18 CIECULAR NO. 124, BUREAU OF PLANT INDUSTRY. 



center of such a softening area, although in some cases no imper- 

 fections or breaks could be seen. Only rarc^ly could a bright orange 

 be found rotting on a tree, but usually decaying fruit was ammoni- 

 ated or severely melanosed. 



THE CAUSES OF DECAY. 



Tliis paper on orange decay as it occurred in Florida during the 

 past season aims only to bring together some of the most ob\nous facts 

 as related to that particular epidemic. The attention is centered 

 chiefly on the weather conditions, cUseases, and other injuries sus- 

 tained by the fruit in the groves and the relation of these factors to 

 decay. As the rot of oranges resulting from improper hantUing is 

 only incUrectly related to decays due to the natural environment 

 it is unnecessary to discuss here the ciuestion of fruit handling. That 

 phase has been fully investigated and some of it has been reported.^ 



STIGMONOSE AS RELATED TO MOLD INFECTION OF FRUITS. 



In December, 1912, while looking more particularly for agents that 

 might aid in infecting fruits which have a perfect 'rind, several 

 species of pumpkin bugs or stinkl)ugs were found sticking their long 

 beaks into oranges and apparently sucking the juice from the fruits. 

 It is, of course, uncertain just how effective such punctures are in 

 carrjdng the mold spores wliich may be present on the rind into the 

 fruit, but since the bugs were fairly common and could often be seen 

 making tlu*ee or four punctures in a few minutes it is probable that 

 only comparatively few of their punctures caused infection, in spite 

 of the fact that the mold spores were plentiful throughout the groves. 

 On making hand sections of such orange rinds, especially where very 

 tiny discolored spots could be found in the rag or where one or more 

 pulp cells were found partially empty or cUscolored, it was sometimes 

 possible to get fairly good views of the path of the puncture through 

 the rind by the rod of yellow gumhke substance wliich occupied its 

 place. No incUcation of the puncture was visible on the surface view, 

 even after such a canal or rod had been exposed in section. The sur- 

 face cells seem to close in on the withdrawal of the beak. In a num- 

 ber of such sections of orange rinds the tissue of the inner portion of 

 the outer rind surrounding a bug puncture was found dead and dis- 

 colored, but it was impossible to demonstrate the presence of a fungous 

 mycehum in these inconspicuous early stages. Nevertheless, it is 

 Hkely that tliis stigmonose of the orange was responsible for many 

 mold infections and considerable decay during the height of the period 



1 Tenny, L. S., Hosford, G. W., and White, H. M. The decay of Florida oranges while in transit and on 

 the market. U. S. Department AKricultiiro, BiiriMH of I'lunl Industry. Circiil'ir 19, p. 8, 2 fig., 1908. Sec 

 also Ramsey, U. J., l'roceeding.s, Florida State Horticultuial Society, 1912. 

 H'lr. 11^4] 



