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Observations on the life history of the insect were made during the summer and though necessarily incomplete, some of the results are given herewith. June 9No sign of the Oriental peach moth at Greenwich or New
Haven. June 23-A few tips infested at Greenwich, the larvae one-half or
two-thirds grown. June 25–First infested tip seen at New Haven. June 30-Most of larvae have left twigs at Greenwich; signs of one
having entered a peach-doubtful.
Grouping the adult emergence (from larvae collected June 23,
15 Aug. 21-Sept. 1.
14 Sept. 1-9.
2 Sept. 9-31
0 All larvae spinning after August 25 hibernated and did not pupate. Larvae were abundant in fruit from September 13 till October 2, but none of the larvae obtained at this time pupated.
We estimate the presence of at least three broods in Connecticut, but it is evident that adults of the insect did not reach the maximum period of abundance in 1924 until August and that the larvae were most abundant from August 15 until the last of September. From this it is apparent that some of the control
ineasures must be used towards the latter part of the season if the insect is to be controlled effectively.
A general summary of the habits of the Oriental peach moth has already been givent and it is advisable to mention here only such features as bear directly on its control, or affect its economic status. The eggs are laid on the underside of the peach foliage and sprays must be made to cover the leaves thoroughly if control is to be secured. The very short length of the egg stage naturally necessitates frequent nicotine or other egg sprays and at least one a week would appear to be necessary from this standpoint alone.
The young larvae soon after hatching may be killed with arsenicals but the older larvae are not easily killed as has been repeatedly demonstrated. Thus we find arsenical applications of little use in mid-summer when the larvae are migrating from twigs to fruit, but later in the season when many go directly into the fruit, such applications may possibly be more effective.
The larvae frequently spin on the ground or near the ground on the trunk and clean cultivation together with such controls as the use of paradichlorobenzene, winter strength lime-sulphur and the like should be of help. The silken cocoon of the larva is water proof and it is not known exactly how sprays of the sort mentioned affect the larvae. Owing to the fact that many of the drop fruits which fall shortly before harvest time contain larvae, it would seem advisable to remove this fruit from the orchard and destroy it as soon as possible because it furnishes material for reinfestation.
Larvae entering peaches some time before ripening usually leave conspicuous evidence of the infestation due to the fact that gum is rapidly thrown out by the growing peach. Early fruit, too, is often infested by larvae migrating from the twigs. As a result there is usually little difficulty in grading out early infested peaches. Larvae which enter the fruit, however, when the latter begins to ripen (owing to the fact that little gum is thrown out and to the fact that many very minute larvae enter direct from the egg) cause much infested fruit which cannot be detected. Many of the larvae enter at the stem end and as shown in the illustrations (See Plate XXVII, a), leave only a very insignificant trace at the point of entrance. Still others enter through the side of the fruit and the frass thrown out at the point of entrance may be washed off or rubbed off in handling which results in a fruit wholly without external signs of infestation. Such fruit cannot be graded out and some of it naturally finds its way to the consumer as well as being shipped into districts where the Oriental peach moth is not yet established; sometimes with unfortunate results. 1 Britton, W. E., Conn. Agr. Exp. Sta., Bull. 256: 284–287; 1923. Peterson, Alvah, Journal of Economic Entomology, 13: 391–398; 1920.
We have been much surprised at the amount of fruit infested in some orchards in 1924, especially when the amount of twig injury was relatively small as will be seen in Table 4. Such an increase may be due to the normal increase of the pest but there are also other possibilities-namely that of the shipment of wormy fruit from other infested sections and the consequent increase of the insect in the particular district concerned. Possibly there is also a natural flight of the moths in late summer similar to the case of the cotton moth and apparently so with the corn ear worm.
The adults are active about sundown, but have been seen near midday by some workers. There is some possibility that adults may be killed by nicotine or other dusts; but not much is known of this phase of the problem.
In general the history of the Oriental peach moth thus far has been that it appears in destructive numbers for a few years, and then becomes relatively scarce. This has apparently been the case in Maryland and Virginia, due without doubt to the beneficial action of parasites. How often these waves of injuriousness will occur remains to be seen, and what will happen next year in Connecticut is only a guess but it will probably increase in intensity in sections hitherto not greatly affected, and decrease in sections where the greatest amount of damage was done in 1924.
