ANTHRACNOSE OF CUCURBITS. 9 



In the cucumber crop grown for pickling purposes, anthracnose 

 may become epiphytotic, especially in warm wet seasons, and may 

 result in serious loss due to foliage injury and consequent reduction 

 in yield, as well as to occasional direct loss from fruit infection. 

 The latter development is rather uncommon and is noted as a rule 

 only on the larger dill stock and on pickles that have remained too 

 long in transit. 



To illustrate the severity and importance of the anthracnose of 

 cucumbers, the results of disease surveys made in Wisconsin. Michi- 

 gan, and Indiana in 1915 and 1916 are herewith presented. 



In Wisconsin, the disease usually assumes the proportions of an epiphytotic only 

 late in the season and is not therefore as serious as some of the other diseases. In 1915 

 out of 84 fields anthracnose was found in 24 and was causing serious loss in 5. In 

 1916, anthracnose was found in 1 field out of 12 visited near Baraboo and in 10 out of 

 11 examined near Princeton. As previously noted, the disease seems to be much 

 worse in certain localities than in others. 



In Michigan in 1915, anthracnose was reported from 6 fields out of over 35 inspected 

 and was very serious in 2 fields. In 1916 the disease was not at all prevalent and was 

 noted in only 4 fields out of about 30 visited. 



In Indiana in 1915, anthracnose was considered second only to mosaic in impor- 

 tance and was reported from 18 fields in 9 localities. It was the cause of serious injury 

 in 9 fields. In 1916 the disease was found in 64 fields in 18 localities and was causing 

 serious damage in 20 fields. Anthracnose was considered the most serious foliage 

 disease of cucumbers in northern Indiana during 1915 and 1916. 



Among muskmelons, the attack of this disease on the vines seems 

 to be more severe than in the case of cucumbers, and the factor of 

 fruit injury may assume great importance. Outbreaks of the 

 disease on this crop in 1906 and 1907 have been noted. In 1917 the 

 disease did not seem to be at all prevalent in the commercial 

 muskmelon fields of the South. 



Probably the attack on the watermelon crop is more severe and 

 more universal than is the case with the other economic hosts. 

 The annually recurrent epiphytotics in the Ohio Valley have been 

 noted. The spotting of the fruits is a familiar sight in our northern 

 markets. The potential importance of the disease is, of course, 

 very great in a crop in which the individual fruits represent so much 

 value and are so long exposed to infection in the field. Besides 

 the disfiguration of mature fruits, which may be followed by rotting, 

 there is a large loss in the field, due to reduction in yield by vine 

 injury and by- attack on the immature fruit. Since a vine does not 

 usually mature more than two melons, any injury to young fruits 

 is a very important factor. 



In the southern melon districts in 1917 anthracnose was in gen- 

 eral so retarded by drought that in most fields the attack came too 

 late to cause serious loss. Exceptional fields were found, such as 

 one 120-acre field near Quitman, Ga., in which it was evident that 

 the yield would be reduced by several carloads, a loss of , perhaps, 

 69806°— 18— Bull. 727 2 



