Group Title: biology of Rhyacionia subtropica Miller (Lepidoptera: Olethreutidae)
Title: The biology of Rhyacionia subtropica Miller (Lepidoptera: Olethreutidae)
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Title: The biology of Rhyacionia subtropica Miller (Lepidoptera: Olethreutidae)
Physical Description: xiii, 148 leaves : ill. ; 28 cm.
Language: English
Creator: McGraw, James Robert, 1943-
Copyright Date: 1975
 Subjects
Subject: Pine-moth   ( lcsh )
Tortricidae   ( lcsh )
Entomology and Nematology thesis Ph. D
Dissertations, Academic -- Entomology and Nematology -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by James Robert McGraw.
Thesis: Thesis (Ph. D.)--University of Florida, 1975.
Bibliography: Includes bibliographical references (leaves 140-146).
General Note: Typescript.
General Note: Vita.
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Bibliographic ID: UF00098933
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000433928
oclc - 38046217
notis - ACJ3623

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THE BIOLOGY OF RHYACIONIA SUBTROPICA MILLER
(LEPIDOPTERA:OLETHREUTIDAE)







By



JAMES ROBERT McGRAW


A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY



UNIVERSITY OF FLORIDA


1975














ACKNOWLEDGMENTS


The author wishes to acknowledge his appreciation to the

chairman of his supervisory committee, Dr. R. C. Wilkinson,

for his guidance, patience, assistance, and advice throughout

the course of this study. Special thanks are extended to Dr.

R. A. Schmidt, particularly with respect to the pitch canker

portion of this study. To Drs. S. H. Kerr and F. W. Zettler

the writer wishes to express his appreciation for the criti-

cisms and suggestions during the preparation of this manu-

script. Thanks are also extended to the above for serving on

the writer's supervisory committee.

For their assistance and for providing locations for the

establishment of research plots, gratitude is extended to

S. C. Uhr and E. M. Underhill, presently, and P. D. Kidd and

P. E. Laverly, formerly, Hudson Pulp and Paper Corporation,

and Ben Swendsen, Lykes Brothers Incorporated.

The author thanks Dr. IV. L. Pritchett for his consulta-

tion and fertilizer recommendations, Dr. F. G. Martin for his

consultation and computation of a majority of the statistical

analyses, Dr. H. L. Cromroy for his assistance and use of his

photomicroscopy equipment, and Dr. D. L. Thomas for his

suggestions regarding Fusarium culturing techniques.

For their assistance in the laboratory, thanks are ex-

tended to W. J. Coleman, C. S. Moses, and R. H. Zerba.
ii









Thanks are expressed to the following persons for their

assistance in obtaining R. subtropica-infested shoots and

collection records: G. Z. Rianhard, Hudson Pulp and Paper

Corporation; K. E. Luke, Scott Paper Company; Edgar Barr, Jr.,

St. Regis Paper Company; G. K. Xydias, Continental Can Com-

pany; Dr. W. E. Beers and H. E. Johstono, Buckeye Cellulose

Corporation; Lee Draper, Jr., Container Corporation of Amer-

ica; J. W. Poole, International Paper Company; Harry Orwig,

Alico Land Development Company; F. S. Broerman, Union Camp

Corporation; E. P. Merkel and G. D. Hertel, United States

Forest Service; and G. W. Dekle, Florida Department of Agri-

culture.

For his assistance and cooperation during the artificial

diet, emergence, and mating portions of this study, gratitude

is extended to Dr. C. W. Fatzinger, United States Forest

Service.

For the identification of the hymenopterous parasites,

thanks are expressed to Dr. E. E. Grissell, Florida Department

of Agriculture, and Drs. B. D. Burks and P. M. Marsh, United

States National Museum. Dr. C. W. Berisford is also thanked

for collecting a portion of the hymenopterous parasites.

The author wishes to thank Drs. W. E. Miller and H. 0.

Yates III, United States Forest Service, for their criticisms

and suggestions regarding the proposed common name for R. sub-

tropica.

The author expresses a special thanks to J. L. Templeton,

Camelot Apartments, and Sergeant Robert Posluzny, Alachua








County Sheriff's Department, for their prompt actions in

extinguishing a fire in the building in which this manuscript

was being written and stored.

Finally, deep gratitude is extended to his wife, Janet,

for her patience, encouragement, and aid during both the

course of study and the preparation of this manuscript.















TABLE OF CONTENTS


ACKNOWLEDGMENTS . . . . . .

LIST OF TABLES . . . . . .

LIST OF FIGURES . . . . . .

ABSTRACT . . . . . . .

CHAPTER


I INTRODUCTION . . . . .

II TAXONOMIC STATUS OF RHYACIONIA SUBTROPICAL

III GEOGRAPHIC DISTRIBUTION AND HOSTS OF
RHYACIONIA SUBTROPICAL ......

IV THE NUMBER OF LARVAL INSTARS OF
RHYACIONIA SUBTROPICAL ......

V SECONDARY SEX STRUCTURES AND SEX-ASSOCIATED
SIZE DIFFERENCES OF LARVAL HEAD CAPSULES OF
RHYACIONIA SUBTROPICA ......

VI SEASONAL HISTORY OF RHYACIONIA SUBTROPICAL
IN SOUTH FLORIDA . . . . . . . .

VII LARVAL FEEDING OF RHYACIONIA SUBTROPICAL . .

VIII PUPAL BEHAVIOR, WEIGHT, AND SEX RATIO
OF RHYACIONIA SUBTROPICAL .. . . ......

IX EMERGENCE OF RHYACIONIA SUBTROPICA .. . ...

X EXPERIMENTAL MATING, OVIPOSITION, AND REARING
MEDIA TRIALS OF RHYACIONIA SUBTROPICA . . .

XI HYMENOPTEROUS PARASITES OF RHYACIONIA
SUBTROPICA . . . . . . . . . .


Page

ii

vii

ix

xi









TABLE OF CONTENTS Continued


Page
CHAPTER

XII INCIDENCE OF RHYACIONIA SUBTROPICA IN
FERTILIZER-INSECTICIDE EXPERIMENTAL PLOTS . .84

XITI RHYACIONIA SUBTROPICA AND PITCH CANKER
IN SLASII PINE ...... ........... 103

XIV SUMMARY AND CONCLUSIONS ... . . . .. 135

REFERENCES . . . . . . . . . . . 140

BIOGRAPHICAL SKETCH . . . . . .. .... .147














LIST OF TABLES


Table Page

1 Chi-Square Comparison of the Observed and
Predicted Larval Head Width Means for the
5 Larval Instars of R. subtropica . . ... .22

2 Correlation of Pupal Sex with Presence
or Absence of Secondary Sex Structures
in R. subtropical Larvae . . . . ... 31

3 Chi-Square Comparisons of Observed and
Male and Female Predicted Larval Head
Width Means for the 5 Larval Instars of
R. subtropical . . . . . ... . . . 32

4 Apical to Basal Pupation Sequence of
R. subtropical in 25 Multiple-Infested
Slash Pine Shoots from Glades County,
South Florida . . . . .... . . . 58

5 Apical to Basal Arrangement of R. subtropical
Male and Female Pupae in 12 Multiple-
Infested Slash Pine Shoots from Glades
County, South Florida . . . . . ... 61

6 Test Statistics of the Rayleigh Test
of Randomness and Calculations of tEe
Mean Emergence Times for Both the Uni-
modal and Bimodal Emergence of R. subtropical 69

7 Some Hymenopterous Parasites of R. sub-
tropica from Florida . . . . . . .. 82

8 Application Dates and Rates of Fertilizer
and Phorate Applied to Soil at the Base of
Each Bedded Slash Pine Seedling in the
Relay Tract Plots During 1970 and 1971 .... .89

9 Chi-Square Analyses of Percent Incidence
of 2-Year-Old Bedded Slash Pine Seedlings
Infested by R. subtropical in the Relay
Tract Plots During 1971 . . . . ... 92








LIST OF TABLES Continued


Table Page

10 Numbers of 2-Year-Old Bedded Slash Pine
Seedlings Infested and Not Infested by
R. subtropica in the Relay Tract Plots
During 1971 . . . . . . . . 93

11 Application Dates and Rates of Fertilizer
and Phorate Applied to Soil at the Base of
Each Bedded Slash Pine in the Relay Tract
Plots From 1970 Until 1974 . . . . .. 107

12 The Number of 1972 and 1973 R. subtropica-
Attacked Slash Pine Shoots in the Glades
County Plots Which Developed Pitch Canker
During 1973 . . . . . . . . . 117

13 Number of 1971 R. subtropica-Attacked
Shoots Which Developed Pitch Canker and
the Number of 1973 Pitch Canker-Infested
Shoots Which Had R. subtropical Damage . .. .117

14 Chi-Square Analyses of the Percent Incidence
of Pitch Canker in Fertilizer-Insecticide
Treated 4-Year-Old Slash Pines in the Relay
Tract Plots During 1973-74 . . . . .. 123

15 The Incidence of Fusarium spp. Isolated
from R. subtropica-Attacked and Non-attacked
Paired Shoots from 40 Slash Pines in Glades
County, Florida, During 1971 and 1973 and
Subsequent Pitch Canker Symptoms Produced
by Inoculation in Healthy Slash Pines . .. .125

16 The Incidence of Fusarium spp. Isolated
from R. subtropical Instars Removed from
Slash Pine Shoots Collected in Glades
County, Florida, and Subsequent Pitch
Canker Symptoms Produced by Those Isolates . 127


viii














LIST OF FIGURES


Figure Page

1 The 5th stage R. subtropica larva ...... 10

2 R. subtropica collection sites as deter-
mined from literature, personal communi-
cations, and collections . . . . ... 17

3 Distribution of R. subtropica larval head
widths, with means and ranges of the 5
larval instars . . . . . . . ... 21

4 Diagrammatic sketch of the 8th, 9th, and
10th abdominal sternites of a 5th stage
R. subtropical [emale larva denoting the
location and characteristics of the secon-
dary sex structures . . . . . ... 28

5 Photomicrographs of 8th abdominal sternites
of 5th stage R. subtropical larvae . . ... .30

6 (Top) Superimposed distributions of 4th and
5th stage R. subtropical male and female
larval head widths . . . . . . .. 34

(Bottom) Distribution of non-sexed head
widths of the 5 larval instars of
R. subtropical . . . . . . . ... 34

7 Seasonal history of R. subtropical and
multinodal growth pattern of slash pine
in south Florida during 1972 and 1973 .... .42

