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Weavers, Harvey J.; Knight, Nancy (ed.) / Wisconsin horticulture
Vol.L (September 1965/August 1966)

Wisconsin horticulture, vol. 50, no. 8: June, 1966,   pp. [1]-[20]

Page [1]

                                                                  June, 1966
                WiscnsinNumber 8 
       aiglcoy              ...N 
35¢  a single copy                          ....i .... 
        The Apple Maggot 
MARLIN CONRAD, Survey Entomologist 
       Plant Industry Divisions 
 Wisconsin Department of Apriculture 
 The apple maggot, Rhago!i'~is pomo-- 
 ella, is a most serious p-st of anp'-e fruit 
 throughout much of Wiscý_-isin.  Th'e 
 adult is a fly slightly smalcr than th! 
 common house fly distinguis"'ei by the 
 'W' shaped black markirgs on its wing3. 
 From the soil where it overwintzrs in 
 the pupal stage, apple maggot flies .?m- 
 erge about the first week of July. Early 
 apple varieties are generally the mos, 
 susceptible and most attractive for egg 
 laying. The -egg is inserted just beneati 
 the skin. 
 Larval feeding first occurs just be- 
 neath the skin but later is deeper in tV- 
 flesh of the apple. As it feeds, it tu- 
 nels a winding path which becomes in- 
 creasingly more evident as decay organ- 
 isms turn apple flesh in tunnels to a light 
 brown color. Due to the winding paths 
 within apples, this pest in some local- 
ities is referred to as the "railroad 
  Infestations are commonly found after 
it is too late for control. Egg laying 
miy occur from mid-June until late 
&Agust and since the egg is laid under 
the skin, treatment is aimed to control 
th, adult when it comes to the apple. 
  "here is evidence that larvae will not 
en er pupation when soil conditions are 
t&, dry. There is further evidence that 
it -nay take two years for some of the 
pC :ulation to emerge from the soil. 
  Fcrecasting the exact time when apple 
miaggot adults will appear or their rela- 
tive abundance is difficult for different 
geographical locations. Locally, close 
surveillance by orchardists is advised. 
A number of different bait traps have 
been and are being tried by entomolo- 
  Survey entomologists with the Wiscon- 
sin Department of Agriculture's Plant 
Industry Division have been interested 
in trying to better serve the state's or- 
chard industry with timely information 
in regard to the apple maggot. Weekly 
insect survey bulletins during the grow- 
ing season contain as much current in- 
formation on the pest as is possible. An 
attempt is being made to increase such 
information through personal contact 
with and cooperation of orchardists. 

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