Reduction of dieldrin concentration in cucumber fruits using Cueurbita rootstocks and activated carbon

Dieldrin uptake by cucumber fruits was examined using a variety of cucumber scions and squash rootstocks. The effect of activated carbon on reducing uptake was also determined. Three varieties of cucumber (Cucumis sativus L..- Sharp 1, Natsusuzumi and Nankyoku 2) and three varieties of squash (Cucurbita spp.; Kirameki, Yuyuikki-black and Shintosa) were used. There was no significant difference in dieldrin uptake between cucumber scion varieties. The order of uptake between the varieties of rootstock was Shintosa > Yuyuikki-black > Kirameki=self-rooted plants. In tile case of Shintosa, a change to Kirameki or self-rooted plants reduced the dieldrin concentration to 53-34%, treatment of soil with activated carbon to 57%, and the combination of changing the rootstock to Kirameki with activated carbon to 16%. In the case of Kirameki, treatment of soil with activated carbon reduced tile dieldrin concentration in Cucumber fruits to 42%. In the case of self-rooted plants, a change to grafting culture with Kirameki rootstock and treatment of soil with activated carbon was effective in reducing dieldrin concentration. (c) Pesticide Science Society of Japan.