in Massachusetts. Of the eight medium-density third- 

 level IPM blocks and the eight companion first-level 

 blocks, five pairs were selected for sampling here. Se- 

 lection was based on the fact that azinphosmethyl was 

 the insecticide applied against AMF in all five first- 

 level blocks. 



Within one week of harvest, ten mid-sized Mcin- 

 tosh fruit were selected randomly from each block, 

 bagged, and placed within 6 hours in a deep-freeze at 

 ?20"C until the analyses were performed. Fruit forti- 

 fied with known levels of azinphosmethyl showed that 

 there is no significant breakdown of residues while in 

 storage. From each experimental block, three samples 

 were analyzed, each sample consisting of three fruit. 

 For analysis details, see the note at the end of the text. 



Results 



In the five blocks under first-level IPM, growers 

 used an average of 2.4 sprays against AMF between 

 early July and late August, resulting in an average of 

 0.2% AMF injury (Table 1). Analysis revealed that 

 fruit treated with 2-3 sprays of azinphosmethyl con- 

 tained an average of 95.6 parts per billion of 

 azinphosmethyl residue at harvest, roughly 5% of the 

 current EPA tolerance. 



In keeping with the principles of behaviorally- 

 based AMF control, no insecticides were applied to 

 the five third-level IPM blocks after mid-June. 

 Expectedly, none of the samples taken from these 

 blocks contained a detectable level of azinphosmethyl 

 residue, even though these blocks received an average 

 of 2.8 applications of azinphosmethyl against plum 

 curculio in May and June (Table I ). Blocks managed 

 under third-level practices received slightly more in- 

 jury by AMF (0.4%) than did first-level blocks. 



Conclusions 



This study has shown that the amount of 

 azinphosmethyl residue present on apples at harvest 

 in 1997 in test blocks managed under first-level IPM 

 practices averaged far less (about 95% less) than the 

 amount of residue allowed by current EPA regulations. 

 This study also showed that no detectable residues of 

 azinphosmethyl were found on apples at harvest in test 

 blocks managed under third-level IPM practices. 



Although it may seem logical that no insecticide 

 treatment during July and August (as under third-level 

 1PM) ought to result m no insecticide residue on frait 



at harvest, such would not necessarily be the case if 

 insecticide applied against plum curculio were to be 

 present on harvested fruit. All ten blocks in this study 

 received two to four sprays of azinphosmethyl from 

 mid-May to late June against plum curculio. Our data 

 from fruit samples taken in third-level IPM blocks 

 clearly show that treatments of azinphosmethyl applied 

 in May and June did not result in detectable levels of 

 azinphosmethyl on harvested fruit (Table I). This in- 

 formation could be important to EPA consideration of 

 continued allowable use of azinphosmethyl against 

 plum curculio. 



Even though our findings here indicate that use of 

 third-level IPM practices results in no detectable resi- 

 dues of azinphosmethyl on fruit at harvest and pro- 

 vides acceptable commercial-level control of AMF, 

 more work is needed to refine third-level IPM prac- 

 tices so that they will become as economical and reli- 

 able as first-level IPM practices. 



Acknowledgments 



This work was supported by state/federal IPM 

 funds and USDA SEA CSREES Grant # 97-34365- 

 5043. We are grateful to the eight growers that par- 

 ticipated in this study: Bill Broderick, David Chan- 

 dler, David Cheney, Dana Clark, David Shearer, Joe 

 Sincuk, Tim Smith, and Mo Tougas. 



Note: Whole fruit were blended with water and sub- 

 mitted to extraction with ethyl acetate, then reduced 

 using a sample concentrator, leaving a concentrate of 

 residual material. Azinphosmethyl residues from ex- 

 tracted apples were analyzed using a Varian model 3400 

 GC gas chromatograph (Varian Associates, Sunnyvale, 

 CA) equipped with a nitrogen phosphorous detector 

 (NPD). The capillary column was a fused silica DB-5 

 liquid phase, 0.53 mm i.d. X 1 5 m, 0.25mm film thick- 

 ness (J & W Scientific). A deactivated cyclodouble- 

 gooseneck injection port liner (Restek, Bellefonte, PA) 

 was used for splitless injections. Operating conditions 

 were as follows: injection volume, 1.0 ml; injection 

 port temperature, 250"C; detector temperature, 300"C; 

 column temperature, 1 75"C for 0.5 min, ramped at 

 20'C/min to 250"C and held for 12 min. The carrier 

 gas was helium at a rate of 8 ml min '. Detector gas 

 flow rates were: nitrogen, 25 ml min'; oxygen, 175 

 ml min ': hydrogen, 2.5 ml min ' (Kadenczki et al., J. 

 Assoc. Off. Anal. Chem. 75, No.l, 53-61). 



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Fruit Notes, Volume 63 (Number 2), Spring, 1998 



