisture percentage was obtained from mancozeb
treated plants (82.28%) followed by imidacloprid (82.84%), and nonsignificant
reduction was obtained from lambda-cyhalothrin and abamectin
(83.02 and 83.17%, respectively).
5. Dry matter percentage of cucumber fruits was significantly higher in all
tested pesticide treatments than that in untreated plants (RC% values are
positive). The highest dry matter was happened in mancozeb treated plant
(17.73%) followed by imidacloprid (17.16%).
c. Effect of tested pesticide residues on quality parameters of orange:
1. Ascorbic acid concentration of orange fruits was increased in imidacloprid
treatment while, it was decreased in lambda-cyhalothrin and dimethoate
treatments.
2. Total protein content of fruits was decreased in treatments of all tested
pesticides except in treatment of chlorpyrifos and lambda-cyhalothrin that
significantly increased the total protein content compared to control (0.88,
0.84 and 0.73g/100g respectively.
3. Pesticide residues did not cause any significant effect on the total soluble
solid (TSS %) contents when compared to untreated orange fruits. Lambdacyhalothrin,
mancozeb and dimethoate increased the TSS percentage
compared to untreated plants. Imidacloprid and chlorpyrifos did not change
in TSS%.
4. Date revealed that pesticide residues did not cause any significant effect
on the acidity% compared to the untreated orange fruits. The acidity% was
decreased (RC% values are negative) in imidacloprid (-15.575%),
chlorpyrifos (-15.462%), dimethoate (-14.334%) and lambda-cyhalothrin (-
3.950%).
5. Lambda-cyhalothrin significantly increased the moisture percentage of
orange fruits, while imidacloprid and chlorpyrifos significantly decreased
the moisture% mancozeb did not effect on the moisture percentage of
orange fruits.
6. The RC percentages indicated that the dry matter content of orange
fruits was significantly increased in all tested pesticide treatment except
in the case of Lambda-cyhalothrin which did not effect on the dry matter
content of orange fruits.
In general, it could be concluded that the t½ values of all tested pesticides
on/in tomato, cucumber or orange fruits were shorter than two days.
However, the pesticide residues reach to lower level compared to their
MRLs few days. Therefore, it was suggested that the PHI is 5 days for
imidacloprid and 14 days for fipronil on tomato while, that for abamectin
on cucumber and for lambda-cyhalothrin on orange is 7days. In addition,
it is very interested to state that the insecticide abamectin and lambdacyhalothrin
did not significantly effect on quality parameters of tomato
and cucumber fruits. However, lambda-cyhalothrin significantly reduced
ascorbic acid and dry matter content while, it significantly increased
protein and moisture content in orange fruits. The fungicide mancozeb did
not significantly effect on quality parameters of tomato and orange fruits,
but it significantly reduced the ascorbic acid and moisture content on
cucumber fruits. The insecticide imidacloprid significantly increased the
levels of ascorbic acid and dry matter content in tomato and orange fruits,
while it significantly decreased the levels of ascorbic acid and moisture
content in cucumber fruits. Fipronil increased all tested quality parameters
in tomato fruits except dry matter content.The ascorbic acid and protein
content in tomato fruits and protein and dry matter content in orange fruits
were increased in chlorpyrifos treatment. The dry matter content was
significantly increased while, ascorbic acid concentration was
significantly decreased in dimethote treatment compared to that in orange
fruits of control.