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Scraping and Banding Apple Trees as a Supplementary Codling Moth Control Measure in the Pacific Northwest

By M. A. YorHerRS and F. W. Cartson, entomologists, Bureau of Entomology and Plant Quarantine, Agricultural Research Administration *

CONTENTS

Page Page

introductions] 2440p 2 sa 1| Sticky bands as compared with Location of overwintering larvae_ 2| beta-naphthol bands-------_-- 11

Percentage of larvae removed by Large-scale orchard tests of SORA Y OMI OVS NG a gan ae ae t scraping and banding_----- 1 Proportion of larvae caught in Experimental methods- --_-—-~ - Tat bands after leaving the fruit__ 4 Description of plots___------- at Larvae caught in trunk bands esults Ol veSts.2 == 45" see 13

audelimibpoands= sels LS 6| Methods of scraping and band- Effect of density of infestation on DE ey Nee ete wee ee ee 16 number of larvae caught in SChApIn ge Sa) a ae eee 16 limb bands and trunk bands-_- tf Ban Gineeckos oe ea See Ei Influence of apple variety on Band Temoval en 22 222 bk ile number of larvae caught__-___ 7 | Cost of scraping and banding_ - - - 20 Time required for beta-naphthol Sula Taye a ee AY a es 21 lostacl SeGOp lanl See seo PP oiteracureicited-s: 7) Se) eS! 22

INTRODUCTION

Scraping and banding apple trees to trap the larvae of the codling moth (Carpocapsa pomonella (1.)) have long been common supple- mentary control practices. During the last century these practices were followed very extensively, but with the advent of spraying they fell more or less into disuse. However, in about 1927 difficulties encountered with spray residues and the development of chemically treated bands by Siegler e¢ al. (10, 11, 12)? and by others gave re- newed impetus to scraping and banding.

The band developed by Siegler and other workers consists of cor- rugated paper strips coated with beta-naphthol dissolved in a heavy

* Acknowledgment is made to E. J. Newcomer, in charge of the Yakima, Wash., laboratory of the Bureau of Entomology and Plant Quarantine, where these studies were made, for suggestions throughout the work, and to F. P. Dean, also of this laboratory, for assistance with the statistical analyses.

* Italic numbers in parentheses refer to literature cited, p. 22.

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2 CIRCULAR 828, U. S. DEPARTMENT OF AGRICULTURE

lubricating oil. The chemical kills the larvae that enter. The older types of band, consisting of burlap, building paper, or other material, had to be removed at intervals of 10 to 14 days, so that the larvae might be destroyed by mechanical means. The new chemical bands. work automatically and are allowed to remain undisturbed until well after fruit harvest or until the following spring.

The bands are appled to the trees in June, just before the first jarvae leave the fruit.

All but a few of the larvae caught before the end of July would have produced a second brood of moths during the current season. Only a few of the larvae caught after the third week in August, however, would have changed into moths. Banding, therefore, is immediately effective during the fore part of the season in reducing the second- brood population the same season, but late in the summer the effect is greatest in reducing the overwintering larvae.

It is necessary to scrape the rough bark thoroughly from the trees to obtain the maximum benefit from banding. Scraping serves a two- fold purpose: (1) To remove and destroy the hibernating larvae and thereby reduce the potential moth population for the following sea- son, and (2) to eliminate the cocooning quarters for the later full- grown larvae after they leave the fruit, thus inducing a greater pro- portion of them to enter the bands and be destroyed. In this way scraping and banding constitute one supplementary control measure, although either will afford some benefit if used alone.

Experimental scraping and banding and related studies have been carried on in different parts of the country under a great variety of conditions. Some of this work is discussed in the following refer- ences: Baker (7, 2), Gould and Geissler (4), Marshall (5), New- comer (7), Newcomer et al. (8), Steiner (73, 14), Steiner and Acker- man (75), Steiner and Marshall (16), Woodside (17, 78), Worthley (19), Yothers (20, 21, 22), and Yothers and Carlson (24, 25, 26).

This circular brings together work done by the present authors in ~ the Northwest during the period 1935-43, after which this phase of the work was discontinued. Comparatively little emphasis is now being placed on scraping and banding for codling moth control, be- cause of the use of the highly effective insecticide DDT, the greatly increased cost of labor and the development by the authors ( Yothers and Carlson 27) of trunk sprays, which are about as effective as scraping and banding and are less expensive and require less labor.

LOCATION OF OVERWINTERING LARVAE

Over a period of 6 years near Yakima, Wash., the location of the larvae on or near 80 trees in 8 orchards that had never been scraped, and on 104 trees in 11 orchards that had been scraped and banded the preceding season, was recorded after minute examination. Larvae on trunks, in the lower crotches, and in the soil at the base of the trees were classed as on the trunks; those on the scaffold limbs above their union with the trunk and as far up-as the rough bark extended, or to secondary limbs, were classed as on scaffold limbs; while those on secondary and smaller branches beyond scaffold limbs were classed as on the branches.

The trash and soil were sampled as follows: The surface trash from one-fourth of the area (a 90° sector) under a tree, for a distance of

3

SCRAPING AND BANDING FOR CODLING MOTH CONTROL

6 feet from the tree base, was run through a sifting machine (Carlson and Yothers 3), and the residue was carefully examined for cocooned larvae. The soil below the place where the trash had been removed was also sifted and the residue examined. The number of individuals recovered from the trash or soil was then multiphed by four to obtain the total numbers presumably present under the tree. The results of these studies are summarized in table 1.

