الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
SUMMARY
The present study aims to investigate the effect of ecological factors
(biotic and abiotic) on the pdiapaused pink bollworm (PBW), Pectinophora
gossyplella (Saunders) larvae, the biological and histological effects of the bioinsecticide
(Xentari) against the spiny bollworm (SPW), Earlas lnsulana
(Boisd.) larvae; and evaluation of certain control programs against cotton
bollwonns. The obtained results revealed the following:
I. Studies on the dipaused larvae of the pink bollworm (Pectinophora
l1ossypiella) seasons :
1.1- The excluded dipaused larvae from cotton seeds during the rest period
seolt~ (H’J
of 1994/95 and 1995/9~
The excluded P. gossypiella resting larvae from cotton seeds were
classified to dead larvae (266 & 108) and alive larvae (140 & 169) during the
rest period of both years 1994 - 95 and 1995· 96, respectively.
Follow-up the excluded alive larvae obtained from the cotton seeds
. during 95 & % years revealed that some of these larvae reached to the adult
stage (78.57, % & 55.03 o/~respectively), while 21.43 %& 44.97 % of the”,
died either as larvae or pupae. However, at the end of the lSI and 2nd rest
periods only 27.10 % and 33.57 % of the larvae completed their metamorphosis
and reached the adult stag~..
It was found that the death of PBW during diapause was due to either
normal or due to bacterial and/or viral infection as well as to the effect of the
parasitoids Pyemotes heFfS; and P. robarlltor.
1.2- Spring emergence of P. gossypiella in both years of 1995 and 1996 :
Emergence of PBW adults took place from March until May and the
peak of emergence occurred during April.
1.3- Forecasting of timing of PBW spring emergence on the basis of degreedays
(dd’s) or aeeumutated heat units (A.H.U.) during 1994-95 and
1995-96 seasons :
Adult emergence started in 9th and Slh of March and nearly completed,
However, in 14th and 261h of May for lsI and 2nd season. respectively.
However, present study indicated that PBW spring emergence was initialized
when about average of 433.5 dd’s were accumulated. Also, It was found that
the low rate of heat units accumulatiou worked as a mortality factor on the
pink bollwonn; so it was concluded that A.H. U. is an important factor for
timing and detennining size of pink bollwonn spring emergence (1.”
generation).
II. The biological effects of the blo-~nsecticide(Xenlari) against the
spiny bollw’ormneonate lantae :
Six concentrations ofXentari (1.25, 0.63, 0.31, 0.16, 0.08 and 0.04) gil.
at rate of 2.5 rol/50 gm of diet were tested against neonate larvae of E.
im.’ulana. The mortality percentages were 87.5, 80.0, 65.0, 37.5, 15.0 and
12.5%. respectively after two days of feeding on contaminated diet.
The LCSO and LC90 values of Xentari against Eo tnsuiana neonate
larvae were 0.29 gil and 1.30 gil, respectively with upper and lower
confidence limits of (0.29 & 0.18 gil) and (1.96 & 0.88 gil).
Xentari displayed latent effects during the subsequent stages. The
\~ ..
obtained effects were :1) death ”),the different larval instars due to feeding the
E. im”ulana neonate larvae for 2 days on contaminated artificial diet contained
the L
C
50 of Xentari; the percentage of surviving subsequent larvae was
31.’JO/~ 2) increase in larval and pupal durations and 3) decrease the Iongivity
of the adult and the number of deposited eggs/female comparing with the
untreated check.
III. IIIstopathol.,glcal enet:ts of Xentarl 011 the spiny boIlWOnn larvae:
Feeding the 4th instar larvae of E. insy/ana on Xentari - eon\8l1;l;Ii.n-:adted
diet, using the highest coneentration( 1.25 g / I ) at the nit of Sml / 100g liK, f{)l”
24 hrs caused many pathological eff~ in the mid-gut of the treated larvae.
These effects, as shown in cross sections of the mid-gut, were separation of
the ’epithelial cells from the basement membrane as well as elongation,
vaeulization and breakdown of the larval epithelimn mid-gut. Also, Xentari
caused disorganization and disintegration of pretrophic membrane.
IV-Evaluation of certain control pntgrams against cotton hollWOnns:
Three control programs were evaluated against the cotton bollwonns
(P. gossypiella, E. insulana and their complex) during 1994 cotton season.
Another three control programs were rested during 1995 cotton season. During
1996 cotton season, the previous six control programs were reevaluated.
The tested control programs during 1994 season were program ”A”. (a
sequence of 4 sprays with the bio- insecticide Dipel.2X at the. nile of 400
gmlfed; program ”B” a sequence of 3 sprays with the mixture of Dipel. 2X at
400 glfed. with chemical insecticides at the half recommended rate and in the
recommended sequence; and program ”C”, recommended. sequence and rate of
chemical insecticides, Dursban EC 450/0, Cutabron EC 500.4 and Bundock EC
15%
•
During 1995 cotton season. the tested control programs were : program
”D”, sequence sprays with the bio-insecticide Xentari at 500 g/fed; program
”E”, a sequence of sprays with the mixtures ofXentari (500 glfed.) + chemical
insecticide at half of the recommended rates; and program ”F” (a sequence of
sprays with chemical insecticides (Cyanophos EC 500/~Cutabron EC 500.4 and
Bundock EC 150/0) at the recommended rates and sequence).
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During 1996 cotton season. the efficacy ofll.c progran.s
1\. 13.C D. E
and F was evaluated against the bollw()TIIISPBW & SBW and their complex
BWS.
The cotton plants received the lsI spray in July 241h. August 2nd and
71h during 1994. 1995 and 1996 seasons. respectively. Spraying of each
program was perfonned when the correlation betWeensmall larvae (lsi instar)
and all counted larvae in infested bolls was significant,
The conclusions of this set of experiments were :
1- ProgflUU”Co (DutSban. Cutabron and Bulldock) was the most effective
program against PBW. SBW and their complex BWS.
2- The tested control programs were more effective against PBW than SBW
especially program ttott (Xentari alone).
3- The efficiency of prognun ”D” (Xentari alone) against PBW larvae was
higher than that of program ”F” (Cyanophos, Cutabron and Bulldock).
while prognun ”F” was most effective against SBW and BWS.
4- ProgflUU”13” (mixture of Dipel-2X + chemical insecticides) revealed
higher potential protective efficacy against bollworms than the two bininsecticides,
Dipel-2X and Xentari when used alone.