8 First stage R. subtropical larval feeding
injury to slash pine . . . . . ... 49

9 Second stage R. subtropical larval feeding
injury on slash pine . . . . . ... 51

10 Pupation sequence of R. subtropical instars
in a slash pine shoot with dead, partially
elongated secondary needles . . . . .. 60








LIST OF FIGURES Continued


Figure Page

11 Frequency distributions of R. subtropica
emergence by hours of non-sexed moths and
sexed moths .... . . . . . . 71

12 Relay Tract Plots . . . . . . ... 88

13 Frequency distribution, by site and without
regard to treatments, of the number of
R. subtropica larval feeding sites on the
1st four flushes of the apical terminals
of 2-year-old bedded slash pine seedlings
in the Relay Tract plots during 1971 . ...96

14 Frequency distributions, by height class
and without regard to treatments, of the
number of R. subtropica-inFested and total
number of 2-year-old bedded slash pine
seedlings in the Relay Tract plots during
1971 . . . . . . . . . . . 99

15 Glades County plots . ... . . ... .111

16 Diagram of procedure employed to obtain
Fusarium Spp. isolates from R. subtropical
larvae and pupae removed from slash pine
shoots collected in Glades County, Florida . 115

17 Frequency distribution of 275 R. subtropica
larval feeding sites on the internodes of
1971 apical shoots and 70 pitch canker
symptoms at the nodes of 1973 apical
shoots of slash pines in the Relay Tract
plots . . . ...... .. . . 119

18 De-barked apical slash pine shoots showing
pitch canker symptoms occurring at the
branch nodes . . . . . . . . . 122








Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy


THE BIOLOGY OF RHYACIONIA SUBTROPICA MILLER
(LEPIDOPTERA:OLETHREUTIDAE)


by

James Robert McGraw

March, 1975


Chairman: Dr. R. C. Wilkinson
Major Department: Entomology and Nematology


The biology of Rhyacionia subtropical Miller, a tip moth

which attacks young pines in Florida, was investigated.

R. subtropical was collected or recorded as attacking

Pinus elliottii Engelm. variety elliottii, P. elliottii

variety densa Little and Dorman, p. palustris M., and P. thun-

bergiana Franco in Florida; p. elliottii elliottii and P. pal-

ustris in southern Georgia; and P. caribaea Morelet at Free-

port, Grand Bahama Island.

R. subtropical has 5 larval instars and the larvae are

described and illustrated. The 4th and 5th female larval

instars have paired secondary sex structures on their 8th and

9th abdominal sternites.

R. subtropical was bivoltine with a partial 3rd emergence

in September and October, and the seasonal histories of both

R. subtropical and P. elliottii elliottii exhibited inter-

synchronization.








The host tissues which larvae eat are described and

how the various types of larval feeding affected P. elliottii

elliottii growth are discussed.

Larval feeding sites were recorded more frequently in

the upper portion of a flush and most frequently on the first

two flushes of apical shoots. The percentage of infested

pines within a height class increased as total height of

2-year-old pines increased.

The activities of 5th stage larvae prior to pupation are

described. Pupation generally proceeded downward in multiple-

infested shoots with an apparently random distribution of

pupal sexes. The weight by sex, sex ratio, colors, and sta-

dium duration of pupae are also reported.

The activities of encased pharate adults prior to eclo-

sion, general adults during eclosion, and fully dried adults

after eclosion are reported. The daily pattern of emergence

under natural light cycle was bimodal, with major and minor

peaks at 0858 and 1935 hours EDST, respectively.

Adults did not mate under laboratory or semi-artificial

conditions, but field-collected larvae fed and developed on

an artificial diet and produced pupae which issued adults.

Six species of hymenopterous parasites, Bracon gemmaecola

(Cush.), Temelucha new species, Hyssopus rhyacioniae Gah.,

Arachnophaga ferruginea Gah.,Haltichella rhyacioniae Gah.,

and Sphilochalcis flavopicta (Cress.), were recovered from

individual R. subtropica larvae and pupae.









In fertilizer-insecticide experimental plots of 2-year-

old bedded P. elliottii elliottii, the 0-P-K and 0-0-0 treat-

ments, either with or without the phorate insecticide, were

superior to any of the N-0-0 or N-P-K treatments for the

avoidance of infestation by R. subtropica. Plots which

received phorate had a significantly lower percentage of

R. subtropica-infested pines.

Field and laboratory studies were conducted to also in-

vestigate the association of R. subtropical and pitch canker,

a disease of pines caused by the fungus Fusarium lateritium

f. pini (Nees.) Hepting. R. subtropical was concluded not to

be a prime agent in the initiation and spread of pitch canker

in P. elliottii elliottii in Florida.

A common name, subtropical pine tip moth, for R. sub-

tropica was submitted to the Entomological Society of America.


xii














CHAPTER I

INTRODUCTION



Shoot moth or tip moth larvae of the genus Rhyacionia

mine and kill buds and shoots of pines. Until 1960, when

R. subtropica Miller was described, R. frustrana (Comstock)

and R. rigidana (Fernald) were the principal tip moth species

known to attack pines in the southeastern United States.

In 1963, Merkel reported the status of knowledge about

R. subtropica as follows: "Virtually nothing is known about

its life history and habits, and it could be hazardous to

assume that the biology of this species is the same as other

tip moths, ." To date, the status of knowledge of R. sub-

tropica includes morphological description of the adult

(Miller 1960), identification characteristics of the pupa

(Yates 1967c) and larva (Miller and Wilson 1964), host plants

(Miller 1960, Miller and Wilson 1964), and geographic dis-

tribution (Miller 1960,1965; Bethune 1963; Frost 1963,1964;

Miller and Wilson 1964; Kimball 1965); but the biology of

R. subtropica remains unreported.

In recent years, five factors have aroused the need to

investigate the biology of R. subtropica: (1) use of genetic-

ally superior seedlings to stock large acreage pine planta-

tions, (2) application of fertilizer to existing and newly








established pine plantations (Pritchett and Smith 1970),

(3) awareness that tip moths are the major factor killing

conelets in some pine seed orchards (Yates and Ebel 1972,

Ebel and Yates 1974), incrimination of tip moths in the dis-

ease cycle of pitch canker, a disease of pines caused by the

fungus Fusarium lateritium f. pini (Nees). Hepting (Mathews

1962, Berry and Hepting 1959,1969), and (5) outbreaks of

pitch canker in slash pine plantations and a slash pine seed

orchard in Florida (Laird and Chellman 1972, Schmidt and

Underhill 1974).

In 1970 University of Florida forest entomologists and

pathologists, with technical assistance from private industry

and the U.S. Forest Service, initiated studies to investigate

the biology of R. subtropical and the relationship of R. sub-

tropica and pitch canker disease in Florida.

The objectives of the a. subtropical investigation were

to determine (1) geographic distribution in Florida, (2) num-

ber of larval instars, (3) seasonal history in Florida,

(4) which host tissues larval instars eat and how feeding

affects Pinus elliottii Engelm. variety elliottii growth,

(5) pupation and pupal behavior, (6) emergence activities and

daily emergence patternss, (7) mating, oviposition, and rear-

ing media, (8) parasites, (9) the affect of fertilizer and

insecticide on the incidence of infestation in p. elliottii

elliottii ,(10) distribution of larval feeding sites within

the multinodal annual vegetative long shoot, and (11) inci-

dence of infestation by tree height class.






3


To examine the association of R. subtropica and pitch

canker, studies were conducted to determine (1) if R. sub-

tropica is associated with pitch canker symptoms, (2) dis-

tribution of R. subtropical larval feeding sites and pitch

canker symptoms on the multinodal annual vegetative long

shoots of P. elliottii elliottii, (3) the effect of fertili-

zer and insecticide on the incidence of pitch canker in

P. elliottii elliottii, (4) the association of pitch canker-

producing Fusarium spp. and R. subtropical on pairs of P.

elliottii elliottii shoots, and (5) which R. subtropical in-

star(s) is associated with the pitch canker-producing fungus.

The results of these investigations are reported herein.













CHAPTER II

TAXONOMIC STATUS OF RHYACIONIA SUBTROPICA



Background


R. subtropica was first discussed as a new species by

Miller and Neiswander (1959) and was described by Miller in

1960 from specimens collected in 1927. Miller (1960) also

recommended the common name "Subtropical Pine Tip Moth" for

R. subtropica. A common name has never been approved by the

Committee on Common Names of Insects of the Entomological

Society of America.

Merkel (1963) reviewed tip moth identification problems

resulting from the belated recognition and description of this

species. Miller (1960), Bethune and Hepting (1963), Frost

(1963,1964), and Kimball (1965) reported pre-1960 studies

which could have benefited from an earlier recognition of

R. subtropica.

Yates (1967c) differentiated R. subtropica pupae from

those of R. rigidana Fernald and R. frustrana (Comst.).

MacKay (1959) used previously undetermined specimens

from the type-locality of R. subtropica, collected within ca.

one month of the R. subtropica types, for the basis of her

description of the larvae of R. rigidana Fernald [should be

(Fernald)]. C. H. (MacKay 1959, Miller 1960) was Carl









Heinrich, and Heinrich's initials were on the labels of the

specimens which MacKay (1959) used for the larval description

of R. rigidana and which Miller (1960) designated as types

for R. subtropica. Apparently, Heinrich recognized that

both the larvae MacKay (1959) eventually used and the adults

Miller (1960) designated as types were not specimens of R.

frustrana, R. rigidana, or R. buoliana (Schiffermiiller)

because neither MacKey (1959) nor Miller (1960) reported

species determination information when they (MacKay 1959,

Miller 1960) cited label data. MacKay's (1959) description

of R. rigidana larvae fits the larvae I collected in Glades

County, Florida, that came from the same pine shoot as R.

subtropica pupae which produced males and females whose geni-

talia and wing characteristics were identical to those char-

acteristics described for R. subtropica (Miller 1960).

To prevent future taxonomic and nomenclatural complica-

tions, the approval of Miller's (1960) recommended common name

has been initiated and the larva of R. subtropica is described.



Methods


Common Name Approval

After conferring with W. E. Miller, R. C. Wilkinson, and

H. O. Yates III, I submitted, on 12 June 1974, the common name

Subtropical Pine Tip Moth to G. D. Hertel, Chairman, Common

Names Committee of the Southern Forest Insect Work Conference,

for approval and recommendation to the Committee on Common

Names of Insects of the Entomological Society of America.








