16- 



increased dosage equivalents, in several of the IPM orchards were 

 attributed to the growers' addition o£ low rates of fungicides 

 when applying insecticides or growth regulators. Increased dosage 

 equivalents were mostly due to applications of a high rate of 

 fungicide (esp. Cyprex*) aimed at "burning out" establislied scab 

 lesions . 



4 -year Summary 



The average number of fungicide sprays has traditionally 

 been correlated with weather patterns, especially rain. Increased 

 numbers of spring and summer rains usually has necessitated 

 increased fungicide applications and dosage equivalents. Long per- 

 iods of rain in 1978 and 1979 and weekly wetting periods early in 

 1981 made kickback spraying difficult in IPM orchards. Therefore, 

 protective sprays were necessary prior to predicted long rainfalls, 

 with at least one extra fungicide application to "burn out" esta- 

 blished scab infections and inhibit secondary infections. 1980 

 was a m.uch drier growing season; therefore, fewer numbers of fungi- 

 cide applications were required (Figure 1), with fewer dosage 

 equivalents (Figure 2) . Fungicide applications were greatest in 

 control blocks in 1979, but there were fewer dosage equivalents 

 than the other wet years of 1978 and 1981. This is explained by 

 growers adding low rates of fungicides with insecticides in spring. 

 Regardless of weather, IPM disease management has consistently 

 reduced num.ber of fungicide applications and dosage equivalents in 

 IPM vs. control blocks. 



While the first year of the IPM disease management program 

 reduced fungicide applications onlv by 5.6% and dosage equivalents 

 by 1.21 (Table 5), during the wet years of 1979 and 1981, IPM blocks 

 experienced 18.2 and 15.41 reductions in fungicide sprays and a 

 12.1 and 20.1% reduction in dosage equivalents. The drier year, 

 1979, had an 8.8% reduction in fungicide sprays, with 7.9% fewer 

 dosage equivalents. Percent fruit disease at harvest (Figure 3) 

 has consistently showed IPM blocks to have disease percentages 

 lower or comparable to control blocks. In Table 4, dollar amounts 

 are given for fungicide applications and losses due to fruit diseases 

 IPM benefits per acre for 1979, 1980, and 1981 were ,Ul.82, $15.31, 

 and $7. 79. 



Table 5. Fungicide usage in IPM orchards in comparison to control 

 orchards; 1978 through 1981. 



Trade name 



