year. In most years, if growers apply oil, espe- 

 cially two applications, mites do not begin to 

 increase until late June or early July. This year, 

 however, they were evident in many orchards at 

 petal fall. Some orchards which had problems 

 with their oil sprays had 30 mites per leaf on 

 some leaves at petal fall, and those trees were 

 showing bronzing by the end of May. Most 

 growers were able to control these early out- 

 breaks with miticide or summer oil. Low-spray 

 blocks had noticeably fewer problems with 

 mites, although we had to allow four of the six 

 growers to apply low rates of miticide in our "no- 

 spray" blocks to prevent excessive mite injury. 

 In these cases, however, a single half-rate treat- 

 ment or a spot treatment, was usually sufficient. 



Flyspeck 



There was a significant increase in flyspeck 

 incidence during the third week in September, 

 presumably because of the wet weather in Au- 

 gust. Fortunately, Mcintosh harvest was 

 nearly finished by the time flyspeck became 



AMF CM LR PC TPB EAS LH SJS 



Figure 1: Insect injury to fruit in EPM 

 and check blocks, 1991. AMF = apple 

 maggot fly, CM = codling moth, LR = 

 leafrollers, PC = plum curculio, TPB = 

 tarnished plant bug, EAS = European 

 apple sawfly, LH = leafhopper (frass), 

 SJS = San Jose scale. 



evident in the field. Some growers maintained 

 a conservative fungicide program early in the 

 summer and stopped spraying in mid- to late- 

 August, with varying success. Growers face a 

 dilemma when conditions for infection occur late 

 in the season: use a fungicide and risk the 

 presence of some residue at harvest, or withhold 

 the fungicide and risk some injury at harvest. 



Leafminers 



Where populations were high last year, sur- 

 vival of leafminers through the winter was 

 nearly 100%. This situation presented some 

 control problems in the early season. In one 

 orchard where leafminers were not controlled 

 and populations were high, it became impossible 

 to distinguish generations as the summer wore 

 on. Some low-spray blocks had high levels of 

 parasitism. 



Tarnished Plant Bug 



As has been the case for the past three 

 seasons, tarnished plant bugs were below treat- 

 ment threshold levels in most of our monitored 

 blocks. Total injury in our harvest survey of over 

 10,000 fruit was 5%, but the majority of this 

 injury did not cause downgrading. 



Plum Curculio 



Curculio pressure was very high in the 

 weeks following petal fall, but most growers 

 were alert to the situation and maintained in- 

 secticide coverage. Injury at harvest was not 

 severe in our monitored blocks. 



European Apple Sawfly 



Populations of sawfly returned to near nor- 

 mal from the very low levels seen in 1990. As 

 with curculio, however, growers were able to 

 control sawfly with a prompt petal-fall insecti- 

 cide. 



White Apple Leafhopper 



This insect was not a problem statewide, but 

 we had population explosions in two of our test 

 blocks. Neither block was treated for first- 



Fruit Notes, Winter, 1992 



