Plant Nematology

The Javanese root-knot nematode (Meloidogyne javanica) is becoming a serious threat to okra production in Pakistan. The damaging potential of this nematode has not been studied on resistant and susceptible okra cultivars, therefore, in the present study, the effects of six inoculum levels of M. javanica were compared on a highly susceptible cultivar of okra 'Sharmeeli' and a moderately resistant one 'Sanam'. All the inoculum levels of M. javanica resulted in significant reductions in growth variables and increases in nematode infestations of both the cultivars over their controls. With an increase in inoculum level, the magnitudes of reductions in shoot weight, root and shoot lengths and increase in root weight also increased and were found to be positively correlated with the inoculum levels. Likewise, the numbers of galls and egg masses also showed positive correlations with the inoculum levels. Contrarily, a gradual decline in reproductive factors was observed with an increase in the inoculum level and therefore, appeared to be negatively correlated with the latter. It was also observed that the reductions in moderately resistant cultivar were significantly lower as compared to the highly susceptible at all inoculum levels. It is concluded that the plants of moderately resistant cultivar Sanam suffered less damage and suppressed nematode infections at all inoculum levels and therefore, recommended for cultivation in root-knot nematode infested fields to abate yield losses and repress the nematode from further multiplication.

Yield loss due to M. incognita infection in tomato plants cultivation can reach 60%. The problem is able to be solved through the application of endophytic bacteria. In this study, endophytic bacteria from root Cyperus rotundus were isolated using Tryptic Soy Agar media. The bacteria isolates were then tested their safety against plants and mammals. The phenotypic and physiological properties of selected isolates were characterized and tested to know their resistance to antibiotics, and their ability in suppressing the infection rate of M. incognita on tomato. Eighteen bacterial isolates were obtained and 8 of them are categorized as safe bacteria for plants and mammals, which could be used in further tests. A result of the physiological test showed that bacterial isolates were able to produce protease enzyme (87.5%), chitinase enzyme (62.5%), and HCN (37.5%), having urease activity (75%) and could dissolve phosphate (87.5%). Based on the test results, all endophytic bacteria effect...

RESPONSE OF WHEAT, BARLEY AND OAT CULTIVARS
AND ACCESSIONS TO MELOIDOGYNE JAVANICA
M.R. Karajeh1 , A.H. Abdel-Ghani2 and N. Al-Majali3
1 Department of Plant Protection and IPM, 2 Plant Production Department, Faculty of Agriculture, Mutah University, P.O. Box 7, Karak 61710, Jordan 3 Plant Breeding, National Center of Agricultural Research and Extension, Amman, Jordan
Summary. A screening was undertaken to assess the reaction of three gramineous crops to Meloidogyne javanica. Fourteen cultivars
of barley, seven cultivars of durum wheat and four accessions of oat recently introduced in Jordan, were evaluated by inoculating the test pots with 1000 second stage juveniles (J2
) of the nematode or filling them with field soil containing 520 eggs and
J2
/250 g. Inoculation of J2 showed that two cultivars of barley (Morocco 9-75 and WI2291), one of wheat (Cham 5) and three accessions
of oat (O22, O23, O24) appeared to be immune to the nematode, while the other tested cultivars were ranked resistant to M. javanica infection. Using field soil, all of the tested cultivars and accessions were ranked resistant except two cultivars of barley (Rum and Acsad 176) that were susceptible, and one of wheat (Khayar Tunis) that was tolerant.
Keywords: Cereals, host reaction, root-knot nematodes.

