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BETTER FRUIT 



Page 2(p 



and because of the scarcity of the twig- 

 borers in the orchard it would not be 

 wise to draw any definite conclusions 

 without further experiments. The num- 

 ber of trees treated with lime and sul- 

 phur and their total freedom from borers 

 seemed great enough when compared 

 with the small number of check trees 

 and other sprayed trees with quite a 

 number of borers to justify the con- 

 clusion that "Rex" lime and sulphur is 

 a perfectly effecti\-e spring remedy for 

 this pest. For some unknown reason 

 home prepared lime and sulphur used 

 at the same time as the "Rex" spray, but 

 in another orchard, apparently did very 

 little good. 



Mr. W. T. Clarke, in bulletin 144 of the 

 California Experiment Station at Berke- 

 ley, gives some interesting data in regard 

 to sprays applied at different times of 

 the winter and spring for the control of 

 twig-borer. He found that during the 

 winter season the little larvae, in their 

 hibernating cells, could not be killed 

 either with kerosene emulsion or lime 

 and sulphur. He discovered, however, 

 that the larvae become active in these 

 cells for some time in the spring before 

 emerging, and that during this period of 

 activity the cells are rendered more or 

 less permeable to a spray, and then the 

 larvae can be successfully combated with 

 a contact insecticide. In regard to the 

 effective use of a spring spray of lime and 

 sulphur Mr. Clarke says: "The lime-salt- 

 and-sulphur-sprayed trees, when the 

 spraying had been done in the early 

 spring, showed the most satisfactory 

 results of any at the time of examina- 

 tion. On the various station orchards, 

 comprising over ]2,000 peach trees, the 

 average number of bud worms was about 

 one to every ten trees, and this average 

 was maintained on many orchards in the 

 district. Indeed, it was a difficult matter 

 to find the worms in these orchards, and 

 it was only by the closest scrutiny of the 

 trees that they could be located in them. 

 The general condition of these trees was 

 excellent and a marked absence of 'curl- 

 leaf was noted. An examination of the 

 trees in one orchard that had been 

 sprayed with the lime, salt and sulphur 

 early in February showed that the attack 

 of bud worms was severe. On many of 

 the trees from which we cut the worms 

 we found from five to nine to the tree. 

 The general condition of the trees was 

 good and a very small amount of 'curl- 

 leaf was present." 



From this season's experiment at Clif- 

 ton, from the experience of the man)' 

 Colorado orchardists who have used 

 lime and sulphur for the control of this 

 pest and from the apparent success of 

 this spray in California, we feel justified 

 in recommending it for use in sections 

 where there is injury from twig-borer. 



While arsenate of lead was a total dis- 

 appointment in this season's test it has 

 previously been used with good success, 

 and IS no doubt effective when applied at 

 the proper time. E. P. Taylor, in his 

 annual report of the Western Slope Fruit 

 ln\estigations for T.)(H), gives some very 

 saliNfactory results from the use of fi^•e 

 piiinuls of arsenate of lead to fifty gal- 



lons of water, applied on April 14, at 

 which time the majority of the blossom 

 buds showed their pink tips. Comment- 

 ing upon the results of his experimental 

 work he wrote: "It may be said that 

 arsenate of lead, applied in the spring at 

 the time the buds of the peach are begin- 

 ning to open, will control the peach 

 twig-borer as effectively and cheaply as 

 the lime and sulphur wash, up to this 

 time the most universally used." 



Colorado peach growers are fortunate 

 in that they do not, as a rule, have the 

 crown-borer of the peach to fight. In 



ERECT LAWSONS CYPRESS 



many of the peach-growing sections of 

 the United States this is one of the worst 

 pests preying upon the trees. Unlike 

 the I wig-borer, which feeds upon the 

 tender twigs and fruit, this species feeds 

 just beneath the bark at the crown of 

 the tree, often girdling them. The adult 

 insect is a moth which, at a glance, more 

 closely resembles some kind of a bee or 

 wasp than a moth. The eggs of this 

 moth are deposited on the trunks of 

 peach trees, and the little worm-like 

 larave hatching from them eat their way 

 beneath the bark and there feed until 

 full grown. 



The work of the insect may be detected 

 by masses of gum in which are mixed 

 pellets of wood or borings which the 

 larva chews to pieces as it feeds. These 

 gum masses usually occur at or just 

 below the ground line. Their presence 

 aids in the fight against this pest, as the 

 burrows in which the larvae feed can 

 always l.)e found beneath. By using the 

 point of a knife or a piece (if wire this 



burrow may be followed and the larva 

 located and killed. No better method 

 for combating the peach tree borer has 

 ever been devised than worming, as the 

 above process is called, with a knife or 

 some other implement that can be 

 inserted into the burrow. Worming 

 should be done both in the fall and 

 spring. While the larvae often do not 

 attain a sufficient size in the fall to be 

 readily detected a great many of them 

 can be killed before they get in very far, 

 thus preventing the damage that they 

 might do before they could be detected 

 in the spring. 



Various other methods of control have 

 been tried, such as wrapping the trunks 

 with tar paper to keep the moths from 

 depositing their eggs, applying repel- 

 lants for the same purpose and mound- 

 ing the soil up above the crown of the 

 tree. This last named method is valu- 

 able in that where it is used the larvae 

 may be induced to enter the trunk of a 

 tree some distance above the surface of 

 the ground, then when the mound is 

 removed the worms are high on the 

 trunk, where they can be much more 

 easily destroyed than if they were lower 

 down. 



It is very fortunate that none of the 

 scale insects have as yet been found 

 abundantly on peach trees in Colorado. 

 The San Jose scale has been seen on a 

 very few trees, but not plentiful enough 

 to do any serious injury. This pest 

 seems to confine its attacks more to the 

 apple in the few orchards where it has 

 been found. In one section of the Grand 

 Valley a scale insect closely allied to the 

 dreaded San Jose is found. Samples of 

 this scale were sent to Professor T. D. A. 

 Cockerell, entomologist in the State Uni- 

 versity at Boulder, who kindly deter- 

 mined it for me as the Putnam scale. 

 Only in rare cases has this insect been 

 found doing serious injur)'. 



There are other scales of minor impor- 

 tance that are sometimes found on peach 

 trees; all of these insects may be suc- 

 cessfully combated with an early spring- 

 spray of lime and sulphur or soluble oil. 

 If "Rex'' lime and sulphur is used it 

 should be diluted by using one part of 

 the "Rex" solution to ten parts of water. 

 A good home-made lime and sulphur is 

 as effective as the "Rex," and should be 

 made with twenty pounds of lime and 

 fifteen pounds of sulphur to fifty gallons 

 of water. Soluble oil is ordinarily used 

 at a strength of one part of the oil to 

 from fifteen to twenty parts of water. 



While spring spraying for the control 

 of these scale insects is probably more 

 advantageous than a spray at any other 

 time good work can also be done with a 

 fall application. Very often orchardists 

 would rather spray in the fall because 

 there is more time to do so than in 

 the spring. 



In bulletin 1.52 of this experiment sta- 

 tion an account was given o\ the life 

 habits and injuries from the brown mite, 

 and also the red spider. This mite passes 

 the winter almost entirely in the egg 

 stage. These eggs are tiny, red spherical 

 shaped, glassy objects, usually deposited 

 in or near crotches of the branches. 



