TlIK MONTHLY BULLETIN. 



17 



Last year the cost of control and preventive measures used in fighting 

 all gum diseases, including Botrytis. brown rot and heart-rot, amounted 

 to $1,230.76. Of this amount, $1,104.81 was expended for labor and 

 the rest for bluestone and lime. It was an exceptionally heavy year, 

 as the trees, in their weakened condition, seemed subject to the several 

 gum troubles, and every attention possible was given them. In the 

 ordinary year the total cost of treating the brown rot, applying Bor- 

 deaux and the other preventive measures described, would amount to 

 about $1,000. The inspection and treatment so far this year have cost 

 less than a cent a tree, and the Bordeaux in the past about three cents. 

 This last item, I believe, crin be reduced by .spraying with the power 

 sprayers, and with two sprayings should prove as effective as the hand 

 application. These figures are the maximum and as our experience in 

 the treatment becomes greater we may expect our control methods to 

 be more effective and the cost less. 



GRAY FUNGUS (BOTRYTIS) GUMMOSIS. 



Certain gum diseases, other than the brown rot, have caused some 

 loss in our groves during the past year and a half, and one of these — 

 the gray mold, Botrytis vulgaris — seems to be the most persistent. 

 Although this gum disease has been commonly found in Santa Paula 

 and other districts on lemon trees, it has never been recognized as 

 causing any tree trouble around Chula Vista until after the freeze. 

 During January of 1913 it appeared on the frozen lemons hanging on 

 the trees, and was identified by Professor Fawcett as this fungus. The 

 writer at the same time isolated the fungus in culture and inoculated 

 some of the trees in one of our orchards in an attempt to determine the 

 extent to which the disease would work on our trees, and to just what 

 extent it w^as parasitic. Inoculations Avere made above and below the 

 bud and, as usual, the lemon bark was most susceptible. Several of 

 the inoculations made from the cultures — using the mycelium — began to 

 gum and by July had killed out an area of bark three or four inches 

 wide by five to seven inches long. Inoculations made with the spores 

 failed to develop, but no doubt would have infected the wood had the 

 weather been more favoralile. 



Although we had recognized the presence of the gray mold on the 

 fruit as early as January and February, it was not until June that it 

 began to appear on the branches. From this time on it became quite 



