DETERMINING PESTICIDES WAITING PERIODS AND RESIDUES ON VEGETABLES UNDER JORDAN VALLEY CONDITIONS

Field experiments were conducted for two seasons in Dier Alla station to determine pesticides waiting periods and residues on common vegetables under plastic houses and open field conditions.
Six plastic houses were planted with cucumber, tomato, bean, hot pepper, sweet pepper, and strawberry in the first and second season.
In the same station an open field site was divided into six units planted with tomato, eggplant, squash, cabbage, cauliflower and lettuce.
Nine pesticides (acaricides, insecticides, fungicides) were studied in the first and eleven in the second season.
Three acaricides (Vapcothion, Neoron, Acimite super), four insecticides (Agrothoate, Cypermed, Wopro-Deltamethrin, Karate), and two fungicides (Vydan, Rovral) were used during the first season.
Two acaricides (Vapcozin, Dictator), five insecticides (Vapcocidin, Cliper, Novos, Diazinon, Fenikle), and four fungicides (Triadimefon, Amizol, Sumislex, Topaz) were used in the second season.
During the season each pesticide was sprayed two times, the first on beginning and the second in mid harvesting times.
Acaricides were not used on cabbage, cauliflower and lettuce.
However, insecticides and fungicides were sprayed on these crops only one time during the season when the crop was about to be ready for harvesting started with insecticides and three days later fungicides.
For the other crops, spraying schedule started with acaricides, insecticides, and fungicides with three days interval between each spraying in condition that they did not have closer retentions times.
Random samples of about 4-6 kg were taken three days after spraying with acaricides and just before spraying with insecticides; other random samples were taken three days after spraying with insecticides and just before spraying with fungicides.
After that two samples with three days interval were taken after spraying with fungicides in the first season.
While in the second season three random samples with three days interval were taken after spraying with fungicides.
The same procedure and arrangement were done for the second sprayings schedule during mid harvesting times with at least four weeks interval between the last sample from the first spraying schedule and the first sample from second spraying schedule.
Control samples of about 4-6 kg were taken before starting spraying.
At residue analysis laboratory, samples were chopped and divided into three parts, one for immediate analysis, the rest were kept in deep freeze as stock samples.
Multi residue methods (Luke method) were used to determine pesticides residues.
Gas chromatography (GC) with nitrogen phosphorus detector (NPD) was used for organophosphorous residues and with electron capture detector (ECD) for organochlorines and pyrethroids residues.
Mixed standard solutions are injected prior to sample injection.
Peak shape, resolution, and response for each mixture are evaluated to ensure the instrument is operating properly.
For each crop a table was prepared showing pesticides residues (ppm) for the scheduled harvesting dates compared to maximum residue level (MRL’s) of the codex and European community.

I International Symposium on Fresh Food Quality Standards: Better Food by Quality and Assurance

M. Abdel-Wali, M. Bahdousheh, A. Al-Awamleh, A. Shaderma, S. Arabyat, K. Ananbieh, M. Ayassreh, A. Frehat, N. Romiah, Y. Alawneh, N. Abu-Nab, A. Gharaybeh, S. Qbielat, M. Edwan

pesticides waiting periods and residues, vegetables

https://doi.org/10.17660/ActaHortic.2007.741.11