126 PEAE. 



young Pears at Carnforth, Lancashire, he mentioned that he 

 had dusted the trees with Hme, and also spra.yed with Paris- 

 green, without any good effects ; but relatively to the latter 

 application, it has been suggested that where attack is very 

 bad indeed, so as almost certainly to involve losing all the 

 young Pears, that it might be worth while to spray so strongly 

 with Paris-green, or some other arsenite, as to blast the fruit, 

 and thus prevent the contained maggots coming to maturity 

 and continuing the attack. This would be a point for con- 

 sideration of the grower. 



The best remedy of which we have information at present 

 appears to be (as reported by Prof. J. B Smith) application of 

 kainite to infested ground. In an observation on infested 

 Pear orchard land in New Brunswick, U.S.A., a heavy top- 

 dressing of kainite was applied in late summer, and under the 

 infested trees it was api3lied at the rate of over half a ton per 

 acre. The result was that in the following year scarcely any 

 of the fruit was found to be infested ; whilst in another orchard 

 close adjoining, in which the ground had not been treated, on 

 close examination, it was found that of one kind especially 

 grown fifty per cent, were "midged," and of the other kind 

 named not one could be found to have escaped. 



In laboratory experiment Prof. Smith found that where 

 nitrate of soda was sprinkled in quantity that would represent 

 a fair top-dressing in ordinary field use, on sand in which 

 maggots had gone down, that not ten per cent, of the larvre 

 were alive (so far as examined) in their cocoons ; and where a 

 double quantity of the nitrate was applied, a still lesser pro- 

 portion of the maggots were found to be alive. 



Muriate of potash in about the same quantities showed 

 results of respectively nearly one-half or three-quarters of the 

 maggots dead in their cocoons. 



But in the case of sprinkling with a small quantity of 

 kainite, only three per cent, of living larvfB were found in the 

 cocoons examined ; and where double quantity was used, " not 

 one-third of the larvae in the jar had ever formed cocoons, and 

 those that did seemed all of them to be dead." — (J.B. S.). 



The experiment is given in minute detail in the Bulletin 

 previously referred to,* the period from commencement to 

 final examination ranging from June 10th to Oct. 6th, and I 

 believe may be of great assistance to us in checking attack of 

 this destructive gnat-midge. 



Addendum (June 7th, 1898). — For further observations, 

 taken from examination of advanced stage of attack, see 

 Appendix. 



* See note, p. 121. 