Tasie 1.—Distribution of overwintering codling moth larvae on apple trees, 1938-43

Larvae on or in—

The larval populations in the trash and soil appear to be of little importance in commercial orchards in the Yakima district. The population on the trees that had been scraped and banded the pre- ceding season or seasons had been markedly reduced by the treatment. On these trees the rough bark had been cleaned off and the trash against the base of the tree cleared away, so that there were few places for the larvae to hide. Consequently, most of them settled in the sheltered spots available on the branches, in pruning wounds, and in the trash on the ground.

In 46 trees scraped and banded the previous year and examined in the spring before moth emergence, 1,219 codling moth larvae hibernated as follows : 32 percent in rough bark, 22 percent in pruning wounds and broken limbs, 16 percent in crotches, 11 percent in knots, 11 percent in trash and soil beneath the trees, and 8 percent in miscel- laneous places. In 37 trees not scraped and banded and examined in the spring before moth emergence, 4,072 larvae hibernated as follows: 63 percent in rough bark, 4 percent in pruning wounds and broken limbs, 23 percent in crotches, 3 percent in knots, 4 percent in trash and soil beneath the trees, and 8 percent in miscellaneous places.

Most of the rough bark had been removed in scraping and the crotches were largely cleaned out; therefore the percentage of worms in these places was reduced. In all other locations the percentages were greater In scraped and banded trees. The theory that scraping drives a larger proportion of the larvae into the less accessible places, thereby prolonging moth emergence, is substantiated by these figures; however, although the percentage of larvae driven to these ‘locations was greater, no larger numbers were found there.

The location and type of hibernating places were determined in March, April, and early in May, and do not represent a stationary condition. There is probably considerable variation between fall and spring percentages of larvae in the different locations. Many of the larvae that have spun up in the trash and fruit under the trees and in the soil at the base of the trees, and the more exposed individuals on the trunk, scaffold limbs, and branches had doubtless been destroyed

4 CIRCULAR 828, U. S. DEPARTMENT OF AGRICULTURE

by birds and rodents. ‘The larvae that had not been disturbed by spring were the ones found and recorded in these studies.

Many larvae were also found in such places as rotten spots on trees, empty sacks, papers, old clothes, broken boxes, spliced tree props, dried fungus growths on the trees, under birds’ nests, and in canker wounds.

PERCENTAGE OF LARVAE REMOVEDE BY SCRAPING

Eight Jonathan and six Winesap trees in three orchards were scraped in the regular manner, and the scrapings were examined for larvae. On the Jonathan trees 82 percent of the larvae were removed by scraping, and on the Winesap trees 77 percent. Afterward the trees were carefully examined for larvae that had been missed or were inaccessible. Throughout moth emergence the trees were examined for empty pupal cases. The Jonathan variety, because of the absence of cracks, holes, and sprout clusters, lends itself more readily to thorough scraping than do the Wi inesap, the Delicious, and certain other varieties.

In a single study of four Jonathan trees that had been scraped the previous season, only 50 percent of the larvae were removed. Appar- ently, after the first scraping, the larvae were forced into the more inaccessible situations and therefore were not so readily removed by a later scraping.

PROPORTION OF LARVAE CAUGHT IN- BANDS AFTER LEAVING TEE ERUE

The proportion of the larvae that leave the fruit and are captured in chemically treated bands depends on the variety, age, and size of the trees. The number of larvae caught depends on surface charac- teristics, such as roughness of the trunk and scaffold limbs after scraping, the number of cracks, knot holes, broken limbs, and crotches inaccessible to scraping, as well as the thoroughness of scraping and the fit of the bands.

Two methods of making such determinations were employed. In

each method the trees were first carefully scraped and banded, about the middle of June, with regular corrugated-paper beta- naphthol bands. In one method all the dropped and harvested wormy fruit was cut open and examined, the dropped fruit being examined every 30 days and both dropped and wormy fruit at harvesttime, and the number of exit holes was recorded. At the same time, or a few days later, the bands on these trees were removed and examined for the total number of larvae caught. The final results of these tests on four leading commercial varieties over a period of 7 years in several orchards, are given in table 2. There was considerable variation in the percentage of larvae captured, both for years and var ‘leties.

The other method differed from the foregoing in that, starting about July 10, and ending at harvesttime, all apples on each tree and the dropped fruits on the ground were examined every 30 days for exit holes. Each exit hole for each tree was recorded, and on the same dates the bands were removed and the number of larvae caught was also recorded. New bands were then placed, since those examined were unfit for replacement. After the harvest examination of the fruit, the bands were usually allowed to remain for a few days, to allow

SCRAPING AND BANDING FOR CODLING MOTH CONTROL 5

Tasie 2.—Proportion of larvae that left the fruit and were captured in beta-naphthol bands, 1935-41

