60 THE REPORT OF THE No. 36 



as good, if not better, control of the first brood nymphs as later spraying; it 

 practically eliminates the second brood; in dry seasons it should lessen the danger 

 of staining the fruit; and most probably it would prove to be of greater value 

 in preventing fungus diseases than later spraying. 



Spraying Results in the Infested District. As previously mentioned, 

 a very large percentage of the growers in the leaf-hopper affected district sprayed 

 their vines with bordeaux mixture and nicotine sulphate, or lime and nicotine 

 sulphate. In most graperies the bordeaux-nicotine combination was used. As 

 we expected, the results varied from almost perfect control to practically no 

 control; however, we are pleased to say that in the majority of cases, good results 

 were obtained. For example, in thirty-two graperies which we inspected in 

 the Vineland-Beamsville section, good commercial control was secured in no 

 less than twenty-six of them. In the other six, the results were unsatisfactory, 

 due to lateness or to carelessness in making the application. 



The most important lessons learned from this year's experience are as 

 follows: 



(1) That thoroughness in spraying is more than half the battle. In order 

 to do thorough work, it is essential to use angle nozzles, good pressure and liberal 

 quantities of the spray mixture. By liberal quantities we mean sufficient material 

 to wet practically all the under surface of the foliage — the exact amount required 

 to do this may vary from 120 to 250 gallons per acre, depending on the density 

 of the foliage. 



(2) That early spraying i.e. before any nymphs have transformed to adults, 

 will give the most clean cut results. 



Dusting 



This year lime-nicotine dust containing 2.2 per cent, nicotine was tested 

 on a fairly extensive scale when the hoppers were in the nymphal stage. The 

 dust was applied by means of a Niagara power duster with a vineyard distributor. 

 When the application was made under ideal weather conditions, the dust brought 

 most of the nymphs to the ground, and results comparable with those secured 

 from thorough spraying were obtained. It was observed that a considerable 

 percentage of the nymphs brought to the ground recovered, and that sbme of 

 them returned to the vines by crawling up the posts and grape trunks. However, 

 only an inconsiderable number of them actually got back to the leaves. (In 

 one dusted grapery we noticed ants carrying the nymphs off). Different amounts 

 of dusts varying from 20 to 60 lbs. per acre were used, but out experience indic- 

 ated that 35-40 lbs per acre was the most economical and effective dosage. 

 With improved dusts and machinery, we are of the opinion that this amount 

 could be cut down very materially. 



With our present outfits effective work can only be done with contact dusts 

 when the atmospheric conditions are very calm. Unfortunately, as we found 

 out from experience, these conditions, in sections bordering the Lake Ontario, 

 are seldom present when wanted. Only too frequently this past season dusting 

 operations had to be suspended even at night and early in the morning because 

 the air was not sufficiently calm. Dusting is largely a fumigation process — it 

 is the nicotine fumes which kill the insects — and if some means could be devised 

 whereby the fumes could be held longer among the foliage, the efficiency of 

 contact dusts would be greatly increased. It is possible that this could be effected 

 by shooting the dust into a light canvas structure with a top and two side pieces, 

 suspended over the grape row from a boom. This idea is given for what it is 

 worth. 