The nematicidal potential of ethanol and aqueous extracts of ten wild plant species distributed on agricultural land
of Eritrea against root-knot nematode, Meloidogyne incognita, was studied. Three concentrations of each plant extract
were tested against egg hatching and mortality of second-stage juveniles (J2) of M. incognita at 24, 48 and 72h exposure time. Significant mortality and egg hatching inhibition were observed with aqueous and ethanol extracts of Datura
stramonium. Similar type of hatch inhibition also occurred with both types of extracts of Heliotropium indicum. From
tested extracts, J2 mortality ranged from 8 to 100% for hot water extracts and 26 to 100% in for ethanol extracts.
The nematotoxicity of the tested plants increased with an increase in concentration and exposure time and vice versa.
The hot water and ethanol extracts of D. stramonium caused 75-100% mortality and 57-100% inhibition in egg hatch,
respectively. This M. incognita juvenile mortality was 74-100% in the case of H. indicum. Among the tested extracts, hot water and ethanol extracts of Lantana camara and Xanthium strumarium, respectively, were least effective.

The present field experiments was conducted to know the efficacy of bio agents viz., Paecilomyces lilacinus, Pseudomonas fluorescens, Pochonia chlamydosporia, Trichoderma harzianum, Bacillus subtilis, Consortium of bio-agents (Pseudomonas fluorescens + Trichoderma harzianum) and Carbofuran 3G @ 0.3 ai. alone for management of rice root-knot nematode Meloidogyne graminicola during Kharif-2015 at College of Agriculture, Shivamogga (Latitude: 13° 27’-14° 39’ N, Langitude: 74° 37’-75° 52’ E). The results revealed that all the treatments were significantly superior over check with respect to growth parameters and nematode population. However, the treatment combination of P. fluorescens @20g/m² + T. harzianum @ 20g/m² was found to be the best treatment as it recorded highest plant height (83.33 cm), root length (21.27 cm), maximum grain yield (45.60 q/ha) with least RKI (1.20) and least nematode population (185.44/200g soil) with reduction of 72.77% nematode population followed by Carbofuran 3G @ 0.3 ai /m2, T. harzianum @ 20 g/m², P. fluorescens @ 20 g/m² and B. subtilis @ 20 g/m² respectively.

The potential phytosanitary importance of all named plant-parasitic nematode species was determined by evaluating available information on species characteristics, association with economically-important crop hosts, and ability to act as vectors of viruses or form disease complexes with other pathogens. Most named species of plant-parasitic nematodes (PPN) are poorly known, recorded from a single location only, not associated with economically-important crops, and not known to be associated with other plant disease organisms. However, 250 species from 43 genera fulfilled one or more of the criteria to be considered to present a phytosanitary risk. The genera and number of species (in parentheses) considered as posing phytosanitary risk included: Achlysiella (1), Anguina (8), Aphasmatylenchus (1), Aphelenchoides (12), Aphelenchus (1), Belonolaimus (2), Bitylenchus (3), Bursaphelenchus (4), Cactodera (3), Ditylenchus (8), Dolichodorus (1), Globodera (3), Helicotylenchus (7), Hemicriconemoides (3), Hemicycliophora (3), Heterodera (25), Hirschmanniella (5), Hoplolaimus (5), Ibipora (3), Longidorus (10), Macroposthonia (2), Meloidogyne (38), Merlinius (3), Nacobbus (1), Neodolichodorus (2), Paralongidorus (2), Paratrichodorus (11), Paratylenchus (3), Pratylenchus (24), Punctodera (3), Quinisulcius (3), Radopholus (5), Rotylenchulus (3), Rotylenchus (1), Scutellonema (5), Sphaeronema (1), Subanguina (3), Trichodorus (5), Tylenchorhynchus (8), Tylenchulus (2), Vittatidera (1), Xiphinema (15) and Zygotylenchus (1). For each of the 250 species main hosts and yield loss estimates are provided with an extensive bibliography. Of the 250 species, only 126 species from 33 genera are currently listed as regulated pests in one or more countries worldwide. Almost all of these 250 species were also associated with economically important crops and some also acted as vectors for viruses.

