It was dissolved in water and sprinkled on the soil, but gave only one per cent. kill. A 10 per cent. kerosene emulsion applied to a plot one yard square was worthless, as no dead larvae were found when the plot was examined a few days after the treatment. CARBON DISULPHIDE EMULSION. The most promising of the insecticides and soil fumigants tested was carbon disulphide emulsion. There is a commercial carbon disulphide emulsion on the market which is sold under the name of Kokotone. This was first used on plots one yard square; in the center of each plot a wire cage was buried containing Anomala larvae. Each cage was buried between two and three inches deep. The plots were dosed with one-half pint, one-fourth pint and oneeighth pint of Kokotone. The amount of emulsion to be used on each plot was first diluted in about three gallons of water and then sprinkled on the lawn with a watering pot (Plate XXIV, a) then the ground was soaked with more water from a garden hose to wash the emulsion into the ground. On digging up the cages containing the Anomala larvae two days later, it was found that in each plot all the larvae had been killed. The grass was slightly injured on the plots receiving one-half and one-fourth pint of emulsion, but the one-eighth pint plot was not noticeably hurt. All the grass which was burned recovered after a short time. Another lawn of 32 square yards was then treated with Kokotone using one-eighth pint per square yard, applied in the same manner. Four days later, June 30, the lawn was dug into and 61 dead larvae and pupae were found, also two dead adults. In another place a bunch of tall grass under a Spiraea bush was dug up and five dead pupae and two living larvae were found. This amounts to about a 97 per cent. kill. Grass on this plot was slightly injured but soon recovered. Kokotone was again used late in the fall on a plot of lawn the same size as above. The amount of Kokotone used and the method of application was the same as on the above plot. The temperature of the air was much lower than on June 30, and the soil temperature was 67° F. This probably accounts for the fact that we found only about a 70 per cent. kill when the lawn was examined on October 9. The gas from the carbon disulphide is apparently not given off fast enough at low temperatures to give a high percentage of kill. It is also apparent from the work done thus far that it is important to saturate the soil with water after the emulsion is applied in order that it may reach and surround the grubs. It works both as a contact insecticide and as a fumigant when applied in this manner. Home made carbon disulphide emulsion was prepared after a formula given by Leach and Thomson' in an article on the "Control of Japanese Beetle Larvae in Golf Greens." This formula calls for 12.5 grams of resin-fish-oil soap dissolved in 87.5 cubic centimeters of water. This is heated until the soap is dissolved, then the solution is allowed to cool, after which 250 cc. of carbon disulphide is added and the mixture agitated until a white creamy emulsion is obtained. We have found that a fairly stable emulsion can be made by substituting either fish-oil-soap or the ordinary naphtha laundry soap for the resin-fish-oil soap, and is satisfactory for immediate use. Two plots of one square yard each were treated with this emulsion, one made from fish-oil soap and the other from naphtha laundry soap. In the center of each plot before treatment a small wire cage containing two Anomala larvae was buried about two or three inches deep. Two liquid ounces of emulsion were used on each plot diluted with three gallons of water and then watered with five gallons of clear water. On examination a few days later, all larvae were found dead. The grass was not injured. STUDIES OF THE HABITS AND CONTROL OF THE ORIENTAL PEACH MOTH IN 1924. PHILIP GARMAN. The Oriental peach moth showed up again in Connecticut in 1924 and was on the whole more abundant than in previous years. It appeared for the first time in appreciable numbers in the peach growing district about Wallingford where a number of growers reported its presence. It was found largely in the southwestern section of the State and in the central section extending northward from New Haven into Hartford County. One orchardist near the Massachusetts line stated that he had seen "worms" in his peaches similar to those of the Oriental peach moth, but this locality is well to the north of the main infestation and its presence should be observed another year in the same locality in order to make sure that it has become established. A questionnaire sent out in October to about 20 peach growers indicated that the insect was present in 11 of their orchards, but most of those reporting it were of the opinion that it did little damage. In the orchard at Conyers Farm, Greenwich, about the same amount of damage as occurred last year was observed by the men in charge, but the possibilities of the pest are evident in the amount of damage found in some of the experimental blocks, where the infestation amounted to from 14 to 23 per cent. of the crop. In that orchard the variety most heavily infested was Belle of Georgia. 1 Journal of Economic Entomology, Vol. 16, page 312. 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 9 No 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. July 3-Pupae obtained from June 23 material. July 9-Four adults emerged from June 23 material. July 10-Three adults emerged from June 23 material. July 14-Many young larvae observed in tips at Greenwich-one in peach. July 21-One adult emerged from July 23 material. July 25-One egg found on tree at New Haven. July 28-Many larvae observed in young orchard at Greenwich. Sept. 1-One adult emerged on this date. Sept. 9-One adult emerged on this date. Grouping the adult emergence (from larvae collected June 23, July 14 and 28; August 15 and 22 and September 13, 25, 29 and October 1), we obtain the following results: 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 measures 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 given1 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. 2 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 workers1. 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. CONTROL EXPERIMENTS. 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, 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, pound to 50 gallons in sprays containing lead arsenate and self-boiled lime-sulphur. (6) 90-10 sulphur-arsenate dust. (7) 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. |