Larvae captured— Variety Year Trees Leaving fruit In bands Number Number Number Percent 1935 5 213 183 ) 1936 9 1, 109 698 63 1937 26 6, 098 3, 769 62 Noma hansen 7 Phe sea a 1938 19 10, 849 7, 274 67 1939 18 2, 545 io2) 52 1940 6 251%, 1, 290 il 1941 6 166 86 By AR Ota le ees het Fo es 89 23, 497 14, 621 62 eine Beaut { 1939 2, 268 119 44 Vedapracig ata 1940 10 938 465 50 MR Gall eet sect Fae: Sar Bee y4 1, 206 584 47 1936 De 28 14 50 1937 de eo tZ 794 61 . 1938 4. 1, 598 625 39 Winesap----------------- 1939 6 412 165 40 1940 8 AG 396 35 1941 1 165 54 33 BIR@ (falas Pores e tt | ee 39 4, 631 2, 048 43 1935 5 859 691 80 1936 6 213 LZ 1535) DOING IO WIS eee pe Sei 8 1938 4 1, 558 487 31 1939 6 1, 180 ooo 30 1940 6 5) 158 PAE TOGA 2 SS Sia eT ad ee tea ite meee Zk 4, 385 1, 806 45 Grandecoraleess 28 Se 167 33, 119 19, 059 Oa

any worms that had recently left the fruit to enter them. Dropped fruits at the preharvest examinations and picked wormy fruits were cut open to make certain that the larvae had left. In every test but one a larger percentage of the larvae were caught in the three preharvest examinations than in the after-harvest examinations. For all or- chards and in all preharvest examinations the percentage caught before picking averaged 82, but the after-harvest percentage dropped to 40. In other words, about twice as many of the larvae left the fruit before the preharvest examination as left it thereafter. The seasonal av- erage of larvae captured was 61 percent, which is substantially the same as the 57 percent shown by the first method (table 2).

Since the growing larvae feed within more than one apple, it seems that by this method the number of larvae caught in the bands, as compared with the number of exit holes, is greatly underestimated. Nel (6) stated that a single well-grown larva can leave several exit holes against which but one capture in the bands can be recorded.

6 CIRCULAR 828, U. S. DEPARTMENT OF AGRICULTURE

Baker (2) concluded that the effect of banding (and scraping) on moth emergence and larval hibernation was much greater than was indicated by the percentage of larvae caught in the bands after emerg- ing from the fruit. |

LARVAE CAUGHT IN - TRUNK BANDS AND EIMB BANDS

Experiments to determine the percentage of larvae leaving the fruit that are caught in bands on trunks only and on both trunk and limbs were made on 139 trees of the Jonathan, Winesap, Delicious, and Rome Beauty varieties. ‘The methods followed were similar to those already described, and involved periodic examinations of the bands and of Be fruit on the tree. The results of these tests are summarized in table 3.

TaBiE 3.—Larvae caught in bands on trunks only and on both trunks and scaffold limbs, 1937-41

Larvae in bands

Year Trees _ On trunks only \Ontrunks and scaffold limbs Number Number Percent Number Percent

HOS 2 0 ee re hea al 33 2016 56 2,547 HOSREE ee ee 24 1, 239 33 SOT i = 56 OS Oats cesarean es 32 732 36 1, 241 52 LOO OSes Ces ERORE eS ti are 32 2, 309 46 3, 060 65 PQA a es Oe er ea 18 140 42 261 61 Total and average_____ 139 6, 436 ey By | 61

In 1936-89 three methods of banding were tried in weekly rota- tion on the same trees—trunk bands, limb bands, and both kinds. Jn these tests on 357 trees of 4 varieties in 10 orchards, 41,715 larvae were caught in bands on trunks, 53,773 in bands on hmbs, or 29 per- cent more than in trunk bands, and 62,734 in a combination of both, or 17 percent more than in limb bands alone and 50 percent more than in trunk bands alone.

In 1989 tests were made to determine the numbers of larvae caught in bands on trunks and on scaffold limbs. On 408 trees in 5 orchards, 65,819 larvae were captured, of which 17,871 were in trunk bands and 47,948 were in limb bands, or 27 and 73 percent, respectively. In other words, limb bands captured 2.7 times as many larvae as trunk bands. However, limb bands require an average of 2.1 times as much banding material as trunk bands.

In two tests in which badly infested trees were banded with 3 bands on each limb, about 1 foot apart, an average of 21 limb bands per tree, 73 percent of the total larvae captured were in the upper bands, 18 percent in the middle bands, and 10 percent in the lower bands. In another test where two bands were placed on each trunk, the lower band caught 56 percent of the total. Both these tests indicate that not all the larvae stop in the first band they come to. :

SCRAPING AND BANDING FOR CODLING MOTH CONTROL 7

PREECT OF DENSITY ‘OF INFESTATION ON NUMBER OF LARVAE CAUGHT IN LIMB BANDS AND TRUNK BANDS

Where the infestation was low, averaging only 10 larvae per tree, 66 percent more larvae were caught in limb bands than in trunk bands, and 106 percent more were caught i in both types of bands than in bands on trunks only. On the other hand, where the infestation was high, averaging 265 larvae per tree, only 25 percent more were in limb bands than in trunk bands, and 47 percent more in both types of bands than in trunk bands alone. This difference may be explained by the fact that in more severe infestations a greater proportion of wormy apples fall to the ground, and a larger proportion of the larvae from these fallen fruits get into the trunk bands than into the bands on the scaffold limbs farther up.

