RESEARCH PROJECTS
RESEARCH
PROJECTS
Effect of secondary plant compounds on whiteflies Bemisia tabaci, the cotton whitefly, is one of the
major pests of greenhouse and field crops in Lebanon. The objective of
this study is to manipulate the whitefly population by using synthetic
and extracted secondary plantcompounds. Results of this study have indicated
that the secondary plant compounds: solanine, solasodine, tomatidine and
tomatine were found to act as arrestants to B. tabaci adults. However,
extracts of Melia azedarach seeds were found to be deterrent to
adult B. tabaci and detrimental to nymphal instars of the insect.
Methanol extracts of the mentioned plant were found to yield more of the
bioactive compounds than other aqueous and organic solvent extracts, as
revealed by thin layer chromatography (TLC). The study of behavioral and
ecological aspects of whitefly-plant relationships is essential for the
development of non-chemical control methods and for the improvement of
chemical control methods that whiteflies are resistant to. E. M. Abou-Fakhr.
(Supported by CPP Department.)
Efficacy of natural compounds in leafminer control Liriomyza huidobrensis, the pea leafminer, is one of
the most polyphagous species in the genus Liriomyza. The objective
of this study is to make use of the local Melia azedarach tree for control
of the leafminer. The treatments included: Margosan-O®,
Dipel®, Dynamec®, Trigard®,
Sunspray ultrafine oil®, Confidor®, Afugan,
Melia fruit and leaf extracts and the control. Treatments were applied
twice at the puncture and the larval stage. Results of field experiments
indicated that Trigard® and Dynamec® decreased
the number of mines per plant compared to the control, while Melia extracts
and Margosan-O® have shown a lower number of mines than
the control and were comparable to the synthetic insecticide Confidor®.
In the greenhouse experiment, Dynamec® and Trigard®
have also shown the best results in controlling the larvae. Similarly,
extracts of Melia fruits, Afugan® and Margosan-O®
have shown a potential efficacy for controlling the leafminer compared
to other treatments. E. M. Abou-Fakhr. (Supported by LNCSR.)
Survey and control of viral diseases of cucurbits in Lebanon Major cucurbit growing areas were surveyed using DAS-ELISA
for the relative frequencies of seven cucurbit viruses. Cucumber aphid-borne
yellows virus (CABYV) and zucchini yellow mosaic virus (ZYMV) were by far
the most important viruses. This is the first report of CABYV in Lebanon.
However, many cucurbit plants showed severe yellowing symptoms but tested
negatively with ELISA tests. Double stranded RNA analysis suggests the
presence of another new virus not previously reported in Lebanon. A field
experiment for the control of ZYMV, the major limiting factor of squash
production, revealed that the use of insect-proof nets delayed the onset
of infection from two to three weeks, while cross protection with a mild
strain reduced the incidence of severe symptoms. Further tests are planned
to confirm the identification of the yellowing agent and to develop an
integrated approach for the control of major cucurbit viruses in Lebanon.
Y. Abou-Jawdah. (Supported by URB.)
Reaction of tomato genotypes to infection by tomato yellow leaf curl geminivirus in Lebanon Tomato yellow leaf curl geminivirus (TYLCV), is the major
limiting factor for profitable tomato production in many geographical regions.
Three segregating populations bred to incorporate multiple genes of resistance
from different sources and 51 tomato varieties were screened for resistance
to TYLCV under high inoculum pressure. The performance of the promising
varieties was further tested at three locations under farmers’ conditions.