Larval Description

Decapitated, 5th instar R. subtropica larval integuments

were split longitudinally along the ventral midline, debrised,

mounted in Hoyer's solution on microslides under 20 mm square

coverslips, cleared, and illustrated with the aid of a ver-

tically mounted microslide projector. Other larval instars

were examined with a compound microscope and a dissecting

microscope (magnification 40-100x).

The illustrations and description of the R. subtropica

larvae were prepared following MacKay's (1959) format and

chaetotaxy system to provide consistency of Rhyacionia larval

information. The setal designations were omitted from the

R. subtropical larval illustrations, but can be determined by

referring to Figure 1 on page 168 in MacKay (1959). The dis-

sected larval integuments prepared for and the stylized body

segments used to illustrate the R. subtropical larva reduced

the annulation of the body and expanded the longitudinal axis

of the body, thereby distorting the body length of the larval

illustration relative to the actual body length of a 5th

stage R. subtropical larva. A scale (1 mm) accompanies the

R. subtropical larval illustration.

R. subtropical larvae collected from Glades County,

Florida, were deposited in the Florida State Collection of

Arthropods, Gainesville. R. subtropical adults which emerged

from pupae collected in slash pine shoots at Glades County,

Florida, are located at the Department of Entomology, Univer-

sity of Georgia, Athens (C. W. Berisford, personal communica-

tion).









To the best of my knowledge, T have never seen a R. rigi-

dana larva.

I have sent R. subtropica larvae and pupae to W. E.

Miller and requested that he examine and compare the larvae

of R. subtropical and R. rigidana during his current revision

of the genus Rhyacionia.



Results


Common Name Approval

Subtropical Pine Tip Moth was approved by the 19th South-

ern Forest Insect Work Conference and will be recommended to

the Committee on Common Names of Insects of the Entomological

Society of America as the common name for R. subtropical (G. D.

Hertel, personal communication).


Larval Description

The body length of R. subtropical larvae ranges from ca.

1.5 mm for the 1st instar to ca. 7 mm for the 5th instar.

The range of head widths is 0.241-1.270 mm (1635 larvae) and

the mean head widths (mm) for the 5 larval instars are 0.260,

0.345, 0.489, 0.721, and 1.044 (Figure 3 and Table 1).

The 1st larval instar head is brown with a darker lateral

bar at the postgenal juncture; the body is pink to pale laven-

der; and the prothoracic setae L -L3 are aligned linearly.

The 5th larval instar head is yellowish-tan to golden with a

dark brown or black lateral bar at the postgenal juncture;

the body is ivory or cream colored; and the prothoracic setae

L1-L3 are aligned linearly. The larval head becomes dark









brown prior to moulting and the body light pink following

moulting in all larval instars. The prothoracic and anal

shields' color are the same as and change along with the

head's color.

The 5th larval instar abdominal segments 1-6 have 3 SV

setae and segments 7-9 have 2 SV setae. Setae L3 is absent

on abdominal segment 9. Thoracic segments. 2 and 3 have 4

extra setae; abdominal segments 1-8 have 3 extra setae, and

abdominal segment 9 has 2 extra setae (Figure 1 C and D).

The 4th and 5th female larval instars have paired secon-

dary sex structures on the venter of the 8th and 9th abdomi-

nal segments laterad of each V1 seta and between the V1 and

SV setae (Figure 1 D, Figure 4, and Figure 5 B).

The head shape, head setal and ocellar patterns, body

setae lengths, pinacula shape, extra setae and their place-

ment, spiracular shape and alignment, and the integumental

spinulation can be determined from Figures 1, 4, and 5.

The spinneret, labial palps, tarsus, tarsal claw, and the

tarsal setae are similar to those characters of R. buoliana

(MacKay 1959).

Miller and Wilson (1964) discuss the characters for dif-

ferentiating the larvae of both R. subtropica and R. rigidana

from the larvae of R. frustrana. No characters are known for

the separation of R. subtropica and R. rigidana larvae (Miller

and Wilson 1964); and since I did not study the larvae of

R. rigidana, the majority of the following studies were con-

ducted in Glades County, Florida, outside the zone of




















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geographic distributional overlap of R. subtropical and R.

rigidana to avoid problems of larval identification.



Discuss ion


T believe the above description of the R. subtropical

larva, the morphology of the secondary sex structures on the

female 5th larval instars, and W. E. Miller's current revi-

sion of the genus Rhyacionia will finally resolve the in-

ability to separate R. subtropical and R. rigidana larvae.

Also, I believe MacKay (1959) was probably examining R. sub-

tropica larvae when she described the larvae of R. rigidana;

therefore, 1 foresee R. rigidana (Fernald) (sensu MacKay

1959) becoming a synonym of R. subtropical Miller (1960).



Summary


R. subtropical was described by Miller (1960) and the

name remains valid.

A common name, Subtropical Pine Tip Moth, for R. sub-

tropica has been submitted to the Committee on Common Names

of Insects of the Entomological Society of America for

approval. The larva of R. subtropical are described and illus-

trated.














CHAPTER III

GEOGRAPHIC DISTRIBUTION AND HOSTS
OF RHYACIONIA SUBTROPICA



Background


In the United States, the distribution of R. subtropica

is reported to coincide with the distribution of slash pine

varieties (Miller and Noiswander 1959, Miller 1960; Yates

and Beal 1971, Baker 1972). Critchfield and Little (1966)

and Little (1971) mapped the ranges of Pinus species.

R. subtropica is reported from Alachua, Baker, Bradford,

Broward, Charlotte, Collier, Dade, Escambia, Flagler-St.

Johns, Highlands, IIillsborough, Lee, Levy-Gilchrist, Manatee,

Marion, Martin, Okaloosa (type-locality), Orange, Osceola,

Palm Beach, Pinellas, Polk, Putnam, St. Lucie, Sarasota,

Taylor, Union, and Volusia Counties, Florida; Lanier and Ware

Counties, Georgia; Aiken County, South Carolina; and the

southwestern counties of the Mississippi "boot-heel" attack-

ing Pinus elliottii Engelm. variety elliottii (typical slash

pine), P. elliottii variety densa Little and Dorman (south

Florida slash pine), p. taeda L. (loblolly pine), and p.

palustris M. (longleaf pine) (Miller 1960, Bethune 1963

(circles on map), Frost 1963,1964, Miller and Wilson 1964,

Kimball 1965).









In the West Indies and Central America, Miller reported

R. subtropica from Pinar del Rio Province, Cuba (1960), and

British Honduras (1965), now Belize, attacking P. tropicalis

Morelet (tropical pine) and P. caribaea Morelet (Caribbean

pine), respectively.

The objectives of this survey were to determine the best

location for studying the biology of R. subtropical and to

determine the distribution and abundance of R. subtropical in

Florida.



Methods


From January 1971 until July 1974, J. R. McGraw and R.

C. Wilkinson made collections, and solicited collections and

collection records of R. subtropical.

R. subtropical larvae and pupae collected by and sent to

J. R. McGraw and R. C. Wilkinson are deposited in the Florida

State Collection of Arthropods, Gainesville.

R. subtropical adults which emerged from pupae collected

by J. R. McGraw and G. W. Berisford in slash pine shoots at

Glades County, Florida, are located at the Department of

Entomology, University of Georgia, Athens (G. W. Berisford,

personal communication).









Results


R. subtropica was collected in Alachua, Clay, Dixie,

DeSoto, Flagler, Franklin, Glades, Hardee, Highlands, Lake,

Madison, Putnam, St. Johns, Sarasota, Sumter, Taylor, and

Volusia Counties, Florida, attacking P. elliottii elliottii

and P. palustris by J. R. McGraw and R. C. Wilkinson. R. C.

Wilkinson also collected R. subtropical from Sugarloaf Key,

an insular component of Monroe County, Florida, and the most

southern site on which pine (P. elliottii densa) grows

naturally in the United States. R. C. Wilkinson collected

and preserved larvae in Freeport, Grand Bahama Island, attack-

ing P. caribaea.

Cooperative Research in Forest Fertilization (CRIFF)

program Technical Representatives, II. E. Johstono and B.

Poole, collected and supplied P. elliottii elliottii shoots

containing R. subtropical from CRIFF A-Series test plots

located in Bay, Franklin, Madison, and Taylor Counties,

Florida, and Clinch County, Georgia.

R. subtropical specimens identified for the Division of

Plant Industry (DPI), Florida Department of Agriculture and

Consumer Services, were from P. thunbergiana Franco (Japanese

black pine) nursery stock in Dade, Hillsborough, and Volusia

Counties, Florida.

E. P. Merkel (personal communication) provided collection

records of R. subtropical from Collier County, Florida, attack-

ing P. elliottii elliottii and P. elliottii densa, and from

south Georgia attacking p. palustris.









G. D. Hertel (personal communication) provided collec-

tion records from Baker, Columbia, Dixie, Nassau, Taylor, and

Union Counties, Florida, of R. subtropica attacking P. elliottii

elliottii in his research plots.



Discussion


R. subtropical was reported throughout coastal south-

eastern United States, the West Indies, and Central America.

R. subtropical could be native to Central America and the

West Indies and could have migrated or have been introduced

into the southeastern United States.



Summary


This survey reported collections of R. subtropical attack-

ing pines in southeast Georgia, on Grand Bahama Island, on

Sugarloaf Key (the most southern site pines grow in the

United States), and throughout Florida (Figure 2). R. sub-

tropica was most abundant in the southern and coastal areas

of Florida. Research plots for studying the biology of R.

subtropical were established in a bedded 2-year-old p. elliottii

elliottiil plantation located in southwestern Glades County,

Florida, in the vicinity of Lykes Fire Tower (Sections 17, 18,

and 20, Township 42 South, Range 29 East).


Future references to slash pine, whether in north Florida
or south Florida, mean P. elliottii elliottii and references
to south Florida slash pine mean p. elliottii densa.






























Figure 2. R. subtropica collection sites as determined
from literature, personal communications, and
collections; with circles denoting the south
Florida counties, not exact sites, where
Bethune (1963) worked, a star denoting type-
locality, and arrows denoting the exact loca-
tions of J. R. McGraw's study plots in Flagler
and Glades Counties.
















































































coo













CHAPTER IV

THE NUMBER OF LARVAL INSTARS
OF RHYACIONIA SUBTROPICA



Background


During initial studies of the biology of R. subtropical,

knowledge of the number of larval instars was required for

identifying where each instar fed on the slash pine host

plant. Larval head capsules were measured to resolve the

number of larval instars.



