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Rahmlow, H. J. (ed.) / Wisconsin horticulture
Vol. XXX (September 1939/July-August 1940)

Wisconsin horticulture, vol. 30, no. 9: May, 1940,   pp. [241]-272


Page 243

 
WISCONSIN  HORTICULTURE 
Wisconsin 
APPLE INSECTS OF 1940 
                             John A. Callenbach 
NSECT     pests of apples will 
   again present a serious prob- 
 lem to the fruit grower in 1940. 
 The codling moth did not cause 
 the damage in 1939 that it did in 
 1936 and 1937, but qeveral faetor, 
 were at work to build up a heavy 
 infestation for 1940. 
 Weather Favorable for Larvae 
           Last Fall 
  As has been stated in these 
columns before, in southern Wis- 
consin there is generally one com- 
plete generation and a partial 
second  generation  of codling 
moths. A certain proportion of 
the first brood always hibernates. 
The proportion of the second gen- 
eration of worms that is able to 
successfully complete and enter 
normal hibernation depends ul)On 
the following factors: The \wea- 
ther (luring the latter part of the 
growing season, the time of har- 
vest, and the care taken in dis- 
posing of wormy apples. The 
\weather during August and Sep- 
tember was especially favorable 
for late season development and 
a larger proportion of second 
brood larvae than normal com- 
pleted development. While in 
general, the crop was removed 
somewhat earlier than    usual, 
nevertheless, a considerable part 
IL- 
  Too late for the calyx spray. The 
  calyx lobes have already closed. 
of the crop remained on the trees 
through the hot weather of late 
September and early October. 
Codling Moth From the Cull Pile 
  Market conditions, as growers 
know all too well, were poor. As 
a result of this, many orchardists 
left their fruit on the trees or 
dunmped the culls in piles through- 
out the orchard. The extent to 
which these factors will operate 
will vary from orchard to or- 
chard. It seems reasonable to 
hazard the guess, however, that 
conditions being what they were, 
most growers were none too 
careful in the disposal of cull 
fruit and accordingly a rather 
sizable codling moth population 
entered winter hibernation. Win- 
ter temperatures were relatively 
mild and little winter mortality 
has resulted. 
  The leaf roller has been in- 
  creasing in numbers in southern 
  Wisconsin and growers should be 
  on the lookout for this pest. 
Aphids are not expected to be se- 
rious this year. Plum and apple 
curculios, and apple maggot may 
be serious in some localities. 
           Spraying 
  General spray    recommenda- 
tions remain the same as for 
1939. Place special emphasis upon 
first brood codling moth control. 
Use bait pans to accurately time 
the sprays and then apply the 
sprays thoroughly. If dormant 
sprays for leaf roller have been 
applied, use lead arsenate at the 
rate of 2-3 pounds per 100 gallons 
in the codling moth cover sprays. 
If no dormant spray has been ap- 
plied for leaf roller, and no ar- 
senical was used in the pre-blos- 
som sprays, use lead arsenate at 
the rate of 3 pounds per 100 gal- 
lons in the calyx and first cover 
spray, then use 2-3 pounds per 
100 gallons i4 later cover sprays. 
Use 3-4 pounds of lead arsenate 
per 100 gallons in the pre-pink 
May, 1940 
243 


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