476 Journal of A gricuUural Research voi. xxii. no 9 



picking time, as shown in figure 6, was 1.6 per cent and the average 

 amount on the untreated prunes was 4.6 per cent. The orchard loss 

 from rot with either the prunes or the cherries would be considered of 

 very minor importance in practical operations, scarcely justifying the 

 expense of spraying; yet even under these conditions the orchard spray- 

 ing has shown decided beneficial effects in the carrying quality of the 

 fruit in transportation and storage. The good eft'ects, however, have 

 been largely if not entirely confined to the control of Monilia rot. With 

 both the prunes and cherries the unsprayed fruit has developed approxi- 

 mately four times as much of Monilia rot as the sprayed fruit, 

 but has shown .practically no greater susceptibility to Penicillium 

 and Rhizopus rots. These contrasting results are in harmony with 

 the nature of the different fungi. Monilia is a parasitic fungus and 

 able to penetrate the sound skin of both ripe and green fruit; 

 PenicilHum and Rhizopus are saprophytic fungi, able to attack only the 

 harvested fruit and dependent upon bruises and skin cracks for first 

 points of entrance. The Monilia spores come primarily from the orchard, 

 but Penicillium and Rhizopus have an almost universal distribution. 



/?Or^L /9^/^ r ^ '^ ^^ /.^ ^ ZS- 



\sp/f/?yi^£> "^ =— ■ ■ 



P£N/C/LUU»? ^SP/?/?yS£> 



/>A/D ffH/20PLis\y/vs/'/?/9rep 



i 



Fig. s. — A comparison of the average development of rot on sprayed and unsprayed cherries in i8 different 

 shipping and storage experiments. 



Under such circumstances it would be expected that orchard spraying 

 would furnish at least partial protection against brown rot in transpor- 

 tation and storage, since it would both decrease the supply of spores and 

 furnish a more or less complete protecting film on the fruit. On the 

 other hand, orchard spraying could not be expected to have any appre- 

 ciable effect upon the spore supply of fungi like PenicilHum and Rhizopus 

 that are of general occurrence, and a film of spray on the skin could 

 offer little protection against fungi that enter through breaks in the skin. 

 While these contrasts in the different fungi are of importance in con- 

 nection with the present studies, it should not be inferred from the fore- 

 going statements that skin punctures have no effect upon the occurrence 

 of Monilia rot, for it is well known that any abuse to the fruit is decidedly 

 favorable to the development of the disease; ^ nor should it be inferred 

 that Rhizopus and Penicillium are entirely unable to penetrate the sound 

 skin, for when these fungi are once well established in a crate they may 

 spread out from a center of infection without much regard to the sound- 

 ness of the adjacent fruit. This is particularly true of Rhizopus, and 

 especially where it is favored by a high temperature. Under such a 

 condition it often spreads through a package of stone fruit in a most 

 rapid and indiscriminate manner. 



1 Ramsey, H. J. the h.\ndling and shipping op fresh cherries prom the wxi,i,.\mette valley 

 U. S. Dept. Agr. Bui. 331, 28 p., ii fig., 1916. 



