Dec. ao, 1915 
Cherry and Hawthorn Sawfly Leaf Miner 
527 
Profenusa collaris has been under observation, T. minutum has twice 
made its appearance in conspicuous numbers in infested cherry orchards, 
in 1912 and in 1915. During the former year the larger percentage of the 
eggs of the leaf miner were attacked, and on some trees it was difficult to 
find an egg-bearing leaf which had not been visited by the parasite. In 
1915 parasitism ranged from about 40 to 90 per cent on individual trees. 
Taking all trees into consideration, of the eggs deposited by the insect a 
larger percentage of them certainly failed to hatch than hatched, and for 
this mortality T. minutum appeared to be largely responsible. 
The parasite was reared from both cherry and hawthorn foliage. The 
majority of the eggs of the leaf miner that were dissected contained a 
single parasite, and in only a few instances were twin larvae or pupae 
observed. On June 2, 1915, the parasites were all in the larval state, 
but on June 5, when the larvae of P. collaris were beginning to abandon 
their mines in the foliage, about 50 per cent of the parasites were in the 
pupal state. By June 7 they had nearly all transformed to pupae, and 
on June 9 the first adult appeared. During succeeding days the chal- 
cidids appeared in large numbers, and the last specimen to make its 
appearance emerged on June 14. While the parasite was abundant about 
Geneva during this year, it was relatively quite scarce on plantings of 
Crataegus spp. at Rochester. 
Besides the foregoing parasite there has been reared from P. collaris 
an ichneumon which proved to be a new species and has been listed by 
Rohwer 1 as “ Pezoporus tenthredinarum. ,} Apparently there is associated 
with this ichneumon an undescribed tryphonine, but owing to the small 
numbers collected it is impossible to make any definite statement at this 
time as to its status as a parasite of the sawfly leaf miner. 
METHODS OF CONTROL 
REMOVAL OF AFFECTED LEAVES 
Of the operations systematically practiced, one that will probably 
prove most effective and economical in controlling the sawfly leaf miner 
is the picking of affected leaves. This species is peculiarly susceptible 
to this kind of repressive method, since there is only one brood of larvae 
to attack the foliage, and oviposition extends over only a short period. 
The effect is that hatching of eggs and maturing of larvae are, practically 
speaking, almost simultaneous for all of the creatures, and their activities 
during their injurious stages are therefore restricted to a relatively short 
period. By careful timing it is possible at a single picking to collect 
practically all of the larvae by removing the affected leaves, which should 
then be burned to destroy the insects therein. The removal and de¬ 
struction of all mined leaves, coupled with another practice—the destruc- 
1 Rohwer, S. A. Descriptions of new species of Hymenoptera. In Proc. U. S. Nat. Mus., v. 49, p. 216. 
1915- 
12572°—15 - 3 