Me thods


Biweekly from August 1972 to October 1973, slash pine

shoots attacked by R. subtropica were collected in Glades

County, Florida. Larvae were removed from the shoots, indi-

viduals were positioned on a small mound of 10% boric acid

ointment in a BPI dish containing 70% ethanol, and maximum

head widths were determined with the aid of an ocular microm-

eter mounted in a binocular dissecting microscope (magnifica-

tion 40x).

The frequency distribution plot of head widths was ana-

lyzed by visual inspection. Instar means were calculated and

X analysis (Snedecor and Cochran 1967) was used to compare









the goodness-of-fit of the observed calculated means to the

means predicted by Dyar's rule (1890).



Results


The distribution of 1,635 head widths produced a histo-

gram with 5 major peaks and 2 secondary peaks in the 4th and

5th instars (Figure 3). Chi-square analysis showed that the

means predicted by Dyar's rule for the first 3 instars were

highly correlated with the observed means (Table 1).



Discussion


The presence of 5 larval instars in R. subtropica corre-

sponded to the number of larval instars in R. frustrana (Fox

et al. 1972) and also conformed to Dyar's (1890) rule of

geometric progression.



Summary


R. subtropica has 5 larval instars which conform to

Dyar's (1890) rule of geometric progression. The means pre-

dicted by Dyar's (1890) rule for the first 3 larval instars

were highly correlated with observed means for the first 3

larval instars of R. subtropica.



















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CHAPTER V

SECONDARY SEX STRUCTURES AND SEX-ASSOCIATED
SIZE DIFFERENCES OF LARVAL HEAD CAPSULES
OF RHYACIONIA SUBTROPICA



Background


The investigation of larval head widths of R. subtropica

showed the presence of 5 larval instars, corresponding to the

number of larval instars in the smaller R. frustrana (Fox

et al. 1972). In the larger R. buoliana, the uncertainty of

the number of larval instars (possibly 6) is apparently com-

plicated by a sex-associated difference in later stadia head

widths (Friend and West 1933, Miller and Neiswander 1955,

Pointing 1963).

Previous larval instar investigations by Drooz (1965) on

Ennomos subsignarius (H[lbner) (Lepidoptera:Gcometridae), the

elm spanworm, and by Wilkinson (1971) on Neodiprion merkeli

Ross (Hymenoptera:Diprionidae), the slash-pine sawfly, showed

that sex-associated size differences existed in the head

widths of last stage larvae. Drooz correlated larval head

width and sex by measuring a living individual larva's head

capsules and by sexing its adult. Wilkinson found paired

secondary sex structures invaginatedd plates) he named "ovi-

positor bud plates" on the 8th and 9th abdominal larval

sternites diagnostic of the female sex. Wilkinson studied









the metamorphosis of living larvae possessing the secondary

sex structures to correlate the function and the sex associ-

ated with the structures. In 1967, Nielsen and Bohart

reported structures on the 9th abdominal sternite of larvae

(principally male) of certain wild bee species (Hymenoptera:

Apidae). These latter authors did not investigate head

widths or the number of larval instars.

The pupal sex-determining characters of R. subtropical

are on the 8th and 9th abdominal sternites (Yates 1969).

The objectives of this investigation were to (1) locate

and characterize any secondary sex structures present on 4th

and 5th instar R. subtropica larvae, (2) correlate the pres-

ence or absence of these larval structures with pupal sex, and

(3) describe possible sex-associated size differences in 4th

and 5th instar larval head capsules.



Methods


Location of Secondary Sex Structures in Larvae

Preserved 4th and 5th instar R. subtropical larval integu-

ments were split longitudinally along the dorsal mid-line,

debrised, mounted in Hoyer's solution on microslides under

20 mm square coverslips, cleared, examined microscopically,

illustrated, and photographed at 100x magnification.


Correlation of Pupal Sex with Larval Structures

R. subtropical larvae were collected 30 August 1972 in

slash pine shoots in Glades County, Florida, removed from the









shoots, asphyxiated in a cool-water bath, and examined micro-

scopically (magnification 60x) to determine the presence or

absence of the structures located on the 8th and 9th abdominal

sternites. The larvae then were revived and placed between

moistened No. 2 Whatman filter paper disks in individual cups

containing an aseptic agar medium (Batcheler and Emmel 1974)

to await pupation. After pupation, the pupae were sexed

according to Yates' (1969) technique to determine if the

structures were associated with one sex.


Sex-Associated Size Differences in
4th and 5th Larval Instar Head Capsules

The 4th and 5th larval instars measured in the larval in-

star study were sexed according to the presence or absence of

the secondary sex structures (magnification 60x) and head

widths were correlated with sex. Larvae with damaged heads

or missing abdominal segments were discarded.

The frequencies of the sexed 4th and 5th larval instar

head widths were plotted separately and then superimposed.

Separate male and female means were calculated for both the

4th and 5th larval instars. Student's t-test (Snedecor and

Cochran 1967) was used to compare the 5th stage non-sexed

(observed), male, and female means. Using Dyar's rule (1890)

and both sets of sexed 4th and 5th larval instar means, two

hypothetical series of means for the first 3 larval instars

were calculated. The two hypothetical series of means were

compared by x2 analysis to determine the goodness-of-fit to

the observed non-sexed larval instar means.









Results


Location of Secondary Sex Structures in Larvae

Paired elliptical, aspinulose areas, surrounding trans-

verse integumental folds, laterad of each V1 seta and between

the V1 and SV setae were found on the 8th and 9th abdominal

sternites of R. subtropical larvae (Figure 4 ). These 4 aspinu-

lose areas were strongly similar and were not present on all

4th and 5th larval instars (Figure 5 ).


Correlation of Pupal Sex with Larval Structures

Larvae without the paired elliptical, aspinulose areas

surrounding the transverse integumental folds on the 8th and

9th sternites (Figure 5A) produced only male pupae; and larvae

with the paired structures (Figures 4 and 5B) produced only

female pupae (Table 2), verifying only Female larvae bore

the secondary sex structures.


Sex-Associated Size Differences in
4th and 5th Larval Instar Head Capsules

Frequency plots of segregated male and female 4th and 5th

larval instar head widths produced bimodal distributions for

each stadium (Figure 6, top). The superimposed histogram

showed the exact overlap between the ranges of the 4th instar

females and 5th instar males. Twelve 4th stage female larvae

were involved in this overlap and were considered 5th instars

in the non-sexed data, calculations, and histogram (Table 3

and Figure 6, bottom).

Student's t-test comparisons between non-sexed, male,































Figure 4. Diagrammatic sketch of the 8th, 9th, and 10th
abdominal sternites of a 5th stage R. sub-
tropica female larva denoting (arrows) the
location and characteristics of the secondary
sex structures.










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Table 2

Correlation of Pupal Sex with Presence (Female)
or Absence (Male) of Secondary Sex Structures
in R. subtropica Larvae



LARVAE PUPAE

SEX PREDICTED DIED PUPATED SEX VERIFIED

(number)

MALES 29 2 27 27

FEMALES 24 4 20 20


















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and female 5th larval instar means showed that the 3 means

were significantly different.

Chi-square analysis showed that the hypothetical first

3 larval instar means predicted from the male Dyar's ratio

were more closely correlated with the observed (non-sexed)

means than the hypothetical means predicted from the female

Dyar's ratio (Table 3).



Discussion


The location and appearance of the paired transverse

integumental folds found on the 8th and 9th abdominal stern-

ites of female R. subtropical larvae were similar but not iden-

tical to the transversely invaginated ovipositor bud plates

of female NJ. merkeli sawfly larvae (Wilkinson 1971) or the

secondary sex structures of certain wild bee larvae (Nielsen

and Bohart 1967).

The secondary sex structures were evident without the use

of stains, but high magnification (60x) and excellent lighting

were required. The use of stains (Nielsen and Bohart 1967)

is advised when light colored or small larvae are studied.

A careful microscopic examination of the 8th and 9th

sternites of unstained, preserved last larval instars of

R. frustrana, Malacosoma americanum (F.), M. disstria (Hbn.),

Porthetria dispar (L.), Ceratomia catalpae (Bdv.), and

Tetralopha robustella Zell. revealed that a portion of the

specimens of each of these lepidopterous forest pest species

also possessed structures similar in appearance and location









to those structures found on female R. subtropica larvae and

the species discussed in Wilkinson (1971) and Nielson and

Bohart (1967). Additional studies are required to determine

the sex of the larvae of these 7 additional species which

possessed the paired structures. Such structures could be

common in other lepidopterous larvae.

Larval mortality during the sex verification experiment

probably was attributable to (1) injury to larvae during

removal from slash pine shoots, (2) cross-contamination with

unknown pathogenic organisms during asphyxiation of larvae in

common cool-water bath, (3) injury to larvae being handled

during sexing procedure, and (4) use of penultimate larval

instars which starved to death before pupation.

The inclusion of 12 female 4th larval instars in the 5th

larval instar non-sexed head width data and calculations

could not have been known, nor the exact extent of the over-

lap of 4th and 5th stadia determined without sexing the 4th

and 5th larval instars.

The Student's t-test comparisons of the male and female

5th larval instars head width means proved the head capsules

of the female R. subtropica 5th larval instar were signifi-

cantly larger than those of the 5th larval instar males. Chi-

square analyses of the male, female, and non-sexed Dyar's

ratios were not widely dissimilar; since the size of male and

female 5th larval instar head capsules were not the same and

the 4th and 5th larval instar means used as starting points

for Dyar's geometric progression were not equal, neither the









male nor the female ratio predicted the first 3 larval instar

means as well as the non-sexed ratio.

The unbalanced sex ratio in the 4th stadium was caused

by my inability to discern microscopically the secondary sex

structures, and not by the lack of female larvae. If female

larvae develop faster than male larvae, which is not the case,

the frequency and number of collections during this 13-month

study would have tended to have equalized the 4th larval

instar's sex ratio. Also, the balanced 5th larval instar sex

ratio suggested that the number of 4th instar females probably

equaled the males but the failure to discern secondary sex

structures resulted in larvae being identified as males. Care

should be taken and caution applied when sexing R. subtropica

4th larval instars.

The ability to sex 4th and 5th stadium larvae elucidated

the instar limits; determined the exact instar overlap; deter-

mined the larval sex ratios; eliminated secondary peaks in

the non-sexed histogram of head widths; produced bimodal dis-

tributions within the 4th and 5th instars; eliminated skewed,

non-sexed distributions in the non-sexed histogram of head

widths; and proved a sex-associated size difference in head

capsules of 4th and 5th instar R. subtropica larvae. The use

of larval sex also supported the presence of 5 larval instars.

