20 



ideal as regards freedom from fungi, only about 1 per cent of the 

 changas handled could be even doubtfully classed as killed by this 



fungus. 



Two experiments on a small scale with Micrococcus nigrofaciens, 

 a bacterium pathogenic to white grubs and to some Blattids, 1 re- 

 sulted negatively as far as the changa was concerned. 



CANNIBALISM. 



Cannibalism among changas is common under laboratory condi- 

 tions. When changas were kept in pairs, although provided with 

 plenty of vegetable food, one or the other sex was almost certain to 

 be killed within a month. Under natural conditions cannibalism is 

 probably greatest during the first few days following the hatching 

 of an egg cluster. At that time the newly hatched changas remain 

 together in their chamber, and a few of the weaklings, as well as 

 some of the eggs, serve as food for the stronger or earlier hatched 

 members of the brood. Both adult males and females devour the 

 eggs when opportunity offers, but in nature they rarely happen upon 

 the egg chamber. Imperfectly molted individuals in the breeding 

 jars were often killed by other changas. 



ARTIFICIAL CONTROL. 



Control measures for the changa may be divided into preventive 

 and remedial. The value of either class depends entirely upon local 

 conditions. 



PREVENTIVE MEASURES. 



Mechanical devices. One of the earliest methods used in combat- 

 ing the changa was the wrapping of mamey leaves (Mammea ameri- 

 cana) about the roots of seedlings in transplanting. This method 

 was in use chiefly among tobacco growers and gardeners. Other 

 leaves said to be effective in protecting the roots from the mole 

 cricket's ravages are those of pomarrosa (Eugenia jambos) and 

 ausubo (two species are included under this common name, Mimusops 

 nitida and Sideroxylon fcetidissimum). This method of leaf-wrap- 

 ping hinders the rooting of the plants and sometimes causes water 

 to stand about the roots. Mamey leaves rose in price as they became 

 more scarce, and their use practically ceased. Their place was taken 

 by cylinders made of tin, heavy paper, or wire. Plants are set within 

 these cylinders, and the top of the cylinder allowed to project on 

 inch or two above the surface of the ground. These cylinders are 



Northrup, Zae. Michigan Sta. Tech. Bui. 18 (1914). 



