الفهرس 
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Abstract
(11) the other inclUding six cotton growing-provinces in Upper
Egypt but are common.lyregarded as of secondary importance as
far as leaf’wo.rminfestations are cOncerned (Giza, Bani-Suet’,
Fayyoum,Menya, A.ssiout and Bohag :Provinces).
The grand totals of the cotton’ leafworm eggmasses collected
from the whole country were also worked out and made use of.
Th~ s~C?_9nHd-0l.!I2 comprised the annual areas for cottoncUltivations
in each of the 14 provinces. These were obtained,
again, from the Ministry of Agriculture fOr the years 1960-1968.
~he t~rdE.roU~ constituted the daily records of the major
thermal factors in each of the eight Delta Provinces under consideration.
These records covered the period from 1A!:January
1960 up to the end of June 1968 and were obtained from the
Central Meteorology Department, MinistrY of Scientific Ressarch,
U.A.R. The factors are :
The day minimumtemperature (00.),
the day maximumtemperature (00. ), and
the daily average temperature (00.).
In addition, records of the average soil tempera’ture (00.)
as taken in the Giza area, again, for .the period January 1960 _
December1967 were eventually used; a10llg with the sbove factors,
in the analysis. The daily readings of ’the day minimum. ’temperature
(°0.) in the same period (January 1960 _ June 1968) were
also available for five of ~he six proVinces of Upper Egypt.
-~- _.----._. __ ..- ....•----, --.--- .~~----~-~.--------- c ,:::~,:.,,,...~~. ,_. ,2•••••• ’...- - -- - ~- - - -
. 1.
- 165 -
8eve~al preliminary trials involving the above data were
attempted at first. Those finally adopted as procedure are the
following :
1. The daily readings of each factor were grouped into a
series of 5-day intervals. The averages of these intervals were
considered in all subsequent analyses.
2. The annual average number of 2. 1ittoralis eggmasses per
feddan were calculated for :
(a) Every province separately,
(b) the Delta area (as averages of 8 provinces), and
(c) for the whole-country~
The egg-mass averages in each case were regarded as representatives
of the annual population level of the cotton leafworm
in the respective area.
3. The annual averages denoting the level of the infestation
in every province were further represented in terms of index
numbers on log. basis.. This transformation was quite helpful.
It gave a relative categorical definition to each year thus
rendering the comparisons more practical. In the meantime the
calculated (predicted) levels of the infestation became more
precise and mean;ngful than when expressed as expected nUlllbers
of eggm.asses.
4. The ndssing data of the soU ’teper-sture, which was lackiDs
in most of the provinces, were ..-tiJla1ied. The eB1iiaations were
based on the standard mathematica~ re~a~ionsbip (regression value)
-- ._~ --._- -_.- --.---._- -- ---~--- -~. .-- -- -
._.~ .. _.-.~.~
- 166 -
between the minimum.temperature and the soil temperature at Giza.
The data contributing towards this linear relationshi.p involved
the ave~ages of these two factors in 18 successive 5-day
intervals for eaah 0 P the nine years 1960-1968. The intervals
considered in tihf.s step were those extending between I§!. Feb-
”ruary and 50th April in eac.h year.
Part II,±: Alf:(ect of certain ecological factors prevailing
during the ori tical period, on the .J)Opulatio~
~e~~ity of the cotton leafworm and the poc’ediction-
PFocedure of the i.n:festa.t.i.on level in the
pelts Pr2vinces
In this part of the studyt the following analytical st~s
and procedures were carried out :
1. r~~”7l.”:ifJ.;:.a~;·70 s·::;udiesbetween all years in each prOVince
wi ~~ re,gard to the level of infestation
This was conducted Over three steps and resulted in ’the
following :
B~~(?l : The calculation of deviations of ”each thermal
factor in the years wi.th ”normal or below-normal” infestation
from its cOl.”responding .readings in ”above-no.rmal”infestation
,
years. This indicatedt in all cases, a conspicuous positive
departure during a certain critioal period.
