A system of classifying cabbage according to the extent of caterpillar injury

MISSING IMAGE

Material Information

Title:
A system of classifying cabbage according to the extent of caterpillar injury
Physical Description:
Book
Language:
English
Creator:
Reid, W. J ( William John ), 1902-
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Department of Agriculture, Bureau of Entomology and Plant Quarantine ( Washington, D.C
Publication Date:

Record Information

Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 30345941
oclc - 781639527
System ID:
AA00023087:00001

Full Text

August 1940


United States Department of Agriculture
(Bureau of Entomology and Plant Quarantine


A SYSTEM OF CLASSIFYING CABBAGE ACCORDING TO THE EXTENT
OF CATERPILLAR INJURY


By W. J. Reid, Jr., Division of Truck Crop
and Garden Insect Investigationst


During the course of investigations on the control of certain
species of cabbage caterpillars in the Charleston, S. C., area
during the period 1935-39 a system of classifying the cabbages at
harvest time as to their market qualities and the degree of insect
injury was devised A discussion of this system follo,,s.

General Considerations

It was recognized at the outset that any classification
system devised should be based on accepted market standards, that
only caterpillar injury visible aL harvest or known effects of
earlier injury could be considered, and that in the use of the
classification there would be variations that resulted from dif-
ferences in the personal judgment of different graders. It also
was recognized that there are differences in the requirements of
various markets.

According to the U. S. Standards for Cabbage issued by the
Agricultural Marketing Service, U. S. Department of A --Lculture,
cabbage is classified as U. S. No. 1, U. S. Commercial, and Un-
classified. The term Unclassified is not a grade name but is pro-
vided as a description to show that i.o definite grade has been
applied to the lot. The U. S. No. i grade requires the cabb'age
to be free from damage by worm injury. The U. S. Commercial grade
is the same as U. S. No. 1 grade except for an increased tolerance
for defects.


1 In cooperation with the South Carolina Agricultural
Experiment Station. Credit is due C. F. Stahl, C. E. Smith, C. 0.
Bare, and L. B. Reed for their contributions in the development
of this classification of cabbage, and to Mr. Bare for his assist-
ance in obtaininE the photographs.




-2-


It should be noted that there is a distinction between the
terms "damage" -nd "injury" as used in the U So Standards for
Cabbage and in this paper. Damage refers to caterpillar inj uy
which is of a nature or extent as to cause a plant lo be
ineligible uo tbe T S No. 1 grade Probably the mosL important
factor invclvdc7 the classification described herein is t;he 1at
ter of deciding when caterpillar injury or injuries should be
considered as d c-age. For use as a guide in this ,or, nographs
were secu. ,j2 o ea hich a licensed inspector of th Department
of Agri c-uLre l for No. 1 grade and also tho i( :,,1o) failed
to grade U because they were damaged by worm injury.
In the case < ; studies for which this clesstfj cation was
designed, -, -,- c, s to gracing procedure was obtained by -the author
from Messrs Rolert Bier, Supervising Inspector of the Agricul-
tural Marketing Cervico of the U. S. Department of Agriculture,
T A. in Aet iM marketingg of the Soit a-,ricultural
Extension Stff, and' J. F, Jones, then Assistant Agricultural Agent
of Charleston Co aty, S. C, Plants graded by Mr. Cole were photo-
graphed.

Among crier acquirements for the U S. No. 1 grade there
must be *oc- o than four loose outer o wrlpper leaves, unless
the crop is to sold under the g, U Geen",
which permits as mny as seven wrapper leaves The classification
described horcin is based on the appearance of the firm head and
four rapper terh, ejth sit)able classes rovid for those plants
which do not pr u.e such a be3, T order to provide fair com-
parisons of the various experimental control trea -zn3 as to
niumbers of plants, the classification does not permit the stripping
of outer leavc-_o to less than four. Stripping of the oater leaves
to less than this number in order to eliminate sct injury is
sometimes u one in .ommercial practice, but ouch, procure is, not
considered desirable in experimental work.

