THE MONTHLY BULLETIN. 



471 



TOBACCO TREATMENT FOR APHIDS. 



By O. E. Bremner, County Horticultural Commissioner. Santa Rosa, Cal. 



It has been well established for a number of years that tobacco extracts or 

 nicotine sprays are effective in the control of aphids and other soft-bodied insects. 

 However, the most efficient means of application, as well as the most economic 



solutions to use. are problems with which we si ill 

 wrestle. 



During the past few years the Pacific coast has 

 been waging an uphill fight against an Increasing loss 

 from the depredations of various forms of aphids, 

 and perhaps the hardest attack has been against the 



applet ti s. prunes, walnuts and pears also suffering 



greatly. The appearance of the pear-root aphis has 

 spurred us to greater activities to find some remedy 

 for root-infesting forms. With this end in view, tin- 

 soil around some old greening apple trees which were 

 infested with woolly aphis was well saturated with 

 a solution of "Black Leaf 40" at a strength of about 

 1 part of the solution to 1,000 parts of water. 

 Shortly before treatment the soil was spaded and the 



f ling roots were found to be white with woolly 



aphis, but today these trees are almost free from 

 aphis and no solution for control has been used on 

 the tree itself. 



The success of this experiment led us to carry on 

 a larger one last season and in this case a plot of 

 .'SO apples and 270 old pear trees was used. This orchard when inspected by Mr. 

 Weldon and myself a few years ago was badly infested with the pear-root aphis and 

 woolly aphis: the soil is of a sandy loam texture and situated so as to be well 

 drained. Instead of using tobacco extract we used tobacco waste. Twenty-five 

 hundred tobacco plants were grown, being set 12 inches by 3 feet 10 inches in rows 

 on a plot of good ground. From the tobacco produced 555 pounds of cured leaf was 

 sold at 20 cents per pound: the refuse was chopped and placed in trenches around 

 the trees, 5 pounds being used for each tree. The first was applied in November. 

 I he rest toward the end of February and it was the last application that gave 

 success, for it is extremely hard to find an aphid in this orchard today except on the 

 eight trees where the tobacco was applied in November. 



When it is not possible to grow tobacco, the waste from cigar factories can be 

 procured very cheaply. Last year we bought it in bales at 1* cents per pound 

 f. o. b. San Francisco; this brings the cost per tree down very low. In one case 

 this waste was used as a spray; it was soaked in the bale in 2.000-gallon tanks. 

 first at the rate of 1 pound of waste to 4 gallons of water for 48 hours, then the 

 same tobacco was put into another tank at the rate of 1 pound to 2 gallons of water 

 for 4 days. A chemical analysis by the insecticide laboratory at Berkeley of the 

 solution in the first tank, showed that it contained .02 per cent of nicotine or 

 practically the same amount as a 1 to 2,000 dilution of "Black Leaf 40-" 



The spray tank was loaded directly from the tanks and the solution used in 

 combination with commercial flour paste jelly 6 pounds to 100 gallons, and atomic 

 sulfur 10 pounds to 100 gallons. This combination not only cleaned the trees of 

 aphis and red spider but also canker worms and tent caterpillars. While this treat- 

 ment for root infesting forms of aphids is still in the experimental stage, we believe 

 it will recommend itself to the horticultural commissioners and growers for at least 

 a trial. 



