الفهرس 
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Abstract
Evaluation of some Phaseo/us germ plasm for resistance to the
two spotted spider mite T. urticae Koch (Acari: Tetranychidae).
Field and laboratory experiments were conducted in the
experimental farm and laboratories of both the Plant Protection and
Horticulture Departments at the Faculty of Agriculture, Moshtohor,
Qalubia Govenorate and also in a field at Beni Ady, Beni-Suef
Governorate, during the 1997 and 1998 seasons. Such work aimed
to study the different biological aspects of the phytophagous mite
Tetranychus urticae (Koch), which was reared on different
Phaseolus genotypes, namely; Lima bean (P. lunatusy Henderson
and King of the Garden cultivars, Tepary bean (P. acutifolius),
Tepary 13 and Tepary 16 lines, and COlTIlTIObenan (P. vulgaris),
Bronco and Giza 3 cultivars, under two different temperatures
(25°C and 28°C). In addition, different Phaseolus genotypes, were
evaluated for resistance to T urticae in the field, under various
infestation conditions (Natural and artificial) as well as chemical
mite-control. Results are summarized in the following:-
I- Biological, Histological and Chemical studies:
A) Biological studies :-
Duration of different developmental stages of T urticae,
significantly, varied with both the different Phaseolus genotypes
and variable temperatures. Lima bean (P. lunatus) Henderson
cultivars, showed uncompatible interactions with the different
developmental stages of T urticae, comparatively with Giza 3 (P.
vulgaris) cultivar, which showed some kind of compatible
interactions with the different developmental stages of the mite pest.
1-The longest periods of egg incubation, larval, protonymphal and
deutonymphal stages and life cycle were associated with
Henderson cultivar of lima bean (P. lunatus), while opposite
responses and behaviors of T urticae were observed with Giza 3
cultivar of P. vulgaris.
2-The shortest period of pre-oviposition was significantly
associated with Giza 3 cultivar (P. vulgaris).
3- The shortest period of oviposition was recorded when T urticae
was fed on Lima bean (P. lunatus), Hendersson cultivar at 25°C
(3 days) and at 28°C (3.5 days). The longest ones, at the two
temperatures were 12.3 and 12.5 days when the mite females
reared on Giza 3 cultivar (P. vulgaris) at 25°C and 28°C,
respectively.
4- Longevity and post-oviposition periods of T utricae adult female
reared on lima bean (P. lunatus) Hendrson cultivar, were very
short, comparatively with that was fed on other cultivars and lines.
5- Maximum longevity of T urticae adult female was observed
when it was reared on Giza 3 cultivar (P. vulgaris).
6- Leaves of Giza 3 cultivar (P. vulgaris), were most attractant site
for the egg-laying female T. urticae than those of lima bean (P.
lunatus) Henderson cultivar, since number of deposited eggs
was greater on the former than on the latter.
B) Histological studies :-
I-Both Henderson and King the Garden (P. lunatus) cultivars,
exhibited the highest thickness of the epidermis layer of the leaf
upper-surface, comparing with that of all other cultivars and
lines.
2-Lima bean (P. lunatus) Henderson cultivar, had the highest
thickness of epidermis layer of the lower surface of the leaf
3-Density of leaf hairs (number/mm’) was the highest on both
Henderson and King of the Garden cultivars of P. lunatus.
4-King of the Garden cultivar seemed to posses genes preceding
both high density and length of leaf hairs, which are considered
as important aspects of physical resistance factors against T
urticae.
c) Chemical studies:
1-Negative correlations between leaf contents of nitrogen,
phosphorus, reducing-, non-reducing-, & total-sugars, and protein
and each of the incubation period and different periods of the
developmental stages of T. urticae were, significantly observed.
2- Positive correlation, on the contrary, were significantly observed
between leaf contents of nitrogen, phosphorus, reducing-, nonreducing-
& total-sugars, and protein and the whole life span,
oviposition, and post-oviposition periods and female longevity.
About similar trend was, also shown with female fecundity.
3- Positive correlations also between leaf contents of potassium and
sodium and each of the periods of egg incubation, different
developmental stages, life cycle and pre-oviposition, were
detected.
4- Negative correlations were obtained between leaf contents of
potassium and sodium and each of life span, oviposition and post
oviposition periods, and female longevity and fecundity.
II-Resistance of Phaseoius genotypes to the infestation with
the red spider mite (T. urticae):-
A) Density of both eggs and moving stages on the lower surface of
leaves :-
1-Under natural infestation condition, numbers of moving
individuals of T urticae, which were detected from leaves of
Henderson (P. lunatusi cultivar, in the first week of count, were
the lowest, while the highest numbers were associated with Giza
3 (P. vulgaris) cultivar. In the same time, under artificial
infestation condition, about the same trend of results was
exhibited.
