146 MINNESOTA STATE HORTICULTURAL SOCIETY. 



The Codling Worm is always with us. East or west, north 

 or south, this is the worst pest of the fruit of the apple tree. 

 Like many other bad pests, it is an imported variety, not a native 

 of America. In working against this insect we literally take the 

 offensive, because the valuable spray is given ten days or two 

 weeks before the insects appear. The worms have a habit of 

 finding the blossom end of the fruit and starting their operations 

 from that end. The moths that lay the eggs fly a week after the 

 blossoms drop, and the larvae hatching from these work their 

 way through the closed bracts of the blossom and begin feeding 

 in the calyx cup. If we should spray at the time these worms are 

 working, our poison would do no good, because we could not 

 reach their feeding grounds. The time to spray is just as the 

 petals have fallen, and while the calyx cup is wide open. The 

 material to use in the spray is arsenate of lead. 



The Plum Curculio. The damage done by this insect is by 

 the adult. When working on apples they disfigure the fruit, 

 while in plums they produce worms, which feed upon the pulp, 

 causing the fruit to drop. These forms hibernate as adult insects 

 and come out fairly hungry in the spring, when they often eat 

 the opening buds and young leaves. As the fruit begins to form 

 the females begin depositing their eggs in the crescent-shaped 

 marks that you all have noticed. About the first of August, or 

 about the time the plums begin to show color, adult beetles are 

 seen again. At this time they feed on the fruit, making nice 

 openings for the spores of brown rot and other diseases to enter. 

 Spraying with arsenate of lead at the time these forms are feed- 

 ing and egg laying will keep the insects in check. 



Scale Insects. There are three very important scale insects 

 found in Minnesota, the San Jose scale being the most dangerous. 

 This insect has been found in a few places in the state but has 

 not yet secured a good foothold in any orchard. The Oyster 

 Shell scale and the Scurfy scale have been present here for a num- 

 ber of years, and often we see large trees badly damaged or killed 

 by them. Scale insects are sucking forms of insect life. Besides 

 this they have an armor-like or scale protection. This makes 

 them doubly hard to combat. However, the dormant spray of 

 lime sulphur will control the pests. The action of this material 

 is somewhat different on the different scales. With the San Jose 

 scale, where the insect goes through the winter under the scale, 

 the lime sulphur softens the edge of the scales and along with 

 other chemical actions practically suffocates the insects. The 



