110 THE MONTHLY BULLETIN. 



is made. The concern handling the fungus has everything to gain and 

 nothing to lose, for it is well known that the black scale frequently fails 

 to reach its maximum of abundance through the action of the hot 

 summer, but nevertheless, regardless of the cause of the failure of the 

 scale, the grower pays the additional charge to the fungus men, for 

 they are always careful not to leave a check for determining whether 

 or not it was the fungus or something else which was effective. 



In contemplating the practical use of the fungous diseases of insects 

 it is important to consider whether or not the disease is indigenous, i. e., 

 whether it is native to the locality, or is absent but obtainable from 

 some other place. 



Where a fungous disease is absent and the reason for its absence is 

 that it has never been introduced and not that conditions are unfavor- 

 able, it is always worth while at least to attempt to introduce it into the 

 locality under consideration. In cases where the disease is native, or, 

 if not native, so thoroughly established that it has become a component 

 in the local flora and is therefore on the same basis as a native, the first 

 question that arises is : What is the efficiency of the disease in this 

 locality from a practical standpoint? The second. Can its efficiency be 

 increased in any practical Avay open to man? This second question is 

 the one of greatest interest to us in the present connection. It can not 

 be answered by "yes" or "no." Even in Florida, where conditions 

 are ideal for the growth of fungi, our best authorities differ as to 

 whether anything is gained by the artificial distribution of the spores 

 in the orchard. The writer is not a mycologist, but it seems to him 

 that if the value of such practice admits of doubt under ideal con- 

 ditions, such as obtain in Florida, there is occasion for much doubt 

 under such conditions as obtain in California. 



A recent article on the value of fungous diseases of insects, by an 

 expert in the Federal Bureau of Entomology* is so applicable to the 

 situation in Southern California that I take the liberty of quoting a 

 portion of it here : 



"There can be no doubt that at certain times of the year, under 

 certain conditions, epidemics of fungous diseases naturally contribute 

 much toward controlling noxious insects. This, however, is a balance 

 established by nature of her own accord. Can we help her? 



Let us suppose that a given locality is heavily infested by a noxious 

 insect; also that a number of individuals in this locality has died from 

 fungous parasitism and, lastly, that we have found an infested locality 

 free from such fungus. We will naturally ask ourselves the following 

 questions : 



(1) Can we cultivate this fungus? 



(2) Can we introduce it into the infested locality where it is not 

 known to occur? 



(3) Will the fungus establish itself and will it spread and become 

 effective ? 



On the whole, a favorable answer can be given to the first two 

 (juestions. Many of the parasitic fungi have been cultivated on artifi- 

 cial media or on living insects kept in confinement. Such fungi have 

 been introduced among healthy insects when the occasion warranted 

 such procedure. The third question, however, has offered difficulties 



*The Economic Status of the Fungous Diseases of Insects. R. W. Glaser. Journal of 

 Economic Entomology, page 473, December, 1914. 



