204 THE CHIEF SOUTHERN AGRICULTURAL CROPS 



delicate cocoon on the under side of the leaves. 

 Experiments at the Cuban Experiment Station have 

 shown that it is possible to kill large numbers of the 

 insects when in this stage by spraying with kerosene 

 emulsion. As the pupal stage lasts but a few 

 days, frequent sprayings are required in order to be 

 effective, and in most cases the expense will prob- 

 ably be found to be too great to make the remedy 

 a practical one. 



A large aj)his and various scale insects sometimes 

 attack coffee, but they are usually soon controlled 

 by their natural enemies. 



The rust fungus (^Hemileia) that has caused such 

 heavy losses in the East Indies has so far not 

 appeared in the American tropics, but there is a 

 rust-colored leaf spot (^Stilhum) that occurs quite 

 commonly and which sometimes causes considerable 

 injury. The spots are sometimes confused with 

 those caused by the leaf miner, but the Stilhum 

 spots are always circular, not irregular, in outline, 

 and in moist weather close examination will show 

 them to be covered with the minute, short-stalked, 

 orange-colored, fruiting bodies of the fungus. This 

 disease is usually troublesome only when the coffee 

 is overshaded. Thinning out the plants and re- 

 moving some of the shade is the only remedy 

 required. 



In some regions many coffee trees are lost from the 

 attack of a fungous root rot. The disease spreads 

 slowlv in concentric circles, from each center of 

 infection. It has not been thoroughly studied, and 

 the only remedy that can be suggested would be to 