Few varieties were tolerant with a good level of production. As for the
segregating populations 21 plants, out of 1252 plants tested, were selected
and seeds were collected and sent back to INRA-France to be included in
future breeding programs. Three diagnostic techniques were successfully
used for the detection of TYLCV in infected tomato plants. The virus could
be detected in infected plants two weeks before the appearance of visible
symptoms. Virus concentration was usually higher in susceptible varieties
than in tolerant ones. Our survey for TYLCV secondary hosts using TBIA
(tissue blot immunoassay) revealed that out of 57 plant species tested
only four species may act as TYLCV carriers. Y. Abou-Jawdah and
R. Maalouf Sarrouf. (Supported by LNCSR.)
Effect of osmotic stress on reproductive growth of drought-tolerant and drought-susceptible wheat cultivars The effects of drought, applied at specific growth stages,
on the development and yield of wheat was investigated. Cham-6, a drought-tolerant
cultivar, and Mexipak, a drought-susceptible cultivar were grown in perlite
and irrigated with half-strength Hoagland’s nutrient solution. In addition
to two P levels, two drought stresses were imposed, one during the third
leaf development stage, the other at 50% anthesis. The number of tillers
was moderately affected by early drought stress, and number of fertile
tillers was reduced when stress was imposed at a later stage. Final shoot
fresh and dry weight and biological yield varied with cultivar and stress
treatment, but were not significantly affected by P. Leaf relative water
content was found to be a sensitive indicator of drought tolerance. Seed
yield was significantly reduced by drought stress for both cultivars, with
greater reductions occurring at early imposition of stress. R. Baalbaki,
A. Abdel Rahim and R. Zurayk. (Supported by LNCSR.)
Methods of evaluating germplasm and their applicability to wheat genotypes The objectives of this study were to evaluate Lebanese wheat
germplasm and also evaluate several methods of germplasm characterization
and identification. One hundred and four wheat genotypes were collected
from several locations around Lebanon. The collection was characterized
using physiological, morphological, and molecular techniques. Physiological
evaluations included tests for drought, salinity and high temperature tolerance
during different phases of development, and yield potential. Morphological
characterisation included describing the different morphological traits
of the genotypes from planting till yield, such as plant height, number
of fertile tillers, seed number, etc. Molecular evaluation included DNA
fingerprinting of the different genotypes as well as storage protein analysis
using polyacrylamide gel electrophoresis. Germplasm identification techniques
were evaluated based on their sensitivity, ease of use, applicability,
cost and reproducibility. (Research in progress.) R. Baalbaki, A. Al-Khatib,
M. Abi-Antoun*, S. Talhouk and Y. Adham* (Supported by
the International Plant Genetic Resources Institute.)
Interactive effects of salinity and drought on wheat seedling growth This study aimed at examining the responses of wheat seeds
and seedlings to salinity and drought stress, and the nature of response
to each type of stress. Four wheat cultivars known to be differentially
tolerant to drought were used. Seed imbibition was highly tolerant to salinity
and drought. Germination speed was more sensitive to solution salinity
than either percent germination or imbibition. A strong correlation existed
between drought and salinity tolerance as far as speed of germination.
A significant effect of osmotic potential on shoot and root growth was
observed in all cultivars. As osmotic potential decreased, root and shoot
growth also decreased. MgSO4-based salinity was generally more
tolerable to plants than NaCl-based salinity, at the same osmotic potential.
Although all cultivars were similarly affected, the rate of decrease in
fresh weight of Cham-6, a drought-tolerant cultivar, was less than that
of other drought-susceptible cultivars, like Mexipak. R. Baalbaki, A.
Al-Khatib and C. Jazzar. (Supported by URB.)
Priming effects on germination and emergence of local parsley seed Local parsley seeds are characteristically slow germinating.
This experiment was carried out to determine if osmoconditioning of local
parsley seeds could improve their germination counts and reduce germination
time. Seeds were soaked in solutions of polyethylene glycol 6000 with osmotic
potentials of -9, -11, and -13 bars, for 3, 5, 7, 9 and 11 days. The germination
index, a measure of the speed of germination, was used as an indicator
of a seed lot’s potential for sucfield establishment. Although many combinations
of osmotic potential and soaking period produced acceptable results, the
ideal combination was found to be a soaking period of 3 days at -13 bars.
R. Baalbaki, E. Haddad* and M. Abi Antoun*.
A comparison of two-phase barley-based rotation systems for nutrient recycling, grazing, lamb fattening and utilizable conserved feed production A barley based two-course rotation was initiated at the AREC.
The first phase of the experiment is scheduled to be from 1994-95 to 1999-2000.
The first two years of the experiment were considered as establishment
years, and the following four-year-long sequence is being subjected to
experimental and economic analysis. Tested rotations include barley/ lentils,
barley/vetch, barley/medics, barley/vetch with barley mix, and barley/barley,
with lamb fattening and ewe pasture grazing on the vetch and medic cropping
systems. Data is being collected on changes in soil fertility, grain and
straw yields of the different crops, changes in plant biomass availability,
weight gains of grazing livestock, and prices and costs for economic analysis
of the different rotations. (Research in progress.) R. Baalbaki, S.
Hamadeh, N. Nersoyan*, S. Christensen*, A. Nassar*, M.
Abi-Said and S. Haj Hassan*. (Supported partly by the International
Center for Agricultural Research in Dry Areas and the Lebanese Agricultural
Research Institute.)
