6 MAINE AGRICULTURAL EXPERIMENT STATION. I9I2. 



lead arsenate had some fungicidal jDroperties, or at least was 

 capable of inhibiting fungus attack. Taylor came to this con- 

 clusion from work done in Missouri peach orchards where the 

 curculio {Conotrachelus nenuphar, Herbst) and the brown rot. 

 (Sclerotinia fructigena (Pers.) Schroet.) were very pernicious. 

 In this instance the control of the rot is largely ere lite :1 as 

 indirectly due to the insecticidial action of the spray in warding 

 ofif the insect whose fruit punctures form sources of infection 

 bv the fungus. In another instance, however, reference is 

 made to the absence of peach scab following the use of lead 

 arsenate, and this is ascribed to its probable fungicidal prop- 

 erties. 



In Waite's experiments in Virginia with apples, however, the 

 action of lead arsenate is specifically recognized as fungicidal. 

 Discussing the results obtained on the lead arsenate plot, the 

 author states : "This spray gave excellent results, not only in 

 its absence of injurious effects on the foliage and fruit but In 

 preventing fungous diseases Further- 

 more, the spraying seemed to protect the fruits from the fly- 

 speck, the smut fungus, and the fruit spots, just as in the case 

 of the other mixtures." * 



He concluded that "this insecticide seemed to possess con- 

 siderable fungicidal value, though probably not enough to be 

 depended upon for general use." 



Wallace et al.** have also made extensive field and laboratory 

 stud'es of the fungicidal value of spray mixtures, and included 

 therein a test of the efficiency of lead arsenate diluted to spray- 

 ing density, uncombined with other solutions. When so used 

 it was found to re:Hice apple scab considerably and in mild 

 cases to control it fairly well. Better percentages of control 

 were obtained under field conditions than in the laboratory 

 studies, and in both kinds, of tests the addition of lead arsenate 

 to lime-sulphur solutions increased the fungicidal value of the 

 latter. Such increase is regarded by Wallace as due more to 



*Waite, M. B. loc. cit., p. 12. 



** Wallace, E., Blodgett, F. M., and Hessler, L. R. "Studies of the 

 Fungicidal Value of Lime-Sulfur Preparations," N. Y. (Cornell) Agr. 

 Exp. Sta. Bui. 290 (1911). 



(Note — The author does not indicate in his report the specific organ- 

 isms thus controlled. The lead arsenate in question was used at the 

 dilution of 2 lbs. to 50 gallons.) 