Tn addition to the above uses and the uses mentioned by Neil-

sen and Bohart (1967) and Wilkinson (1971), secondary sex

structures would be useful for identifying living female

larvae and establishing sex ratios in behavioral, ecological,

biological control, and pest management studies.









Dyar's rule of geometric progression has been applied

many times to estimate the number and mean head widths of

larval instars of various lepidopterous and hymenopterous

species. Predictions calculated by using Dyar's rule have

been accepted about as many times as they have been rejected.

Probably the major factors contributing to the rejection of

predictions calculated by using Dyar's rule were (1) the

small number of head capsules measured, (2) large differences

in the widths of the head capsules of penultimate and ultimate

stage male and female larvae, and (3) an unbalanced sex ratio

in the penultimate and ultimate instars causing their head

width means, from which Dyar's ratio is calculated, to be

skewed. When a person has studied the biology of a particu-

lar species, measured numerous larval head capsules of all

instars (with or without segregating sizes according to sex),

and constructed a clear frequency distribution of the larval

head widths, the Dyar's ratio and geometric progression cal-

culated should be used as tools for gauging the natural sequen-

tial size increases of larval head capsules, not used to set

the progression.



Summary


The 4th and 5th R. subtropica female larval instars had

paired secondary sex structures on their 8th and 9th abdominal

sternites. The 5th larval instar female head capsules were

statistically larger than the head capsules of the 5th larval

instar males.














CHAPTER VI

SEASONAL HISTORY OF RHYACIONIA SUBTROPICA
IN SOUTH FLORIDA



Background


The seasonal history of R. subtropical was studied in

slash pine plantations in south Florida because (1) this tip

moth was more abundant there than in other areas of Florida,

(2) R. frustrana and R. rigidana did not occur in south

Florida, and (3) previous pitch canker disease studies, which

incriminated R. subtropical, were conducted near La Belle,

Hendry County, in south Florida (Anonymous 1958, Bethune and

Hepting 1963).



Methods


Biweekly from August 1972 to October 1973 and periodic-

ally thereafter until July 1974, slash pine shoots attacked

by R. subtropical were collected from 2- and 3-year-old bedded

plantations in the vicinity of Lykes fire tower, north of La

Belle, in southwest Glades County, Florida (Sections 17, 18,

and 20, Township 42 South, Range 29 East).

Larvae were removed from shoots and preserved in 70%

ethanol. Head capsules were measured for instar determina-

tion. Pupae removed from shoots were placed in individual









rearing cups containing an aseptic agar medium (Batcheler and

Emmel 1974) and were held until adult emergence in a rearing

room at 27 + 2C with north light for exposure to natural

photoperiod (Gainesville, Florida).

Observations on the seasonal height growth (flushing) of

slash pine were also made in Glades County, Florida.



Results


The seasonal history of R. subtropical and the multinodal

growth (flushing) pattern of slash pine in south Florida

during 1972 and 1973 are illustrated in Figure 7. R. sub-

tropica was bivoltine with a partial 3rd generation during

the fall. R. subtropical pupae "overwintered" in the field in

south Florida; however, once the pupae were taken into the

laboratory, adult emergence soon occurred. R. subtropical

eggs were never found, and the probable occurrence of eggs

in Figure 7 was based on the relative abundance of adults

and 1st stage larvae.

R. subtropical collected by R. C. Wilkinson on 23 June

1973 at Freeport, Grand Bahama Island, were synchronized with

the Glades County population.

The seasonal height growth (flushing) of slash pine in

Glades County began during early March, with the majority of

the trees attaining 3 flushes of growth and others attaining

4-6 flushes. After first flush initiation, subsequent flush-

ing was not synchronized among trees.































Figure 7 Seasonal history of R. subtropica and multi-
nodal growth pattern (flushing) of slash pine
(P. elliottii elliottii) in south Florida
during 1972 and 1973.











E = eggs
1-5 = larval stadia
P = pupae


A = adults





























Rhyacionia subtropical
Shyacionia subtropica


V 4-
w




O PLus o var. eitn

J F M A M J J A S O N D


P--
.............









Needle elongation on each flush of growth occurred from

the base upward and was completed before the next flush elon-

gated. In the spring of 1974, 1st flush needles did not

elongate or elongated from the apex downward, apparently due

to a severe spring drought followed by early summer torrential

rains.



Discussion


The partial September-October emergence observed in south

Florida possibly represents a third generation during some

years. Second generation R. subtropica pupae collected in

north Florida also exhibited a tendency for a partial third

generation.

The seasonal multinodal growth characteristic of slash

pine in south Florida was similar to the multinodal growth

characteristic of slash pine in north Florida (Kaufman 1965,

Pritchett and Smith 1970), but periods of shoot elongation

(flushing) varied between slash pines growing in north and

south Florida.

In south Florida, the seasonal histories of both R. sub-

tropica and slash pine exhibited intersynchronization in the

(1) initiation of 1st generation 1st instar larval develop-

ment and 1st flush shoot elongation, (2) completion of 1st

generation larval feeding and attainment of a majority of

the height growth before 21 June, and (3) termination of 2nd

generation larval development and host plant growth. The






44


synchronization of flushing from June-August continuously

provided new and undamaged host plant tissues suitable for

tip moth oviposition and early larval instar development.



Summary


R. subtropical was bivoltine in south Florida with a

partial 3rd emergence in September and October. The seasonal

histories of both R. subtropical and slash pine exhibited

intersynchronization in south Florida.













CHAPTER VII

LARVAL FEEDING OF RHYACIONIA SUBTROPICAL



Background

Yates (1967a) reported the location of R. frustrana and

R. rigidana larval feeding on loblolly pine shoots during

April and May. lie found that 1st, 2nd, and 3rd larval instars

fed on the exterior of shoots (i.e., injury) and that 4th

larval instars began internal boring (i.e., damage) after

such shoots were almost completely elongated.

Yates (1966) has defined injury and damage caused to

loblolly pine and slash pine by larval feeding of R. frustrana

and R. rigidana as follows: "injury refers to needle and

external shoot feeding by the larvae; damage refers to inter-

nal feeding which causes distortion or death of the shoot or

bud." Yates (1960) also divided damage into deformation of

the tree (main stem), retardation or loss of height growth,

and reduction of cone crops. Heikkenen (1960) outlined defor-

mations of the main stem of red pine as crooks, forks, prun-

ing, brushing, and spike-tops. Miller (1967) defined

IHeikkenen's (1960) deformation categories as follows: (1) "A

crook is a departure of the stem from straightness," (2) "A

fork . occurs when two or more shoots closely compete for

dominance," (3) "Pruning . is a reduction in the normal









number of branches at a whorl due to killing of one or more

buds or shoots," (4) "Bushing . is an increase in the

normal number of branches at a whorl due to fascicle buds

which appear after all or most of the original leader buds or

shoots are killed," and (5) "Spike-tops . are dead leaders

killed back so that fascicle buds form well below the tip or

do not form at all."

The objectives of this R. subtropica larval feeding

study were (1) to determine which host tissues the 5 larval

instars ate, and (2) to determine how the various types of

feeding affected slash pine growth.



Me thods

Tissues Eaten

The descriptions of R. subtropica larval feeding were

made from laboratory observations of field-collected material,

and the botanical terminology used to describe the slash pine

structures and tissues which R. subtropical larvae ate is that

of Doak (1935).


Effect on Slash Pine Growth

The definitions and categories of Yates (1960, 1966),

Heikkenen (1960), and Miller (1967) were used to report labo-

ratory examinations and field observations made in both

Flagler and Glades Counties. R. subtropical larval feeding

injury and damage and the effect of the feeding on slash pine

growth are reported.









Results


Tissues Eaten

First stage R. subtropical larvae fed (1) on young scales

and fascicles on elongating young vegetative long shoots,

(2) inside the fascule sheath on the bases of unelongated or

partially elongated secondary needles of a fascicle, (3) in-

side one elongating or completely elongated secondary needle

of a fascicle, and (4) on juvenile needles of elongating young

vegetative dwarf shoots (Figure 8).

Second stage R. subtropical larvae (1) fed on young scales

and fascicles on elongating young vegetative long shoots,

(2) fed in the groove between scales subtending a fascicle,

(3) bored into the side or keeled-ridge of a scale subtending

a fascicle and fed on the internal tissues under the fascicu-

lar insertion, and (4) fed on juvenile needles of elongating

young vegetative dwarf shoots. During the second type of

feeding described above, the larva exited the scale through

the "entrance" hole before boring into another scale; conse-

quently, the internal scale feeding sites were not connected

by internal tunnels (Figure 9).

Third stage R. subtropical larvae initiated boring into

the vascular tissues of the elongated vegetative long shoots.

Fourth and 5th stage R. subtropical larvae extended the

tunneling initiated by 3rd stage larvae, tunneled up the

shoot into the apical bud, and consumed the bud's tissues.






























Figure 8. First stage R. subtropica larval feeding
injury to slash pine.

A. Dead partially elongated secondary needles
with a larval exit hole in the fascule sheath.

B. Elongated secondary needles with larval
mining and the distal portion of the upper
needle dead.














Exit Hole

A. O <









SIDead Needle






B.-- Larval Mine



Entrance Hole


__ ~_






























Figure 9 Second stage R. subtropica larval feeding
injury on slash pine.

A. A scale with an entrance and exit hole in
the scale's keeled-ridge.

B. A cross-sectional view of a young vegetative
long shoot with an arrow denoting the depth
of larval feeding injury in the groove
between scales. This particular R. sub-
tropica larval feeding site was invaded by
Cecidomyia sp. larvae (Diptera:Cecidomyiidae).








51














































































-r*









Effect on Slash Pine Growth

Injury occurred (1) when 1st stage R. subtropical larvae

bored inside the fascule sheaths of unexpanded secondary

needles, (2) when 1st stage R. subtropical larvae bored inside

elongating or completely elongated secondary needles, and

(3) when 2nd stage R. subtropical larvae bored into scales

subtending fascicles. The result of injury was the death of

all foliar tissues distal of the larval feeding.

Damage occurred (1) when 1st and 2nd stage R. subtropical

larvae fed on young scale and fascicles on elongating young

vegetative long shoots, (2) when 1st and 2nd stage R. sub-

tropica larvae fed on juvenile needles of elongating young

vegetative dwarf shoots, (3) when a single 3rd stage R. sub-

tropica larva bored into a small diameter elongating vegeta-

tive long shoot, and (4) when one or more 3rd stage R. sub-

tropica larvae bored into the vascular tissues of the vegeta-

tive long shoot, moulted, and the succeeding 4th and 5th in-

stars continued to tunnel up the shoot and into the bud. The

extent of damage (length of shoot killed) was directly pro-

portional to the number of larvae feeding in a shoot.