INBEWENGE: OF APPLE VARIETY ON NUMBER OF LARVAE CAUGHT

Varieties of apple differ in their adaptability to scraping and band- ing. Jonathan and Rome Beauty are particularly well suited for maximum scraping and banding efficiency, whereas Delicious and Winesap are much less so, because ‘of their knotty limb surfaces, cracks, crotches, and numerous scallops on the trunks (figs. 1, 2, and 3).

These differences are reflected in the varying paannibere of larvae

caught on trees of the four varieties tested (table 2). The total captures are also influenced by the susceptibility of the different varie- ties to codling moth attack, a factor not directly involved in the work reported on in this circular.

The more difficult a tree is to scrape and band the less efficient the bands are in capturing the larvae. The more severely infested varie- ties, such as Jonathan, should be given special attention in the treat- ment, not only to protect their own crop but also that of less suscept- ible neighbori Ing varieties.

TIME REQUIRED FOR BETA-NAPHTHOL BANDS LO: KILL

In tests of freshly applied bands on tree trunks in the orchard, all the larvae that had been in the bands from 24 hours to 8 days were killed by the chemical, whether the bands were removed from the trees and kept in the orchard at temperatures of 60° to 98° F. or were taken to a semidark, cool basement at 66° to 68°. Tests in which orchard conditions were simulated showed that all the larvae in bands on the sunny side of a section of apple limb 4 inches in diameter were killed within 8 hours. An exposure of several hours in the sunshine and overnight killed all the larvae in 18 hours. On the shady side of the same sticks all larvae were killed in 24 hours. With lower tem- peratures, as in the basement at 66°, only 90 percent were killed in 24 hours. In properly prepared bands the chemical kills the larvae so quickly that few are able to transform to pupae.

AGRICULTURE

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SCRAPING AND BANDING FOR CODLING MOTH CONTROL

I'r@urE 2.—Jonathan apple tree that ha scraped and banded on trunk and limbs, after the bands had been removed at the end of the season. The dis- coloration from the oil is in the outer bark only.

842504—50 2

10 CIRCULAR 828, U. S. DEPARTMENT OF AGRICULTURE

FIGURE 3.—Delicious apple tree showing split crotch and many-scalloped -trunk. Least benefit is gained from scraping and banding this type of tree.

SCRAPING AND BANDING FOR CODLING MOTH CONTROL 11

STICKY BANDS AS COMPARED WITH BETA-NAPHTHOL BANDS

Two proprietary sticky-banding or barrier materials are used in the Yakima and Wenatchee districts, primarily as barriers for mites and climbing cutworms but also from time to time for capturing codling moth larvae. In orchard tests to compare the efficiency of the two types of bands, the beta-naphthol bands caught 13 times as many worms per inch of band as did the sticky bands. The latter cannot. be depended on as an effective barrier or trap for the codling moth larvae.

LARGE-SCALE ORCHARD TESTS OF SCRAPING AND BANDING

A large-scale experiment was begun at Yakima in July 1935 to determine what control could be obtained from scraping and band- ing blocks of several acres of apple trees as a supplement to the spray- ing program. ‘This experiment was continued and enlarged upon for 8 years, during which time tests were made in six orchards, on five common commercial varieties of apples grown in the Pacific North- west—Jonathan, Winesap, Rome Beauty, and a few Delicious and Arkansas Black.

EXPERIMENTAL METHODS

The tests were set up with plots of several acres of scraped and banded trees, with adjoining plots of the same varieties that were not scraped and banded. All the plots received the same spray treat- ments. On the banded trees the rough bark was scraped from the branches, scaffold limbs, and trunks, including 2 to 3 inches below the ground line. Scrapings were caught on a tarpaulin spread under the tree and were burned. Except as otherwise noted, the scraping was done in the spring before moth emergence began. Only proprie- tary bands were used in these tests. The bands contained approxi- mately 2 pounds of beta-naphthol to each 100 linear feet of 2-inch band, in the proportion of 1 pound of beta-naphthol to 114 pints of heavy oil. They were applied about the middle of-June, in time to capture the first larvae to leave the fruit.

The bands were removed either in November after fruit harvest or the following spring. The number of larvae captured in the bands was recorded for each tree. The control value of scraping and band- ing was determined by examining representative samples of harvested and dropped fruit from the treated and the check plots.

Samples of 250 apples per count tree were taken at random, an ~ equal number from each box of picked and dropped fruit, as discussed by Newcomer, Dean, and Cassil, (9). Samples were taken from each variety that was sufficiently represented in both treated and check plots. Records were made of the number of apples that were clean, wormy, and stung, and of the number of worms and stings per injured apple.

DEscrRIPTION OF PLoTs

The first tests were made in the Gilbert orchard in July 1935. Large bearing trees on approximately 10 acres were scraped and banded.

i CIRCULAR 828, U. S. DEPARTMENT OF AGRICULTURE

Trees on an adjoining 10 acres were left unscraped and unbanded as acheck. Both plots received the same regular spray treatment. Each plot contained two varieties, alternating 2 rows of Jonathan and 6 rows of Winesap. Each plot consisted of 33 rows of 16 trees, or ap- proximately 528 trees. The trees were thoroughly scraped and the bands apphed on July 13-16. Since the scraping was not done until July 1-13, long after all spring-brood moths had emerged and after some of the first-brood larvae had already left the fruit, httle imme- diate value was anticipated for this test.

