the New York Agricultural Experiment Station at 

 Geneva, we have done tests toward the economic use of 

 the SI fungicides. This program was tested in 4 grower 

 blocks this year. In all 4 blocks, primary scab control 

 was superior to that in check blocks, with virtually no 

 scab present at the end of primary season in the test 

 blocks. The first applications were delayed, on average, 

 until the tight cluster stage of tree development, and 

 involved an average of 4 primary season sprays, com- 

 pared to an average of 5.5 applications in check blocks 

 where the SI fungicides were not used. 



Diseases in 1989 



With the very wet weather we had this year, dis- 

 ease problems were by and large more notable than 

 insect problems. Incidence of fruit injury is given in 

 Figure 1. 



Fire blight . Of major concern to some growers in 

 Massachusetts was a severe outbreak of fire blight, 

 most often in orchards which previously had not had 

 problems with this disease. Most growers who previ- 

 ously experienced a fire blight problem had used a 

 dormant fixed copper spray, and did not have trouble 

 this year. The problem seemed to be primarily in the 

 central region of the state. The outbreak was all stem 

 blight, with no blossom blight. In the past, this problem 

 generally has occurred in conjunction with aphid or 

 leafhopper population development at the end of June. 

 This year, the first date of occurrence was mid- June to 

 mid-July. In two cases, large parts of entire orchards 

 were infected. 



Scab . Scab was evident late in the season on 

 poorly-pruned trees, and pinpoint scab was noted on 

 some fruit at harvest. In most cases where a spray was 

 misapplied (timing or amount), there was disease 



3 



1.50-- 



1.00 



0.50-- 



0.00 



SCAB CALYX BLACK SOOTY OTHER 



END- ROT ROT BLOTCH/ 



FLYSPECK 



Figurel. Harvest injury in first-stage IPM blocks. Disease injury 

 in 1978-88 as compared to injury in 1989. 



development. Primary pressure was high and lasted 

 about 5 to 7 days later than last year. In the majority of 

 orchards, however, scab control was satisfactory. 



Flyspeck/sooty blotch . Not surprisingly, in view of 

 the very wet weather this year, flyspeck was a signifi- 

 cant problem in orchards which had not been ade- 

 quately covered with summer fungicides. Sooty blotch 

 was less prevalent but also present, particularly in 

 orchards that had used a very light summer fungicide 

 program. Since light summer programs were being 

 promoted, growers found themselves in a dilemma: 

 high disease pressure vs. potentially adverse public 

 opinion. This year had the worst overall summer 

 disease situation we have seen in over ten years. 



Ron Prokopy observed approximately 5% flyspeck 

 and 60% sooty blotch on non-fungicide treated Liberty 

 on his farm. 



Brooks spot . Possible Brooks spot was seen on the 

 cultivar Spencer in one block, although the field iden- 

 tification was not confirmed by isolation. 



Summer rots . More summer rots were seen this 

 year than in most years, but the level was still not 

 economically important. Bitter rot and black rot were 

 the predominant rots, depending on the orchard. 



Insects in 1989 



Insects and mites were less of a problem in most 

 orchards this year than in other years, as can be seen 

 from the incidence of fruit injury in Figure 2. 



Plant bug . Activity was very low again this spring. 

 As always, it was difficult to assess tarnished plant bug 

 damage at harvest because of similarities with other 

 insect damage, but on the whole it appears that virtu- 

 ally no downgrading occurred as a result of plant bug 

 damage. 



Leafminer . Parasitism and other 

 causes of leafminer mortality were 

 unusually high this year (over 60% of 

 second-generation mines in some 

 monitored blocks). Due to the cool 

 weather, mine development was 

 slowed and should have caused less 

 tree stress. Leaf mines were observed 

 on pear trees in Belchertown. Al- 

 though signs of emergence were seen in 

 some mines (indicating that pear trees 

 are an acceptable host for this insect), 

 we were not successful in trapping 

 emerging moths to see if they were the 

 same species as the leafminers infest- 

 ing apples. The larvae were veiy simi- 

 lar, however. 



ES 1978-88 

 E2S 1989 



28 



Fruit Notes, Winter, 1990 



