;254 



THE AGRICULTURAL NEWS. 



Auci'sT 9, 1919. 



THE WITHER-TIP OF LIMES IN TRINIDAD 



The following paper by Mr. J. B. Korer, Mycologist, 

 Board of Agriculture, Tnni'lad, is reproduced from 

 the Bulletin of the Department of AgriciiKare, 

 Trinidad, Vol. XVIII, Part 1. We are indebted to the 

 Board for the loan of the block illustrating this article: — 



During July and .\ugust 191S, there was a severe 

 outbreak of a disease of lime trees throughout the colony, 

 practically all districts being equally affected. Specimens 

 were received from a large number of different estate."!, and 

 all showed 'wither-tip' in its characteristic form. This is 

 one of the commonest and most destructive diseases of 

 limes, though heretofore, it has not been very prevalent in 

 Trinidad-V, It is due to the fungus known -as Gheosforniiii 

 limtttkolum, Clausen. The fungus is able to attack the 



If the weather is not so d imp, the water-soaked appearance 

 is not so pronounced, but the attacked part is light green in 

 colour at first, and then becomes brown. In all cases, the 

 affected shoots wither up, thus giving the popular name of 

 the disease. When the larger young leaves are affected they 

 often become curled and distorted, and the infected areas 

 drop out or become cracked, so that the leaf is punctured 

 with holes. Only young growing loaves and the young 

 shoots apparently can be attacked by the fungus ; leaves 

 and .shoots that have become hardeaed and matured are ipiite 

 immune to the disease. 



In addition to ihe leaves and the tender shoots, the 

 flowers (O and young fruit are very susce[jtible to attack, 

 and on this account, the disease onuses a great loss of fruit. 

 If the Howers are attacked, they fail from the tree without 

 setting fruit. \»hej]. young fruits are attacked, they elmw a 



WlTHEn-TIP 1) 



young growth of lime plants of all ages; in fact, at the 

 St. Clair Experiment Station it has caused the death of a great 

 many nursery plants of from 6 inches to a foot high, 

 during the'past two years, 'i) 



APPEARAXCE OK THE DISKA.-iE. 



The attacks of the fungus generally show on the tips 

 and edges of the very young leaves, but they affect also the 

 leaf-stalk, at the point where the leaf joins the stem, or any 

 point in the very young shoots. The fir.'-t sign of infection 

 ifl indicated by a somewhat water-soak' d ajjpearance, until 

 the young loaves and tip of the shoot are entirely destroyed. 



f**' (1.) 'riii.s disease must not be «)nfu8u(l with tin- '1 ).iiiipiii^;- 

 <iH" disua.se which is very severe on gueillini^s wlirn tliey are 

 from 1 to :5 iiielie.s high, and which has already tieen 

 dfc'crilied in the J't'Cecliiiiii of tif A'jri<;i(ll\oid S i ielu, XV, 

 1J«1.'), 14-15. ' Wit lier-tij) ' generally attacks the plants when 

 they are a little f)liler. 



ISKASE 01-' LiMKS. 



rough scabby appcrance and become cra.'ked, and generally 

 fall from the tree in two or three weeks. 



After the fruits have become half grown, they seem to 

 be immune to further attack. Full-grown fruits, after 

 having fallen to the ground, however, may be attacked 

 through wounds, and the fungus in this way. probably 

 causes a good deal of rotting (if the fruit from the time of 

 gathering until it reaches the factory. 



TIIICAT.MENT OF HUE DISEASE. 



As this disease became epidemic last year, it is quite 

 probable that under favourable coiulitioiis, it may do even 

 more damage this year, and everyone should bo prepared to 

 combat it. Fortunatsly, it is comparatively easy to treat, 

 li possitile, all the dead svood and di-eased leaves should be 

 rollected and b irned during tlie Hry seison, andas soon as 

 the trees begin tf) make their new growth after the rains 

 begin, they should be thoroughly sprayed with Bordeaux 