Evaluating and characterizing safflower (Carthamus tinctorius) germplasm Among the oil crops, oil seeds such as safflower account for
the majority of oils and fats produced worldwide. Safflower is a potentially
important plant that can contribute to the efforts to increase plant oil
production. This study has three objectives: first, to determine the morphological
and developmental characteristics of local and regional safflower germplasm.
Second, to determine yield and oil quality of the different genotypes under
our existing environmental conditions. Third, to investigate the distribution
and extent of variation of local and regional safflower genotypes. To this
end, 84 genotypes were collected from different parts of the world, including
Lebanon. Field and lab studies are being performed to evaluate and characterize
the collected genotypes, and the extent of diversity among these genotypes
will be determined. (Research in progress.) R. Baalbaki, S. Khalifeh,
S. Talhouk, R. Zurayk and Y. Adham*. (Supported by the International
Plant Genetic Resources Institute.)
Pesticides for dodder (Cuscuta spp.) control Research was initiated in August 1996, to evaluate the efficacy
of various herbicides, insecticides and fungicides in controlling dodder.
Research is still in progress. M. Haidar and W. Combargi*.
(Supported by URB.)
Effect of soil solarization on dodder seeds, weed seedbank and weed population A field experiment was carried out at AREC, to examine the
effectiveness of various durations of soil solarization on germination
of dodder seeds present in bags at different depths, and on controlling
other weeds in cabbage. Clear polyethylene sheets were applied to the soil
for 0, 10, 20 and 40 days between July and August of 1995 and 1996. Peak
soil temperatures reached 63, 58, 50, 44, and 40°
C at depth of 0, 5, 10, 15 and 20 cm, respectively. All tested solarization
treatments significantly reduced weed number and dry weight in cabbage
during the following season. Results on germination and viability of dodder
seeds are still in progress. M. Haidar and N. Iskandarani.
(Supported by LNCSR.)
Chemical weed management in corn A field experiment was carried out at AREC in 1996, to test
the effect of several soil-applied herbicides and their combinations on
weed growth and development in corn. The pre-emergence effects of Fortrol®
(cyanazine) at 3.5, 4.5, 5.5 and 6.5 kg a.i./ha, Buctril®
(dicamba) at 0.3, 0.4, 0.5 and 0.6 kg a.i./ha, Primextra®
(metalachlor + atrazine) at 1.5, 2.0, 2.5 and 3.0 kg a.i./ha and DPXE9636
(rimsulfuron) at 0.008, 0.012, 0.016 and 0.020 kg a.i./ha on weed control
in corn was investigated. The results showed that Fortrol®
and Primextra® at all tested rates were highly effective
in controlling the following weeds: Amaranthus retroflexus, Avena sterilis,
Chenopodium album, Portulaca oleraceae, Setaria viridis, and Tribules
terrestris. Primextra® at all rates tested gave over
98% control of all the above weeds. Buctril® and DPX9636
at all rates showed moderate to low effectiveness in controlling various
weeds. All tested herbicides had no effect on the number of corn plants,
ear numbers and ears fresh weight as compared to the control. M. Haidar
and N. Iskandarani. (Supported by CPP Department.)
The end-of-day phytochrome control of coiling and prehaustoria development in Cuscuta planiflora Irradiation of five-day-old de-etiolated segments of Cuscuta
planiflora with 8 h blue light promoted coiling and prehaustoria formation
after another 40 h in darkness. No coiling and prehaustoria were observed
when excised seedlings were pulsed with 10 min red light given directly
after blue light. Coiling and prehaustoria in blue-treated segments were
observed after photo-reversible far-red/red/far-red pulses of blue-light
treated excised seedlings, but not after red/far-red/red pulses. However,
far-red pulse had no effect when given 10 h after red pulse. M. A. Haidar
and G.L. Orr* (Work carried out at Colorado State University,
USA and supported by URB.)
Effects of light and mechanical stimulation on coiling and prehaustoria formation in Cuscuta spp. Irradiation of four-day-old dark-grown seedlings of Cuscuta
campestris Yuneker and Cuscuta indecora Choisy with 1 min red
light stimulated coiling and prehaustoria formation in excised upper 4-cm
segments of seedlings over a 48 h dark period when zeatin was applied.
Coiling and prehaustoria development were completely reversed when irradiated
with 2 min far-red light applied directly after red light. When de-etiolated
segments were exposed to prolonged exposure of pure blue light, or mixtures
of ultraviolet-A/far-red, blue/far-red, or red/far-red light, coiling and
prehaustoria development were induced. Blue light at photon fluxes lower
than 1 µmol m-2 s-1 did not promote coiling and formation of prehaustoria.