Three different organic inputs viz., Neemastra, Agniastra and Brahmastra were evaluated for the management of root-knot nematodes, Meloidogyne spp. in tomato. All three organic inputs were prepared by using indigenous cow urine and dung. Total three different concentrations of each organic input were used and applied 500 ml water solution as drenching per plant near root zone area at the time of transplanting and repeated it after 15, 30 and 45 days after transplanting. The results based on the data the root-knot index (RKI), the minimum RKI was found in Agniastra @ 800 ml/10l water followed by in Neemastra @ 400l /acre and in Brahmastra @ 800 ml/10l water as compared with all other treatments. These organic inputs were found effective to manage root knot nematodes and reduce RKI significantly. Whereas, the data on fruit yield showed that these organic inputs were not found effective and the result was found non-significant.

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An investigation was carried out for two consecutive years, 2016 and 2017, to test the efficacy of different pre sowing nursery treatments with two fumigants viz., dazomet (@ 40g/ m) and metham sodium (@ 14ml/ m), one organic formulation i.e., jeevamrit (@ 10%), and two bioagents viz., Trichoderma viride (@ 50g/ m) and Pseudomonas flourescens (@ 50g/ m), along with untreated control, against root knot nematodes (Meloidogyne incognita) infesting tomato nursery. The results revealed that maximum percent germination and shoot lengths were of jeevamrit, dazomet and metham sodium followed by T. viride and P. flourescens treated seedlings, all being better than control. In reference to nematode soil populations and root gall index, dazomet and metham sodium had better efficacy in comparison to T. viride, P. flourescens, jeevamrit and control. There was no significant difference in nematode soil population between jeevamrit and control.

El objetivo del presente estudio fue realizar una prospección de nematodos fitoparásitos asociados al cultivo de cebolla en el valle de Asunción Mita y relacionarlos con la presencia de Fusarium oxysporum. Se realizaron muestreos de suelo en diferentes puntos del valle de Asunción Mita en parcelas con cebolla. En cada punto se tomaron 10 submuestras para obtener una muestra compuesta de aproximadamente 1-2 Kg. Se trasladaron las muestras al laboratorio de patología vegetal en el Campus Central de la Universidad Rafael Landivar y se utilizó el método de tamizado y centrifugado con flotación en azúcar para la extracción de los nematodos. La identificación de géneros de los especímenes extraídos se realizó con base a la clave de identificación para hembras de Mai y Mullin (1996). Se cuantificó la incidencia de F. oxysporum en parcelas matrices de un metro cuadrado colocando un marco de madera en tablones con plantas sintomáticas y se contó la cantidad de plantas afectadas entre en total de plantas que cabían dentro del marco. Los resultados indican la presencia de diez géneros de nematodos: Aphelenchoides, Helicotylenchus, Meloidogyne, Paratrichodorus, Pratylenchus, Scutellonema, Hoplolaimus, Criconemoides, Tylenchorynchus y Tylenchus. En promedio se encontraron con mayor presencia el género Helicotylenchus (26.5 nematodos/100cc de suelo) y menor cantidad los géneros Meloidogyne y Paratrichodorus (1 nematodo/100cc de suelo). Se pudo observar una incidencia de F. oxysporum distribuido en parcelas del valle que va de 10%-50%. Los resultados indicaron que no existe  relación de la incidencia de F. oxysporum con la cantidad total de nematodos, lo cual se concluye que los nematodos fitoparásitos en el valle de Asunción Mita, no son factores inductivos de esta enfermedad.

