PREVENTIVE MEASURES FOR " WITCH -BROOM " 105 



the death of trees from disease, are generally attacked, 

 so that only a few survive. Not infrequently whole 

 nurseries of young plants are destroyed. 



It has not been noticed that any particular variety of 

 cocoa is less susceptible to the disease than others. 



The quantity of shade appears to have no influence on 

 it, but humidity is favourable to its development. 



The remedial measures suggested consist of the lopping 

 and burning of all leaf -bearing branches, tarring the ends 

 of the stumps, and spraying the pruned trees with a 

 3 per cent, solution of sulphate of copper. This solution 

 not only destroys the fungus spores, but moss and similar 

 small epiphytes on the trees as well. The " Deming 

 Success " pump-sprayer was employed to apply the spray, 

 and is reported to have given satisfaction. 



Trees which were treated in this manner produced new 

 crowns in a surprisingly short time, and comparatively 

 few " witches'-brooms " appeared during the first year 

 following the pruning operation. 



The principal dry season, when growth is least active, 

 is considered the best time to carry out the work of 

 pruning and spraying. 



Subsequent pruning operations recommended entail 

 the removal of undesirable growths which form on the 

 trunk and main branches, and also of any "witches'- 

 brooms " which appear, together with a small portion 

 of the growth below the diseased area. 



Trees which had been lopped commenced to produce 

 new foliage in from fourteen to twenty-one days. A few 

 of these trees yielded fruit the first year after being 

 lopped. Two years after lopping a moderate crop was 

 obtained, but it is anticipated that a normal crop would 

 not be yielded until the third season. A plantation of 

 cocoa trees which had been treated in the manner 

 described above yielded 5, 2J, and 2J per cent, of in- 

 durated fruits during the first, second, and third years 

 respectively following the lopping. 



The rate at which the yielding capacity of lopped trees 

 increases is well demonstrated by the results of the 

 experiments described below : 



Experiment field No. 1. ; 5 acres in area, containing 

 900 trees, forty years of age, which were lopped in 

 November 1904: 



