monas syrincae or P. morsprunorium, is thought 

 to be an increasing problem in Massachusetts 

 peach orchards. Damage by Pseudomonas var- 

 ies among types of host fruit. On peaches, leaf 

 and flower buds fail to open in the spring and are 

 thought to have been infected during winter 

 months. Or, in other instances, infected spurs 

 show normal growth in the spring but collapse 

 during sunmier months, turning into wilted 

 leaves and dried-up fruit. If infection occurs 

 annually, trees lose bearing surface. 



Bacteria overwinter in infected buds or can- 



kers. Spring rains wash bacteria to unfolding 

 plant tissue. Frost-injvired leaves and blossoms 

 are thought to be more susceptible to Pseudo- 

 monas infection. Periods of cool, rainy weather 

 foster early-season infections and disease 

 spread. Disease spread also occurs under simi- 

 lar weather conditions in the fall. 



Canker removal is the only known cultural 

 control practice 



For additional information on any of these 

 diseases, please refer to references listed in 

 "Peach Pests III." 



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rj% •^ rj% rj* rj% 



Apple Maggot Fly Behavior: 

 Probability of Fly Capture on 

 Red Sticky Spheres in Relation to 

 Fly Age and Fruit Maturity 



Max P. Prokopy, Jian Jun Duan, Gabriela G. Galarza, and Ronald J. 



Prokopy 



Department of Entomology^ University of Massachusetts 



To augment our current program of second- 

 level apple IPM involving the use of baited 

 sticky red spheres to intercept and capture apple 

 maggot flies (AMF), we have been tracking 

 foraging behavior patterns of female AMF. We 

 want to know if the probability of a fly being 

 captured on a sphere or of laying eggs in apples 

 changes as flies age or apples mature. 



Methods Used 



In 1991, two potted apple trees were placed 

 in screen cages on the campus of the University 

 of Massachusetts. Each tree had approximately 

 the same canopy size as a normal four-year-old 

 dwarf (M.9) fruit-bearing tree. We placed either 



50 green or 50 red evenly-spaced Gravenstein 

 apples on a tree. The leaf-to-fruit ratio was 

 about 20: 1 . The green fruit were picked on June 

 19 and had a diameter of about 3 cm. The red 

 fruit were picked on August 1 and had a diam- 

 eterofabout4.5cm. In all, 36 AMF of each of five 

 ages were tested in the presence of only green 

 finiit, and 30 of each of five ages in the presence 

 of only red fruit. The flies were collected fix)m 

 naturally infested fruit and were 3, 7, 11, 15, or 

 19 days old when tested. FUes seven days old or 

 younger usually are not capable of lajdng eggs in 

 fruit. 



A single fly was released onto a leaf at the 

 lower center of the tree. A sticky red sphere, 

 baited with one vial of the synthetic apple odor 



Fruit Notes, Winter, 1993 