Root-Knot Nematode (RKN) Meloidogyne spp. is one of the important pests in pepper plants that can cause withered. The antagonistic effect of three endophytic bacteria Pseudomonas sp. strain A175 and F23, and Micrococcus sp. strain S54 were tested against RKN under greenhouse condition. The efficacies of these endophytic bacteria were further confirmed by comparing their efficacy with synthetic nematicide. The results obtained showed that these three endophytic bacteria significantly reduce the gall formation and nematode population for >23% and >41%. These antagonistic efficacies are at par with chemical treatment with the efficacy percentage of 24% and 40.9% respectively for gall formation and nematode population reduction. This indicated that these bacterial isolates could reduce the ability of M. incognita to reproduce in soil. The greenhouse trial also revealed that the application of Pseudomonas sp. strain A175 and F23, and Micrococcus sp. strain S54  significantly increase pepper growth performance of pepper in term of plant height, number of branches number of leaves, number of segments, shoot fresh weight, shoot dry weight, root fresh weight, and dry weight. On the basis of aforementioned results, it is suggested that Pseudomonas sp. strain A175 and F23, and Micrococcus sp. strain S54 can be an effective biological control agent against pepper root knot nematode.
Keywords: culture filtrate, nematode suppression, pepper growth

A green house study was conducted to evaluate the comparative efficacy of Pasteuria
penetrans under the influence of organic amendments of four oil seed cakes namely
Azadirachta indica (Locally known as Neem), castor (Ricinus communis), mustard
(Brassica campestris) and Citrullus (Citrullus colocynthis) on suppression of populations of
Meloidogyne incognita in Chilli. Oil seed cakes were applied at the rate of 20 mg/Pot (500
kg/ha), either individually or in combination with one dose of P. penetrans (100 g/kg soil).
Application of oil seed cakes and P. penetrans, singly or in combination, proved effective
in reduction of gall and final root-knot nematode population. Combination of castor and
P. penetrans showed greater reduction in galling index (84.75%) and final population
(85.74%) over the M. incognita control than other treatments. In addition, oil seed cake
significantly improved the shoot and root dry matter of chilli. Among the four oil cakes tested, the combined application of P. penetrans with castor oil cake seemed to be more promising in the management of M. incognita in chilli as it resulted in greater nematode suppression and improved plant health.

Plant parasitic nematodes (PPNs) are important constraints in
crop production. On global basis plant parasitic nematodes are known
to cause estimated average crop losses of about12.3 per cent (Sasser

and Freckman, 1987). In developing countries having tropical and sub-
tropical climates, the losses due to plant parasitic nematodes have been

estimated at 14.6% as compared to 8.8 % in developed nations. In
another estimate plant parasitic nematodes are known to cause losses
equivalent to US$173 billion per year globally in major crops (Elling,
2013). Recent crop assessment carried under All India Coordinated
Research Project (AICRP) on nematodes in Agriculture revealed 21.3
per cent average crop losses in India amounting to RS 102,039.79
million (1.48 billion USD) annually (Kumar et al, 2020). The losses in
19 horticultural crops have been assessed at Rs. 40,224.98 million.
Morphologically, nematodes are triploblastic, bilaterally symmetrical
and cylindrical invertebrates without cilia and true coelom. Plant
parasitic nematodes bear a needle like structure in their mouth known
as stylet/ spear which is used to puncture plant roots and suck the cell
sap. PPNs feed on plant roots or other parts ectoparasitically or
endoparasitically depending upon their mode of parasitism. Further,
the endoparasitic nematodes are more damaging than ectoparasites.
PPNs are considered as hidden enemies as majority of them are soil
inhabiting; the above ground symptoms produced are mainly
nonspecific which are generally go unnoticed and confused with
nutritional deficiencies. Besides causing direct damage to plants, PPNs
also form interactions with other plant pathogens resulting in disease
complexes (Atkinson, 1892). Plant damage is increased manifold in
these disease complexes. PPNs are also known to transmit soil borne
plant viruses. The intensification of agriculture to meet the demands of
growing human population has resulted in increase in nematode
problems.

Experiments were carried out to evaluate the nematicidal effect of Oleander (Nerium oleander) extracts on controlling root-knot nematode Meloidogyne incognita in-Vitro and in-Vivo. Five different organic solvents i.e., Petroleum Ether, Chloroform, Acetone, Ethyl Alcohol and Methyl Alcohol were used. Plant extracts screened for nematicidal activity against egg hatching and mortality of second-stage juveniles of M. incognita under laboratory conditions and on nematode infecting tomato plants under greenhouse conditions. Results showed significantly effect of all tested oleander extracts on egg hatching and larvae mortality under laboratory conditions. A great reduction in number of galls; eggmasses; females/root system of tomato plants and number of second stage juveniles (J2S)/250 g soil was recorded compared to the treated plants with nematode alone. Tomato plant growth parameters and oxidative enzymes were markedly enhanced compared to the non-treated control.

