The Banded Pine Weevil. 



[feu., 



brown bore-dust marks the path of the grub. The grub on being 

 fully fed gnaws into the outer wood layers at the end of its 

 gallery, and in this hollowed-out bed, protected by a cover of 

 sawdust and wood chips, the pupal stage is passed. The beds 

 may be made all down the stem of the young pine, and also for 

 an inch or two below ground. A very favourite place is imme- 

 diately below the whorl of branches, where, in an infested plant, 

 one is almost sure to find several beds clustered together. The 

 yellowish-white coloured pupa gradually darkens into the beetle, 

 and when the beetles are ready to issue they bore a circular hole 

 through bed cover and bark. 



The generation is typically an annual one. MacDougall has 

 shown* that the Pissodes have a remarkably long life in the 

 adult stage, and that those beetles which have bred in one year 

 may, after hibernation, proceed anew to egg-laying. In his 

 experiments two females lived in the imago or adult stage two 

 years, and a male for three. Adult beetles may be met with 

 from April (March in a favourable season) onwards to and 

 including September, and egg-laying may take place at any 

 time during this period. 



Plants Attacked. — The favourite breeding places are young 

 pines from three or four up to eight years of age, but trees in the 

 pole stage are also infested. The favourite host plant is Scots 

 pine (Pinus sylvestris), but in Britain uotatus has also been 

 found in Austrian pine {P. austriacd) and Weymouth pine 

 (P. strobus). The beetle also breeds in pine cones. There are 

 Continental records of attack on spruce and larch, but this is 

 exceptional. Whilst amongst older trees the weak and sickly 

 will be chosen for egg-laying, the thinner branches of sound 

 trees and any part of the stem or branches of a young pine 

 may be used. 



Preventive and Remedial Measures. — I. Where the beetles 

 have not yet got a footing a timely and vigorous rooting out of 

 all suppressed or sickly pines will go far to prevent injurious 

 attack. 



2. Where the beetles occur in numbers, collecting them would 

 be a useful measure ; at an)- rate, the plan could be adopted in 

 nurseries with good results. 



* Proceedings of the Royal Society of Edinburgh. Volume XXIII. 



