204 



Insect, Fungus and other Pests. 



[JUNE, 



Abnormal Growth of Plants. — Celery plants which were sub- 

 mitted for examination from Cardiff exhibited no signs of 

 insect or fungus attack, but showed a precocious branching of 

 the tap root. A similar appearance has been observed in the 

 case of seedlings damping off owing to the presence of excessive 

 moisture in the soil. 



Geranium leaves from Limpsfield, Surrey, were free from 

 disease, but had assumed a crinkled appearance, probably 

 owing to an error in culture. If repotted in loam mixed with 

 silver sand they would probably grow normally. 



Tomato plants at Blackburn were found to have gone 

 " blind/' This blindness is not the outcome of injury caused 

 by a fungus or insect, but is usually due to over-feeding and 

 a " rushing " mode of growth. 



In the case of strawberry blossoms received from Morecambe 

 the central portion had shrivelled and turned black. This was 

 due to the fact that they had not been fertilised, 



Blossoms from a six-year-old Black Tartarian cherry tree 

 were received from Stroud, Glos., during May. The tree is 

 stated to bloom profusely every year, but fails to set fruit, even 

 under the most favourable weather conditions. It appears 

 possible that many varieties, and even particular individual 

 fruit trees, pears, cherries, &c, are quite incapable of setting 

 fruit when limited to their own pollen. When a tree which has 

 blossomed well has failed to fruit for some years without other 

 apparent reason, it is highly probable that the failure is due to 

 lack of cross pollination. To secure cross-pollination the 

 pollen should be produced by a tree of a distinct horticultural 

 variety, and not from another tree of the same grafted variety as 

 the sterile tree. This end is gained by planting mixed orchards 

 in place of blocks of one variety, unless experience has proved 

 the variety to be perfectly self-fertile. In a case such as that 

 recorded a second cherry tree of another variety might well 

 be planted in proximity to the sterile tree. Cases are known 

 where it was necessary to do something like this in India. 