The previous study revealed that root-knot nematode was the common nematode disease on the plants cucumber .This problem is one of the most determined factors of productivity of cucumber. The management of this nematode disease on cucumber must carried out during the safely and friendly methods to environment. The experiments were conducted under both greenhouse and field conditions to determine seasonal fluctuation and application of some bioagents to control of root-knot nematode Meloidogyne incognita on cucumber. Seasonal fluctuation of the root knot nematode M. incognita were studied on two cucumber cultivars (Madia and slaprty) during the period from March to November in seasons2015/2016and 2016/2017.Soil population increased gradually on two cultivars during Spring and throughout Summer to reach peak in August began decrease during Autumn and reach the lowest in Winter (January and February) in two seasons where soil temperature reached 15± 4ºC. Seven treatments Paecilomyces lilacinus, Arthrobotrys oligospora, Glomus faciculatum, Eucalyptus globules, Tagetes erecta, Allium sativum, and Fenamiphos (10%G) were evaluated to control M. incognita. All the treatments gave decrease in nematode population M. incognita in soil and on roots compared with check. Data indicated percent increases of fresh weight of the whole plant which was greatly improved in all treatments.

The profitable cultivation of cucumber is seriously threatened by root-knot nematodes. As the damaging effects of Meloidogyne incognita have not been assessed on cucumber, therefore, the present studies report the effects of five initial population densities of M. incognita on growth and yield of cucumber and nematode reproduction. All inoculum densities caused significant reductions in growth and yield of cucumber and were found to be positively correlated with the latter. On the other hand, ages of plants at inoculation had negative correlations with reductions in these parameters at each inoculum density. The production of galls was found to be positively correlated with the inoculum densities and plant ages. However, rate of nematode build up decreased with an increase in inoculum density and appeared to be negatively correlated with inoculum densities and, on the contrary, was found to be positively correlated with plant ages. The results demonstrated that M. incognita has the potential to severely impair the growth of cucumber and by delaying early exposure of the latter to nematodes can significantly abate yield losses.

A survey was conducted in Udaipur, Chittorgarh, Bhilwara, Kota and Bundi districts of Rajasthan to know the occurrence of entomopathogenic nematodes during 2007-08. Total 105 soil samples were collected from different localities by random sampling technique. The soil samples were baited twice using last instar larvae of the greater wax moth. The occurrence of entomopathogenic nematodes in the soil samples was established on the basis of mortality of G. mellonella larvae. Out of 105 soil samples, three samples were positive for EPNs in these surveyed districts of Rajasthan.

A system, method, and apparatus for quantification of pre-determined particles in a soil or feces sample with certain automated steps. In one aspect it includes an input station for inputting a soil or feces sample; a sieving/filtering station for separating soil or feces from particles or particle carriers, and/or separating particle carriers from particles; and a collection station for receiving the extracted particles. It can include quantification of the collected sample with an imaging station to digitally image the particles and recognize and count the particles collected. A mechanism can mechanically move the filtered particles from the sieve/filter station to the collection station. A controller can be programmed to automatically control at least certain functions of the mechanism. An optional feature includes acquisition of chemical, biological, physical, or other parameters of the sample with one or more sensors positioned or positionable at the sample.