Forking was the only deformity resulting from R. sub-

tropica damage to slash pine shoots at Relay in north Florida.

Crooks, forks, bushing, and spike-tops were caused by R.

subtropical damage to slash pine in Glades County in south

Florida.

No definitive studies have been reported or were conducted

to determine the extent of loss of height growth in slash pine

caused by R. subtropical damage in either north or south Florida.








Reduction of cone crops of slash pine caused by R. sub-

tropica damage was not studied. R. C. Wilkinson (personal

communication) collected R. subtropica larvae feeding in male

catkins on P. elliottii densa at Sugarloaf Key, Monroe County,

Florida.



Discussion


The slash pine tissues eaten by the larval instars of

R. subtropical were essentially the same tissues Yates (1967a)

reported consumed when R. frustrana and R. rigidana larvae fed

on loblolly pine. The generalizations Yates (1966) made con-

cerning the larval feeding of R. subtropical, R. frustrana,

and R. rigidana were valid.

Crooks, bushing, spike-tops, and reduction of height

growth were not usually caused when R. subtropical larvae

damaged slash pines growing in north Florida because (1) later-

als rapidly expressed apical dominance and the main stem

straightened within 1 to 3 years, and (2) R. subtropical did

not frequently or repeatedly attack the new apical shoots of

previously attacked trees. Yates (1966) concluded that

R. frustrana and R. rigidana did not severely damage slash

pines growing in central Georgia.

Crooks, forks, bushing, spike-tops, and reduction of

height growth occurred when R. subtropical larvae damaged

slash pines growing in south Florida because (1) slash pine

was planted out of its natural range (Bethune 1963), and








(2) R. subtropica continually attacked new apical shoots of

previously attacked trees. Bethune (1966) also reported

Rhyacionia spp. repeatedly attacked and damaged slash pines

in south Florida.

Cone crop damage caused by R. subtropica in slash pine

seed orchards in the southeastern United States probably has

not been as severe as R. frustrana cone crop damage in short-

leaf pine seed orchards (Yates and Ebel 1972, Ebel and Yates

1974), and has not been studied because (1) investigators

have just become aware of the potential conelet mortality

that tip moth damage can cause, (2) most slash pine seed

orchards are not located in south Florida where R. subtropical

is most abundant, and (3) insect control practices are an

integral component of seed orchard maintenance programs.



Summary


First and 2nd stage R. subtropica larvae fed on foliar

tissues or tissues associated with foliar tissues. The 3rd,

4th, and 5th stage R. subtropica larvae tunneled into the

internal tissues of vegetative long shoots and apical buds.

Injury was associated with Ist and 2nd stage R. sub-

tropica larval feeding, with two exceptions.

Damage was caused by 3rd, 4th, and 5th stage R. sub-

tropica larval feeding. R. subtropica damage did not usually

produce deformities in slash pines grown in north Florida,

but usually caused the deformity of slash pines growing in

south Florida.













CHAPTER VIII

PUPAL BEHAVIOR, WEIGHT, AND SEX RATIO
OF RHYACIONIA SUBTROPICA



Background


Pupation, the act of becoming a pupa, was initiated with

the pre-pupation activities of mature 5th stage larvae of

R. subtropical and terminated with the initiation of the pre-

eclosion activities of the encased pharate R. subtropica adult.

The objectives of this study were to report (1) the

activities of R. subtropica from the mature 5th stage larva

to the pro-eclosion pharate adult, (2) pupal weight, and

(3) the pupal sex ratio.



Methods


General

The descriptions of the pupation behavior of R. buoliana

(Pointing 1961, 1963) were used as guides for observing the

pupation activities of R. subtropica. The observations on

pupation activities were made during the removal of R. sub-

tropica instars from slash pine shoots collected in Glades

County, Florida, from August 1972 through June 1974.








Pupation Sequence

On 31 August and 15 September 1972 the apical to basal

sequence of pupae and larvae in 35 multiple-infested shoots

was recorded. The arrangement in 25 shoots was reported.

Shoots containing all pupae, all larvae, or single instars

were not recorded.

The apical to basal pupal sex sequence in all shoots con-

taining multiple pupae was recorded on 13 September 1973.

Shoots containing a single pupae or all larvae were not

recorded.


Pupal Weight

The pupae recovered on 31 August 1972 were also weighed

and sexed. The mean weights of those male and female pupae

which later issued adults were calculated.


Pupal Sex Ratio

The sex ratio before eclosion was calculated for 425

R. subtropical pupae collected during August and September,

1972, and 276 pupae collected during July 1974.



Results


Pre-pupation Behavior

R. subtropical 5th stage larvae constructed a silk-lined

pupation chamber and prepared the pupal exit hole in the api-

cal portion of the mined shoot. The pupal exit hole was at

or in the vicinity of the point of fascicular insertion above








the fascicular scale. On multiple-infested shoots the exit

holes were scattered along the apical portion of the mined

shoot. R. subtropica pupal exit holes were not obvious or

easily located.


Pupation Sequence

Pupation proceeded almost entirely from the apex toward

the base in multiple-infested shoots (Table 4 and Figure 10)

and the vertical sequence of pupal sex had no apparent pattern

(Table 5).


Pupal Weight

The range of weights for 34 male pupae was

with a mean weight of 18.9 + 0.13 mg (x t0.0

range for 44 female pupae was 17.1-47.4 mg with

+ 0.08 mg.


7.2-25.6 mg

s-) and the

a mean of 29.9


Pupal Sex Ratio

The September 1972 pupal population (n = 425) was 44%

females, and the July 1974 pupal population (n = 276) was 62.4%

females. The total pupae of the 1972 and 1974 populations

averaged 51.2% females before emergence. The sex ratio (?:&)

considering all 701 pupae from 1972 and 1974 was 51:49 (ca.

1:1), without regard to adult emergence.


Variation of Pupal Color

Newly formed pupae were yellowish-brown. Thereafter,

pupae darkened to become amber colored. Prior to eclosion,

the amber pupae turned dark brown with the eyes, antennae,







58



O 1 ,









(' 4 -I
ct




S-O
r0







ro a
rD^ P. 1,-1
13 0s O -1 _









0 (
S~) r(N















SOs O U
4 4-' ,-. -.
42 0 '.-



al rL 4 C-


Os Os C .- ll


























a, 1 -
*U









O
00 O4 C1 4

U CUl t- II J
Os ri '-4- A A i

Cl 0/i ,-) U




cyl (Ny-






A I fA Os >

Cl l '4 C') _ ^ s _i l























r-l fc Fc i ai Q< i- _ _
































Pupation sequence of R. subtropica instars
(P = pupa, L = larva) in a slash pine shoot
with dead, partially elongated secondary
needles (N).


Figure 10.




60














P-O





61


Table 5

Apical to Basal Arrangement of R. subtropica
Male (d) and Female (9) Pupae
in 12 Multiple-Infested Slash Pine Shoots
from Glades County, South Florida



APEX

(1) (2) (3) (4) (5) (6) (7) (8) (9)(10) (11) (12)
d 9 9 9 9 9 9 d d 9 d 9

d 9 d 9 d d 9 d 9 9 9 d

9 9 f 9 d 9 d 9 d

d d 9 d 9 & d

9 & 9 d
dd9'd 9





d d

d


BASE








banded wings, and banded legs of the pharate adult becoming

evident.


Duration of Pupal Stage

The duration of the pupal stage of individual pupae was

not specifically studied, but in south Florida R. subtropical

pupae were present from late August until February and from

early June until late July (Figure 7).



Discussion


The mature 5th stage R. subtropical larvae which were

head-up within the silk-lined pupal chamber had usually termi-

nated feeding, and could be removed from the shoot and held for

pupation to provide additional adults for laboratory investi-

gations. Furthermore, since the mature 5th stage larvae can

be sexed, these larvae could also provide a source of insects

of known sex, age, and stage of physiological development for

laboratory experiments.

The pre-pupation activities of 5th stage R. subtropical

larvae were biologically similar to those activities of R.

buoliana (Pointing 1963), but unlike R. buoliana, the R. sub-

tropica pupal exit hole was not usually located in the wall

of the bud.

The multiple infestations and pupations per shoot as

observed for R. subtropical attacking slash pine in south

Florida were also commonly observed for R. frustrana attack-

ing loblolly pine shoots in north Florida. A single pupa per








bud was reported for R. buoliana (Pointing 1963).

The distribution of multiple R. subtropical larvae and

pupae in shoots probably reflected termination of feeding

activities and maturation of larvae. Based on the downward

progression of pupation and the apparently random vertical

distribution of pupal sex within a given shoot, apparently

neither male nor female larvae required additional feeding

time as a larva nor did either sex larva pupate first.

The R. subtropical pupal sex ratios fluctuated over time

similarly to the reported (Pointing 1961) sex ratios of

R. buoliana adults.

The pupal weights were reported for the use of future

workers wishing to evaluate artificial diets developed for

or used to rear R. subtropical larvae.



Summary


The mature 5th stage R. subtropical larvae constructed

silk-lined pupal chambers in and prepared pupal exit holes

along the apical portions of mined shoots. In multiple-

infested shoots, pupation generally proceeded downwardly with

an apparently random vertical distribution of pupal sex. The

weight by sex, sex ratio, colors, and duration of R. sub-

tropica pupae are also reported.














CHAPTER IX

EMERGENCE OF RHYACIONIA SUBTROPICAL



Background


Emergence was considered to begin with pre-eclosion

activities of the encased pharate R. subtropica adults and

end with the activities immediately following eclosion and

wing expansion of the moths. The objectives of this study

were (1) to describe individual emergence activities and

(2) to determine the daily pattern of emergence.



Methods


General

Accounts of emergence activities in R. buoliana (Pointing

1961, 1963; Green 1965) and Dioryctria abietella (Dennis and

Schiffermiller) (Lepidoptera:Pyralidae) (Fatzinger and Asher

1971) were used as study guides.

R. subtropical pupae collected 31 August and 15 September

1972 in Glades County, Florida, were used to determine emer-

gence times, and emergence patterns were analyzed by

Batschelet's (1965) statistical methods. Mean times were

calculated for wing inflation, wing drying, and complete wing

expansion.