Mechanical stimulation promoted tendrils to coil and form prehaustoria
in blue and blue/far-red, but not in darkness. Zeatin substituted for high
irradiance blue light and mechanical stimulation and promoted coiling and
prehaustoria formation. M. A. Haidar, G.L. Orr* and P. Westra*.
Identification and study of insects and pests in the Pinus pinea forests in Lebanon The symptoms of partial and total dryness of Pinus pinea trees in Lebanon was studied to determine the causes and to suggest specific remedies. Periodic collection of insect species occurring in the P. pinea ecosystem was carried out. Monitoring of beneficial insect species and their contribution to maintaining the ecological balance in the forest is also being studied. The following pests have been identified: 1. Wood borer. Ernobius spp. (Coleoptera: Anobiidae). Larvae of this beetle tunnel in the upper new twigs leading to the gradual dieback of the branches. 2. The pine processionary moth, Thaumetopea wilkinsoni, has been observed for the first time on P. pinea trees. The presence of this pest poses difficulties to the harvesters of pine cones due to the itching it causes upon contact with the skin. 3. Black aphids, Cinara spp., are widespread on P.
pinea trees of the southern warm and dry slopes. The insect sucks the
sap of trees and secretes honeydew leading to development of sooty mold
which interferes with photosynthesis, leading to general weakness of trees.
(Research in progress.) N. S. Kawar, T. El-Masri*, E. M. Abou-Fakhr,
and H. Tohmé*. (Supported by LNCSR.)
Fate of fenitrothion in artificially fortified grape juice processed into alcoholic drinks: comparative determinations by immunoassay and GLC methods Wine and “Arak,” were prepared from grape juice to which 20
ppm of the insecticide fenitrothion were added. Samples of 11 fractions
produced by fermentation and distillation steps were analyzed by iand GLC
methods. Results of residue analyses showed that the two techniques were
highly correlated (r=0.996) and indicated that fenitrothion was stable
during fermentation. The clarified wine contained 79% (15.3 ppm) of the
fenitrothion added to juice. Arak was prepared by a two-steps distillation
of the clarified wine. Alcohol distillate and undistilled fraction from
the first distillation contained 32% (4.8 ppm) and 38% (5.8 ppm), respectively
of fenitrothion residue in wine. No fenitrothion residues were detected
by either technique in the four fractions collected from the second distillation
step. Immunoassay proved to be as reliable an analytical tool as GLC in
this case. N. S. Kawar, Z. K. Hawi and S. M. Dagher. (Supported
by URB.)
Environmental modification with plasticulture technology for improved crop production Plasticulture technology is the cornerstone of intensive production
systems for vegetable production. Plastic mulches today are available in
various colors, i.e. white, yellow, green, aluminium, in addition to the
conventional black and clear. These newer colors offer more variation in
environmental microclimate of the plant, so that growth can be modified
more effectively. Work concluded so far has shown promising beneficial
effects on tomatoes grown under rowcovers of the floating type over black
plastic mulch. The time of removal of the rowcover should be much earlier
before flowering. Work with beans, strawberry and cantaloup is in progress.
I. G. Rubeiz. (Supported by URB.)
Poultry manure use as a fertilizer for horticultural crops Organic gardening practices, for the production of horticultural
crops, is gaining renewed interest nowadays. Reducing environmental contamination
from the application of synthetic fertilizers can be achieved by replacing
those fertilizers with organic materials. Poultry manure is produced in
large quantities due to the expanded demand for poultry products by urban
populations. Discarding the excess manure is a necessary problem, and applying
it as an organic nutrient source would be of help to crop and plant growers,
as well as poultry farmers. Work conducted so far has identified certain
rates of application on crops such as strawberry, cabbage and lettuce that
would be beneficial to the crop. The response varied with the type of plant
and season of growth, with long harvest season plants being more responsive;
leafy crops were less responsive. More work to identify rates and combination
with synthetic fertilizers is in progress. I. G. Rubeiz. (Supported
by LNCSR.)
Vegetable selection for adaptation to heat stress Heat stress in the Bekaa plain of Lebanon is a major cause
of crop losses from vegetables grown in the open field. This condition
also prevails in many regions around Lebanon. Cultural practices to lessen
the effect of heat would only have a slight effect on the plant, whereas
the genetic make-up of the plant will allow more tolerance to heat stress
and offer better successful yield from the crops grown. Present work is
to evaluate new genetically released vegetable lines for their tolerance
to heat stress, as well as their quality for various consumer demands.