Examination of the harvested fruit showed substantial results in favor of the scraped and banded plot, as compared with the adjoming unsprayed, unbanded plot. Obviously, this apparent difference could have been in the original coding moth population.

In 1936 the same test was again used in the Gilbert orchard. The scraping was done before moth emergence and the bands were applied by the middle of June, before larvae began leaving the fruit. The crop in both plots was much cleaner than in 1935, probably owing to a much more intensive and better spray program.

In 1957 the test in the Gilbert orchard was the same as in 1935 and 1936, except that one of each double row of Jonathan in the treated plot and two rows only in the check plot had been removed by the grower. In 1938 the test was the same as in 1937. In 1939 two more rews of Jonathan had been removed in the check plot, leaving one row of this variety to each six rows of Winesap, the same as in the treated plot. This year the third cover spray was omitted in the treated plot but not in the check plot. In 1940 the treated plot received two sprays less (the third and fifth cover sprays) than the check plot and the re- mainder of the orchard.

Work in the Zier orchard was started in 1936. The scraped and banded plot and the check plot each consisted of approximately 400 trees or about 10 acres. ‘There were six varieties in each plot—W ine- sap, Jonathan, Delicious, Arkansas Black, Rome Beauty, and Spitzenberg. In the treated plot all the trees were scraped and banded, but only the first four varieties were examined at harvest- time. The test in 1937 was the same as in 1936, except that some Spitzenberg trees had been removed. In 1988 both plots were reduced in size by removing a number of trees. The treated plot in 1938 in- cluded 278 trees, and the check plot 330.

In 1938 an experiment was begun in the Bounds orchard, adjoining the Zier tract. The scraped and banded plot consisted of 453 trees and the check plot of 501 trees. Counts were made on Winesap, Jonathan, Delicious, and Arkansas Black. Similar tests were made in 1939.

In 1939 a test was begun in the Buchanan orchard, in a different part ot the district, using 368 scraped and banded trees and 332 check trees. An unsprayed orchard was across the road from the scraped and banded plot. In 1940 the treated plot was enlarged by 4 rows and the check was reduced 4 rows. The adjoining neglected orchard of the previous season was well cared for and was cleaner than the experi- mental tracts.

SCRAPING AND BANDING FOR CODLING MOTH CONTROL 13

In 1940 a test was set up in the Bannister orchard, consisting of approximately 30 acres of 30-year-old trees, which was more isolated than any/used before. On three sides there were no orchards for a inile or more, and on the fourth side this orchard was separated from the nearest neighboring one by a distance of more than 500 feet. ‘The scraping was not completed until May 9, when moths had been emerg- ing for 2 or 8 weeks. One-half of the orchard was scraped at this time and after July 1 the scraped area was increased to about two- thirds (1,150 scraped trees and 420 unscraped trees). That part scraped in May was banded early in June and the remainder in July. No count trees were taken from the latter section, but it served as a buffer block.

The followin varieties were scraped and banded: Winesap, De- licious, Rome Beauty, and Arkansas Black, also some Jonathan trees that were partly grafted to Delicious. Arkansas Black and Jonathan were not used in harvest counts.

In 1941 only the Bannister orchard was used. ‘The trees were scraped by April 20, before moths emerged, and the bands were ap- vlied on two-thirds of the scraped tract by June 26 and on the other third by July 2, a few days late for catching the earliest worms.

In 1942 a test, which was a part of another experiment, was begun in the Briskey orchard with 200 Winesap trees in the treated plot and 70 trees in the check plot.

RESULTS OF. LESTS

The results of these 14 experiments, involving 47 tests of varieties for the 8-year period 1935-42, are summarized in table 4. They show that in general the scraped and banded plots had more clean fruit, fewer wormy apples, and fewer stings than the unscraped, unbanded plots. These gains from scraping and banding were made notwith- standing a number of adverse conditions. It was necessary to have an unscraped and unbanded check plot in each orchard, and from this untreated plot infestation doubtless spread into the treated area, somewhat reducing the potential control. In one orchard the treated plot was joined on the north by a heavily infested, unsprayed orchard, the effects of which were very noticeable, especially in the nearest sev- eral rows. Large-scale community or orchard-district scraping and banding would obviously give the best results.

For all varieties (table 5), analysis of variance shows all differences except in the Rome Beauty variety, to be highly significant at odds of 99 to 1 in favor of the scraping and banding treatment. Although the Rome Beauty plots showed from 1.6 to 4.2 times as many worms per 100 apples in the untreated as in the treated plots, the 4 tests showed too great a variance to be statistically significant. In the check plots each variety averaged 2 to 2.3 times as many worms per 100 apples as were found in the treated plots.

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16 CIRCULAR 828, U. S. DEPARTMENT OF AGRICULTURE

Taste 5.—fesults of scraping and banding apple trees for codling moth control, in comparison with results on plots not scraped and banded, 1935-42

Mean number ot WiOUTES per 100 Variety ees of See Treated Untreated

PAT KAM SASH Be Cle oe te eye el pn eee eRe ee le 5 6. 0 12. 0 POW CIOUS Es iyae— Rice ce eaae we 2 Orn DON oe eee 9 1256 XG ff Jona thaw ae Ds Ba ee Ree ae a iat: 16. 9 BID 7 Rome Beauty it is ae ces tps Se aes 4 14. 2 32. 6 WHITES 8p i cor, oer A eee les San Pew 14 3. 7 8. 1

1 All differences highly significant at odds of 99 to 1, except with Rome Beauty, which was not significant because of the variance in the 4 tests.

