282 Inaeetlcifh's 



blossom was to a great extent dispensed witli, only 

 varieties which were badly attacked by aphis, sucker, 

 or catcj'pillar, or all three pests being sprayed. This 

 was a great relief, and it is not by any means certain 

 that it might not have been extended to all varieties 

 without any bad results. For on every occasion rain 

 fell a few hours after the spraying was done, probably 

 washing most of the spray fluid off the trees, and off 

 the insects that had been wetted by it. There was 

 no question of waiting for settled hne weather,, as 

 the work had to be done before the expansion 

 of the blossom. Arsenate of lead was combined 

 with the soft-soap wash for aphis and sucker, in order 

 to poison the food of caterpillars. If pests should 

 attack the varieties not sprayed, they will be treated 

 after the fall of the blossom, and in any case varieties 

 subject to scab will be sprayed with hme-sulphiu: of 

 summer strength. 

 Results of spraying One of the most unsatisfactory featm-es of spraj'uig is 



the diflftculty of determining its results, and that diffi- 

 culty has proved particularly great this season. Even 

 in the cases of Apples most infested, such as those in 

 which five or six out of twenty trusses of blossom were 

 found to contain aphides, and three or four a few 

 suckers, I could not And more than one dead aphis or 

 sucker in fifty trusses examined a day or two days after 

 the sprayuig. I found niore Uve ones, but very few 

 even of these. The question, then, is whether the pests, 

 killed or weakened by the wash, were washed out of 

 the trusses by heavy rain. It is commonly assumed 

 that aphides are washed off the trees by rain, and 

 particularly by a thunderstorm ; but, so far as I know, 

 this is an assumption which has never been actually 

 proved. Some trusses found to be infested by aphides 

 could be labelled, some of them being sprayed and 

 others not sprayed, care being taken to avoid any more 

 thorough spraying than would be given on a large 

 scale. If the insects could be counted beforehand, so 

 much the better. Exammation could be made 24 

 hours after the spraying, results being noted ; and again 

 after the next fall of rain, if it occmTcd soon enough. 

 Rain might hold off too long, and the experiment would 

 then have to be repeated. In notuig-thc results after 

 rain, if any pests were found to have been washed off 

 the trees, it should be noticed whether more were 

 ousted from the sjjrayed trees than from the others. 

 As to a tliuiulcistiHiii. tlicre can harilly he any special 