I. G. Rubeiz and K. Melki*. (Supported by Unifert.)
Investigation of late blight of potato Late blight disease, incited by Phytophthora infestans,
is a very serious production problem on potatoes in the coastal area of
Lebanon. Recent field surveys in the Akkar plain indicated that the threat
of the disease has increased with the apparent appearance of resistant
populations of the pathogen to metalaxyl, the systemic fungicide used for
its control. Disease samples were collected from 12 different potato growing
areas in Northern Lebanon. Forty-six isolates of the pathogen were isolated
in pure cultures. The sensitivity of the isolates to metalaxyl and other
fungicides will be assessed on amended agar media. The Lebanese isolates
will be paired individually with known A1 and A2 testers to determine their
mating type. Information on fungicidal resistance and sensitivity of pathogen
isolates and genotypes is essential for an integrated disease management
strategy for the control of this economically important disease of potatoes
in Lebanon. A. T. Saad. (Supported by URB.)
The red leaf blotch disease of almonds in Lebanon The red leaf blotch disease, incited by the pathogen Polystigma
ochraceum, is a major disease of almonds in Lebanon. An investigation
was conducted to study its severity in almond-growing areas of Lebanon,
and the cycle and developmental stages of the pathogen in orchards in the
coastal area. The disease was found to be widely spread and severe in the
coastal and mountainous areas, moderate in the North, and mild in the interior
Bekaa plain. Ascospore discharge began early February, just before flowering,
and continued until mid May. Maximum ascospore discharge occurred about
one month after flowering. Pycnidia started to form in the stromata when
turning red in color and acquiring a crusty appearance. Perthecia initials
appeared later during the month of July. However, they continued their
development and maturation during fall and winter to start discharging
their ascospores in February. The pathogen could not be grown in vitro
on culture media. No secondary infections by pycnidiopores were noticed.
A. T. Saad.
Fibrosin bodies in the conidia of powdery mildews The occurrence, chemical nature and ultrastructure of fibrosin
bodies (FB) in the conidia and conidiophores of 18 species in seven genera
of Erysiphaceae were studied. The specimens were collected from
67 host plant species belonging to 55 genera in 29 families. Fibrosin bodies
were very common in the conidia and conidiophores of the species of genera
Podosphaera and Sphaerotheca, and to a lesser extent in the
conidiophores of Blumeria, but not in the other genera. They disappeared
during the process of conidial germination. FB exhibited positively to
lipid staining with Sudan black B and Nile Blue but not to tests for other
groups of substances. Ultrastructural studies revealed FB to have a fibrillar
core enclosed by a double layer membrane. A. T. Saad. (Supported
by Plant Pathology Dept., University of Wisconsin, Madison, WI, USA.)
Survey, collection and characterization of almond (Amygdalus spp.), and pistachio (Pistacia spp.) germplasm in Lebanon Following a worldwide awareness of the importance of biological
diversity, the preservation and characterization of plant genetic resources
throughout the world has become a priority. During its first meeting in
1993, the Horticultural Crops Working Group (HWG), established by IPGRI
(International Plant Genetic Resource Institute) for the WANA region (West
Asia North Africa), recommended that almond (Amygdalus spp.) and
pistachio (Pistacia spp.) be considered as priority crops among
other fruit trees for conservation. No efforts have yet been made to initiate
such a project in Lebanon. The present study aims at surveying, characterizing,
and collecting wild species and local varieties of almond and pistachio
germplasm throughout Lebanon. (Research in progress.) S. N. Talhouk.
(Supported by the International Plant Genetic Resources Institute.)
Evaluation of genetic diversity of natural populations of Cedrus libani in Lebanon using RAPD markers There are several forest stands of Cedrus libani extending
north from Kammoua, to the Shouf in the South. The genus Cedrus includes
four species having distinct geographical origins, but difficult to differentiate
phenotypically. As a result of previous reforestation efforts some of the
Lebanese cedar forest stands include, in addition to C. libani,
C. atlantica, C. brevifolia, and/or C. deodora, while
other stands remain natural. Interest in reforestation of cedar stands
will require information on the genetic diversity of the stands which will
affect the future strategy for reforestation. In this study we are assessing
the genetic diversity of Lebanese cedar stands through the use of Random
Amplified Polymorphic DNA (RAPD), a technique that has been shown to differentiate
between morphologically indistinguishable strains and varieties. (Rin progress.)
