Apple trees, spray depositions

Table 3.8 summarises the deposition of spray on soil surface underneath apple trees in orchards. When spraying apple trees in full leaf, spray deposition on the ground is on average 25% (18-35%), (Heer and Schut, 1986 Crum and de Heer, 1991 Porskamp et al., 1994a, 1994/ Ganzelmeier and Osteroth, 1994 Heijne et al., 1995). Spray deposition on the soil is not significantly different between axial and cross-flow sprayers, but tunnel sprayers (Zande et al., 1998) can decrease soil deposition by 50%. When trees are not in leaf, spray... 

Table 3.8 Spray deposition (% dose) on the soil surface underneath orchard trees (apple) for different periods during the growing season, and different spray techniques...

Apples. The Rome Beauty apples used in the wash tests were sampled from trees that had received varying amounts of DDT mixtures in as many as six cover sprays. Duplicate or triplicate samples of 30 apples each were taken at random for the residue analyses from the fruit passed through each experimental wash mixture. Additional lots of 30 washed apples each were placed in cold storage for subsequent examinations. Unless otherwise indicated, all washing tests were run in a flood-type washer of recent design (a BADD washer with a heated prewash tank unit, an unheated main tank unit, a water rinse tank unit, and a velour roller dryer unit, manufactured by the Bean-Cutler Division, Food Machinery Corporation, San Jose, Calif.). Surface deposits of DDT were determined as described (10, 12) on samples taken just before and immediately after the washing treatments. 

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