Garnet Beauty and Glo Haven. There were 2 randomly 

 placed blocks of 4 trees of each cultivar in each fungicide 

 treatment, for a total of 8 trees per treatment. 



At harvest, fruit on each tree were evaluated for the 

 amount of rot present. All trees were mature (10 years) and 

 were in adjacent rows in a block at the Horticultural 

 Research Center (HRC), Belchertown, MA. Each cultivar 

 was grown in two adjacent rows, 20 ft apart. Peaches were 

 harvested, yield recorded, and a subsample of approxi- 

 mately 40 random, apparently healthy fruit from each 

 treatment were placed in a box and kept at room tempera- 

 ture for 3 to 4 days. The fruit then were rated for the 

 number of peaches which showed rot, and for the average 

 intensity of the rot present, rated on a to 5 scale (0 = no 

 rot, 1 = < 10% rot, 2 = 10 to 25%, 3 = 26 to 75%, 4 = 76 

 to 90%, 5 = >90%). The postharvest ratings for rot 

 intensity were not made on the Garnet Beauty fruit. 



All fungicide treatments had significantly less rot than 

 the non-treated controls (Table 1). Harbinger has been 

 particularly susceptible to postharvest brown rot at the 

 HRC,asindicatedbythe 100% postharvest rot. Even in the 

 treated Harbingers, there was some rot on between 70 and 

 93% of the peaches. Ronilan treatments at the higher rate, 

 either with or without X-77, significantly reduced rot 

 intensity and preharvest rot. The 0.5 lb rate of Ronilan was 

 slightly better than Funginex at reducing the rot intensity, 

 but not the percent of rotted peaches. The 0.25 lb. rate of 

 Rovral was equivalent to Funginex. Ronilan at either rate 

 was significantly better than Funginex or Rovral at reduc- 

 ing the preharvest rot. There was no difference between 

 Ronilan treatments for preharvest rot on the Harbingers. 



In the other two cultivars, adding X-77 to the Ronilan 

 at either the 1/2 rate or 3/4 rate significantly reduced the 

 preharvest rot. Not adding X-77 depressed Ronilan's 

 performance compared to that of Funginex. The 1/2 rate 

 of Rovral was sometimes better and sometimes worse than 



the standard rate of Funginex. 



The best treatment for brown rot in this experiment 

 was generally the 3/4 rate of Ronilan with X-77. The 1/2 

 rate of Ronilan with X-77 also did reasonably well. The 1/ 

 2 rate of Rovral was as good as the standard rate of 

 Funginex. 



Does this mean that 3/4 or 1/2 rates of Ronilan may 

 be substituted for other fungicides? Not really. This 

 experiment indicates that in a season with moderate pres- 

 sure, such as last year, the 3/4 and 1/2 rates of Ronilan or 

 the 1/2 rate of Rovral will work as well as a standard rate 

 of Funginex. The question remains, does Funginexwork as 

 well as some of the older materials such as thiram and 

 captan? Research in other states indicates that Funginex 

 is at least as good as either captan or thiram, and that is why 

 we used a Funginex standard. However, without including 

 these materials in the test, we cannot be sure that captan or 

 thiram would not have done better. This year we hope to 

 repeat the test using captan or thiram. 



However, if Funginex at 12 oz is a good standard, then 

 the lower rates of Ronilan not only did as well, but usually 

 did better. In that context, reduced rates of Ronilan can do 

 as well as or better than Funginex, and therefore might be 

 considered as an alternative to a full rate of Funginex. 

 However, the economics of the situation do not necessarily 

 favor even the reduced Ronilan, Rovral, or Funginex 

 treatments. For the season (given 3 applications for brown 

 rot), the cost of Ronilan at the low rate was $114.00/acre 

 more than captan; at the 1/2 lb. rate, Ronilan cost $66.00 

 more than captan (Table 2). Funginex at the 12 oz rate cost 

 $25.50 more than captan. Rovral at the 1/4 lb rate cost 

 $15.00 more than captan. Since 3 applications is a low 

 estimate, the cost difference in many cases would be 

 greater. In short, a full rate of captan is always much less 

 expensive than the newer materials. Among the materials 

 tested, Ronilan is more effective, yet it is also several times 



Table 2. List of retail prices for fungicides at recommended and decreased rates (January, 1988). 



Material 



High rate^ 



Cost 

 per acre'' 



Low rate 



Cost 

 per acre 



Reduction 

 per acre" 



Cost comp. 

 to captan 



Ronilan SOW lib $192.00 3/4 lb $144.00 $48.00 +$114.00 



Ronilan 50 W 1 lb $192.00 1/2 lb $%.00 $96.00 + $66.00 



Rovral 50 W 1/2 lb $90.00 1/4 lb $45.00 $45.00 + $15.00 



Fungmex 1.6 EC 16 oz $74.25 12 oz $55.50 $18.75 + $25.50 



Captan SOW 21b $30.00 21b $30.00 $0.00 + $0.00 



Ter 100 gal. 



Iligh rate of material in 250 gal, 3 applications; January, 1988 approximate prices from retail source. 



"Dollars saved by using the reduced rate for 3 applications. 