S. N. Talhouk. (Supported by URB; research was partly conducted
at the Forest Biotechnology Group, North Carolina State University, Raleigh,
NC, USA.)
Somatic embryogenesis of the cedars of Lebanon (Cedrus libani) Somatic embryogenesis offers a great potential for large scale
production of Cedrus libani which is important not only as a forest
tree but also for the development of a timber industry. The first phase
of this project aims at optimizing embryogenic callus induction through
the determination of the optimal stage of zygotic embryo development as
explants for the initiation of embryogenic tissue, the comparison of different
media and their effect on the induction frequency and quality of embryogenic
tissue, and determination of the effect of different concentrations and
ratios of auxin (2,4 D) and cytokinin (BA) on the induction frequency and
quality of embryogenic tissue. Results indicate that post-cotyledonary
immature embryos had the highest induction efficiency. Four different media,
namely 1/2 MS, Durzan, Litay’s, and Von Arnold, supplemented with similar
hormone levels showed no significant difference in efficiency of callus
induction. Induction frequencies of embryogenic callus from explants subjected
to different hormone levels and combinations were dependent on the developmental
stage of the explant. (Research in progress.) S. N. Talhouk and
R. Baalbaki. (Supported by URB.)
Effect of polyethylene wraps and container material on storage life of loquat Lebanese ‘Ahmar’ loquat Eriobotrya japonica Lindl.
targeted for export is packaged in fields as one Kg units in wooden boxes,
covered with cellophane, and transported in refrigerated trucks (12°
C). The produce reaches export markets in two weeks. In a previous study
we found that under the aforementioned conditions, 35% of fruits were either
bruised, decayed, or shrivelled. Furthermore, decreasing transport temperature
to 5° C, and wrapping fruit boxes with low
density polyethylene film, significantly delayed the incidence of fruit
decay and shrivelling respectively. The results however indicated that
the wooden containers used are probably causing fruit bruising since the
latter was not decreased either by decreasing the storage temperature,
or by changing the wrapping material. The authors are testing the impact
of different containers on the incidence of fruit bruising. (Research in
progress.) S. N. Talhouk, and I. Toufeili. (Supported by
Mediterranean Agronomic Institute of Chania.)
Characterization of grape (Vitis vinifera) germplasm in Lebanon Among the various fruit commodities (excluding olive) produced
in Lebanon, grape ranks first in importance. Unlike imported varieties,
local varieties have not been classified according to their use and quality,
and therefore they are indiscriminately used both as table grapes and for
processing. However, high quality fruits from each variety are usually
selected for fresh consumption, and the remaining produce is sold as mixed
load of different varieties and different quality fruits. Thus, the wine
and arak produced locally are of inferior quality due to low quality fruits
and/or unsuitable mix loads of varieties sold to the processing plants.
In this study, the authors will survey all of the major grape growing areas,
sample all plant material and other information necessary for both morphological
as well as physiological ampylographic classifications, and delineate current
and future potential grape growing areas using the Geographical Information
System (GIS). (Research in progress.) S. N. Talhouk and R. Zurayk.
(Supported by CPP Department.)
Abou-Fakhr, E.M., Bjostad, L.B.* and Hibbard B. E.*, Electrophysiological responses of adults of western corn rootworm, Diabrotica virgifera, to volatile compounds in corn silks. Environmental Entomology, 25 (2), 430-435, 1996. Abou-Jawdah, Y. and Itani, H.M., Sensitivity of Botrytis cinerea isolates to fungicides used in Lebanon. Phytopathologia Mediterranea, 34, 100-108, 1994. Abou-Jawdah, Y., Soubra, K.H. and Shebaro, W. A., Evaluation of the reaction of tomato genotypes to tomato yellow leaf curl geminivirus in Lebanon. Phytopathologia Mediterranea, 35, 91-99, 1996. Atiyeh, R.*, Aslam, M.* and Baalbaki, R., Nitrogen fertilizer and planting date effects on insect pest populations of sweet corn. Pakistan Journal of Zoology, 28 (2), 163-167, 1996. Hibbard, B.E.*, Randolph, T.L.*, Bernklau, E.J.*, Abou-Fakhr E.M. and Bjostad L.B.,* Electroantennogram-active components of maize silk for adults of the western corn rootworm (Coleoptera: Chrysomelidae). Environmental Entomology, 26 (2), 285-295, 1997. Orr, G.L.*, Haidar, M.A. and Orr, D.*, Smallseed dodder (Cuscuta planiflora) phototropism toward far-red when in white light. Weed Science, 44, 233-240, 1996. ———, Smallseed dodder (Cuscuta planiflora) gravotropism in red light and in red plus far-red. Weed Science, 44, 795-796, 1996. Rubeiz, I. G., Aslam, M., Chahine, H. and Al-Assir, I.A., Whitefly populations in greenhouse cantaloupe as affected by poultry manure and inorganic nitrogen fertilizer application. Biological Agriculture and Horticulture, 12, 277-281, 1995. Rubeiz, I. G. and Freiwat, M. M., Rowcover and black plastic mulch effects on tomato production. Biological Agriculture and Horticulture, 12, 113-118, 1995. Saad, A.T. and Masannat, K.*, Economic importance and cycle of Polystigma ochraceum (red leaf blotch disease) on almond in Lebanon. European and Mediterranean Plant Protection Bulletin, 27, 1997. Talhouk, S. N., Chahine, R. A., Hamadeh, S., Hamdar, B. C.
