THE AGRICULTU RAL COLLEG E OF MICHIGAN. 



EXPERIMENT STATION.— BULLETIN NO. 39.— SEPTEMBER, 1888. 

 DEPAETMEKT OF ZOOLOGT AND EKTOHOLOGT. 



EXPERIMENTS WITH INSECTICIDES. 



CODLING MOTHS. 



For the past eight years I have demonstrat- 

 ed annually the value and safety of London 

 purple, arsenite of lime, as a speciflc against 

 the codling moth. 



This season (1888) I repeated the experi- 

 ments with three objects in view. First, to 

 ascertain the relative value of spraying once, 

 twice, and three times. Secondly, to study 

 the efflects of the mineral on the foliage when 

 used more than once, and thirdly, to note if 

 the quantity of fruit on a tree was important 

 in the results attained. As previously report- 

 ed, I have several times sprayed the trees only 

 once; just after the blossoms had all fallen, 

 with perfect success; and that when the ap- 

 ples on trees adjacent, not sprayed, were seri- 

 ously injured. Last season; as reported, once 

 spraying was not so effective; yet, still enough 

 so, not only to pay well, but in most instances 

 practically good enough. As we had heavy 

 rains last year, soon after the treatment, I 

 was led to believe that the rains caused the 

 diminished effects. 



Again, reports came to me of the injurious 

 effects of the poison in blighting the foliage, 

 even though as dilute as one pound to one 

 hundred gallons of water. I hoped that by 

 applying the poison on some trees once, on 

 others twice, and on others three times, I 

 might be able to formulate some rule, and the 

 following are the 



CONCLUSIONS. 



It is more and more patent that it pays remark- 

 ably well to spray our apple trees. It is, if not the 

 only way, certainly by far the cheapest and most 

 practical way that we can conquer this terrible 

 apple pest and secure nice, sound marketable apples. 



We should never spray until the blossoms fall from the 

 trees. To spray earlier endangers the bees, and the 

 honey they gather, and is too early to give the best 

 results. Too early, first, because it is not needed till 

 the blossoms fall, and the earlier it is scattered the 

 sooner it will disappear, or lose its effect ; and sec- 

 ond, because the longer the poison is on the trees the 

 more likely it is that it will be washed off by heavy 

 rains. We should, however, spray as soon as the 

 blossoms have all fallen from the trees. At this date no 

 possible harm can come to bees or honey ; to wait 

 longer, is to wait so long that some of the larva will 

 already have entered the fruit, and be safe from the 

 poison. I think we shall be in time if we wait tm 



the blossoms have (alien, even from such trees as 

 Northern Spy, where the blossoms are slow to ap- 

 pear and so, late to fall. In case there is no heavy 

 rain, this one application is enough. In csfee there is 

 a heavy rain, especially if the trees are bearing 

 sparingly, it will often pay well to spray a second 

 time, two weeks after the first. 



STBENGTH OT THE MIXTUEB. 



The proportion of the mineral (London Purple or 

 arsenite of lime, as 1 have proved some years since, 

 is the best) to the water is important. One l-l) pound 

 to one hundred (100) gallons of water is abundantly 

 strong. And as even this strength is sometimes in- 

 jurious to the foliage, especially if applied so thoro- 

 ughly as to insure contact with each apple, we 

 should never use a stronger mixture. Even three- 

 fourths of a pound to one hundred (100) gallons will 

 often prove more satisfactory than a stronger mix- 

 ture, especially so if two applications are to be made. 

 The second application should never be stronger 

 than one pound to one hundred and fifty gallons 

 of water. 



PUMPS, ETC. 



As spraying with insecticides Is becoming so ex- 

 ceedingly profitable, every person with few or many 

 fruit trees will desire to know of and to seoure the 

 best pump. 



For a large orchard, I know of no pump compara- 

 ble with the Victor Field Force Pump. 



This runs with gearing attached to the hind wheels 

 of any common wagon ; so the force that draws the 

 wagon does the pumping at the same time. The 

 pump is double acting, and by driving at a rapid 

 walk of the horses, the liquid is thrown with great 

 force and so is thoroughly scattered, and very likely 

 to reach the calyx of every apple. A second pipe 

 discharges into the barrel with great force, and so 

 the poison is kept stirred. This pump operates so eas- 

 ily ,the horses doing the work,that a lazy man is liable 

 to do good service, even if the wind blows, and he has 

 to go on all four sides of each tree. In truth it is fun 

 to simply drive and man the hose. I think it will 

 often pay for four or five neighboring farmers to 

 unite and buy this pump at $30, its cost, rather than 

 for each to buy a cheaper one. One farmer might 

 buy this pump, and then spray all the orchards in 

 the neighborhood. His neighbors could well afford 

 to secure his services, and doubtless would generally 

 be very glad to do so. I urge this pump, for it is 

 natural (or the average man to do more thorough 

 work when the work is easy. 



This same company, Field Force Pump Company, 

 Lookport, New York, also makes a fine hand pump, 

 the "Perfection Outfit," which is reasonable in 

 price and stirs the liquid a.utomatioally. The Gradu- 

 ating Nozzle works well, and can be made to throw 

 much or little, and also maintain the force. This 

 nozzle and the Perfection pump make a most ex- 

 cellent combination. 



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