396 



THE AMERICAN FORESTRY 



blister rust kills the bark, the sawfly eats the leaves. Like 

 the blister rust, the sawfly is an alien undesirable, of 

 course. It was probably introduced on nursery stock 

 before the institution of the rigid inspection require- 

 ments, and is thought to have only recently been intro- 

 duced into this country. 

 The larvae of the insect is about an inch long, of green- 



NATURAL SIZE OF THE PINE SAWFLY COCOONS 



The cocoont on the left have been torn open probably by birds, those on the right 

 show exit holes of the chalcid parasite. 



ish-yellow color, has a black head, a brown 

 stripe down its back, and a yellow stripe with 

 brown markings on it on each side of the body. 

 The adult is a small wasp-like insect with a 

 wing spread of about an inch. The cocoon is 

 formed among the leaves and branches or falls 

 to the ground beneath it. The cocoon is about 

 three-eighths of an inch long and brownish in 

 color. 



The adults emerge from their cocoons late in 

 April or early in May. There are two, rarely 

 three, broods. The larvae feed during May and 

 June for the first brood and during August and 

 and September for the second. 



curred in the pine forests of southwestern Russia, in 

 Sweden, Prussia and France. In England its attacks 

 upon Scotch fir have occasionally been serious. In Con- 

 necticut it has already been found on the following 

 species of pines: 



White pine (Pinus strobus), limber pine (Pinus flex- 

 Ms), Scotch pine (P. sylvestris), Japanese or Botan pine 

 (P. excelsa), Japanese red pine (P. densiflora), 

 Korean pine (P. Koraiensis), Austrian pine (P. 

 Austrica), Cembrian pine (P. cembra), Mugho 

 pine (P. montana). 



Only the first two are native forest trees, yet 

 there is no reason to suppose that it would not 

 occur on all our native pines as well as those of 

 Europe and Asia. It might also occur on other 

 conifers as well as pines in this country as it 

 does to some extent in Europe. For the present 

 at least it will doubtless do more damage to 

 white pine than any of the others, since it is the 

 most common and important pine in the region 

 where the insect has become established. 



So far the insect has been found in this coun- 

 try only in Connecticut, but seems to be well dis- 

 tributed over the State, and is doubtless present 

 outside of it, possibly wherever imported pine 



TWO VIEWS OF THE LARVAE 



The dorsal and the lateral views of the larvae of the pine 

 sawfly, twice enlarged. 



The larvae feed on the needles of the pines particu- 

 larly seedlings, often entirely defoliating them. In Eu- 

 rope the insect has several times caused serious damage 

 in its outbreaks. There it attacks mature trees as well 

 as seedlings and young trees. These outbreaks have oc- 



A PILE OF COCOONS 



These cocoons of the pine sawfly were collected from pine twigs. There are 1,617 

 cocoons in this heap. 



stock has been planted, and much has been planted. 



Dr. Britton finds that when the pine sawfly is present 

 in nurseries or on small ornamental trees, spraying 

 with lead arsenate when the larvae are active is a good 

 remedy. As some of the cocoons fall to the ground it 

 is desirable to rake up the leaves and litter beneath the 

 trees and destroy it. All nursery stock should be care- 

 fully inspected and cocoons removed to prevent the 

 spread of the pest. 



Whether this pest will prove serious, or whether, like 

 the pine weevil, we will be able, by a little care at the 

 proper time, to keep it in check remains to be seen. It is 

 certainly too early to discourage the planting of white 

 pine because of it, but nurserymen, foresters and all pine 

 plantation owners should keep a sharp watch for the in- 

 sect and take prompt action to exterminate it wherever 

 it appears. 



