1905.] 



Larch Canker. 



307 



other fruit, and one (i.e., the last named) injures field crops, e.g., 

 mangolds ; their larvae, however, are carnivorous as well as 

 vegetarian. 



These beetles live in the day-time in holes in the soil or in 

 litter on the fruit bed. Anything that would disturb them in 

 their day shelter-places would be useful ; those disturbed and 

 collected could be killed by their being dropped into boiling 

 water or into a little paraffin. 



The proved practical remedial measure is to trap the beetles 

 by placing here and there smooth-sided basins baited with some 

 attractive sweet stuff. Two out of the three above species are 

 wingless and once in the traps are unable to get out owing to 

 their inability to get a grip on the slippery sides. As to trapping, 

 Miss Ormerod quotes Messrs. Laxton, of Bedford, as follows : — 



" We purchased a large quantity of cheap pudding-basins 

 early this spring ; these are let into the ground level with the 

 surface, at distances a few yards apart, and kept baited with 

 pieces of lights and sugar-water. When the weather was dry 

 we often caught half-a-basinful of a night until the number 

 gradually diminished to two or three and now none at all. It is 

 laborious but well worth the trouble, as this season we lost no 

 fruit." 



This destructive parasite (Dasyscypha calycind) is present in 

 greater or less quantity, depending on local conditions, 

 wherever the larch (Larix europced) grows. 



Larch Canker. In this country it also occurs on the Scots 

 pine (Pinus silvestris), the silver fir (Abies 

 pectinata), the Corsican pine (Pinics laricid), and the Japanese 

 larch (Larix leptolepis}. 



The fungus is a wound-parasite ; in other words, it cannot gain 

 an entrance into the tissues of a living tree except through 

 a wound. The wounds ordinarily occurring in nature through 

 which infection takes place, may be grouped under four head- 

 ings :— (1) Wounds caused by wind, or by snow resting on the 

 branches ; (2) cracks caused by late frosts ; (3) nibbling of the 

 bark by rodents or by insects, and more especially the punctures 

 made by the larch aphis {Chermes laricis) ; (4) wounds made 

 near the base of the stem in planting. 



B B 2 



