8o OSIERS AND WILLOWS 



Willow Sawfly (Nematus salicis). Reference is made 

 to this insect as it causes much loss on the Continent 

 and occasionally does so in this country. The larva 

 is a livid blue and orange caterpillar which feeds on 

 the willow leaves and may completely defoliate the 

 rods. It can hardly be confused with any other pest. 

 Recently notes of serious damage have only been 

 received from the Peterborough district, and informa- 

 tion in the event of further attacks would be welcomed. 



Willow Gall Sawflies (Pontania gallicola) . There are 

 also other species of sawfly besides N. salicis which 

 may be expected at times to do damage. Enquiry is 

 often made as to the cause of the red and green globular 

 or bean-shaped swellings which are so common on the 

 leaves of willows. The insects responsible are certain 

 species of gall sawfly, of which that mentioned above 

 is most common. The sawfly larva lives in the gall, 

 and when full fed burrows out and pupates in the 

 soil. Unless the galls are so numerous as to weigh 

 down the rods, the injury does not seem to be serious. 



Willow Moths. The larvae of many different moths 

 feed on willow, but with certain exceptions they are 

 seldom present in sufficient numbers to do serious 

 harm. The exceptions comprise (i) various species 

 of small moth, the larvae of which feed in spring and 

 summer in the terminal shoot of the rod; (2) certain 

 clearwing moths whose larvae burrow in the stumps 

 and in the rods. 



(i) Further investigation is required before the life- 

 history of each species can be described in detail. 

 The larvae first become noticeable in late spring when 

 they spin together a few leaves at the tips of the grow- 

 ing rods, forming small tubes or nests, one larva only 

 being found in each shoot. They feed on the growing 