As shown in the final results (table 4), the percentage of worm- and sting-free fruit was increased by the treatment for all plots, varieties, orchards, and years. At the same time the stings per 100 apples were reduced from 90 to 47, a reduction of 48 percent.

METHODS OF SCRAPING AND BANDING

SCRAPING

Thorough scraping requires the removal of all rough bark and, as far as possible, the cleaning out of all other places where the larvae may hide on branches, scaffold limbs, and trunk, including a depth of 2 to 3 inches in the soil at the base of the tree. Unnecessary cutting of the live bark should be avoided. “Peeling” the trees, as is some- times done, is injurious to them, a waste of time, and entirely unneces- sary elther in removing the larvae or in preparing the trees for banding.

Scrapings should be caught in tarpaulins spread under the trees and should be burned whenever five or six trees have been finished. A cuptul of stove oil or used crankcase oil poured over each pile of scrap- ings will facilitate starting the fire. Old beta-naphthol bands, dis- cussed elsewhere, may also be used advantageously to aid in burning the scrapings.

Scraping can be done at any time between fruit harvest and moth emergence the following spring, usually before mid-April in the Pacific Northwest. After moths start to emerge much of the effec- tiveness of the operation will be lost; however, it is better to have the scraping completed after a few moths have emerged than not to get it done, especially if the trees are to be banded.

Broken or split limbs should be removed, and holes, cracks, and narrow crotches, where larvae are likely to hide, should be filled with concrete or other suitable material. Concrete has proved satisfactory for this purpose.

The upper part of the tree should be scraped first, leaving the crotch to be thoroughly cleaned out after all scraping above has been finished.

The most satisfactory scraping tools are a box or tree scraper (fig. 4, A) for use in removing the rough bark, and a long-handled, narrow

SCRAPING AND BANDING FOR CODLING MOTH CONTROL [Eve

blade, which is used to gouge into cracks too narrow for the scraper (fig. 4, B). BANDING

By the middle of June, or just before the first worms leave the fruit, scraping should be followed by banding, using corrugated-paper bands treated with beta-naphthol. These should contain a minimum of 2 pounds of chemical to each 100 linear feet of 2-inch band. They should be prepared by using 1 pound of beta-naphthol to 114 pints of heavy oil. In sections of the country where there is much more sum- mer rain than in Yakima County, a larger dosage of 2 pounds per 100 linear feet should be used (Baker 7). Chemically treated beta- naphthol bands may be obtained commercially in most sections of the country. When properly prepared and used they have consistently given practically 100 percent kill of all larvae entering them in the Yakima and Wenatchee districts. The bands should be placed around

IIguRE 4.—Tools used in scraping apple trees: A, Tree scraper; B, gouge for cleaning out narrow cracks and crotches.

the trunks, well up near the forking of the scaffold limbs (fig. 5), or on the limbs a foot or so above the crotches, or on both trunk and scaf- fold limbs.

As an aid in the banding operation a reel for carrying the rolls of banding material (Yothers and Carlson 23) will be found advan- tageous and can be made as shown in figure 6. Where two persons work together a rod inserted through the handle will enable several rolls to be carried on the spindle at one time.

In a single season’s test, treated bands on sprayed apple trees from June 10 to September 4 showed by chemical analysis a loss of ap- proximately 50 percent of the beta-naphthol. The quantity remain- ing, however, was sufficient to kill the larvae that would have trans- formed to moths the same season.

BAND REMOVAL

The bands should be removed and burned before moth emergence begins the next spring to destroy any live larvae present and to prevent a new crop of worms from entering. Old bands that remain on the trees from the year before contain so little chemical that they would kill very few of the larvae the second season, and will do more

18 CIRCULAR 828, U. S. DEPARTMENT OF AGRICULTURE

FIGURE 5.—Beta-naphthol corrugated-paper band on apple-tree trunk,

SCRAPING

AND BANDING

FOR CODLING MOTH CONTROL

19

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reel with roll in p

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eel for carrying beta-naphthol banding roll

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20 CIRCULAR 828, U. S. DEPARTMENT OF AGRICULTURE

(Get than good by furnishing the best possible cocooning quarters g. 7).

The most practical time to remove and destroy the bands is at scraping time, when they are a convenient aid in burning the scrapings.

Examination of the beta- naphthol bands after they have been on the trees a few months in badly infested orchards will show consid- erable numbers of dead and live larvae attached to the bands (fig. 8), to the bark between the band and the tree, and inside the corrugations. The live worms are recent entrants but. most t of them will be killed

I'IcureE 7.—An al beta- near band that has lost all its value but is allowed to remain on the tree affords highly suitable quarters for the larvae. Empty pupal cases are shown at the edges of this old band.

Figure 8.—Section of beta-naphthol band showing dead larvae.

within a few days. The larvae entering late in the fall after cool weather has set in will be killed during the winter, but it will take longer to kill them at that time.

