CITEUS MELANOSE AND ITS CONTROL, 31 
control in seedling orange groves presenting essentially the same 
conditions as those prevailing in this grove. These pruned trees 
had a greater vegetative growth than the unpruned ones, and mela- 
nose infection was about equal the, first season. The second year 
after pruning, melanose was invariably worse on pruned growth than 
on unpruned trees, owing to the overstimulating effect of pruning. 
PRUNING AS A SOURCE OF INFECTION 
The removal of prunings from a grove is expensive, especially 
where the trees are planted so thickly that it is difficult to drive a 
team through without bruising the fruit or trees. Therefore if prun- 
ings can be left to rot where they fall, there would be less general 
objection to this highly desirable grove practice. With that thought 
in mind, tests during two seasons were made to determine if prunings 
left to decay on the ground around orange and grapefruit trees re- 
sulted in harmful effects on the tree or the fruit. 
After many careful observations the conclusion reached was that 
prunings on the ground around citrus trees are not a source of ap- 
preciable increase of melanose or of Phomopsis stem-end rot infec- 
tion. This deduction seems logical, since the causal organism is 
spread mostly by rain drip and dew drip. 
COMMERCIAL PRUNING TESTS 
Eepeated observations have been made during the last few years 
on commercial pruning operations in normal bearing groves where 
in most cases the pruning was done once a year but occasionally 
twice a year. Almost without exception the pruning out of dead 
twigs resulted in a more vigorous growth and, some growers thought, 
in a heavier set of fruit as well, which seemed to make pruning a 
good investment notwithstanding a usual failure to reduce melanose 
infection. In only rare instances has there been observed any appre- 
ciable reduction in melanose in lightly pruned normal bearing groves, 
but a marked reduction often follows heavy pruning. On the other 
hand, melanose sometimes becomes markedly worse in trees pruned 
lightly than in unpruned trees in the same grove. This usually 
occurred the year following the pruning. 
There are conditions under which pruning for melanose control 
has been very effective, — namely, in normal, young, nonbearing 
groves where there is very little deadwoocl present, and in groves of 
any age following severe freezes, wherever there is a large increase 
in the quantity of deadwood. This method of preventing melanose 
on trees severely killed back was clearly demonstrated in 1917 in 
many groves throughout the State.* (PL 9, A, B.) In that year in 
several large groves in Lee County in the southern part of the State, 
and in others in Putnam County"close toward the northern limit of 
commercial orange growing, pruning was begun within a few weeks 
after the freeze and kept up until the job was completed, even 
through late summer and into fall. All of the trees were severely 
cut back in order to remove the recently killed parts, and in many 
instances the trees were severely headed in or "deheaded." Where- 
ever this severe pruning was done in early or mid-spring before much 
