14 BULLETIN 1043, U. S. DEPAETMEXT OF AGRICULTURE. 



this connection should be mentioned the importance of reducing 

 risks of loss by the careful selection for seed purposes of varieties 

 of the different kinds of crops which mature within the space of 

 the reasonably safe growing season of a given locality. 



At Grand Eapids, JVIich., for example, the average date of the 

 last killing frost in the spring is May 11, while the average date 

 of the first killing frost in the faU is about October 8. This gives 

 an average growing season of 150 days for crops which are readily 

 injured by frost. Weather Bureau records further indicate that 

 five times in 20 years the date of the last killing frost in the spring 

 had been 10 days or more later than the average, and, similarly, that 

 four times in 20 years the date of the first killing frost in the fall 

 had been 10 days or more earlier than the average date. The reason- 

 ably safe growing season for crops subject to damage by frost in this 

 locality, therefore, is a little less than 130 days, covering a period 

 from the last week in May to the last week in September. By 

 adjustment of his dates of planting, as well as by the selection of 

 the varieties of grains planted with careful regard to local climatic 

 conditions as revealed by data covering extended periods of time, 

 the farmer, in effect, can insure himself against frequent losses from 

 frost. To a certain extent, he can also adjust his plan of farming 

 to minimize the losses from drought and other climatic dangers. 



Thus far we have considered only safeguards against forces which 

 the farmer can not control and against which his only chance, with 

 minor exceptions, is to adjust his business in such a way that the least 

 possible danger will result from their adverse action. There are, 

 however, many other causes of loss which can be directly eliminated 

 or at least partiallj^ removed. 



Loss from failure of seed to germinate can be eliminated to a great 

 extent by planting only tested seed. This is particularly true in the 

 case of croj)s, such as corn, where the germinating quality is fre- 

 quently injured, even when the yield is bountiful and the crop, to 

 all outward appearances, is sound. Individual plant diseases, such 

 as smut in wheat, oats, and barley, may be eliminated by a single 

 treatment of the seed before planting. In sections where wheat scab 

 occurs this evil may be largely controlled hj a system of rotation in 

 which wheat never directly follows corn, unless the corn is cut for 

 fodder and all litter removed or thoroughly covered hj plowing in 

 the fall. The elimination of black rust by the removal of the com- 

 mon barberry bush is a method of insuring against loss from this 

 source. In the case of certain insect enemies, spraying or poisoning 

 by one method or another may reduce or even eliminate their ravages. 

 It is, of course, neither practical nor necessary to apply all preventive 

 treatments at all times. The progressive farmer keeps himself 

 informed as to the invasion of his region by any common disease or in- 



