generation nymphs. The first, which had been 

 well under the threshold this year although 

 leafhoppers had been a problem last year, had 

 an explosion in the second generation which the 

 grower was able to control with Thiodan™. The 

 second, which was marginally under the thresh- 

 old, showed very little activity during the second 

 generation, and did not appear to be a problem 

 early in the third generation, but suddenly ex- 

 ploded in mid-September. It appears that an- 



other, very similar, species of leafhopper, the 

 rose leafhopper, may move into apple orchards 

 shortly after the first generation of white apple 

 leafhopper; this immigration may explain the 

 unusual outbreak patterns that we saw. 



Scab 



Fruit scab was noted in a number of blocks 

 that had used a sterol-inhibiting fungicide pro- 

 gram through primary scab season. Levels were 

 not excessively high, averaging 0.5% in our 

 harvest surveys, but it was a severe reminder of 

 the unforgiving nature of these materials. 



Apple Maggot Fly 



There was immigration of apple maggot flies 

 into some orchards in early June ~ just on the 

 tail end of curculio season. Active tunnels were 

 noted at this time, so we advised growers to base 

 sprays on trap captures and not wait until July 

 if the threshold was reached. There was a drop 

 in apple maggot fly pressure in most locations 

 after Hurricane Bob (August 20). 



Calyx End Rot 



This disease was not a severe problem this 

 year; however, it was present in nearly all of the 

 orchards we visited. 



Black Rot 



Frog eye leaf spot was common this year, and 

 more fruit injury than usual was noted. 



•A* +1* *1* *i* *i* 

 *J» *f% rj* *J» *J* 



8 



Fruit Notes, Winter, 1992 



