Another Insect Enemy of the White Pine 



Bv P. L. BuTTRICK 



THE white pine is the most important timber tree in 

 eastern North America and has long been a favor- 

 ite tree for planting purposes, both commercial and 

 ornamental. Hundreds of acres are each year planted 

 to it in the expectation that they will in from 40 to 60 

 years bring in a considerable revenue from the sale of 

 their timber. As 

 an ornamental tree 

 — whether in small 

 or large sizes — it 

 needs no introduc- 

 tion. 



Some fifteen 

 years ago when 

 white pine plant- 

 ing operations on 

 a commercial scale 

 were first under- 

 taken it was 

 thought that the 

 tree in its earlier 

 stages had almost 

 no enemies ; how- 

 ever, it has been 

 acquiring the m 

 ever since. First 

 the white pine 

 weevil ( Pisodcs 

 strobi) started its 

 depredations. This 

 insect, like t h e 

 poor, has appa- 

 rently always been 

 with us, but un- 

 like the poor, has 

 only recently be- 

 c o m e abundant. 

 The weevil dam- 

 ages young pine 

 plantations by bor- 

 ing into the lead- 

 ing shoot and kill- 

 ing it. Foresters 

 and entomologists 

 working together 

 have devised means 

 of holding this in- 

 sect in check by 

 cutting out the in- 

 fested shoots and 

 collecting the 

 adults in nets be- 



THli DESTRUCTIVE PINE SAWFLV 



1. Tlie adults, which, followiTig the white pine blister rust, are now attacking pines in 

 Connecticut and doing considerable damage. 



2. The eggs of the pine sawfly in a pine needle about four times enlarged. 



3. The cocoons — natural size 

 4 Tlie larvae feeding on pine — natural size. 



fore they dig into the shoots. As the trees get 

 older they become immune to the pine weevil. The 

 weevil problem largely disposed of, along came the white 

 pine blister rust — an undesirable alien from Europe 

 brought in on importations of white pine nursery stock. 

 This disease attacks white pine and currents or goose- 

 berries at different 

 stages of its 

 gtowth. If the 

 two are permitted 

 to grow close to- 

 gether the rust will 

 severely damage or 

 kill the young 

 pines. xA.lthough 

 all importations of 

 white pine from 

 Europe have been 

 stopped the disease 

 has spread to some 

 extent in this coun- 

 try and the Fed- 

 eral Government 

 and some of the 

 States are busy 

 fighting it. It is 

 thought that by 

 prompt action its 

 further spread can 

 be prevented. 



The latest addi- 

 tion to the ranks 

 of the enemies of 

 the white pine has 

 been recently 

 studied and re- 

 ported upon by 

 Dr. W. E. Britton, 

 the State Entomo- 

 logist of Connecti- 

 cut, who first dis- 

 covered it in this 

 country. 



The pest is an 

 insect known as 

 the pine sawfly 

 ( Diprion simile : 

 Hartig). While 

 the white pine 

 weevil attacks the 

 leading shoot of 

 the tree and the 

 395 



