MICHIGAN EXPERIMENT STATION BULLETINS 333 



they notust be applied before the moths ascend the tree, and must be 

 kept in a condition to act as a barrier, whenever tlie ground is not frozen 

 from October to Ma3'. As this is a serious taslc and as, even at the best, 

 some of the insects may evade the traps, the principal reliance is upon 

 spraying with arsenites. 



Some failures are reported, but it is probable that the spraying was 

 delayed too long, or that it was not thorough. The eggs hatch about the 

 time the trees blossom, and if the trees have been infested in previous 

 years, a thorough spraying should be given just before the blossoms open, 

 and it should be repeated as soon as the blossoms have fallen, and again 

 if necessary. The spray should be in the form of a fine mist and should 

 cover every leaf. To hold the arsenite upon the trees it is well to add lime 

 to the spraying mixture. This will also aid in determining when the work 

 has been thoroughly done, and will permit the use of a larger amount of 

 Paris green, or other arsenite. Although it will add considerably to the 

 cost of the mixture, from the fact that nearly all varieties are attacked 

 upon their foliage, if not upon their fruit, by the apple scab fungus, it will 

 generally pay to add Bordeaux mixture to the spraying material. If 

 Bordeaux mixture is not used, a good formula will be, one pound Paris 

 green, ten pounds of lime and one hundred and fifty gallons of water; or 

 use one fourth of a pound of Paris green with forty gallons of Bordeaux 

 mixture. 



BLACK PEACH APHIS. 



For several years the orchards in the vicinity of Grand Rapids, and in 

 various sections along the lake shore, have been injured by w^hat is 

 known as the " Black Peach Aphis." This is a brownish-black, shining 

 insect that feeds upon the roots of the trees. The individuals are so small 

 that they can barely be seen with the naked eye, but they often appear 

 in such large numbers on the roots that they are easily detected. These 

 insects suck the sap from the roots, giving them a flabby appearance, and 

 the effect upon the foliage is so marked that one familiar with their w^ork 

 can readily detect their presence by this alone. The leaves are generally 

 more or less drooping, and are of a dark yellowish-green color; they are 

 generally smaller than the leaves on healthy trees and are folded and 

 wrinkled. Another characteristic is that numerous red spots, due to the 

 work of fungi, appear on the leaves. Later in the season, the injured 

 portions fall from the leaves, which appear as if perforated with a charge 

 of shot. Trees having the appearance given above, will almost certainly 

 be found affected with the aphis, but in a few cases the same appearance 

 has been noticed where the trees were planted deeply, especially if they 

 were in hard-pan or a cold, wet soil. Most, if not all, of the Michigan 

 nurseries are free from this insect, but it may appear unexpectedly in any 

 of them, or upon trees brought in from without the state, and, as it is 

 so destructive, it will pay to take precautions to destroy the insects if 

 they should be on the trees. This can be done by dipping the trees in 

 strong tobacco water, made by soaking one half bushel of stems in a bar- 

 rel of water. If, later on, it should appear upon the trees growing in the 

 orchard, the cheapest and most effectual remedy will be the application of 

 from one half to one bushel of unleached wood ashes about the trees. 

 It will be more effectual if the soil is scraped back over a circle as large as 

 the branches of the tree, and replaced after the ashes have been scattered. 



