51 



CORAL SPOT. 



(Nectria cinnabarina.) 



No fungus is perhaps more plentiful on dead twigs and 

 branches and more familiar to every gardener than the Coral 

 Spot fungus, Nectria cinnabarina. It is abundant and con- 

 spicuous in damp weather on dead branches of elm, lime, 

 poplar, sycamore and many other trees, and is always to be 

 noted plentifully on old pea sticks, particularly hazel, in 

 autumn and winter. In these dead branches the fungus 

 occurs in the condition known as saprophytic, i.e., living on 

 dead or decaying material, but though it usually occurs as a 

 saprophyte it not infrequently becomes parasitic, that is, it 

 invades living tissues. In this form it attacks trees of many 

 kinds, ornamental shrubs and bush fruits, of which lime, 

 sycamore, horse chestnut, apple and currant may be mentioned 

 as being more particularly susceptible. The present leaflet 

 deals specially with its attack on fruit trees, though the general 

 remedial measures recouimended apply equally to other plants. 



The Coral Spot fungus may be recognised by the small 

 pink or flesh-coloured warts which are thickly scattered over 

 the surface of the dead and dying branches. The warts are 

 in reality spore-pustules which consist of fungus filaments 

 bearing masses of spores. In damp weather the pustules are 

 slimy and salmon coloured, in dry weather they are powdery 

 ;ind pale pink in colour. 



Method of Attack. On fruit trees Coral Spot is particu- 

 larly common on red and black currant and gooseberry, but 

 it also attacks apples and pears. In all these cases it attacks 

 the plants in one or other of two ways ; either by commencing 

 on the dead twigs and working from them into the living 

 tissues or, more rarely, by gaining entrance by means of a- 

 wound to the stems or branches lower down. 



In red currants the evidence suggests that, by far the largest 

 amount of infection occurs through small branches which 

 have died back. The fungus spreads from these dead shoots 

 into the main healthy branches, causing them to wilt. This 

 wilting occurs in May and June and is a very conspicuous 

 feature of badly affected plants.* The fungus probably obtains 

 entrance in a similar way in the case of gooseberries. 



In young apples cases have been observed where, owing 

 to rank grass and weeds having been allowed to grow round 

 the stems, the Coral Spot fungus gained an entrance through 

 dead branches or wounds near the ground level and caused 

 the death of the entire trees. 



* For information as to Ked Currants the Ministry is indebted to 

 Mr. F. T. Brooks, of Cambridge University, who has this disease under 

 investigation. 



