416 



Insect, Fungus and other Pests. 



[OCT., 



Hymenoptera. — From Saffron Walden and Sundrum, Ayr- 

 shire, specimens of the giant wood wasp (Sirex gigas) were 

 sent by correspondents who stated that conifers were being 

 damaged. Wood wasps were fully dealt with in the May 

 (1907) issue of this Journal. 



The caterpillars of the large larch saw-fly (Nematus Erichsoni) 

 appeared in large numbers, in August, on young Japanese 

 larch in a plantation at the foot of Skiddaw, close to the 

 original outbreak (on the Merehouse Estate) described in 

 this Journal in October, 1906. Leaflet No. 186 deals fully 

 with the large larch saw fly. The measures recommended 

 in par. 7 on p. 8 of the leaflet should be carried out during 

 the winter if the area attacked by this pest is not too large to 

 render treatment impracticable. 



Eelworms. — Among other pests, ears of wheat forwarded 

 from Aldbourne, Wilts, were found to be affected with 

 " purples " or " ear-cockles," caused by the eel worm Tylenchus 

 tritici, Bastian. The blackish grains were crowded with eel- 

 worms, and when such grains are sown with sound seed the 

 eelworms escape and enter into growing seedlings. As the 

 plants grow, the eelworms ascend until they eventually reach 

 the ear and enter the young grains. It is important that 

 diseased grain should not be sown, and to ensure this all grain 

 for seed may be covered with water and well stirred. The 

 diseased grains will rise to the surface and may be skimmed off 

 and destroyed. 



Fungi. — A correspondent at Chipping Norton sent specimens 

 of diseased wheat, the straw of which bore numerous brown 

 spots. These it was found were caused by a minute parasitic 

 fungus (Helminthosporium gramineum, Rabh.), which, when 

 present in quantity, produces " blindness " of the ears. Oats, 

 barley, and some wild grasses are also attacked. It is advisable 

 to avoid sowing seed grown in an infected district. If such 

 seed is sown it should first be sprinkled with 1 per cent, of 

 commercial formalin, or 10 per cent of copper sulphate (blue 

 stone) in water, and thoroughly turned and mixed so that every 

 portion is brought into contact with the solution. This 

 disease was described in the Journal, Vol. xii, p. 347, September, 



Celery Leaf Blight. — Diseased celery plants from Norwich 



