2 FLOUR PASTE AS A CONTROL FOR RED SPIDERS. 



ers of sulphur 15 pounds, water 100 gallons, and flour paste (as a 

 "sticker") 4 gallons — a formula advised for red spiders in Bulletin 

 No. 154 hy Mr. W. H. Volck of the California Experiment Station, 

 it was observed that the mixture spread over the leaves very readily. 

 The flour paste was evidently the spreader and was accordingly 

 mixed with the lime-sulphur solutions. The result was a smooth 

 mixture which spread over the foliage very readily and gave unusual 

 results as an arachnicide. The proper proportions were found to be 

 4 gallons of paste (4 pounds of flour) to 100 gallons of spray. Table 

 I graphically represents the relative effectiveness of the lime-sulphur 

 spray, with and without the flour paste, for the red spider on hops. 



Table I. — Relative effectiveness of lime-sulphur spray, icith and iritJiont flour 

 paste, against the red spider on hops in the Sacramento Valley of California, 

 in J9J2. 



Formula. 



Number 

 of mites 

 present. 



Number 

 of mites 

 killed. 



Per cent 

 of mites 

 killed. 



Lime-sulphur, -Se" Baum^, 1-75; flour paste, 4-100. 

 Lime-sulphur, 36° Baume, 1-75 



f)98 

 360 



692 

 1.35 



99.0 

 37.5 



From the foregoing table it is very evident that the use of flour 

 paste greatly increases the efficiency of the lime-sulphur spray and 

 that without the paste the spray was very ineffective. These results 

 were substantiated by other experiments and, by a check experiment 

 with the flour paste, 4-100. used without the lime-sulphur, it was 

 found that the increased efficiency was mainly due to the spreading 

 effect of the paste. 



Having proved a most efficient, cheap, and convenient spreader for 

 the lime-sulphur solutions, some experiments were conducted with 

 flour paste in combination with nicotine sulphate upon the hop aphis 

 (Phorodon humul'i Schrank). (See Table II.) 



Table II. — Results obtained &// spraying iritli comhinations of flour paste and 

 nicotine sulphate in different proportions ayainst the hop aphis, Sacratnento 

 Valley of California, 1912. 



Formula. 



Number 



lof aphides 



present 



Nicotine sulphate, 1-2,000: flour paste, 4-100 ! 627 



Nicotine sulphate. 1-2,500: flour paste, 4-100 1 611 



Nicotine sulphate, 1-3.0(X); flour paste, 4-100 1,668 



Nicotine sulphate, 1-3,000: flour paste, 4-100 148 



Aphides 

 killed. 



Per cent. 

 100 

 100 

 99 

 99 



Cost per 



100 

 gallons. 



Cents. 



0.71 



.60 



.50 



.50 



From the preceding table it is very evident that flour paste, 4-100, 

 is a very effective .spreader for nicotine sulphate. 



The efficiency of flour paste as a spreader was A^ery evident to the 

 writer, but it was deemed advisable thoroughly to illustrate this point. 



