110 DEPARTMENT OF AGRICULTrRE. [Pub. Doc. 



operate very satisfactorily. The field inspection requires a large 

 force of men, and if the crop inspected is found free from the 

 corn borer and the surroundings the same, a certificate is granted 

 and tags issued allowing the gardener to dispose of the crop as 

 he sees fit. In case the crop does not come up to the inspec- 

 tion standard, it cannot leave the infested area. This inspec- 

 tion applies to celery, green beans in the pod, beets with tops, 

 spinach, rhubarb, oat and rye straw as such or when used for 

 packing, cut flowers or entire plants of chrysanthemum, aster, 

 cosmos, zinnia, hollyhock, and cut flowers or entire plants of 

 gladiolus and dahlia, which are all the quarantined plants ex- 

 cept corn. Corn on the cob is quarantined absolutely, and 

 cannot leave the infested area even after inspection. Seed corn 

 may be shipped, however, if shelled, but not on the cob. The 

 scouting for the corn borer has been continued, and in Massa- 

 chusetts a few more towns were found infested this past year, 

 so that to date 147 towns are in the quarantined area. A small 

 increase in area will probably be evident each year through 

 natural spread, but the quarantine is proving very effective 

 here in checking any new outbreaks. The infested areas in 

 New York and Canada are not from the Massachusetts infesta- 

 tion, but are separate or individual infestations, resulting from 

 shipments of European broom corn to those localities, while the 

 outbreaks in Ohio and Michigan are a result of spread from the 

 Canadian infestation. An interesting point in the life history 

 of the corn borer has been brought out, namely, that in Massa- 

 chusetts the borer has two broods and infests an unlimited 

 number of food plants, while in New York, Canada, Michigan 

 and Ohio the insect is single-brooded and confines its attack to 

 corn and one or two weeds. This shows that the insect we 

 have in Massachusetts is more injurious than the single- 

 brooded insect, and should be controlled as far as possible. It 

 is recorded by European writers that in Austria the corn borer 

 is single-brooded, while in Italy it is two-brooded, so it may 

 be that Massachusetts was indebted to Italy for her infestation, 

 while the other American infestations originated from ship- 

 ments of corn from Austria. 