and Baalbaki, R., Low-input cherry production: A horticultural alternative
for marginal highlands as a case study from Lebanon. Hortscience,
31 (7), 1077-1079, 1996.
ABSTRACTS, CONFERENCES AND PROCEEDINGS Abou-Fakhr, E.M., Chinaberry Extracts. IPM Practitioner, 18 (3), 16, 1996. Abou-Fakhr, E. M. and Kawar, N.S., Aphid-endoparasitoid complex on vegetables and other plants. Lebanese Abstracts, D-359, 1996. Abou-Fakhr, E.M. and Khoury, K., Use of pheromone traps for control of the potato tuberworm Phthorimaea operculella (Lepidoptera: Gelechiidae). Proceedings of the First National Synposium on Agricultural Research, Beirut, Lebanon. LNCSR Publication, 1995. Abou-Fakhr, E.M., Chaker, A., Haddad, N.*, Leger, N.*, Ashford, R.W.*, Sadek, R. and Nuwayri Salti, N., Survey of phlebotomine sandflies in Lebanon. Preliminary findings. Fifth International and Pan-Arab Seminar on Leishmaniasis and other Econoses, Amman, Jordan. Abstract No. 25, 46, 1995. Abou-Jawdah, Y., IPM in protected cultivation in Lebanon. Abstracts of the Mediterranean Colloquium on Protected Cultivation, Agadir, Morroco, 1996. ———, Integrated production and protection management in protected vegetable crops in Lebanon. Symposium International, Production et Protection Integrées des Cultures, Agadir, Morocco, 14, 1997. Abou-Jawdah, Y.A. and Assi, R.A.M., Effect of fungicides and timing of application on the control of apple powdery mildew in the Beqa’a Valley. Lebanese Abstracts, D-105, 1995. Abou-Jawdah, Y. and Al-Khoury, A.M., First report on the identification of races, 0,1 and 1,2 of Fusarium oxysporum f.sp. melonis in Lebanon. Plant Disease, 80, 711, 1996. Abou-Jawdah, Y.A., Al-Khoury, A.M. and Naja, M.A., Studies on the control of late blight of potato. Lebanese Abstracts, D-107, 1995. Abou-Jawdah, Y., Soubra, K. H., Maalouf, R. and Shebaro, W. A., Reaction of tomato genotypes to infection by tomato yellow leaf curl geminivirus in Lebanon. APS/MSA Joint Annual Meeting, Phytopathology, 86 (11), 571, 1996. Baalbaki, R., Abdel-Rahim, A. and Malhotra, R.*, Selection indices for yield improvement in field peas: 1. genotypic and phenotypic correlation, and path coefficient analysis. Lebanese Abstracts, D-360, 1996. Baalbaki, R., Abdel-Rahim, A. and Zurayk, R., Effect of osmotic stress on reproductive growth of drought tolerant and drought susceptible wheat cultivars. Lebanese Abstracts, D-361, 1996. Baalbaki, R.Z., Kanj, B.R., Zurayk, R.A. and Talhouk, S.N., Salinity and phosphorus effects on vegetative growth of drought tolerant and susceptible whecultivars. Agronomy Abstracts, 141, 1995. Chehab, A.M., Rubeiz, I. G., Freiwat, M. M., and Farran, M. T. Broiler litter and inorganic nitrogen fertilizer influence on yield of cabbage. Agronomy Abstracts, 310, 1996. Diab El-Arab, H. and Abou-Jawdah, Y., Sensitivity of Venturia inaequalis isolates to fungicides used in Lebanon. Plant Disease, 81, 112, 1997. Haidar, M.A., Mechanisms of blue-light signal transduction in dodder (Cuscuta spp) seedlings. Lebanese Abstracts, D-102, 1995. Haidar, M.A., Bibi, W. and Abdel-Khalek, N., Effect of wheat and barley straw on Orobanche ramosa growth and development in potatoes. Proceedings Brighton Crop Protection Conference–Weeds, 3, 871-876, 1995. Haidar, M.A. and Iskandarani, N., Soil solarization for control of dodder and other weeds in Lebanon. Second International Conference on Soil Solarization and Integrated Management of Soilborne