In commercial grading, any single tof a
particu"v cont-ain a certain maximum per>e .tt b. weight,
of heads ,ot "se lng the requirements of the grade Tt t, ic .rance
factor' i:i '. descri bed 1r- in expcr. iI wrk to grade each plant upn its individual
merit-, Io c > it in a class consisting o "ly of plats of
similsi qcalicy n. d to disregard the tolerance alownce.
Inse,.t comnte onily one of the several defects that oau e caboage
to be tnelio h U. S. No. 1 grade, and the proportion cf
insect dar g to the other defects varies greatly in different
plantings. The; assignment of any portion of the toerance to
ins~ect dcrge w" ild have to be done on a rather arbitrary basis.
nmch t T.rance is designed to allow for v riations
incidn o r; er adding, it might be consiered t conneC..
tion Lhat 1 _-.e proportion of the variation that occurred in the







grading operations formed a part of the experimental error trft~s was
calculated for each experiment and used as a basJs fc comparing
the various treatments thereof.

The Classification

Class 1. Plants K;hose firm head and four wrapper leaves are free
of visible caterpillar injury, and in other respects are
eligible to U. S. No 1 grade (fig. I, upper),

Class 2. Plants whose firm head and four wrapper leaves -:how
caterpillar injury not classed as d~amaqe, and in other
respects are eligible to U S. No. 1 grade (fig. 1,
lower).

Class 3. Plants not eligible to U. S. No. 1 grade as a result of
caterpillar damage:
a. Those having firm heads (fig. 2).
b. Those not having firm heads because of caterpillar
feeding (fig. 3).

Class 4. Plants from which U. S No, 1 grade cabbage cannot be
obtained because of defects other than caterpillar
damage (fig. 4)

Some Uses of the Classification

The use of the classification in the interpretation of
results of cabbage-caterpillar studies will be rather obvious from
the nature of the various classes that are described However, it
might be well to state that class 1 represents an extra-fancy-
quality product; the plants of class 2 are those that are combined
with class I to indicate the production of U. S No. 1 grado plants;
the yield losses due to caterpillar damage are indicated by the
class 3 plants; and class 4 consists of thoc< plants which did
not produce marketable heads because of disease hereditary char-
acteristics, or the results- of unfavor .Le -weat.her or soil ondi-
tions.

At the time this classification was devised, the U. S
No. 1 grade was the only market grade for cabbagefo; t provided ...r
the marketing of the crop -r7cording to unifor {ttndards, Con-
sequently that grade was used as a basis for the classification
even though it was realized that in the commercial mc ,,rketing of
cabbage much of the crop is sold without being graded. In the
studies for which this classification was designed plants of
classes 1 and 2 cons'tituted what were termed marketable cabbage.
In actual practice, however, these can be sold as U. S. No. 1
grade even though they iclude the amount of damaged cabbage al-
lowed by the tolerance. The revised U. S. Standards for cabbage ef-
fective December 20, 1939, provide for the sale of cabbage as U. S.





-4-


Commercial Gcade even though as much as 25 percent is damaged. In
this connection, however, it should be remembered that caterpillar
damage is no te only defect that cabbage may have and that a
certain portion of these tolerances may have been already used as
a result of the experimenter's errors in grading,

The separation of class 3 plants into subclasses 3a and 3b
permits an indication as to the time and extent of the caterpillar
infestation which caused the plant to be considered damaged. ;ub-
class 3a plants are those that formed firm heads and were damaged
after Lhe plai-t bean'l heading and possibly by what might be termed
a moderately heavy infestation, whereas the plants of subclass 3b
are those whose buds were destroyed during the early stage of the
development of the plant or they are those plants that encountered
a severe infestation after heading began and consequently did not
form firm heads.

The classification as used served as a uniform means of
evaluating khe caterpillar injury occurring in the various in-
dividual fields and seasons involved in the survey studies, as well
as for comparing the effects of the different treatments in the
control expert ments.
















































Figwe 1 .--Upper: ?ypical Class 1, heads and wrapper leaves of the
Charleston WakefiU variety of cabbe without visible cater-
pilar Injury, and in other respects eligible to U. 8. No. 1 Grade.
Lower: Weal Class 2, heads with visible caterpillar injwy
but not classed as damage, and in other respects eligible to
U. S. No. 1 gde.













'4, A '' ~ ~ 2N ~















Figure 2.--Subclass 3a, heads and wrapper leaves of Charleston
Wakefield variety of cabbage showing caterpillar injury classed
as damae.


























Figure 3.--Subclass 3b, plants of Charleston Wakefield variety of
cabbage damaged by caterpillars to the extent that marketable
heads were not produced.












































Figure 4.-Class 4, plants of Charleston Wakefield variety of cabbage
which did not produce marketable heads because of defects other
than caterpillar damage.




UNIVERSITY OF FLORIDA

1 BIB1111111111 N1111111 lill 111 1 1111111l ll
3 1262 09239 5101