~tep QU-: The gzoaphical area-saes for each ”theraal
factor during the aritioa1 period. This showed that the
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averages of the areas for the ”normal or below-normal” infestation
years were much larger than those in the Case o’f If abovenormal,”
infestation years.
Ste]2 Ccl: The comprehensive statistical analysis. This
analysis involved each thermal factor during the critical
period, and was mounted mainly on :
0-1. A regular HF” test for all the years under consideration
together.
c-2. A contrast analysis for the two groups of years,
in each province; the nabove-normallt infestation years versus
the ”normal or below-normal” infestation years .•
In all cases and for each factor considered, a significant
difference existed between the years when taken together
(step c-l). This is expected since such a group usually includes
different ”types of years, Itabove-normalll and ”normal Or
below-normaltt infestation years. Whenthe latters were contrasted
(Step c-2) again a significant difference occurred
indicating the biologicall.y-diffe.rent natures of the two groups
of years. But when a regular ”]’I’ test (Step 0-1) ·was applied
to each group separately no significant or just significant
differences could be traced, thus ~erring the homogene1’ty of
the years within each.
The results 1Dd.i.cate tJ’lat £or B~~c;,~~, Gbaz’b1a.~ia,
SbarJd.a, lIenoufia, Dakabll8 P.ro’riDces and the De11;a Region, ’the
c.ritieal period extended from ll!!:!, February to 10!A! April;
whereas that period extended between.6~ Feb~ and l5j&
.April for both Ka~ El-Sheikh and Damiet1ia PrO’V1pces.
- -,~ ._. ~~ -- _. ._-- .~. -- -- -.-,e
..•.
- 168 -
2. T_hepia-statistioal relationships between ’the cl1matiic factors
and J!!le seasonal average number of ee;gmasses per feddan
In this analysis the climatic factors were represented by
thtir averages during the critical period while the eggmasses were
rep~eaented both as actual figures (regular data) and as index
num-oers(transformed data). The analysis involved groups of years:
Q-f’.2.,Ul2...A: which included all years together.
Gr”oupB: which included the same years but divided into
two subgroups :
Sub.frollP B
l
comprising the Habov&-normaJ.” years; i.e. ’the
years of high infestation.
p]lbf:5.L:.oBup2 consisting of the years 01’ ”normal or belownormal”
infestation.
In each case, the simple correlation and regression coefficients
were calculated, and the combined latent effect of three
thermal factors on the level of infestation was knownthrough
the partial regression. The responsibility of these three factors
for the degree of variability in that level was expressed
in terms of ”percentage of variance explained”.
The obtained results and ’the ensuing discussions led to the
foliowing biological explanation that the oonsiderable reduction
in the general. air 811Ld soil t_peratures, duriDg the critioal
period, below its general averases delays the _argenee of ’the
insects’ adul’ts, hol4iDg its 4nelopleD.’taJ. stages •• in],. as
pupae. Mass emergence of moths from these pupae would ’then be
..’ ~- ._”
- J.69 -
enforced by the prevalence of W8.rm.ewr eather, normally taking
place during April. The sudden. emergence of a relati ve].y large
number of adults, especially at that time when it is, st:tll! so
early in the season, offers tre!J1endOU8 possibi.lities for mating
and oviposition not likely ·to occur when normal or warmer
eritical periods prevailo Hence, a high. infestation ~akes place
2-3 months later (through multiplied reproducibility) ~
On the other hand, with normal or relatively warmcritical
periods, mating chances become limited due to sparse emergence
of adults, hence, the subsequent generations atrcaf,n, proportionality,
normal or even below-normal levels.
In other words, low temperature averages, during the
critical period induce high population levels of the insect,
through a series of fairly synchronized subsequen’t-generations;
and vice versa.
}. PL’edict1on of the .average number of egnnasses. in each
PfOvi.nce. duriBs; 1.9§9 and 1970
The prediction of the cot1ionleafworm in any particular
year and ’for each provin~e was based on the information,
analytical procedure, and results already outlined in the previous
sections. This couJ.d be worked out, by mid-April, using
the averages of each ’thermal factor during the critiCal period
”which, by tha’t date, would have just ended. Accordingly , it
was possible to calcul.ate the eXpected average DUIIlber of’
.:i
;
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eggmasses and, hence, the level of infestation during the
follOwing season.