COST OF SCRAPING AND BANDING

The cost of scraping and banding depends on so many variable factors that it is impossible to set a definite figure. Some of the fac- tors are the size, age, variety, and general physical condition of the trees, and the prevailing wage and cost of materials (bands, tacks, scraping tools, and tarpaulins) :

The most important factors are the size of the trees and the per hour cost of labor. The approximate cost of the two operations for small,

21

SCRAPING AND BANDING FOR CODLING MOTH CONTROL

medium, and large trees at a wage of 60 cents per hour is shown in table 6. Bands on both trunks and limbs on older, larger trees would triple the cost for the banding (but not for the scraping) and would increase the total costs by 30 to 40 percent. The worm captures would, however, be increased by approximately 50 percent. Estimates on the net gain from scraping and banding under certain conditions are given by Yothers and Carlson (26).

TABLE 6.—Approximate cost of scraping and banding apple trees im the Yakima district of Washington

| Cost per tree | Maximum | Time re- ie Size of tree fruit yield quired for Labor per tree scraping veraee a Material motat per hour) Bozres Minutes Cents Cents Cents Small (rough bark) _____- es 10-15 10-15 10-15 3— 5 13-20 Nile Gatun sek tae sears 20-35 20—35 20-35 5- 8 25-43 WWareg emesis Sioa ae PEE et 40—50 40—50 40—50 8-10 48—60 SUMMARY

Investigations on the value of scraping and banding apple trees to destroy the larvae of the codling moth (Carpocapsa pomonella (1.) ) and related studies were carried on near Yakima, Wash., from 1935 to 1943.

On trees not previously scraped and banded 85 percent of the over- wintering larvae were located on the trunks and scaffold lmbs, 13 percent on other branches, and the remainder in trash and soil. On such trees 86 percent of the larvae were in rough bark and crotches. On trees that had been scraped and banded the previous season, only 41 percent were on the trunks and scaffold limbs, 50 percent on the secondary branches, and 9 percent in trash and soil. Only 46 percent of the larvae were in rough bark and crotches. The average popula- tion per tree, however, was reduced from 168 to 22.

Thorough scraping at any time between apple harvest and moth emergence the following spring destroyed about 80 percent of the overwintering population the first season. On trees that had been scraped the previous year only about 50 percent of the larvae were removed by the second scraping.

On well-scraped trees 50 to 60 percent or more of the larvae were trapped in the bands.

Chemically treated bands on the scaffold limbs caught 29 percent more larvae than did bands on the trunks, and a combination of both trunk and limb bands caught 50 percent more than did trunk bands alone.

The heavier the infestation the greater was the proportion of larvae caught in bands as they were leaving the fruit.

Scraping and banding were most effective on varieties such as Jonathan and Rome Beauty, which were readily scraped.

Larvae entering beta-naphthol bands were killed within a few hours toa day or so. The higher the temperature the quicker was the kill.

Sticky banding materials were comparatively ineffective.

22 CIRCULAR 828, U. 8. DEPARTMENT OF AGRICULTURE

In three orchard experiments reductions in w ormy fruit amounted to 49,37, and 58 percent, The average for all tests showed an increase in clean fruit of 37.5 percent in favor of scraping and banding as a supplement to customary spray programs.

Scraping involves the removal of the rough bark, the clearing out of cracks, crotches, and holes, and the removal of rotten and “split limb stubs and, as far as possible, other places in which the larvae usually cocoon. Scraping should be done in the fall, winter, or spring, before moth emergence starts. The scrapings should be

caught on a tarpaulin and burned.

In recent years banding has consisted in the application of corru- gated paper bands, previously treated with beta-naphthol and heavy petroleum oil, about the trunks or scaffold limbs to capture and kill the full-grown larvae that have left the fruit and are seeking cocoon- ing or pupating quarters. Bands should be applied in June, just before larvae begin leaving the fruit, and may be allowed to remain in position until “the following spring. They should be removed and destroyed before moth emergence starts.

When labor is available at 60 cents per hour, scraping costs 10 to 50 cents per tree, depending on size, age, variety, and physical con- dition. At 1 cent per foot, banding material costs 3 to 10 cents per tree, bringing the total cost of banding and scraping to 13 to 60 cents per tree.

LITERATURE Clik D

(1) BAKER, HowArRpD 1943. ORCHARD TESTS OF CHEMICALLY TREATED BANDS FOR CODLING MOTH CONTROL IN THE MISSOURI RIVER VALLEY. Jour. Econ. Ent. 36: 760-764.

1944. EFFECT OF SCRAPING AND BANDING TREES UPON THE NUMBER OF TRANS- FORMING AND HIBERNATING CODLING MOTH LARVAE. Jour. Econ. Ent. 37: 624-628.

(3) CaRtson, FEF. W., Ba YOTHERS, M. A.

1941. A POWER-DRIVEN SGIL-SIFTING MACHINE. U.S. Bur. Ent. and Plant

Quar. ET-181, 4 pp., illus. eee (4) GouLp, E., and GEISSLER, G. H.

1941. HIBERNATING CODLING MOTH LARVAE. Jour. Econ. Ent. 34: 445-450,

illus. (5) ‘MARSHALL, G. E.

1931. PREPARATION AND USE OF CHEMICALLY TREATED BANDS FOR CODLING MOTH CONTROL. Ind. [Purdue] Agr. Expt. Sta. Cir. 180, 4 pp., illus.

