114 SIXTEENTH BIENNIAL REPORT 



There has been severe injury in restricted areas about Boston, Massachusetts, 

 where there are two broods, and generally speaking comparatively slight damage 

 in the New York areas with but one brood in a season, tliough a Single generation 

 produced from 70 to 90 per cent of infested corn around St. Thomas with pos- 

 sibly 50 per cent of the ears affected, and caused a commercial loss in some 

 cases approximating 20 to 25 per cent. 



Tlie European corn borer attaeks all parts of the plant except the fibrous 

 roots. The young borers work in the developing tasseis. the older ones tunneling 

 the base and causing a characteristic lopping. The bleeding holes and wet borings 

 on corn stalks and ears in midsummer are comparatively conspicuous signs of 

 this pest. Its presence in corn stalks and corn stubble in late fall and winter is 

 indicated by characteristic holes about one-eighth of an inch in diameter, gen- 

 erally with discolored margins and usually plugged with borings. The holes lead 

 into irregulär burrows or galleries from one inch to several inches in length, each 

 of which is inhabited by a yellowish-gray, brown headed, minutely brown spotted 

 Caterpillar aliont three-fourths of an inch long. The moths fly in eastern Massa- 

 chusetts from the middle of May to the latter part of June, and again the last of 

 July and early in August, depositing masses of eggs (700 or more per female) on 

 the under side of the leaves. The insects fly in New York State, where there is 

 but one brood, from the middle of June to the last of July. Borers may be found 

 at work shortly after the eggs are deposited and until the close of the season, 

 the füll grown or nearly füll grown caterpillars wintering in corn stalks, corn 

 stubble, cobs and the stems of various plants. 



The European corn borer breeds by preference in the different varieties of 

 coi'n, causing most injury to the smaller sweet and flint corns. It also breeds 

 freely in eastern Massachusetts at least, as shown by federal investigations, in 

 barnyard grass, cocklebur, dahlia. hemp, Japanese hop, horseweed, Mexican tea, 

 pigweed and smartweed. About thirty other plants are frequently infested in 

 eastern Massachusetts, and the stems of a considerably larger series may be 

 invaded, particularly if growing near preferred food plants. Over 150 of the 

 plants growing in eastern Massachusetts may be more or less infested by this 

 insect. The breeding in other plants than corn appears to be largely restricted to 

 the second brood and, consequently. in areas where there is but one generation, 

 as in the infested territory of New York, there is a very slight infestation of 

 other plants, it being practically limited to those growing in the near vicinity of 

 corn. The probabilities favor two broods in at least the warmer corn growing 

 areas of Oregon. 



It is very desirable to prevent the spread of this pest through the shipment 

 of infested plants or parts of plants, and to accomplish this, rigid quarantine 

 regulations have been established by the general government and the authorities 

 in a number of states. Corn growers in the infested areas of New Y^ork State 

 have been urged to handle corn and corn land in such a way as to reduce to a 

 minimum the probabilities of borers surviving, special emphasis being laid upon 

 cutting corn close to the ground and putting as much of the crop into silos as 

 possible, the remainder of the crop to be cut or shredded, so as to promote clean 

 consumption by stock, or eise Provision made for the burning, burying or sub- 

 merging in water of the waste portions. 



SUCCESS IN APPLE SCAB CONTKOL 



By H. P. Barss, Plant Pathologist, Oregon Experiment Station 



There are some sections of Oregon that have learned the spraying game and 

 are now making a fine record by the production of an unbelievably high percent- 

 age of perfect fruit which means, of course, high profits to the individual growers. 

 In some of the newer orchard sections. particularly in the Willamette Valley. 

 the results of the 1920 season indicate that many of the apple growers have not 



