BETTER FRUIT 



EDITOR: W.H.WALTON 



STATE ASSOCIATE EIUTORS 



OREGON — C. I. Lewis, Horticulturist. 



WASHIN'OTON — Dr. A. L. Melaiuler. Entomologist; 

 O. M. Morris, Horticulturist, Pullman. 



('Ol>nRADO — C. P. Gillette. Director and EntomolOKLst ; 

 E. B. House. Irrigation Expert, State Agricultural College, 

 Ktirt Collins;. 



\RlZoXA- E. P. Tavlnr. Horticulturist, Tucson. 



WISCONSIN— Dr. E. D. Ball. Madison. 



MONTANA— H. Thoniber, Victor. 



CALIFORNIA — C. VV. VVoodwort li , Entomolo;riat. Berke- 

 ley; W. H. Volck. EntomolOirist. Watsouville; l.#on D. 

 Batchelor. Horticulturist. Riverside. 



INDIANA— H. S. Jackson. Palliologist, Lafayette. 



An Illustrated Maga/inc Devoted to the Interests 



of Modern, Progressive Fruit Growing 



and Marketing. 



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A^OLTIME XIV 



Portland, Oregon, June 1, 1920 



Number 12 



The Flat-Head Apple Tree Borer-Methods of Control 



By Fred E. Brooks. Entomologist, Deciduous Fruit Insect Investigatiors U. S. Departmert of Agriculture 



OF the several kinds of wood and 

 bark boring insects which attack 

 fruit trees in the United States, 

 the flat-headed apple-tree borer is one 

 of the most widely known. The adult 

 form is a medium-sized beetle, native 

 to American forests, which has attacked 

 cultivated fruit trees since the pioneer 

 days of orcharding in this country. It 

 is now known to occur in nearly every 

 state of the union and also in southern 

 Canada. Throughout this region it in- 

 jures every year a great variety of fruit 

 trees, as well as many kinds of shade 

 and forest trees. 



Trees of almost any size after they 

 are one or two years old may be at- 

 tacked, but, as a rule, injury is confined 

 to those that have already been weak- 

 ened by some other agency, or that are 

 abnormal either in their jjosition or in 

 general health. Trees that are newly 

 transplanted, that have assumed a lean- 

 ing position, that are deficient in vigor 

 from starving or over-bearing, that 

 have been subjected to the injury of 

 the trunk or branches by sun-scald or 

 other diseases or weather conditions, 

 or that have suffered injury from tools, 

 rodents, or insects, invite attack by this 

 insect. On the other hand, trees that 

 are normally vigorous, u|)right in 

 growth, and have sound, healthy bark, 

 very rarely, if ever, are injured by the 

 flat-headed borer. 



Location and Nature of Injury 



Injury to trees is done by this insect 



only while it 

 stage, and the 

 mon name from 

 is flat-beaded, 

 enier the bark 

 larger branches 



is in the larva 

 species receives 



or grub 

 its com- 

 the fact that the grub 

 The grubs or boreis 

 of the trunk of the 

 and feed between the 

 bark and sapwood until about full 

 grown. The\ then usually burrow a 

 short distance into the wood, where 

 they pass the winter and, in the spring 

 following, change to the pupa, or rest- 

 ing stage and a little later into beetles. 

 The burrows in the bark and sai)wood 

 are broad and irregular in shape, the 

 form depending very much upon the size 

 of the tree an 1 thickness of the bark. 

 In cild trees most of the feeding is done 

 in the tliick inner bark, and the wound 

 made is often more or less circular in 

 outline. In xoung trees tlie feeding is 



mostly from the sapwood, 

 wound is likely to 

 often encircling the 

 The borer while 

 clear space around 

 free movement, but 

 fion behind with a compact 

 gested wood particles. In 



and the 



be more elongate, 



tree and killing it. 



fec-.ling keeps a 



itself to allow of 



packs the excava- 



mass of di- 



large trees 



injury almost invariably is confined to 

 the sunny side. In such a place a 

 wound that was small in the beginning 

 may be enlarged year after year by 

 succeeding generations of the borers 

 working around the borders of the 

 woun<l at the point where the live and 

 dead tissues of the tree meet. 



Scarcely any castings are thrown out, 

 and the place where borers are at work 

 is not always clearly marked on the 

 surface of the bark. Injured spots, 

 however, usually can be detected from 

 the outside by the darker color anti 

 slight depression of the bark and often 

 by cracks which form in the bark, 

 through which the frass (excrement) 

 shows. I'sually, where an area on the 

 trunk of a tree is killed by borers, a 

 strip of dying wood soon extends some 

 distance above it, and this strip is in 

 turn attacked and enlarged by the 

 borers. 



Food Plants 



Following trees and shrubs are known 

 to be attacked by the flat-headed apple 

 tree borer: Apple, pear, peach, apricot, 

 l)ium, prune, cherry, ([uince, currant, 

 walnut, pecan, hickory, Carolina pop- 

 lar, willow, weeping willow, beech. 



lliil-lH:idc 

 trees at 



In 



ipple In 

 ost any 



m (if the yeai-. 



chestnul, oak, elm, hackberry, syca- 

 more, mountain ash, service berry, 

 hawthorn, redbud, sugar maple, soft 

 maple, horse-chestnut, linden, Japanese 

 persimmon, and box elder. Where or- 

 chards are planted adjacent to wood- 

 lands, the beetles often come from the 

 forest trees and deposit eggs in the fruit 

 trees before they have recovered from 

 the shock of transplanting. The borers 

 hatching from the eggs deposited on 

 the newly-set trees find the devitalized 

 bark and wood exactly to their liking, 

 and often girdle and kill many of the 

 trees. After the trees have had one 

 season's growth, they are usually safe 

 from attack so long as they are kept in 

 a vigorous condition. 



Appearance and Habits of the Insect 



The Adult 

 The adult of the flat-headed apple- 

 tree borer is a broad, flat beetle, aver- 

 aging about half an inch in length by 

 less than one-fourth of an inch in 

 width, though individuals differ consid- 

 erably in size. It tapeis from the cen- 

 ter towards both ends. The color of 

 the back is dark brown, indislinctly 

 marked with sjxits and irregular liands 

 of dull gray, the whole, when viewed 

 under certain conditions of light, hav- 

 ing a slight brassy sheen. The under- 

 parts of the body are bronze, and the 

 back beneath the wings is brilliant me- 

 tallic greenish blue. In flight the 

 beetles produce a musical buzzing 

 sound not unlike the humming of a bee. 

 The beetles issue from the wood soon 

 after the blooming period of 

 the apple, anil remain ujion the 

 wing for several weeks. They 

 are active, run rapidly, and 

 take Might (piickly wlien dis- 

 turbed. On hot, clear days they 

 may be found on the sunny 

 side of the trunks and larger 

 branches of their host trees, 

 where mating lakes place and 

 where the eggs are deposited. 

 Tlie female spends much time 

 running with an intermittent 

 gliding movement over the 

 bark, feeling out places with 

 lier ovipositor for laying her 

 eggs. When a suitable crack or 

 opening in the bark is found 

 she inserts her slender, fube- 



iiMid in inlested 

 Natural size. 