Emergence Cup Technique

R. subtropica pupae were removed from shoots, sexed

according to Yates' (1969) technique, placed in individual

clear plastic cups containing an aseptic agar medium (Batche-

lcr and Emmel 1974) and capped with serially numbered lids,

then held in a rearing room at 27 20C with north windows

for exposure to natural photoperiod (Gainesville, Florida;

see Table 6 ) until pharate adults developed. Pupae were

examined daily under a dissecting microscope (magnification

20x) to determine the presence of pharate adults. The rear-

ing room's overhead incandescent and fluorescent lamps were

set for a 12-hour light:12-hour dark diel light cycle synchro-

nized to come on after sunrise and go off before sunset.

Daily until emergence, cups containing pharate adults

were removed from the darkened rearing room and placed out-of-

doors on the south wide of the laboratory at least one hour

before sunrise. The cups with non-emerged pupae were returned

to the rearing room after 1100 hour Eastern Daylight Saving

Time (EDST). The cups were again placed outside at least one

hour prior to sunset and only returned to the darkened rear-

ing room after sunset. These arrangements subjected the

mature pupae to a natural sunrise, photoperiod, and sunset.

During the night pupae were examinedin the darkened rearing

room with the aid of a battery-operated light dimmed with a

red acetate film.

Times of adult emergence were recorded in hours and min-

utes EDST while times required for wing inflation and drying








were recorded to the nearest 1/4-minute.


Emergence Board Technique

Twenty shoots suspected of containing R. subtropical

pupae were affixed vertically to a board as described by

Pointing (1961). and Green (1965). This board and its affixed

shoots were held and handled daily in the same manner as the

emergence cups containing pharate adults. Activities of

adults which closed from shoots were recorded in the same

manner as for adults which closed in the emergence cups, but

their sex was not determined.

The emergence board technique was used to simulate con-

ditions as they might occur on vertical shoots in the field

and to observe post-eclosion activities of moths under such

conditions.


Emergence Recorder Technique

Pupae were taken to the Naval Stores and Timber Produc-

tion Laboratory, USDA Forest Service, Olustee, Florida, and

held in C. WI. Fatzinger's (1970b) emergence recorder. The

recorder was placed in an outdoor insectary to provide expo-

sure to natural sunrise, photoperiod, and sunset. Otherwise,

the recorder was operated and maintained as reported by

Fatzinger (1970b).

The emergence recorder's charts were used to corroborate

emergence observed in the previous tests and general emergence

behavior in the absence of an observer.









Results

Pre-Eclosion Activities

The darkened R. subtropica pupae containing pharate

adults held in emergence cups rotated their abdomens fre-

quently and vigorously during the day and hours preceding

emergence. Immediately prior to eclosion, the pupae held in

emergence cups straightened, lengthened, and initiated pos-

terior to anterior peristalsis.


Eclosion Activities

As the adult began to eclose,the head of the pupal case

split dorsally. Once the pupal case started splitting, adult

eclosion was completed rapidly (ca. 30 sec). Empty pupal

cases were translucent golden brown and retained the frontal

horn.


Post-Eclosion Activities

After eclosion, moths ascended vertically (ca. 40 mm or

less) to an apical position on a shoot before expanding their

wings. Wing expansion began as soon as the adults came to

rest and progressed until the wings were completely expanded

and slightly elevated above the body. Expansion ended with

the quick and complete elevation of the wings to an upright

position above the moth's thorax.

From the time eclosion was completed until the wings

were fully expanded required an average of 8.7 0.02 min

(x + t.05 sx) with a range of 4-16 min measured for 44 moths
0Sb X








(13 ', 31 ). While the wings were in the elevated position,

5.9 0.21 min with a range of 2-12.5 min (13 3, 31 ) were

required for drying the wings before they were lowered to

rest over the abdomen of the moth. The total time from eclo-

sion, through wing inflation, drying, and until the wings

were lowered to rest required an average of 14.6 0.04 min

with a range of 7.0-25.0 min (136, 31 ).

After the moth's wings were expanded and returned to

rest, moths remained motionless in emergence cups until dis-

turbed.

On shoots affixed to the emergence board, the moths

periodically moved to a more shaded portion of the shoots as

the sun traversed. Charts from the emergence recorder cor-

roborated that only slight periodic movements occurred between

the completion of wing expansion and evening flight.


Daily Emergence Patterns

The results of emergence in relation to time of day are

given in Table 6 and Figure 11. All critical values of all

z test statistics for the Rayleigh Test of randomness

(Batschelet 1965) were greater than the tabulated z values

at the 0.01 level (Table 6). Therefore, the distribution of

the time-of-day emergence data (Figure 11) did not have a

uniform distribution, but rather a unimodal or bimodal pattern.

Assuming P. subtropica emergence occurred once daily, the

mean time of emergence (9) was 0925 EDST with an angular devi-

ation (s) about the mean of 3.26 hr for non-sexed data,














CC 00
On 0L

In


01 0.1
r--i
O 0
'0 -l +1


'--4

cn





t -D
t-'
ri C)






i-4

iD cc





rC i
Lu oo
c^ o


C) C'l


0 0


N o
o OC)
'00-



F-9 c N F: in C/


C)
4-1 3


C)0
), c

401

-3 .f






C4-4 L -4


0
U 0







C) C)








-4J
U (UC











0D
4, -H























C) CD
Fn 4-' n






CS )


4-4
0


H
u




4 4- J (- ]















O
C) H 0)

S -C,
4-J






V)l 73
0 r- 0
















moo
C)F:O
Ii I i 11













01

CoC



0 (
4-i ~



UC cl
-S)
















m ,u c



o c
0 C













nC e 4-1
-4 ., -

F: aC





























Frequency distributions of R. subtropical
emergence by hours (EDST = Eastern Daylight
Saving Time) of non-sexed moths (n = 101)
(bottom) and sexed moths (n = 96). Mean
emergence times are indicated above histogram.


Figure 11.








08:24 9


0 6
HRS.


12 18
(EDST)


20-




10-


~*1








0827 EDST 3.37 hr for males, and 0927 EDST 3.22 for

females (Table 6). Peak emergence occurred between 0700

and 0800 EDST (Figure 11). The assumption of and the statis-

tics calculated for a unimodal pattern of emergence were not

mathematically incorrect, but biologically misleading. The

test statistic r, which measures the concentration about the

mean and which was not close to the value 1.0, also indicated

the emergence was not unimodal.

R. subtropica emerged twice daily

and the values of the test statistic r were closer to the

value 1.0 for the bimodal calculations. The major emergence

occurred just after sunrise with the mean time of emergence

of the non-sexed data at 0858 EDST +2.21 hr, males 0824 EDST

1.42 hr, and females 0913 EDST 2.42 hr (Table 6 and Figure

11). The minor emergence was during the evening crepuscular

period with the mean time of emergence for non-sexed moths at

1935 EDST 0.81 hr, males 1941 EDST 1.40 hr, and females 1929

EDST 0.24 hr (Table 6 and Figure 11).



Discussion


Although the pre-eclosion movements of R. subtropical

pupae were only observed in emergence cups and not inside a

shoot, similar movement and activities of R. buoliana pupae

inside a shoot served to elevate the pupa from the base of

the pupal chamber, up the silk-lined chamber's walls, up to

and out the pre-cut exit hole (Pointing 1961, 1963).








R. subtropical adults had no apparent difficulty escaping

from the pupal cases of pupae removed from shoots and held in

the emergence cups. R. buoliana adults experienced difficulty

escaping from pupal cases of pupae removed from buds (Pointing

1961).

The bimodal daily field emergence pattern of R. subtrop-

ica was strongly similar to the field emergence of a. buoliana

(Pointing 1961, Green 1965) and peak emergence for both

species occurred between 0700 and 0800 EDST.

The early morning eclosion of adults, vulnerability of

adults to attacks during the flightless period of wing expan-

sion, and inactivity of adults on the shaded portion of termi-

nals might be exploited by releasing predators which are

active in the early morning or by applying chemical adulti-

cides on the shaded portion of terminals for the suppression

of R. subtropica.



Summary


The activities of R. subtropical encased pharate adults

prior to eclosion, general adults during eclosion, and fully

dried adults after eclosion are described. Teneral adults

walked a short distance (ca. 40 mmn) after eclosion and before

expanding and drying their wings. The average time required

for wing expansion and drying was 14 minutes. The daily

pattern of emergence under natural light cycle was bimodal

with peaks at 0858 and 1935 hours EDST.














CHAPTER X

EXPERIMENTAL MATING, OVIPOSITION, AND REARING
MEDIA TRIALS OF RHYACIONIA SUBTROPICAL



Background


In 1970, Daterman described procedures he found useful

for mating Rhyacionia spp. in the laboratory. In early 1971,

correspondence and consultations with G. E. Daterman and

C. IV. Fatzinger were initiated to obtain the most current

information about rearing media for forest insects in general

and specifically R. buoliana (Daterman, personal communica-

tion) and D. abietella (Fatzinger 1970a, 1970b).

The objectives of this study were to (1) breed R. sub-

tropica moths under artificial or semi-artificial conditions,

(2) rear R. subtropica larvae on an artificial medium, and

(3) establish a laboratory colony of R. subtropica larvae and

adults.



Methods


Mating and Oviposition

Three mating and oviposition techniques were tested.

Daterman's mating technique. A replica of Daterman's

(1970) mating and oviposition apparatus was constructed. The

apparatus was designed to simulate natural twilight and to








create an airflow necessary for carrying the female sex phero-

mone to the male. The light intensities and airflow of the

apparatus were calibrated and R. subtropica adults were pre-

pared for mating per Daterman's specifications. The mating

chamber was located in a rearing room having a north exposure

to light, 70% relative humidity, and temperature of 27 + 20C.

The mating chamber's twilight and photoperiod were synchron-

ized with the natural twilight and photoperiod (Gainesville,

Florida). A battery-operated light, dimmed with a red acetate

film, was used when entering the rearing room during scoto-

phase.

The initial mating trial was conducted on 16-18 May 1972

using 2 males and 3 females which had emerged in the laboratory

from pupae collected in Dixie County, Florida, on 9 May 1972.

Slash pine shoots suspected of bearing R. subtropical

eggs were incubated in the rearing room on moistened No. 2

Whatman filter paper in a petri dish to determine if oviposi-

tion had occurred and if 1st stage larvae would eclose. This

mating trial was terminated 29 May 1972.

During September 1972, the mating-oviposition chamber

was re-synchronized with the natural photoperiod and operated.

Adults for these mating trials were obtained from the pre-

viously discussed adult emergence and wing expansion studies.

These mating trials were terminated in October 1972.

