656 IOWA DEPARTMENT OF AGRICULTURE. 



treatment, with especial care taken to destroy the old squash vines in 

 the fall. Insects which eat the leaves are combated best with ar- 

 senicals. 



The Colorado potato beetle and the long striped bettle which als« 

 feeds upon other garden plants require about three times as much poison 

 as the caterpillar. Paris green is commonly used. It is a salt of copper 

 and to a certain extent acts as a fungicide, a thing usually needed by 

 potatoes because of their susceptibility to fungus disease. The flea beetles 

 which eat little round holes in potato and tomato leaves are readily 

 controlled by any of the sprays. Most of the damage they do is in fur- 

 nishing an entrance for the spores of the many potato diseases. This 

 must always be taken into account in estimating the injury to a plant 

 from any insect. Adults of the pea and bean weevil hibernate within 

 the seed, none of which should be allowed to remain in the garden. Be- 

 fore planting fumigate infested seed by placing in a closed vessel like 

 a fruit jar and pouring in one teaspoonful of carboni bisulphide to one 

 gallon of beans. The jar should remain closed for forty-eight hours. This 

 treatment will kill the weevils without injuring the seed. Care must 

 always be taken in using this gas, as it is very explosive when ignited. 

 Beans not used for seed should be fumigated or heated. Cabbage worms 

 of which there are two species may be held in check by spraying or 

 dusting with some of the arsenicals. When the heads are about ready 

 to use pyretheum or hellebore mixed with three parts of flour or lime 

 may he used. These are just as efl!ective for the insects and less injurious 

 to man than the arsenicals. These materials may always be used on 

 fruit or leaves which are ready to use. A bacterial disease destroys many 

 of the cabbage worms. Sometimes not a healthy one can be found. In 

 considering injurious orchard insects .the codling moth which causes our 

 wormy apples easily demands first place. There are two generations and 

 sometimes a part of a third in our locality. The second one does the 

 most damage and is most difficult to combat. On this account it is most 

 Important to destroy the first generation as completely as possible so 

 there will be fewer eggs laid for the second. One-half pound of paris green 

 or its equivalent in arsenite of lime, or still better, of lead arsenate, in 

 fifty gallons of water applied just after the petals fall and again ten days 

 later will destroy most of the young larvae. Some make five applications 

 ten days apart. The first two are the most important, especially if made 

 before the calyx or blossom end of the apple closes. The young larvae 

 of the first generation almost invariably do their first eating in this end. 

 For a few 'days just after the petals fall, the calyx stands open, forming 

 a cup-like receptacle, which catches the poison; later it closes and re- 

 mains closed. To supplement these sprayings the trees may be banded 

 just beneath the limbs with strips of burlap or other dark colored ma- 

 terial. The bands should be about a foot wide and long enough to reach 

 around the tree twice. A small nail with its head nipped off and driven 

 into the tree is convenient for holding the ends of the band. This forms 

 an attractive place for the larvae to pupate and most of them which 

 escape the poison will spin their cocoons under these bands. They then 

 may be easily destroyed by unwrapping the bands evei-y week and crush- 

 ing them. Removing dead stubs, filling rotten cavaties, and scraping off 



