-17- 



cases, drop severity appeared more related to factors such as calcium 

 chloride application, stop-drop use, tree vigor, or crop size. 1981 

 data collected with the cooperation of IPM grower Elmer Fitzgerald, Jr. 

 of Ashby, MA., indicated that while STLM injury undoubtedly predis- 

 posed apple trees to a certain amount of pre-harvest drop, moderate 

 to severe phytotoxicity from calcium chloride sprays in one block 

 where third generation STLM was controlled (only 0.8 mines per leaf), 

 resulted in substantial drop (19-0 compared to an adjacent block 

 (11% drop) where second generation and third generation mines reached 

 l.S and 4.5 mines per leaf, respectively. 



Fruit Injury - As mentioned above, degree of grower cooperation with 

 IPM special ist advice was generally excellent . Consequently, compari- 

 son of good cooperator blocks (18) with the few partial cooperator 

 blocks (5) as in 1980 was not feasible. For the following reasons, 

 we chose for purposes of analysis to group IPM blocks as either First 

 Year IPM or previous year IPM (those blocks which have been on the 

 IPM program for one or more years previous to 1981) : (a) First Year 

 IPM blocks typically present numerous residual pest problems (1st 

 year growers frequently assign field staff to monitor "problem" 

 blocks) , (b) there may be less likelihood of bio-control agents 

 being present in First Year blocks in substantial numbers due to 

 previous spray practices, (c) program field staff are hampered by a 

 lack of knowledge as to which pests can be expected to exert the 

 most serious pressure on First Year blocks. 



Overall, fruit injury in Previous Year IPM, First Year IPM, and 

 check blocks was 2.5, 3.7 and 2.0"^ respectively (Table 1). All 

 these were within acceptable injury limits for Massachusetts commer- 

 cial orchards. 



As in previous years, injury from Tarnished Plant Bug (TPB) , 

 represented the largest single source of fruit injury from insects 

 in Massachusett 's commercial orchards. It is questionable whether 

 or not this injury is economically important, however, since a relative- 

 ly small proportion (4%) of such injury results in downgrading of 

 fruit quality during packout. White rectangular TPB traps indicated that 

 several IPM blocks could safely eliminate pre-bloom insecticide sprays 

 directed at TPB. Due to substantial pressure from Gypsy Moth and 

 Spotted Tentiform Leafminer, however, only three such blocks were 

 actually able to do without pre-bloom insecticide sprays in 1981. 



San Jose Scale (SJS) injury ranks third in importance in Pre- 

 vious Year IPM (0.271) or check blocks (0.23%) but second in im- 

 portance in First Year IPM blocks (0.94%). The relatively high average 

 injury from SJS in First Year blocks resulted primarily from assess- 

 ment by 2 growers that SJS was not a serious enough problem to require 

 the recommended spray treatments. We feel that a year of experience 

 in IPM blocks allows us to develop a management program for SJS that 

 leads to effective control. For example, a partial cooperator IPM 

 block that in 1980 had 55% injury to fruit from SJS sustained only 



