

Figure 1. Schematic illustration of a wooden pes- 

 ticide-treated sphere capped with a disc comprised 

 of hardened sucrose. 



1997 but placed each disc in an open 0.75-by-l .5-inch 

 plastic Petri dish to extend residual amount available. 

 Again, rainfall and dew caused too rapid a dissipation 

 of discs. In 1 999, discs were formed from a mixture of 

 15% paraffin wax and 85% sucrose. Wax and sugar 

 were heated separately to 150''C until liquid and then 

 blended. After cooling, the resulting granular mixture 

 was compressed into a mould, where it hardened. No 

 Petri dishes were used beneath discs in 1 999. Residual 

 amount of sugar available in discs after rainfall was 

 much greater in 1999 than in 1997 or 1998. Discs atop 

 spheres were replaced every 2, 4, and 6 weeks, respec- 

 tively, in 1997, 1998, and 1999. 



For sugar/ flour spheres, ingredients of sphere bod- 

 ies each year were very similar: 18% pre-gelatinized 



com flour, 1 8% wheat flour, 22% granulated sucrose, 

 21% com syrup (containing fmctose), 7%glycerin, 8% 

 water, 5% cayenne pepper (aimed at deterring rodents 

 feeding on spheres), and 1% sorbic acid (an anti-mi- 

 crobial agent). Each sphere was formed by hand around 

 a cord in the center and was dried in an oven for hard- 

 ening. Drying time and temperature proved important 

 to sphere durability under field conditions. In 1997, 

 spheres were dried at 125°C for 48 hours, in 1998 at 

 140°C for 72 hours, and in 1999 at 200° C for 2 hours. 

 Sphere durability improved successively each year, 

 with spheres in 1999 maintaining integrity throughout 

 the 3-month period of deployment provided they were 

 not consumed by rodents. 



After hardening, sugar/flour spheres received two 

 coats of latex paint, as described for wooden pesticide- 

 treated spheres. Each year, sugar/flour spheres were 

 replaced once (at midseason). In 1997, and to a lesser 

 degree in 1998, replacement was necessary primarily 

 because of pre-mature cmmbling of spheres following 

 rainfall. Indeed, in both years, spheres should have 

 been replaced more than once for complete continuity 

 of sphere presence in orchard blocks. In 1999, there 

 was little pre-mature crumbling but a greater amount 

 of feeding by rodents, sometimes resulting in complete 

 consumption of some spheres. 



For sticky spheres, Tangletrap was applied to the 

 sphere surface. Each sticky sphere was cleaned of all 

 insects and debris every two weeks and retreated with 

 Tangletrap (if necessary) to maintain fly capturing ef- 

 fectiveness. 



To evaluate the success of each treatment in con- 

 trolling AMF, we monitored comparative amounts of 

 fly penetration into blocks by hanging one unbaited 

 sticky-coated red sphere from each of four trees near 

 the center of each block and counted captured flies 

 every 2 weeks, at which time spheres were cleaned of 

 insects and debris and retreated with Tangletrap if 

 needed. In addition, every 2 weeks we examined ten 

 fruit on each of ten randomly selected interior trees 

 per block (20 fmit on each often trees at harvest) for 

 oviposition punctures made by AMF. Fruit with sus- 

 pected punctures were dissected to confirm larval pres- 

 ence. 



Results 



Assessment via captures of AMF on interior 

 unbaited monitoring traps (Figure 2) showed that each 

 year, significantly more flies were captured on moni- 



Fruit Notes, Volume 64 (Number 4), Fall, 1999 



15 



