Rural School Leaflet 



899 



greatly in controlling this cabbage pest. Very often one of the dead 

 green caterpillars is found attached to a cabbage leaf and partially covered 

 by many small, white objects, usually considered eggs by those who do 

 not know. As a matter of fact, these are the cocoons of the tiny para- 

 sites that have lived within the body of the caterpillar and killed it. When 

 the parasites are full-grown they leave the caterpillar and spin their small 

 white cocoons on the outside, from which the small, dark-colored, wasp- 

 like parasites emerge in a few days ready to parasitize other " cabbage 

 worms." Whenever a lot of these white cocoons are seen about a green 

 caterpillar they should not be destroyed, but should be allowed to remain 

 undisturbed so that the parasites may emerge to work on other " worms." 



Methods of control. — This cabbage pest is best controlled by spraying 

 the plants with one of the arsenicals, paris green or arsenate of lead. There 

 is no danger in spraying cabbages with a poison up to the time they are 

 half-grown, and even later. A cabbage is only a gigantic bud and grows 

 from the inside outward as does any other bud. The outside leaves 

 never fold up about the head, hence there is little danger of enclosing 

 the poison within the cabbage. 



If paris green is used it should be applied at the rate of i pound to 150 

 gallons of water, or sifted on dry, in the latter case being thoroughly 

 mixed with flour at the rate of i pound to 2 5 pounds of flour. This should 

 be applied in the morning while the dew is yet on the cabbage leaves. 



Arsenate of lead may be applied at the rate of 2^ pounds to 50 gallons 

 of water. 



The first applications of poison should be made when the " worms " 

 first appear, while the cabbages are young. Other applications should 

 follow as needed. 



OBSERVATIONS FOR PUPILS 



Watch the butterflies in the garden 

 and describe their manner of flying. 

 Do they soar like a bird and do they 

 fly long distances at a time? When 

 one alights on alcabbage leaf see, if 

 possible, what she does. See whether 

 a tiny egg can be found sticking to 

 the leaf. 



Where on the cabbages are the 

 green caterpillars found? How do 

 they injure the leaves? What kind 

 of mouth parts do the " worms " have? 



A dead cabbage " worm " with a cluster of 

 the cocoons of the parasite that killed it 



What color are they ? Do the 

 bodies have any colored Hues or spots ? How can the caterpillars be killed ? 