The results indicated that the years 1969 and 1970 are of
the ”normal, or below-normari type.
Part IV: ~J’1ec~ertain ecolog..i,£.alfactors, prevailing,
9F the population dens~t:y of the cotton leafworm
.in tJle Upper Egypt Provinces
The provinces investigated in this part are Giza, Beni-
Suef, Fayyoum, MeDYa, Assiout and Bohag. ~hough these represent
the main cotton-growing of Upper Egypt, yet no strjking
outbreaks or even high infestation levels, by Delta-standards,
coilld be detected in any of them throughout the period 1960-
1968. Neither there have been a marked difference between the
generally low-levels of infestation from one year to another
and from one province to the next adequate tor a reliable
analysis. It was, therefore, finally concluded that there has
always been a marked inconsistency in the level of infestation
did not exceed 5.2% of its total for the country during the
established outbreak-years in the U.A.R. In other words, the
term ”outbreak years” or even ”high i.D:testa’tion year” does not
apply to this part of ’the country.
___________-+------- Summary -170-
SU¥MARY
>,
Onion (Allium eepa 1.) lis~ undoubtedly, one of the important
I
I vegetable crops in Egypt, for local consumption and Exportation. Due to
I
the steady increase of areas cultivated with this crop, the present study
was carried out at the Experime1tal Farm of the Faculty of Agriculture at
Moshtohor throughout two sudcessive onion seasons (1993 / 94 and
I
1994 / 95) in the nursery and Ipennanent field to study the relationship
between three factors (onion tariety, seeding or transplanting date and
I
the rate of nitrogen fertilization) and the infestation rate of onion plants
f
by two main onion pests; the pnion thrips, Thrips tabaci Lind. and the
onion maggot, Delia a/liaria Fons, Another study was carried out to
evaluate the possibility of usJg traps of different colours placed in
different directions of the onion ifield for attracting and trapping adults of
r
the mentioned pests. The obtained results may be summarized as follows
1- Nursery experiments:
The obtained results of two onion seasons (1993 /94 and 1994/
95) indicated the following:
A- The Improved Giza 6 onion variety was more susceptible to
infestation by T.tabaci larvae and adults than Giza 20 variety, the two
season mean numbers of Tsabaci larvae / 10 plants were 60.95 ±
10.41 and 41.15 ± 6.37 while those of adults were 7.90 ±1.45 and
5.58 ± 0.93, respectively. ~ for infestation of the two onion varieties
by Dialliaria larvae, the djfferences between mean counts recorded
from the two varieties were insignificant. This may be attributed to
that the larvae were detected in onion seedlings in very low numbers
_-----------1~:---- Summary
i
-171-
I
(two season mean counts were 0ry O.16±O.04 and O.15±O.031arvae /
10 plants of Giza 20 and Improv~ Giza 6 varieties, respectively).
B- The population of T tabaci jarvae and adnlts was found to be
increased by retarding the S1eding date. The two season mean
numbers of T.tabaci individuals ~ere 35.09±4.88 ,43.54±7.10, 55.34
±11.52 and 69.93 ± 12.24 / ~O seedlings, while the corresponding
counts of adults were 4.30±O.~9) 5.36±l.06, 7.23±1.15 and 10.06±
i
1.75 by sowing in the first (Sep., 25th), second (Oct., 11th), third
(Oct., 27th) and fourth (Nov., 12th) dates, respectively. Generally, by
seeding in either of the fo dates, T.tabaci larval and adults
population showed low abun ce in October and increased gradually
I
from first of November till the second half of January.