The only field control experiments were conducted at Conyers Farm and were made possible through the kindness of Messrs. G. A. Drew and H. B. Reed, who granted the use of the treated blocks and furnished the labor for spraying and other operations. Four plots were used each consisting of six rows containing 54 to 61 trees. Nearly all were bearing, well cared for, and fertilized so that good growth resulted and a good crop of fruit was harvested, amounting in many cases to 10 to 15 baskets per tree.
The ingredients of the sprays and dusts used are as follows: (1) Nicotine sulphate, 1 pint to 50 gallons. (2) Lead arsenate, 1 pound to 50 gallons. (3) Self-boiled lime-sulphur, 8-8-50 formula. (4) P. & G, Naphtha soap, 2 pounds to 50 gallons. (5) Casein lime spreader, 1 pound to 50 gallons in sprays containing
lead arsenate and self-boiled lime-sulphur. (6) 90-10 sulphur-arsenate dust.
Commercial nicotine dust, guaranteed 2.7 per cent. nicotine. The following applications were made on the four different blocks :
1 Guyton, T. L., Journal of Economic Entomology, 17: 415; 1924.
(1) Fungicide only--self-boiled lime-sulphur, June 9 and July 14. Self-boiled lime-sulphur plus lead arsenate, plus nicotine sulphate,
plus casein lime, June 9 and July 14; nicotine sulphate plus soap,
June 30, July 28 and August 15. (3) Self-boiled lime-sulphur plus lead arsenate, June 9 and July 14. (4) Sulphur arsenate dust followed by nicotine dust, June 9 and July
14; nicotine dust, June 30, July 15 and August 2. Counts were made of all drop fruits from 10 selected trees in the center of each block and of all fruit from five selected trees in each block, the scoring being done by exterior examination, grading into infested and uninfested lots. A number of each of these lots were then cut open and the correction for infested peaches overlooked in the first grading, applied to those figures. The results are seen in Table 3.
No conclusions will be drawn from these experiments until checked by similar tests, but they are presented here in order to show what was obtained in the way of control measures in 1924.
ORIENTAL PEACH MOTH CONTROL-1924.
TABLE 1-PICKED FRUIT FROM FIVE SELECTED TREES.
10.8 5 sprays containing nicotine sulphate 2 with lead arsenate 2,528
6.9 Fungicide plus lead arsenate
10.3 5 dusts containing nicotine, 2 with arsenate
TABLE 2-ALL FRUIT FROM FIVE SELECTED TREES.
7.8 12.1 6.0
TABLE 3—CORRECTED FIGURES FROM TABLE 1 BASED ON CUT FRUIT. 1
TABLE 4-TWIG COUNTS OF ALL TREES MADE JULY 28, 1924. Block
Injured Twigs Twigs per Tree 1
EFFECT OF VARIOUS INSECTICIDES ON THE EGGS OF THE EUROPEAN RED MITE (P. pilosus C. & F.)
PHILIP GARMAN. Since the publication of Bulletin 252, on the European red mite, a number of tests have been made of the killing power of certain insecticides on the winter eggs. These tests are laboratory tests and results are comparable to what was obtained in previous experiments. For convenience, two proprietary oils now on the market have been compared and the results are shown in Table 2. Results in this table are a total of all tests made to date, including those reported in Bulletin 252.
Total No. of
Hatched Materials Used
Number Per Cent, 1. Niagara dormant dust.
19 15.9 2. Soluble sulphur 1 oz. in 1 quart. 115
29 25.2 3.
32 16.1 4.
98 20.5 5.
99 43.0 6.
49 24.3 7. Sunoco spray oil 1-15.
.4 8. 1-15.
3.7 9. 1-15.
.5 10. 1-20.
1 11. Carboleine 1-15..
1.0 12. 1-20.
2 13. Volcks 3%.
2 14. 6%
1.9 15. Sherwin Williams Free Mulsion 1-15 202
4 1.9 16. Check-no treatment. ...
225 46.5 Note. Tests 2-5 were made with fresh soluble sulphur of good yellow color; No. 6 with the same material after standing a year.
Number Per Cent. 1. Scalecide 1-15.
4.9 2. 1-20.
0 0.0 3. 1-25,
68 5.4 4.
66 6.8 5. Sunoco 1-15.
18 1.7 6. 1-20.
1 7. 1-25.
6 3.3 8. 1-50.
56 17.2 The percentage of hatch in the two lots should not necessarily be taken to indicate superiority of either oil, since the experimental error and variation is considerable. The experiments, however, indicate consistently that a dilution of 1 to 20 or 1 to 25 does not greatly reduce the toxicity of miscible oils of this type. As indicated in Table 1, soluble sulphur compounds do not give