Azinphos-methyl was applied to Shiraz winegrapes by commercial high-volume and hand-held sprayers during seasons 1993/94 and 1994/95.
Residue levels in grapes resulting from treatments applied by commercial sprayer were below the maximum residue level (MRL) of 2 mg kg~1 for grapes in Australia, whereas residues resulting from treatments applied by hand-held sprayer still exceeded the MRL Ðve weeks after Ðnal application. There was a strong correlation for most treatments between treatment concentration of azinphosmethyl and residue level in grapes, and in wine made from treated grapes. Applied at the recommended rate (1É2 g litre~1 wettable powder (WP) and 2É4 ml litre~1 suspension concentrate (SC)) by commercial high-volume sprayer, azinphos-methyl residue levels in wine were well below the MRL, and below the MRLs of most importing countries, except Denmark and Sweden. When applied by hand-held sprayer, residue levels in wine were 5É9È29É6 fold higher than those previously obtained by commercial application of insecticide. Since wines are often blends from di †erent grape blocks and grape-growing districts, in practice, this is unlikely to be of concern. Wine made from grapes treated by commercial sprayer showed no detectable residues of azinphos-methyl after one year of storage. In both years, residue levels in grapes of both formulations of azinphosmethyl Ñuctuated during the Ðve-week post-treatment period, although there was an overall downward trend. Previously unrecorded systemicity in azinphosmethyl was demonstrated in laboratory studies with barley seedlings, and this may explain these Ñuctuating data in grapes. The reduction of azinphos-methyl residues in grapes over time appears to be a complex phenomenon involving translocation of active ingredient combined with an increase in the size and weight of berries, producing Ñuctuating residue levels.