:
I
The larvae of D.alliaria w~re found in low numbers in all seeding
I
dates, but larval counts in seedling from the third seeding date were,
relatively, higher than those fro~ the three other dates. The two season
mean larval counts were 0.06±O.03, 0.08±O.04, O.28±O.lO and O.22±
0.05 larva / 10 seedlings from the 1.s1 , 2nd., 3m. and 4th-dates,
respectively. The lowest number of D.alliaria larvae was recorded in
October and increased gradually from the end of November till the
second half of January.
c- By studying the combined effect of onion variety and seeding date
on the rate of T.tabaci larval and adults’ infestation to onion
seedlings, data indicated ~at seedlings of Improved Giza 6 variety
that grew after sowing ~ the latest date suffered the heaviest
infestation level (overall means of twa seasons 81.04±11.75 larvae
and 11.91 ± 1.96 adultsl~O seedlings) than all recorded on the
remaining 7 treatments. 0$ the contrary, seedlings of Giza 20 onion
-----------+1------ Summary -172-
,
I
variety that grew after sowfng in the earliest date harboured the
lowest counts of larvae and ,dults (28.06±4.79 larvae and 3.26±0.59
adults / 10 seedlings). II
I
11- Permanent field experimenb :
A - Date indicated that Improved Giza 6 onion variety was more liable
I
to infestation with T.tabaci larvae and adults than Giza 20. (Two
season means of 49.2±7.82 larvae and 4.4±0.56 adults on Improved
I
Giza ~ plant opposed to 35.~±5.17 larvae and 3.7±0.47 adults on an
Giza 20 plant). As for the I onion maggot, D.alliaria larvae, those
were detected in, relatively, ~ery small numbers in the two seasons of
study with no significant b~tween the two varieties. The two season
mean counts were only 0.178±O.022 and 0.084±0.023 larva / plant
for the two mentioned varietirs, respectively.
i,
B- Infestation by T. tabaci larvae and adults on onion plants increased
significantly as the transplanting date was delayed. The lightest
infestation rates (means of )O.71±4.83 larvae and 3.13±0.42 adults)
were detected on plants of the earliest transplanting date (December,
6th.) while on the contrary ithe heaviest infestation level (overall
means of two seasons, 56.$9±9.12 larvae and 4.91±O.64 adults)
occurred on plants of the ~test transplanting date (January, 20th).
The intermediate transplanting dates (December, 21st) and January,
5th.) gave plants that sowed intermediate positions between the
earliest and latest transplanting dates. from inspection of the weekly
samples, it was noticed that ~e number of T.tabaci larvae and adults
I
started low in January and ifcreased from the end of February to the
end of May. Concerning ~festation of onion plants transplanted at
___________ -+- Summary -173-
different dates on the infestati n level by D.al/iaria, the larvae of this
pest appeared in very low n bers also and the differences between
the mean infestation rates er transplanting at different dates were,
statistically, insignificant. Th~ recorded means, for the number of
D’.alliaria larvae were 0.040 0.010, 0.035±0.010, 0.071±0.024 and
0.067±0.023 larvae/plant aft r transplanting on December, 6th and
2ls1and January, 5th and 20 ., respectively
I
C- Evaluation of the effect Of+onium nitrate, as a nitrogen fertilizer,
to soil after transplanting of o*ion at 3 rates (60, 90 and 120 N units /
feddan) revealed a positive Srgnificailt correlation in both seasons of
study between the applied r~te of nitrogenous fertilizer and the rate
T.tabaci infestation. That w~ clearly evident in cases of the pest
larvae and adults. The lightest infestation level occurred on plants of
the control check which di~ not receive any N - fertilization as the
two season averages were 15.34±2.l3 larvae and 1.68±O.l9 adults /
plant apposed to 36.98 ±5.Sl8, 50.34±7.75 and 66.34±10.57 larvae,
and 3.55±0.47, 4.81±0.64 and 6.l6±O.79 adults / plant in treatments
that received N - fertilization at 60, 90 and 120 N-units / feddan,
respectively. D.alliaria larvae were detected in onion plants of all
treatments in very low numbers (mean of two seasons; 0.024±0.007,
0.OI9±O.006, O.037±O.015 and 0.027±0.008 larvae / plant in the
control treatment and the three treatments of ammonium nitrate
applications, respectively). T)Ie differences between the mentioned
means were found, statistically, insignificant.