2- Numbers of counted eggs of T urticae on plant leaves under
both natural and artificial infestation conditions, during both
1997 and 1998 seasons, exhibited the lowest standard with
Henderson (P. lunatusi cultivar, while showed the highest level
of egg numbers with Giza 3 (P. vulgaris) cultivar.
3- Results indicated that, the week of counting should be
considered, when evaluating plants of Phaseolus species for
resistance to T urticae.
B) Plant fresh weight :-
1-Various Phaseolus genotypes showed significant differences in
plant fresh weight under both natural and artificial infestation
conditions, and also under chemical control application.
2- Decrease in percentages of plant fresh weight under both natural
and artificial infestation conditions were slightly higher with
King of the Garden (P. lunatusi cultivar than with Henderson (P.
lunatus) cultivar. However, much low percentages were
associated with Tepary 16 and Tepary 13 lines (P. acutifolius)
and 13 Bronco and Giza 3 (P. vulgaris) cultivars.
C) Flowering and pod characteristics :~
1-Results showed that, the required period until start flowering
didn’t exhibit any significant difference for Henderson (P.
lunatus) cultivar, neither under natural nor artificial infestation
conditions. Such findings could be attributed to the relative
resistance of Henderson (P. lunatusj to T. urticae, since the
artificial infestation didn’t affect the earliness of flowering,
comparatively with the natural infestation.
2- Under conditions of T. urticae artificial infestation, the highest
percentages of fruit set, were associated with Henderson (P.
lunatus) cultivar.
D) Dry-seeds yield :-
The obtained dry-seeds yield was weighed for all the different
studied varieties under the various infestation conditions (natural and
artificial infestations and pesticidal treatment conditions). The
acaricidally treated plots were utilized as control upon which, yield
losses were estimated. Results are presented in the following:-
1- The lowest yield-loss percentages due to the natural infestation
(3.420/0, 3.26%) or due to the artificial one (8.12%, 13.02), were
associated with Henderson (P. luna/us) cultivar during both 1997 and
1998 seasons, respectively.
2- The highest yield-loss percentages due to the aforementioned two
conditions of natural and Artificial infestations were 19.430/0,27.5%
,
and 51.32% 457.31%, respectively for 1997 and 1998 seasons, were
associated with Giza 3 (P. vulgaris) cultivar.
from the previously mentioned results, the following could be
concluded:
1-The most resistant genotype to the two-spotted spider mite
infestation is Henderson cultivar, which exhibited, highly
significant high level of resistance to such mite species Tunicae.
2- King of the Garden cultivar is considered as resistant genotype to
spider mite infestation.
3- Tepary 16 line is considered here as a tolerant variety, which
produce considerable high yield in spite of attaining high level of
mite- infestation.
4- Tepary 13 line can be considered as super moderately tolerant
variety to the infestation with the two-spotted spider mite.
5-Both of Giza 3 and Bronco cultivars are considered to be
sensitive to the two-spotted spider mite T. urticae.
According to such obtained results, the Phaseolus varieties,
which exhibited either highly or normally resistance level against
the two spotted spider mite, can be utilized, in future in the
following applicable studies or in crop production:-
A)Using of the resistance varieties itself (i.e. Henderson and King
of the Garden) in producing crops under suitable environmental
conditions, which allow high rate of plant production.
B) Involving such varieties in breeding programs in combination
with other econOlnic varieties, which prove to attain high level
of yield using the genetic theories for producing high-yield
breeds in addition to its resistance to the mite infestation.
C) The translocation of resistance genes from such resistant
varieties to other econOluic varieties for gaining high yield and
considerable level of resistance using genetic engineering.
D) The utilization of such resistant varieties in the translocation of
resistance genes not only to other Phaseolus species and
varieties but also to other vegetable or field crop species using
genetic engineering.
It is worth to note, that such work may realize beneficial
results, in which such resistant varieties can be used in producing
economic species and varieties from different economic groups of
plants, which will be characterized by having the ability of
producing high yield in addition to having pest-resistant feature
with such concept, chemical control programs will be entirely,
excluded from control strategy, which will be reflected in raising
populations of various natural enemies of different plant pests, that
will efficiently suppress densities of various pests including mites
and insects. Such strategy is happed to prolific one, which will
prevent environmental pollution and simultaneously play an
important role as participating agents in returning the natural
balance to the Agro-Ecosystem.