Pests, Abstract No. 29, Aleppo, Syria, March, 1997. Kawar, N. S., Chemical control of insect pests: present status and impact on environment. Proceedings of the First National Symposium on Agricultural Research, Beirut, Lebanon, 1995. ———, The role of pesticides and fertilizers in environmental pollution. Conference on Environmental Problems in Lebanon: Facts and Alternatives, Beirut, Lebanon, 1997. Knio K., Baydoun, E., Abou-Fakhr, E., Malak, J. and Nuwayri-Salti, N., Isoenzyme characterization using starch gel electrophoresis of leishmania isolates from Lebanon. The Lebanese Abstracts, C-180, 1996. Rubeiz, I. G., Freiwat, M.M., and Chehab, A. M., Fresh markets and long shelf life tomato response to rowcover treatments in a dry temperate climate. Hortscience, 31 (4), 667, 1996. Rubeiz, I. G., Khansa, M. and Freiwat, M., Comparison of poultry layer manure rates as a fertilizer in winter-grown strawberry and cos lettuce. Agronomy Abstracts, 262, 1995. Rubeiz, I. G., Nadi, K.M., Farran, M.T. and Freiwat, M. M., Effect of yield and mite infestation in four strawberry cultivars due to rowcover application in a subtropical region. Hortscience, 30 (4), 884, 1995. Saad, A. T., Williams, P.H.* and Smalley, E.B.*, Occurrence and characteristics of fibrosin bodies in the conidia of powdery mildews. Phytopathology, 86 (11), 518-519, 1996. Sobh, H. and Abou-Jawdah, Y., Effect of soil solarization on soil-borne pathogens in Lebanon. Second International Conference of Soil Solarization and Integrated Management of Soilborne Pests, Aleppo, Syria, 14, 1997. Talhouk, S. N., Shmoury, M., Baalbaki, R. and Khouri, S., Somatic embroygenesis of cedars of Lebanon (Cedrus libani). The Lebanese Abstracts, D-362, 1996. Talhouk, S.N., Wansa, E.G. and Ghalayini, A.G., Determination of fruit quality and runner production of different strawberry varieties in Lebanon. The Lebanese Abstracts, D-363, 1996. White, S. A.*, Rubeiz, I. G., and Thompson*, T. L., Optimum
soil sampling strategies for subsurface drip irrigated fields. Agronomy
Abstracts, 322, 1995.
Abdel Rahim, A., Genotype environment interactions in field peas (Pisum sativum L.) (1996). Advisor: R. Baalbaki. Adlan, H.A., Ecological studies on faba bean necrotic yellows virus: Virus-vector relationship and yield loss assessment (1996). Advisor: Y. Abou-Jawdeh. Antar, N., Efficacy of biorational insecticides in management of the citrus leafminer, Phyllocnistis Citrella (1997). Advisor: E. Abou-Fakhr Hammad. Bibi, W., Response of broomrape (Orobanche ramosa) growth and development to various animal manures in potato (1996). Advisor: M. Haidar. Chehab, A. M., Broiler litter and inorganic nitrogen fertilizers influence on earliness and yield of strawberry and cabbage (1996). Advisor: I. Rubeiz. Hawi, Z., Effect of fruit extracts of Melia azedarach on Bemisia tabaci infesting tomato (1996). Advisor: E. Abou Fakhr. Kanj, B., Salinity and phosphorus effects on growth of differentially drought tolerant wheat cultivars (1996). Advisor: R. Baalbaki. Maalouf Sarrouf R., Reaction of tomato genotypes to infection by tomato yellow leaf curl geminivirus in Lebanon (1997). Advisor: Y. Abou-Jawdeh. Mansour, D., Effect of seed priming, size and GA on germination and emergence of carrots (1995). Advisor: R. Baalbaki. Sobh, H., Effect of soil solarization on soil-borne pathogens (1995). Advisor: Y. Abou-Jawdah.
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