Hypocreace^:. 



NECTRIA THEOBROMvE. Massee. 

 (Canker of Cacao). 



The disease was investigated by Howard, from Grenada 

 in the year 1901 ; since then it has been met with in 

 Trinidad, Dominica, St. Lucia, and St. Vincent. The first 

 recognisable symptom is the production of a red, gummy 

 liquid which oozes out from the bark of the tree. If the 

 bark is cut off the inner tissues are found to be red in 

 colour, the discolouration extending as far inwards as the 

 young wood. The area affected by the fungus varies ; it 

 may take the form of a narrow band which rings the tree, in 

 which case death soon results, or it may spread in different 

 directions without encircling the trunk, in which case death 

 is slower. The branches above the diseased area are cut 

 off and die, those just above that area dying first. 



It is important that further work should be done on the 

 life-history of the fungus. Two conidial forms have been 

 reported to precede the Nectria, one is said to be a 

 Fusarium-foYtxi, and the other a unicellular form. Obser- 

 vations made at Kew have shown that the ascospores after 

 germination give rise to a Cephalosporinm-ioxm, and 

 experiments are being conducted with a view to investigating 

 the parasitism of this form. 



A knowledge of the life-history of the fungus must 

 aid considerably in the recommendation of effective 

 remedial measures. An excision of the cankered part with 

 a sharp knife and careful sealing of all wounds with a 

 mixture of coal tar and clay in the form of a thick paste are 

 advantageous in checking the spread of the disease. 



Diagnosis : — Perithecia gregarious or scattered, super- 

 ficial, ovate, smooth, with orange-coloured hyphae, red, 

 with a scarcely prominent minute ostiole, '5 mm. high ; 

 asci cylindrical, stalked, 8-spored ; paraphyses septate, 

 hyaline, with a slightly tnickened apex, 3 microns wide ; 

 spores obliquely monostichous, hyaline, ellipsoid, one- 

 septate, slightly constricted at the septum, 28 — 30x8 — 10 

 microns. 



Recently a bulletin of the Agricultural Department of 

 Surinam has appeared, in which Mr. Van Hall considers 

 that the canker disease is caused by a Spicaria-ioxm which 

 in artificial media gives rise to a Fusarium-iorm, and that 

 the ascigerous fungus is saprophytic and has no connection 

 with the disease. It is important to remember that it is of 



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