Woods, hedgerow or open field 



45 m 



45 m 



30 m 



30 m 



PLOT A 



PLOTB 



PLOTC 



Figure 1. Schematic illustration of the 2001 season block layout for evaluation of sticky red 

 sphere traps for controlling AMF: ? = odor-baited traps, wherein front-row traps in Plot A were 

 baited with a five-component blend, front-row traps in Plot B were baited with butyl hexanoate, 

 and all other baited traps received butyl hexanoate; ? = unbaited interior monitoring traps in rows 

 three and four; x = unbaited apple trees. No insecticide was applied to any tree in Plot A or Plot 

 B, but was applied two to three times to all trees in Plot C in July and August. 



comparing AMF captures on red spheres baited with 

 the five-compound blend and placed either 5 or 10 m 

 apart on front-row trees. Methods were, in general, 

 similar to those for 200 1 with the following differences: 

 (1) for 2000, we included data for all 12 orchard blocks 

 initially considered for 2001, (2) in 2000, the perimeter 

 row of each plot was only 30 m long, and (3) in 2000, 

 fraps placed on sides and back rows were spaced 10 m 

 apart. Results of that study are also presented in this 

 article. 



Results 



Results from 2000. Experiments that we 

 conducted in 2000 show that across all five sample 

 periods and all 12 orchard blocks, about 26% more 

 wild AMF were captured per trap on front-row traps 

 that were spaced 5 m apart (mean=27) than 10 m apart 

 (mean=22), but there was virtually no difference in wild 

 AMF penetration into interiors of the plots (respective 

 means of 9 and 8/trap/plot) (Figure 2A). Thus, front- 

 row traps that were spaced at 5 m or 1 m apart captured 

 about three times more wild AMF per trap than interior 

 monitoring traps. Interior-row traps in grower-sprayed 

 plots captured 33 and 12% fewer AMF, respectively, 

 than interior-row traps in plots with perimeter traps 5 



or 10 m apart. The ratio of front-rovv/interior-row trap 

 captures was markedly higher for tolerant cultivars 

 (3.8:1) than for susceptible cultivars (2.3:1) (Figure 

 2C and E). For susceptible cultivars, interior 

 monitoring traps in trapped plots captured about 45% 

 more AMF than interior monitoring traps in grower- 

 sprayed plots (Figure 2C). For tolerant cultivars, 

 interior traps in trapped plots captured about 6% fewer 

 AMF than interior traps in grower-sprayed plots (Figure 

 2E). 



Overall AMF captures in 2001. In 2001 (with 

 much higher AMF population numbers than in 2000), 

 across all six sample periods and all 1 orchard blocks, 

 57% more wild AMF per trap were captured by front- 

 row traps baited with the five-compound blend (termed 

 blend plots) than by front-row traps baited with BH 

 (termed BH plots)(Figure 2B). Unbaited interior 

 monitoring traps in BH plots captured about 1 3% more 

 AMF than interior traps in blend plots and about 47% 

 more AMF than interior traps in the grower-sprayed 

 plots (about 7/trap/plot). About seven times more wild 

 AMF per trap were caught by front-row traps in blend 

 plots than by interior monitoring traps, whereas only 

 about five times more wild AMF were caught by front- 

 row traps in BH plots than by interior traps. 



The effect of front-row cultivar type on AMF 



Fruit Notes, Volume 67, Spring, 2002 



21 



