Lbs./Acre 

 per Year 

 60 



50 

 40 

 30 

 20 

 1 



Captan 



EBDC 



No residue detected 



^j 



[ 



"Residue detected 1 



i 



FT 



nrnrmiiiiiiiin sniniE i 



9 11 13 

 Orchard Block 



15 17 19 21 23 25 27 



Figure 7. The pounds of captan and EBDC fungicide applied over the 1988 season compared, with the 

 EBDC residue on apple samples. Where detectable, the amount of residue increases from left to right; 

 blocks which had no detected residues are represented in the white background, and blocks with a 

 detected residue are in the shaded background. 



EBDC 

 Residues 



y = .036x -.121x + .07 



10 



Lbs. EBDC applied after July 23 



Figure 8. EBDC residues as a function of the pounds of EBDCs 

 applied after July 23. 



to EBDC fungicides used over the 

 season. In general, as the number 

 of EBDC applications decreased, 

 the number of captan applications 

 increased (r = -0.73) (Figure 6). 

 Interestingly, as the combined 

 number of applications for both 

 types of fungicide decreased, the 

 mix of captan and EBDC was the 

 most balanced. These same blocks 

 were also ones in which EBDC resi- 

 dues were not detected. (Only one 

 block, no. 3, had detected captan 

 residues.) The pounds per acre per 

 season of each material were less 

 closely related (r = -0.48), but 

 showed the same pattern (Figure 

 7). The correlation between the 

 pounds of captan per acre for the 

 season and EBDC residues was 

 low, but significant (r = 0.44). Not 

 surprisingly, the pattern suggests 

 that using more captan reduces the 

 use of EBDCs, and reduces the 

 EBDC residue. 



If we could use some simple 

 standards, such as the number of 

 applications or the total pounds per 

 acre applied, to predict whether 

 EBDC residues would remain on 



26 



Fruit Notes, Winter, 1990 



