Detection and Elimination of Certain Insecticide Residues from Tomatoes and Green Peppers Fruits

Document Type : Original Article

Authors

1 Plant Protection Dept. College of Food and Agriculture Sciences,King Saud University, Riyadh

2 Plant Protection Dept. College of Food and Agriculture Sciences, King Saud University, Riyadh

Abstract

Residues of three common insecticide  used lately in greenhouses  were determined;   pyriproxyfen (insect growth regulator and guvenile hormone), fenitrothion (an organophosphate), and spinosad (a biological insecticide). Degradation of these insecticides was followed on tomatoes and green peppers grown in greenhouses. The residue of each insecticide was also determined after cooling and cooking the fruits after one day of application.  Results showed that initial deposits of pyriproxyfen on tomatoes and green peppers were 2.89 and 6.71 mg/kg respectively. Gradually with time the percentage of disappearance reached 84.14% on tomatoes and 88.08% on peppers after 14 days of application. The half life time (t 0.5) was 5.41 days on both tomatoes and peppers. The results also show that cooling resulted in 15.92 %  and 15.35 % loss, while cooking of fruits resulted in 65.4% and 77.35 % loss of pyriproxyfen from tomatoes and peppers, respectively. Regarding fenitrothion, the results showed that the initial deposits on tomatoes and green peppers were 3.48 and 3.37 mg/kg; respectively. Gradually with time the percentage of disappearance reached 97.13% on tomatoes and 98.81% on peppers after 14 days of application. The (t 0.5) was 3.5 days on tomatoes and 1.5 days on peppers. Cooling process resulted in 9.48% and 25.52 % loss,  while cooking reduce 93.1 % and 82.79% of fenitrothion from tomatoes and peppers, respectively.  Initial residues of spinosad  were 0.52 and 0.23 mg/kg  on tomatoes and green peppers. The loss reached 84.62% on tomatoes and 47.83% peppers after 7 days of application. The (t 0.5) was 3.5 days on tomatoes and 7.5 days on peppers. Cooling process resulted in loss of  spinosad residues by 44.23% and 39.13 %  while cooking reduce 50% and 56.52%  from tomaoes and green peppers, respectively.

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