application targeted against LM. With little exception, 

 dominance by STLM in commercial orchards was 

 associated with higher LM population density and no 

 or infrequent use of insecticide to control LM. 

 Conversely, dominance by ABLM was associated with 

 lower LM population density and rather frequent use 

 of insecticide to control LM. 



In any scientific investigation, establishment of a 

 strong association or correlation between two variables 

 should not be taken to imply cause and effect. Further 

 study is needed to determine the true cause or causes 

 underlying the dominance of ABLM or STLM in a 

 given orchard. 



Even so, one can postulate a possible scenario with 

 the following steps: (1) dominance of STLM in 

 abandoned apple orchards either because of apple being 

 a more favored host of STLM than it is of ABLM, 

 because STLM is less susceptible to parasitism than is 

 ABLM, because STLM is a better competitor for host 



resources than is ABLM, or a combination of these, 

 (2) movement of STLM adults into an orchard currently 

 colonized by ABLM, (3) more rapid and extensive 

 buildup of STLM in commercial orchards than is 

 characteristic of ABLM, leading to (4) application of 

 a targeted insecticide against LM that exerts a greater 

 effect on STLM than ABLM and results in (5) 

 temporary dominance by ABLM. Further study is 

 needed to evaluate this possible scenario. 



A cknowledgem en ts 



We thank the apple growers who participated in 

 this study: John Blanchard, Bill Broderick, Dave 

 Chandler, Dave Cheney, Dana Clark, Tom Lincoln, 

 Dave Chandler, Joe Sincuk, Tim Smith, Mo Tougas, 

 and Bob Tuttle. We are also grateful for the support of 

 a USDA Northeast Region S ARE grant and State IPM 

 funds. 



"k i: "k ic "k 



Fruit Notes, Volume 67, Summer, 2002 



13 



