CITEUS DISEASES. 41) 



neglect of these principles, and the disease is rare that is not in- 

 fluenced to some extent by them. It is too often the common atti7 

 tude to expect the plant pathologist, or extension worker, to provide 

 some cure which will eliminate in short order all the ills the grove 

 is heir to : and there has been much disai)pointment when iiot only 

 was such a cure not provided, but suggestions were mad-e that what 

 was needed was improvement in cultural practices. 



SELECTION OF A GROVE SITE. 



The first i)oint to be given attention is the matter of selecting a 

 grove site. The question of the character of the soil, or the soil type, 

 is of minor importance, since citrus can be grown on a very wide 

 range of soils, but the depth, possibilities of drainage, and related 

 points must be carefully looked into. More than one grove in Porto 

 -Rico has been set in land where hardpan. or even rock ledges, were 

 so close to the surface as to effect the growth of the trees witliin a 

 few years. Hardpan is the reason for a number of decadent groves 

 at the present writing. Even where the trees are not checked com- 

 pletely in their growth, they are so weakened as to fall easy prey to 

 various diseases. 



Of equal importance is the necessity of thorough drainage. ( 'itrus 

 trees are very susceptible to injury by standing water around their 

 roots, and irreparable damage can be done by a sudden rise in the 

 water table, or bj- flood water, in a few days' time. Where there is 

 persistently poor drainage not only do weakened trees result, but 

 the way is opened liy the death of the roots to attack by specific 

 diseases of the roots and crown. 



In some districts drouths are of common occurrence, antl it 

 would be most advisable to arrange for irrigation where possible. 

 This would provide for maximum, normal growth at all times. Here 

 again, trees weakened by lack of moisture not only fail to make desired 

 growth, through the loss of leaves, but the resulting weakening paves 

 the way for withertip and similar troubles. A most direct result of 

 drouth is of course the dropping of a large proportion of the fruit 

 before maturity, or at such times as shipment is impossible. 



vStill another point, while on tlie topic of site selection, is that of 

 slope. Blocks of trees set out on even moderate slopes thrive poorly, 

 or even at times prove utter failures, where the soil is light and hence 

 easily washed away, or where on heavier soils such precautions as 

 are necessary to prevent this are not taken. Hillside groves are 

 entirely feasible, if the grower cares to go to the trouble and expense 



