الفهرس 
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Abstract
(85)
SUMMARY
Tomatoes grown for either summer or winter
crop was sprayed with three organophosphorus insecticides;
malathion, pirimiphos methyl and profenofos,
all the three insecticides being recommended against
sap sucking insects on tomatoes. Insecticides were
used at the rates of 570 g~a~i. malathion, 750 g~a.i.
pirimiphos methyl and 540 g.a.i. profenofos per feddan,
all the insecticides used were in commercial emulsifiable
concentrate formulations~
Three methods of exraction were tried out and
one of them was selected by vertue of its reproduceability
and being less complicated~ Residues were
cleaned up and determined by gas chromatography for
deposits on both fruits and leaves~·
Results indicated the following:
1- The largest initial deposit was that of pirimiphos
methyl, indicative of the relat.ionship
between concentration and initial d4:!posit.
When malathion and profenofos were cOJnpared,
however, less deposit of profenofos was found,
the difference was not proportional to the
small difference of rate of application, thus
pointing to the probability of the eff~!ct of
formulation constituents.
(86J
2- In all cases leaves retained more deposits
than frutis indicating the effect of weight
to surface ratio effect on initial deposit
in addition to the effect of the texture of
the sprayed surf4ce~
3- Residues of pirimiphos methyl were the least
persistent of the three insecticides investigated,
followed by malathion with a rather
small difference, while profenofos was conspicuously
more persistent than the other two
insecticides and this observation W,lS true
for both leaves and fruits.
4- In malathion and pirimiphos methyl the deterioration
of residues was slightly slower on the
winter crop compared to the summer crop nlthough
the diference was rather small in mnlathion
and slightly more pronounced in pirimiphos
methyl;; In profenofos, however, the deterioration
rates and pattern were alaost identical
in both seasons.
5- The rate of residues decomposition was always
faster on and in tomato fruits compared to
leaves. This was explained by the fact that
initial deposit vas larger on leaves compared
to fruits in addition to the difference in
(87)
texture and its probable effect on the binding
nature of the insecticide to them.
6- The tolerance limit for malathion on and in
tomatoes is 3 ppm and for pirimiphos methyl
is 1 ppm. Residue determination indicated that
both limit were surpassed after 12 days in both
summer and winter crops, so this period can
recommended to slopes between sprayi.ng and
harvesting of tomatoes. The results indicated
that vegetables grown for the leaf crop should
,t’
require a larger period ._~As for pzofenofos ,
there were no tolerance limit and up to the
15th day after spraying residues wer~~ still
detectable, accordingly, this’ isecticide can
not be recommended until the time required
for the comp1et disappearance of residue was
established.
(85)
SUMMARY
Tomatoes grown for either surnrrier or winter
crop was sprayed with three organophosphorus insecticides;
rnalathion, prrirniphos rnethyl and profenofos,
all the three insecticides being recollllllended against
sap sucking insects on tornatoos. Insecticides were
used at the rates of 570 g-va-u. rnalathion, 750 g-s-a.r.
prrirniphos rnethyl and 540 g.a.i. profenofos per feddan,
all the insecticides used were In cornrrierc.ial emu.lsifiable
concentrate fOTlllulations~
Three rnethods of exraction were tried out and
one of them was selected by vertue of its reproduceability
and being less cOlllplicated~ Residues were
cleaned up and determiried by gas chromatography for
deposits on both fruits and Ieaves->
Results indicated the following:
1- The largest initial deposit was that of pIT1111Iphos
rnethyl, indicative of the relat.ionship
between concentration and initial d4: !posit.
When rna.lathiori and profenofos were cOJnpared,
however, less deposit of profenofos was found,
the difference was not proportional to the
srnall difference of rate of application, thus
pointing to
forrrrulation
the probability
constituents.
of the of
(86J
2- In all cases leaves retained more deposits
than frutis indicating the effect of weight
to surface ratio effect on initial deposit
in addition to the effect of the texture of
the sprayed surf4ce~
3- Residues of pirimiphos methyl were the least
persistent of the three insecticides investigated,
followed by malathion with a rather
small difference, while profenofos was conspicuously
more persistent than the other two
insecticides and this observation W,lS true
for both leaves and fruits.
4- In malathion and pirimiphos methyl the deterioration
of residues was slightly slower on the
winter crop compared to the summer crop nlthough
the diference was rather small in mnlathion
and slightly more pronounced in pirimiphos
methyl;; In profenofos, however, the deterioration
rates and pattern were alaost identical
in both seasons.
5- The rate of residues decomposition was always
faster on and in tomato fruits compared to
leaves. This was explained by the fact that
initial deposit vas larger on leaves compared
to fruits in addition to the difference in
(87)
texture and its probable effect on the binding
nature of the insecticide to them.
6- The tolerance limit for malathion on and in
tomatoes is 3 ppm and for pirimiphos methyl
is 1 ppm. Residue determination indicated that
both limit were surpassed after 12 days in both
summer and winter crops, so this period can
recommended to slopes between sprayi .ng and
harvesting of tomatoes. The results indicated
that vegetables grown for the leaf crop should
,I’
require a larger period. ~As for pzofenofos,
there were no tolerance limit and up to the
15th day after spraying residues wer~~ still
detectable, accordingly, this’ isecticide can
not be recommended until the time required
for the comp1et disappearance of residue was
established.