444 RKPORT OF OFFICE OF EXPKRIMKNT STATIONS. 



miiiilxTs (if the l:ir\;v, luit tlic iiiotlis (•ontinucd in fence till FcbniaiN . 

 Kn)iii 1 to J laiNii' on the ii\ craj^c inhiiltitcd cadi '•spear." Sovcral 

 species of Hies were uttrrtcted to the frass thrown up hy these larvie 

 and some of (he smaller species hi'ed theicin. When mneh diluted, 

 kerosene emulsion, whale-oil soaj), and creolin solution were also 

 tried, hut althou^^li elective in killinj^ the larvaj, seriously injured the 

 corn itself. 



COFFEK INSE(^TS. 



The eoft'ee leaf miner {Leucoptera {Cemiostovia) cojfeelht) has heen 

 studied with the hope that some means nii*;ht be discovered for suc- 

 cessfully conibatinj^ this most serious enemy of the cof!'ee in Porto 

 Rico; hut as yet no parasites of this minute moth have been observed 

 and in only one instance were the larvro found dead in the oalleries 

 between the upper and lower surfaces of the leaf, and no insecticide 

 has been found applicable. This pest is now evenly distributed over 

 the whole island; 20 per cent to 40 per cent of the leaves on each tree 

 are affected, and sometimes (> or more larvas are found in the same 

 burrow. 



An experiment has been begun at the station grounds in Mayaguez 

 to determine the result of removing all afi'ected leaves in a plat of 

 badly infested trees. Data are kept showing the number of leaves 

 removed, the cost of the required labor, the average cost per tree, 

 the reduction of the percentage of infested leaves by each picking, 

 and an estimate of the ])enetit realized subsequently in the plat. The 

 pickings will be repeated as often as reinfection renders necessary. 



The red scale {Lecmiiioii /lenrisp/isericiwi) has proved troublesome 

 locally, but as soon as the number of scales becomes so great that the 

 individuals are clustered together closel}' on the branch, a cream- 

 colored fungus usually appears and annihilates the Avhole colon}' . The 

 hyphte of this interesting and important fungus (which is being 

 studied by Prof. F. S. Earle, of the New York Botanical Gardens) 

 rapidly spread over each scale, the young and adults alike, and 

 extends radially to some millimeters distance beyond. Vei-y few 

 coccinellid larvae have been observed among the scales. 



A plant louse (Aphis?) is occasionally detrimental to the 3'oung 

 coti'ee leaves, but it is usually kept in check by the larvjB of a fly 

 (Syrphus?). 



A scale {Orthesia sp.), parasitic on the roots of unhealthy coffee 

 trees, was observed at the coffee substation. 



A fulgorid bug, having the entire body and wings covered with a 

 grayish-white powder and consecjuently often mistaken for a moth, is 

 rather common, but seldom found in large colonies. It attacks the 

 young branches. 