A study was conducted between August 2014 and May 2015 to identify plant-parasitic nematodes taxa associated with tomato (Solanum lycopersicum L.) and to assess the knowledge, perceptions and experiences of growers of the crop on occurrence and management of the parasites on their farms in nine communities within the semi-deciduous forest, the forest/savanna transitional and the savanna agro-ecological zones of Ghana. Semi-structured questionnaires were designed and administered to 54 randomly selected growers from the nine communities. Composite rhizosphere soil and tomato root samples were collected from two farms in each of the nine communities, and nematodes extracted, identified and recorded. The study revealed that many growers (73%) could not distinguish between nematode infestation, nutrient deficiency and moisture stress and, therefore, lacked knowledge on nematode control. Most of the growers (63%) continually cropped their land to tomato for periods of 4-7 years without fallowing. All growers applied only inorganic fertilizer to their crops. Symptoms of nematode infestation were widespread in fields with high yield losses. Tomato was a host to Helicotylenchus spp. (11.5% in soil), Hoplolaimus spp. (1.0 % in soil), Meloidogyne spp. (37.4% in soil and 69.3% in roots), Pratylenchus spp. (20.6% in soil and 13.7% in roots), Rotylenchulus spp. (11.0% in soil and 12.2% in roots), Scutellonema spp. (9.5% in soil and 4.9% in roots), Tylenchus spp.(7.6% in soil) and Xiphinema spp.(1.4% in soil) across the nine communities surveyed. Semi-deciduous forest and Savanna agro-ecological zones had the highest and least population densities of nematodes, respectively. These nematodes, if not managed efficiently, could also serve as constraint to tomato production in the country. Original scientific paper.

Indonesia is one of the largest pepper producing countries in the world. One of the pepper-producing provinces in Indonesia is the Bangka Belitung Islands (Babel). However, the infection of Radopholus similis and Meloidogyne spp. which causes yellow disease becomes one of obstacles in pepper cultivation in Babel. Thus, alternative solution to overcome this yellow disease is by reducing the amount of nematode inoculum of R. similis and Meloidogyne spp. in soil. This study aimed to determine the effectiveness of the infusion of oyster mushrooms baglog waste enriched with molasses to control the population of R. similis and Meloidogyne spp. and to increase the population of rhizobacteria. Infusion of oyster mushrooms baglog waste was mixed with 1% of molasses and was poured into soil obtained from the pepper plant roots. The concentrations used were 10%, 20%, 30% and 50%. Population of phytonematode, rhizobacteria, proteolytic bacteria, and group of fluorescence bacteria were calculated before and 7 days after treatment. Results showed that the populations of R. similis and Meloidogyne spp. in the soil poured with the influsion of oyster mushroom baglog waste decreased by 29.11% (R. similis) and 24.61% (Meloidogyne spp.), compared to the before and control treatments. The suppression of nematode population was found to be the highest in the influsion treatment at concentration of 50%. Overall, treatment of all concentrations succeeded to increase the population of rhizobacteria, proteolytic bacteria, and group of fluorescence bacteria in soil. Moreover, the highest increase was found in soil treated with concentration of 50%. This study provided new information that the infusion application of oyster mushrooms baglog waste enriched with molasses had the potential to increase the population of rhizobacteria and suppress the amount of pathogens R. similis and Meloidogyne spp.

Plant-parasitic nematodes are economically important pests of banana (Musa spp.) and compromise its productivity. Controlling nematode populations and good agronomic practices are prerequisites for a good yield. A survey of farmers in the Rusitu Valley, Zimbabwe, was conducted to assess their current banana production practices and knowledge of plant-parasitic nematodes associated with banana. Respondents were selected using systematic sampling from three wards. Most farmers (61.9%) grew bananas as a monoculture, and 38.1% intercrop banana with other crops. All the farmers neither rotated banana with other crops nor practiced pest and disease control measures, and only 11.4% apply a fertiliser to their banana crops. Most (82.9%) farmers in Rusitu Valley had little or no knowledge of plant-parasitic nematodes that damage bananas. Sound extension programme in Rusitu Valley should educate farmers on the importance of managing plant-parasitic nematodes and using better banana crop production practices.