I D- The combined effect of both Ionion variety and transplanting date on
the rate of T.tabaci and D.al~iariainfestation were also studied. The
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two factors’ effect was found significant on T.tabaci larval and adults
______ ------+------ Summary -174-
count. The lightest rate of . estation occurred on plants of Giza 20
variety that were transplanted n December, 6th., i.e.; the earliest date
(26.65±4.44 & 24.14±4.7 I ae, and 4.49±0.71 & 4.41±0.8 adults I
plant in 1994 and 1995 seas ns, respectively. On the other extreme,
plants of Improved Giza 6 ariety transplanted at the latest date
(January, 20th) harboured highest rates of (.tabaci infestations
(77.08±12.35 & 63.l±12.54 larvae, and 6.51±O.83 & 4.83±O.88
adults /plant in both seasons, espectively). The remaining treatments
gave intermediate values of .tabaci infestations, although the same
trend of higher infestation 0 Improved Giza 6 variety and delaying
the transplanting date could be, easily, detected. As for D. alliaria
larvae infestations in onion pl ts, the recorded counts were very low
in both seasons of study so t most of the inspected samples were
found free from any onion m ggot infestation. The calculated F value
between the obtained means indicated that the differences between
means of D.alliaria larvae from different treatments were I
I
insignificant.
E- By studying the impact of onion variety and the rate of nitrogenous
fertilization on infestation by the two pests under investigation,
significant F values were detected between treabnents when T.tabaci
larvae and adults’ infestatio* rates to onion plants were concerned.
,
The highest rates of infestation occurred significantly to onion plants
i of Improved Giza 6 variety that received the nitrogen fertilizer (
I
ammonium nitrate) at the $gbest rate; i.e., 120 N-units/ feddan
I (80.01±13.75 & 78.43±13.~8 larvae and 6.84±O.85 & 6.53±1.03
adults/plant in 1994 and ~995 seasons, respectively), while the
lightest infestation rates 04urred, significantly, on Giza 20 onion
I
plants that grew without ~Y N-fertilization (13.93±2.05 & 15.39±
2.38 larvae and 1.49±O.22 & 1.4 ±O.23 adults /plant in both seasons,
respectively). The general tren of data indicated higher rates of
T.tabaci infestation on Improve iza 6 than Giza 20 variety, and also
the rate of infestation increased by increasing the’ N-fertilization rate.
As for Diolltaria infestation t onion plants of different treatments,
the larval counts ranged betw en 0.022 - 0.079 and 0.006 - 0.014
larva / plant of Giza 20, and be een 0.009 - 0.044 larva and 0.009 -
0.016 larva / plant of Improv d Giza 6 variety in 1994 and 1995
seasons, respectively with ins gnificant differences between mean
larval counts from different eatmen.ts, and accordingly no fixed
correlation could be detected between both factors and the rate of
_-----------+----- Summary -175-
” D.alitaria infestation.
I
!
F_ The combined effect of tran~planting date and nitrogen fertilization
level on Titabaci infestation ~ate to onion plants proved significant.
Generally, infestation with larval and adult stages of the pest
increased by increasing the dose of ammonium nitrate added to soil,
on one hand, and by delaying the transplanting date, on the other
hand. The highest overall mean of T.tabaei larval and adults’ counts
occurred on plants of the l.est transplanting date and received the
I
highest dose of ammonium pitrate (91.44±14.25 & 82.36±17.65
larvae, and 8.71±1.16 & 8.~2±1.1 adults / plant in 1994 and 1995
I
I
seasons, respectively). On ~e other extreme the lowest counts
occurred on onion plants tba~ did not receive any N-fertilization and
were transplanted at the two Fliest dates 15.98±2.36 & 11.04±1.76
larvae/plant in 1994 and 11.~4±1.83 & 14.72±1.98 larvae I plant in
1995 on the unfertilized ptcfts transplanted on December, 6th. and
21.st., respectively, while in ejase of adult counts, the receptive counts
were 1.31±O.23 & 1.76±0.3~ adults / plant in 1994 and 1.10±O.15 &
i
I
____________ ------ Summary -177-
with lower populations of T’tabaci. As for the onion maggot the
recorded rates of infestation were very low throughout the two seasons
of study to the level that no: definited recommendation could be
concluded.
