Pomona College Journal of Economic Botany 



47 



to gain such a foothold in so dry a climate. On his advice we discontinued 

 the sulfids sprays and began with a 3-3-50 Bordeaux and distillate mixture 

 on the remaining third of the orchard. 



It may be well to state here that the application of the distillate with the 

 fungicide did not in the end do as efficient work as we at first thought it 

 would. With the Bordeaux its killing power seemed almost entirely lost. 



No further spraying of the orchard as a whole was attempted until 

 Nov. 1910, but in Jan. 1910 and again in June, 1910, one ten-acre plot was 

 thoroughly sprayed with the Bordeaux, leaving as a check four rows through 

 the middle unsprayed. Careful watch was kept on the fruit and trees in 

 all parts of the orchard. During a full year subsequent to the general 

 spraying of the orchard as recounted above, there seemed little difference 

 between the sprayed and unsprayed trees. The former always seemed darker 

 green and possibly set their fruit a little better, but we could not be abso- 

 lutely certain on these points. Perhaps as Rolfs suggested, we were en- 

 joying a non-infectious period such as is often very evident in Florida. 



With the removal of the older lemons that were affected at the time of 

 the first spraying there was left little evidence of the fungus either on leaf 

 or twig or fruit. But in September and October, 1910, the minute reddish 

 brown speck on the fruit and the pale green or yellow spot on the leaf 

 began to show soon after an unusually heavy early rain. By the first of 

 November a trace of it could be found on almost every tree. Occasional 

 leaves had already dropped. 



On the ten-acre plot that had been given the two extra sprayings with 

 Bordeaux it is difficult even at the present time — Jan., 1911 — to find the 

 least trace of the fungus in active development except on the four rows left 

 unsprayed. There it is easy to find it on both leaf and fruit, though not 

 as yet seriously injuring either. The difference conspicuous at a glance is 

 sufficient to convince us that there is great promise in prompt and thorough 

 treatment at the right time of the year. Just what time and just how often is 

 yet to be definitely determined. 



We began spraying this time with a 4-4-50 Bordeaux, on Nov. 12. Three- 

 fourths of the orchard has been treated. Under the trees first sprayed only the 

 leaves already badly affected at the time have fallen since, while trees not 

 yet sprayed have in some portions of the orchard carpeted the ground with 

 leaves, and every shake of the boughs adds to their number. We are exercising 

 great care in the matter of check rows, leaving several in every section of 

 the grove that we may know with certainty the merit of our work and its 

 value in regard to the time of application. 



The conclusions are more or less tentative — we are not sure that we can 

 prevail much against the fungus when weather and tree conditions favor it, 

 but from results thus far apparent from spraying we are sufficiently con- 

 vinced to spend another $3000 this season in combating it with I'ordcaux. 



Whether or not the following facts have any pertinent significance in this 

 discussion may be a matter of question, but it is nevertheless of interest. Our 



