Page 28 



BETTER FRUIT 



June 



Figure 4— PEACH LEAVES CURLED BY GREEN PEACH LOUSE Figure 6~TVV0 GREEN PEACH LEAVES AND TWO 



Figure 5— BLACK PEACH APHIS ON TWIG IN EARLY SPRING FADED, CAUSED BY ATTACK OF BROWN MITES 



third broods. Often this injury to the 

 fruit is extensive enough to render great 

 quantities of it vmmarketable, and we 

 have a condition of peaches comparable 

 to that of apples as a result of codling- 

 moth attack. The larvae usually enter 

 the fruit from the stem end and may 

 feed entirely within the flesh, but very 

 often they eat their way into the pits. 

 Affected peaches may be detected by an 

 issuance of sap mixed with little pellets 

 from the fruit which have been chewed 

 up by the larvae. This sap hardens on 

 the outside and peaches so affected are 

 often termed "gummy peaches." 



The pupal stage of the insect is said 

 to last from six to twelve days, the first 

 brood remaining pupae for the longest 

 time. This period is passed by the first 

 brood pupae, according to Mr. Clarke, 

 principally in curls of bark on the trunks 

 of trees. They may, however, be found 

 in other places, such as between two 

 peaches which come in contact with each 

 other, under rubbish on the ground, etc. 

 The cocoon which they make is a very 

 flimsy one; in fact so much so that in 

 realit}' it should not be termed a cocoon. 

 A few strands of silk are spun by the 



THE LARVAE 



larvae, and to these strands the pupae is 

 attached by means of hooks at the tip 

 of the abdomen. The second and third 

 brood pupae mr)re often pupate in the 

 suture at stem end of peaches than 

 underneath the bark, and the semblance 

 to cocoons is even less than in the case 

 of the first brorid. 



The twig-borer moth is a tiny gray 

 insect about one-quarter of an inch in 

 length, and having a wing expanse of 

 about one-half inch. It is quite a beauti- 

 ful little moth with its dark gray, fringed 

 wings. They are verj' seldom seen in 

 the orchards by the fruit growers 

 because of their small size, their close 

 resemblance to projections of the bark 

 and their habit of resting perfectly still 

 during the daytime on the trees. 



Eggs of this insect were first found by 

 Dr. Marlatt, who kept the moths in con- 

 finement and found that they were 

 deposited above the bases of the petioles 

 of the leaves. Mr. Clarke, in California, 

 found the eggs of the first brood in the 

 orchard in the same location as described 

 by Marlatt. He found, however, that the 

 eggs of the second generation of moths 

 were laid not on the twigs, but on the 

 fruit and in the edge of the stem end 

 depression; the eggs of the third genera- 

 tion were found in cracks of the bark 

 or exposed on its surface just above the 

 crotches formed by the new wood and 

 on the old wood. 



The eggs are pearly white, changing 

 to a deep yellow before hatching. They 

 are quite conspicuous, being about one- 

 sixtieth of an inch in length. These 

 observations of the egg and egg-laying 

 habits of the insect, made in California 

 by Mr. Clarke, are very interesting, as 

 they are the first recorded from studies 

 made under the natural conditions of 

 the orchard. 



The experiments testing the different 

 insecticides for the control of this pest 

 were all conducted in the spring of 1910, 

 and were combined with the green-peach 

 aphis experiments recorded here, with 

 the discussion of the latter pest. 



The comparative scarcity of twig-borer 

 the past season made il difficult to secure 



much reliable data from the experiments. 



The following table, compiled from 

 data gathered in the W. C. Strain orchard 

 at Clifton, Colorado, gives the results 

 attained with different insecticides in 



controlling the 



peach twig 



-borer 







Strcilgtll 



Wilted 



Trees 



Insecticides Used 



Used 



Tips 



Exoviincd 



Black Leaf 



1-30 



5 



3 



Black Leaf 



1-40 



6 



3 



Black Leaf 



1-50 



3 



3 



Black Leaf 



1-70 







1 



Black Leaf "40" . 



. 1-600 







2 



Black Leaf "40" . 



. 1-800 





i 



Black Leaf "40" . 



. 1-1000 



6 



i 



Lime and Sulphur 



. 1-10 







12 



Lime and Sulphur 



. 1-11 







12 



Soluble Oil 



1-20 



4 







L''nsprayed 





16 



i 



Trees sprayed March 7, examined April 26. 



While it is not thought that this year's 



experimental )rk with twig-borer would 

 justify the drawing of many conclusions 

 there were at least some helpful hints 

 gathered in regard to its control. It may 

 be seen that "Rex" lime and sulphur 

 gave- perfect results. ]\Iore trees were 

 sprayed with the "Rex" mixture 1-10 and 

 1-11 than with any other insecticide, yet 

 in a very careful examination of twelve 

 trees by Mr. Strain and myself we failed 

 to detect the presence of a single wilted 

 twig because of the work of the borer. 

 On four check trees in the same block 

 sixteen wilted tips were counted, and on 

 twenty-two sprayed with tobacco prepa- 

 rations and soluble oil thirty-one wilted 

 tips in all were counted. One tree 

 sprayed with Black Leaf 1-70 was free 

 from wilted tips, and also two trees 

 sprayed with Black Leaf "40" 1-600. The 

 fact that the higher strengths of Black 

 Leaf did no appreciable good would indi- 

 cate that it was simply a matter of 

 chance that the one tree sprayed with 

 the weaker strength indicated good 

 results. Black Leaf "40" l-fjOO appar- 

 ently gave good results, however, because 

 of only two trees having been treated. 