III. Efficiency of colour traps and their directions in
attracting T.tabaci andD.alliaria adults to colour
traps:
1- Attractiveness of T.tabaci an. D.alliaria adults to colour traps.
The efficiency of different colour. traps in attracting adults of
T.tabaci and D.alliaria was assayed. Five different colours were
evaluated (white, yellow, blue, ’green and red). Results showed the
following:
A- Attractiveness of T.tabaci adults :
White colour traps proved as superior in attracting adults of the
cotton thrips adults (922.78 and 1392.38 adults / trap left in position in 5
day in 1994 and 1995 seasons, respectively). Blue traps came the next in
both seasons (689.25 and 918.91 adults / trap), while the yellow traps
took the third position (372.41 and 528.97 adults. respectively). The
green and red colour traps were of minor efficiency compared to the
formerly mentioned colours.
B- Attractiveness of D.alliaria adults:
Significant differences between mean adult counts attracted to
traps from different colours were, statistically, detected. The white
colour traps caught the highest adult nwnbers, followed by the yellow
and the blue colour traps (means of two season counts 17.06, 15.02 and
11.59 Dialliaria adults / trap, respectively). The green and red colour
___________ --”* Summary -178-
traps were always of minor efficiency (4.81 and 2.44 adults / trap,
respectively).
2- Distribution of T.tabaci and Dialliaria adults in different
directions of onion field :
A- T.tabaci :
In both seasons of study; the highest mean count of T.tabaci
adults were those attracted to traps placed in southern direction of the
onion field (669 and 793 adults / trap in 1994 and 1995 seasons,
respectively), while the lowest count was detected in traps placed in the
eastern direction (247.93 and ~35.23 adults, respectively). Traps of
different colour, that were placed in the north or west directions showed
intermediate positions. Superiority of southern direction may be due to
the normal wind direction from north to south.
B- D.alliaria :
Dialltarta adult counts that were detected in traps placed in
different directions averaged 4.35-9.19 in 1994 and 10.2 - 14.25 adults/
trap in 1995 indicating low abundance of the onion maggot throughout
the two seasons of study. According to the means of both seasons data,
the density of D.alliaria adults in the 4 directions may be arranged
descendingly as east (11.41 adults), south (10.28), north (9.63) and west
(9.3 adults / trap). The differences between the mentioned means were
statistically, significant.
3- Combined effect of the colour and place of trap on the catch:
A- T.tabaci adults :
Highest mean counts of T.tabaci adults caught to traps occurred
by using white traps placed in the southern direction of the onion field
_____________ ----- Summary -179-
(1481.38 and 1895.25 adults/trap in 1994 and 1995 seasons,
respectively). While the lowest count was, on the other hand, detected in
case of red traps placed in the eastern direction of the field (only 31.13
and 112.25 adults/trap in both .seasons, respectively). It could be
generally concluded that the colour of trap was more effective on the
distribution of T. tabaci adults than wind direction. Using of white traps
placed in either the south or; north directions may be fairly,
recommended as efficient tool tc insure higher catch of T.tabaci adults
to be used for estimating the population, It is thought that using the
white colour traps in southern or northern directions to control T.tabaci
is a point that needs further investigations before any recommendation.
3- D.alliaria :
The caught numbers of Ir.alltaria adults 10 traps of different
colour placed at different directions were, relatively, low, although this
numbers varied from one colour to another and also between the
different directions. It could be also stated, from the obtained results,
that the colour of trap was more effective in attracting Dialliaria adults
than the wind direction. It was clear that the white colour traps attracted
highest D.alliaria adult numbers, whether these traps were placed in the
east, west or southern directions (19.88,18.07 and 15.94 adults / trap,
respectively). That was followed by the yellow traps placed in the east,
south, north or western directions, then came the white traps placed in
the northern direction (15.88, 14.88, 14.51, ”14.44 and 13.88 adults /
trap, respectively). Accordingly, the white or yellow colour traps may
be, fairly, considered valuable in monitoring the population of Dialltaria
adults in onion fields wherever these traps are placed.