(6) Ne, Re i:

1941. VARIETAL INTERPLANTING IN RELATION TO CONTROL OF THE CODLING

MOTH. Jour. Ent. Soc. Southern Africa 4: 111-134. (7) NEWwcoMER, E. J.

1934. PRACTICAL METHODS OF ORCHARD SANITATION FOR THE CONTROL OF

THE CODLING MOTH. Wash. State Hort. Assoc. Proc. 30: 66-67. (8) Newcomer, E. J., Rotrs, A. R., and DEAN, F. P.

1933. A PRACTICAL TEST OF CHEMICALLY TREATED BANDS FOR THE CONTROL

OF THE CODLING MOTH. Jour. Econ. Ent. 26: 1056-1058. (9) ——— DEAv, F. P., and Casstm1, C. C.

1943. EXPERIMENTAL METHODS IN MAKING ORCHARD TESTS FOR CODLING MOTH CONTROL IN THE WEST. U. S. Bur. Ent. and Plant Quar. ET-215, 20 pp., illus. [Processed. ]

(10)

(11)

(12)

(13)

(14)

(15)

(16)

(17)

(18)

(19)

SCRAPING AND BANDING FOR CODLING MOTH CONTROL 93

SIEGLER, E. H., Brown, LUTHER, ACKERMAN, A. J., and Newcomer, E. J.

1927.

1929.

1932.

CHEMICAL TREATMENT OF BANDS AS A SUPPLEMENTAL CONTROL MEAS- URE FOR THE CODLING MOTH. Jour. Econ. Ent. 20: 699-701. Brown, LutTHer, YOTHERS, M. A., and YETTER, W. P., Jr. A SECOND REPORT ON CHEMICALLY TREATED BANDS FOR THE DESTRUC- TION OF CODLING MOTH LARVAE. ° Jour. Econ. Ent. 22: 966-972. and MunGER, F. CHEMICALLY TREATED BANDS FOR CODLING MOTH CONTROL. U.S. Bur. Ent. and Plant Quar. E-316, 7 pp., illus. (Supersedes EH-278 and E-294.) [Processed. ]

STEINER, L. F.

1929.

1940.

MISCELLANEOUS CODLING MOTH STUDIES. Jour. Econ. Ent. 22:

648-654.

CODLING MOTH FLIGHT HABITS AND THEIR INFLUENCE ON RESULTS OF EXPERIMENTS. Jour. Econ. Ent. 33: 486-440.

STEINER, L. FE‘, and. ACKERMAN, A. J.

1936.

1931.

LARGE-SCALE TEST OF ORCHARD SANITATION TO CONTROL CODLING MOTH. Jour. Eeon. Ent. 29: 648-653. and MARSHALL, G. E. FOUR YEARS EXPERIMENTS WITH CHEMICALLY TREATED CODLING MOTH BANDS. Jour. Econ. Ent. 24: 1146-1151.

WoopsIDE, A. M.

1939.

1942:

DISTRIBUTION OF CODLING MOTH WORMS ON APPLE TREES AS _IN- FLUENCED BY BANDING. Va. Fruit 27 (3) : 22-24.

SUPPLEMENTARY CONTROL MEASURES FOR THE CODLING MOTH. Va. State Agr. Expt. Sta. Bul. 342, 19 pp., illus.

WoRTHLEY, H. N.

1932.

CHEMICALLY TREATED CODLING MOTH BANDS IN PENNSYLVANIA. Jour. Eeon. Ent. 25: 11383-1148.

YOTHERS, M. A.

1938.

1939.

1941.

1943.

1945.

SUGGESTIONS FOR SCRAPING APPLE TREES AS A SUPPLEMENTARY COD- LING MOTH CONTROL MEASURE. Better Fruit 32 (8): 8.

RESULTS FROM EXPERIMENTS WITH SCRAPING AND BANDING AS A SUPPLEMENTARY CONTROL MEASURE FOR THE CODLING MOTH. Wash. State Hort. Assoc. Proc. 35: 7-11, illus.

ARE SCRAPING AND BANDING FOR CODLING MOTH CONTROL WORTH

WHILE? Northwest Fruit Grower 11 (38): 4. and CARLSON, F. W.

A REEL FOR CARRYING ROLLS OF TREE-BANDING MATERIAL. U.S. Bur.

Ent. and Plant Quar. ET-133, 1 p., illus. [Processed.] and CARLSON, F. W.

FURTHER RESULTS WITH SCRAPING AND BANDING AS A SUPPLEMENTARY CODLING MOTH CONTROL MEASURE. Wash. State Hort. Assoc. Proce. 37: 93-95, illus.

and CARLSON, F. W.

MISCELLANEOUS FINDINGS RELATING TO SCRAPING AND BANDING IN

CODLING MOTH CONTROL STUDIES. Wash. State Hort. Assoc. Proc. 37: 96-97.

and CARLSON, FEF. W.

SCRAPING, BANDING TREES CHECKS MOTHS. Better Fruit 37 (10):

14, 22. and CARLSON, F. W.

THREE YEARS OF ORCHARD TESTS WITH 4,6-DINITRO-O-CRESOL EMUL- SION AGAINST OVERWINTERING CODLING MOTH LARVAE. (Sci. Note.) Jour. Eeon. Ent. 38: 723-724.

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