Fatzinger's mating technique. On 14 July 1972 R. sub-

tropica pupae collected in Levy County, Florida, on 11 July

1972 were supplied to C. W. Fatzinger for mating trials








employing his (1970a) D. abietella mating and oviposition

techniques. Fatzinger terminated the mating trials when all

moths were dead (C. W. Fatzinger, personal communication).

Caged-seedling mating technique. From June 1972 to

January 1973, wooden-framed screen (100 mesh) cages (.91 x

.60 x .51 m), each containing a one-year-old potted slash

pine seedling, and maintained in the previously described

laboratory rearing room and in a greenhouse (air-conditioned

or heated to maintain ca. 27C) were continuously stocked

with R. subtropica adults which had recently emerged from

pupae periodically collected from throughout

Florida. The caged mating trials were terminated during

January 1973.


Rearing Media

Two rearing media were tested.

Bedard's modified rearing medium. In April 1972, the

pine phloem-based medium of Bedard (1966) was prepared as

modified by Richeson et al. (1971) and was evaluated for rear-

ing R. subtropica larvae. Non-surface-sterilized 3rd and 4th

stage larvae collected 28 March 1972 in Putnam and St. Johns

Counties, Florida, were placed 8 larvae per each of 4 petri

dishes containing Bedard's medium. The dishes were incu-

bated at 27 20C with a high humidity (ca. 85%). Pupae

which developed were placed in individual plastic cups lined

with a moistened disk of No. 2 Whatman filter paper in the

previously described rearing room. This rearing medium exper-

iment was terminated 23 April 1972.








Fatzinger's rearing medium. During May 1973, C. W.

Fatzinger provided cups of his (1970a) VGCS artificial diet

to this author. All stages of R. subtropical test larvae were

collected in Glades County, Florida, and without being surface-

sterilized, were individually placed in 12 cups containing the

VGCS diet on 1 June 1973. The cups were incubated in the pre-

viously described rearing room. Pupae which developed were

placed in individual plastic cups containing an aseptic agar

medium (Batcheler and Emmel 1974) as a moisture source and

incubated in the rearing room until moths emerged. This rear-

ing medium experiment was terminated during July 1973.



Results

Mating and Oviposition

All mating and oviposition techniques failed.


Rearing Media

The R. subtropical larval feeding trials did yield par-

tial success. Six of the 32 larvae fed on Bedard's modified

medium (Richeson et al. 1971) and pupated (5 males, 1 female),

and 2 of the males emerged. The remainder of the pupae died

from desiccation. The use of Batcheler and Emmel's (1974)

aseptic agar medium as a moisture source eliminated pupal

desiccation during later studies.

The 12 larvae placed on Fatzinger's (1970a) diet fed and

pupated. Ten adults emerged during July 1973, in synchrony

with the natural field population from which the larvae were








collected. An ichneumonid, Temelucha Sp. (Hymenoptera:

Ichneumonidae),(determined by R. W. Carlson), emerged from each

of the other pupae.



Discussion


The failure to achieve mating of R. subtropical was not

the first time a tip moth species failed to mate under arti-

ficial or semi-artificial conditions. Initial laboratory

mating trials with R. buoliana failed (Chawla and Harwood

1968). C. W. Berisford (personal communication) also con-

structed a replica of Daterman's (1970) mating chamber and

failed to get R. frustrana, R. rigidana, and R. subtropical to

mate. Until reliable and successful laboratory mating-

oviposition techniques are developed, an aseptic continuously

reared R. subtropical laboratory colony cannot be established

and maintained.

The WGCS medium of Fatzinger (1970a) was the better

medium for the production of R. subtropical adults. The

successful rearing of R. subtropical on Fatzinger's WGCS arti-

ficial diet was not surprising. R. frustrana and Pissodes

nemorensis Germar (Coleontera:Curculionidae) larvae reared

on the WGCS artificial diet completed development and pro-

duced adults; p. nemorensis oviposited and initiated a second

generation on the diet (C. W. Fatzinger, personal communica-

tion).






79


Summary


R. subtropical adults did not mate under laboratory or

semi-artificial conditions. R. subtropical larvae fed and

developed on the WGCS artificial diet (Fatzinger 1970a) and

produced pupae from which adults issued.













CHAPTER XI

IIYMENOPTEROUS PARASITES OF RHYACIONIA SUBTROPICA



Background


Yates (1967b) and Harman and Kulman (1973) compiled the

most current information relating to the parasites of the

genus Rhyacionia for the Neartic Region and the world,

respectively. The objectives of this study were to collect

and to identify some of the hymenopterous parasites attacking

R. subtropica in south Florida.



Methods


From February 1971 through June 1974, R. subtropica-

attacked slash pine shoots were periodically collected in

Florida. Pupae and parasitized larvae were placed in individ-

ual emergence cups containing an aseptic agar medium (Batche-

ler and Emmel 1974) as a moisture source and held in a rearing

room at 27 20C in order that adult parasites could emerge.

When superparasitism occurred, larvae and pupae of the par-

ticular parasite were preserved. All instars of the para-

sites were preserved in 70% ethanol. The parasites were

taken to E. E. Grissell, who forwarded the braconid, eulophid,

and ichneumonid to P. M. Marsh, B. D. Burks, and R. W.









Carlson, respectively, for determination. Grissell deter-

mined the eupelmid and chalcidids. C. W. Berisford returned

parasites, Bracon gemmaecola (Cush.), which emerged from

R. subtropical pupae I provided Berisford for his Rhyacionia

sex pheromone studies. The parasites, along with collection

and emergence data, were deposited in the Florida State Col-

lection of Arthropods.



Results


The six species of hymenopterous parasites (Table 7 )

recovered from R. subtropica are the first parasites reported

for this tip moth (cf. Yates 1967b, cf. IIarman and Kulman

1973). Four of the recovered species were new records for

Florida (Muesebeck et al. 1951, Krombein 1958, Krombein and

Burks 1967, Yates 1967b, Iarman and Kulman 1973). Yates

(1967b) and Harman and Kulman (1973) also reported Hyssopus

rhyacioniae Gah. as being gregarious, but B. gemmaecola has

not been previously reported as being gregarious or having

multiple attacks. These parasites, with the exception of

Arachnophaga ferruginea Gah., are all known parasites of at

least one other Rhyacionia species (Yates 1967b, Harman and

Kulman 1973).



Discussion


Since the six species of hymenopterous parasites reported

occur throughout the ranges of other North American Rhyacionia


__













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species and are variously distributed throughout Florida as

parasites of R. subtropica, the search for additional useful

species of parasites of R. subtropical and other Rhyacionia

species should be increased to include the West Indies and

Central America.



Summary


Bracon gemmaecola, Temelucha new species, Hyssopus

rhyacioniae, Arachnophaga ferruginea, Haltichella rhyacioniae,

and Sphilochalcis flavopicta were recovered from individual

R. subtropica larvae and pupae. These six species of hymenop-

terous parasites are the first parasites reported for R. sub-

tropica.













CHAPTER XII

INCIDENCE OF RHYACIONIA SUBTROPICA
IN FERTILIZER-INSECTICIDE EXPERIMENTAL PLOTS



Background


In 1968, The Cooperative Research in Forest Fertiliza-

tion (CRIFF) program (a joint effort of forest industry,

agricultural chemical companies, and the School of Forestry

and Department of Soils at the University of Florida) estab-

lished replicated experimental fertilizer tests (A-Series,

uniform fertilizer experiments on young stands) in the lower

coastal plains of the southeastern United States. W. L.

Pritchett, CRIFF Coordinator, Department of Soils, University

of Florida, has records of the objectives and information rela-

tive to the CRIFF program.

At the Austin Cary Forest of the University of Florida,

located in Alachua County, Florida, one-half of the experi-

mental plots of 2-year-old bedded slash pine seedlings were

fertilized with 90 Kg P/ha in April 1969 (C. M. Kaufman,

personal communication).

In the summer of 1969, tip moths, Rhyacionia sp.,infested

>7% of the trees in the CRIFF A-Series potassium test sites

(Anonymous 1970). R. frustrana infested >90% of all bedded

trees in Kaufman's phosphorous and non-phosphorous plots but








almost all non-bedded (control) seedlings were free from

infestation (R. C. Wilkinson, personal communication).

These separate but simultaneous tip moth infestations in

variously treated slash pine plantings prompted the planning

by R. C. Wilkinson (personal communication) and Hudson Pulp

and Paper Corporation personnel to establish research plots

near Relay, Florida, to study the relationship of insect

pests (tip moths in particular) to slash pine maintained

under various fertilizer regimes. The Relay Tract plots were

established to duplicate current seed orchard fertilizer prac-

tices, and certain systemic insecticide treatments which had

proven successful for the control of tip moths (Barras et al.

1967).

Objectives of this study were (1) to determine if vari-

ous fertilizer-insecticide combinations applied to bedded

slash pine seedlings would affect the incidence of R. subtrop-

ica, (2) to determine the distribution of R. subtropica

larval feeding sites within the multi-nodal annual vegetative

long shoot (apical terminals), and (3) to determine the inci-

dence of R. subtropical by tree height classes.



Methods


Experimental Plots

Design. In December 1969, P. E. Lavely and R. C.

Wilkinson (personal communication) outlined the design for

the fertilizer-insecticide experimental plots.








Three fertilizer treatments and a check were replicated

3 times in a randomized block design of 40-tree plots. Each

plot (40 trees) was split, and one-half of each plot (20

trees) was treated with the same insecticide as a control

for R. subtropica (P. D. Kidd, personal communication).

Location. The experimental plots were located in the

pollen isolation strip surrounding and adjacent to the north-

ern boundary of a seed orchard located east of the abandoned

settlement of Relay, Flagler County, Florida (Section 2,

Township 14 South, Range 31 East) (Figure 12) (P. D. Kidd,

personal communication). The study area is referred to as

the Relay Tract plots.

Establishment. In January 1970, selected 1-0 slash pine

nursery stock was hand-planted to insure seedlings were

(1) properly planted on beds, (2) free of disease, and (3) not

attacked by Rhyacionia spp. To prevent damage by cattle, and

possible injury to cattle or persons from the insecticide

applications, the Relay Tract plots were enclosed by a three-

strand barbed wire fence and posted as being an "Experimental

Area" (P. D. Kidd, personal communication.

Formulation and application of treatments. The fertili-

zer and phorate (O,O-diethyl-S-[(ethylthio)=methyl] phosphoro-

dithioate) insecticide treatments were based on the fertili-

zer recommendations of W. L. Pritchett and the insecticide

recommendations of R. C. Wilkinson, and were applied per the

formulations and schedule outlined in Table 8. All treatments

were applied to the soil at the base of each tree. P. W.




















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