PORTO RICO EXPERIMENT STATION. 465 



COTTON. 



Cotton culture is beoiniiinu- to iittmct some attention in Porto Rico. 

 I saw no ticlcls of cotton, but scattered plants of the perennial O'ossyj)- 

 iuv) harbadense were not unconmion along the roadsides. These thrive 

 so W(>1I under conditions of absolute neglect that there can be no doubt 

 as to the success of this crop when properl}^ cultivated. Two leaf 

 diseases were noted. 



The true cotton rust. — The true cotton rust ( l^rr(7o (/oi^sypii) was col- 

 lected on some of these wild plants near Mayaguez. It has heretofore 

 only ])een reported from Ecuador. It causes small purplish-brown 

 spots on th(^ leaves and would proba])ly cause them to fall prcmaturel}-. 

 It is not, however, likely to prove particularly troublesome. It is 

 entirely distinct from any of the diseases that have been called " cot- 

 ton rust" in the United States. 



Cotton areolate milde^v. — This well-known disease of the Southern 

 States, caused by Bamular'ia areola^ also occurs on leaves of the wild 

 cotton near Mayaguez. It produces white, frosted patches on the 

 underside of the leaves. It is a disease of secondary importance, 

 mostly occurring oidy on rank plants in moist places and doing but 

 little harm. 



COCO AN UTS. 



Cocoanuts are widely planted in Porto Rico. For the most part 

 they seem ([uite healthy. No trace of cither of the serious diseases 

 found in Jamaica'^ was ol^served. In the neighborhood of Ponce 

 man\- of the trees were 3'ellow and some were dying. Inspection 

 showed that the troul)le was caused by scale insects. Fortunate!}", a 

 lepidopterous larva was present in some numbers feeding on the scales. 

 Specimens were secured l)y Professor Barrett, and it is to be hoped 

 he will succeed in rearing them. Unless this or some other enemy 

 of the scale multii)lies very rapidlv, a munber of trees in the neigh- 

 borhood of Ponce Avill be lost, as they are ver}' l)adly infested. 



CACAO. 



This crop has so far attracted hut little attention in Porto Rico. 

 Tliei-e are, however, some })lanta(ions and others are contem])lated. 

 Only a few o])portunities for obsei-\ing this crop were found, and but 

 two diseases were noted. Some complaint was heard of losses of trees 

 from root rot, l)ut no cases were seen. 



Cacao die had' . — Certain trees that w(>re growing in dry exposed 

 places were gradually dying hiuk fioni the tips of the branches. The 

 appearance was something the sann^ as where trees arc sutfering from 



«Si't' Roj>ort on a trip to .Tanmi<-a. Jour. New York Bot. Gard., 4 (1903), pp. 4-7. 

 Is. Doc. 148, 58-U 30 



