CITEUS DISEASES. 101 



Control. 



No one method will suffice to control or even to check this seri- 

 ous trouble, and it will only be by a judicious combination of the 

 several points to be considered that any success will ])e obtained. 



The first consideration should be given to a careful pruning out 

 of all dead and dying wood, much of which under usual conditions 

 harbors the fungus. A large proportion of the infection comes from 

 this source. All precautions in disposal of prunings and treatment 

 of wounds should be observed. In connection with this work all 

 drops should be gathered up and buried, since, as already noted, 

 they also serve as infection centers. Drops should be removed at 

 frequent intervals. 



The control of scale insects, particularly the purple and the chaff, 

 has an important bearing on the problem, since scale-infested fruit 

 are very liable to infection, particularly when the insects gather 

 around the stem end. The puncture made into the fruit tissues af- 

 fords the fungus a ready means of entrance. Scale insects are readily 

 controlled by various spray compounds. Circular 9 of this Station 

 treating of this phase of the problem. 



Care in picking, packing, and shipping will aid in decreasing 

 loss from this source. Since these points, however, more directly 

 concern blue-mold decay, they are treated in detail under that 

 heading. 



BLUE MOLD. 



Blue-mold decay was formerly more prevalent than at present. 

 since control measures are better understood and are being prac- 

 ticed. This type of decay commences as a soft spot at any point 

 on the surface of the fruit and spreads rapidly, two days being 

 generally sufficient to bring about complete destruction. The af- 

 fected area is soon covered by a thin white mold, which later turns 

 blue-green or olive-green, the color being due to the layer of spores 

 produced. If undisturbed an infected fruit becomes uniformly cov- 

 ered by the fruiting layer, giving off a dust-like cloud of spores if 

 disturbed. Two fungi may produce this type of decay. PenicUUim 

 italicum, which is blue-green in the fruiting condition, and Peni- 

 cillmn difiitatum, which is olive green. Tlie first is marked by a 

 narrow edge of white mycelium around the fruiting area, the whole 

 fungus growth not covering the entire rotted surface; while with 

 the latter species the opposite is true, a broad white mold layer ad- 

 vancing with the rot of the fruit. 