An experiment was conducted to determine the impact of six aqueous leaf extract; Vinca rosea, Datura stramonium ,Tagetes erecta, Aambrosia maritima, Ocimum basilicum , Bougainvillea spectabilis alone or combined with the nematophagous fungus; Paecilomyces lilacinus against the root-knot nematode, Meloidogyne javanica on potato(Solanum tuberosum) cv. Diamant under greenhouse conditions in Egypt. Results indicated that the most treatments tested obviously caused remarkable increase in potato plant growth with different degrees. The combination treatment of P. lilacinus + D. stramonium together revealed the highest value of percentage increase of the whole plant fresh weight (78.1 %), while the treatment of O. basilicum alone gave the lowest value of percentage increase of the whole plant fresh weight (23.8 %). In addition, treatments singly or combined increased fresh weight and length of the whole plants as well as weight of potato tubers. The combination of P. lilacinus + D. stramonium showed the highest efficacy in reducing the nematode population in both soil and roots also. On the other hand; the treatment of P.lilacinus alonel showed the least effect. The combing effect of P. lilacinus + D. stramonium induced a remarkable reduction in the nematode build up and improved both plant growth and tuber weight of potato plants in relation to nematode alone. _______________________________________________________________________________

Root knot nematodes represent important pathogens affecting global crop production due to their wide host range. The attack of root knot nematode on various vegetable crops leads to delayed maturity, reduced yields and quality of crop produce, high costs of production and therefore loss of income. However, their damage in most cases is overlooked and goes unnoticed by majority of farmers because the damage presents symptoms of drought and nutrient stress conditions. The limited knowledge among farmers about the problems associated with root knot nematodes and the inadequate management measures for curtailing the menace presents a major hindrance for vegetable crops protection.  Management strategies should be applied in line with integrated pest management (IPM) practices to enhance adoption by farmers. Also, vegetable producers should be educated on the effects of root-knot nematodes.

Under field conditions, distribution (vertical and horizontal) of eleven nematode genera on three date-palm cvs. Barhi, Samani and Zaghlool. Seasonal fluctuation of Meloidogyne incognita, and its biological control on date-palm cv. Zaghlool were investigated during one year of 2012. Results indicated that all eleven nematode genera recovered were found in high densities at a depth of 30-50 cm for both types of distributions, whereas only three genera viz. Criconemoides , Tylenchus and Trichodorus were detected in low densities at depth over 50 up to 100 cm in the case of vertical. However, at depth of 50-100 cm only three genera e.g. Aphelenchus, Criconemoides and Tylenchus were recovered in low number in the case of horizontal. Meanwhile, seasonal fluctuation of M. incognita population (J2) showed generally high peaks on date-palm cvs. Zaghlool, Samani and Barhi soil in August 2012, where Zaghlool cultivar ranked first in this respect. M. incognita (J2) population increased gradually during July, August and September on tested cultivars, then decreased in November and December 2012. Regarding M. incognita integrated biological control on date-palm cv. Zaghlool, dual treatments gave better results than single one for both percent reduction of reproduction factor and percentage increase of crop yield (78.1%), especially, Paecilomyces lilacinus+ Datura stramonium treatment. Results also indicated amount increase in concentration of total sugar, total phenol, reducing sugar and free phenols in date-palm cv. Zaghlool of dual treatment than the single one, where P. lilacinus plus D. stramonium ranked first, however, the opposite trend was recorded in the case of total amino acids.

Root-knot nematodes (Meloidogyne spp.) are serious disease causing agents and attack nearly all types of plants. In this study 32 seaweeds were evaluated to determine nematicidal activity against Meloidogyne javanica (egg hatching and larval mortality tests) in vitro. Results revealed that seaweed biochemical potential in two different solvents viz., water and methanol @ ratios 2.5, 5 and 10%. It is observed that Sargasssum tenerrimum, Padina tetrastromatica and Melanothamnus afaqhusainii showed maximum egg hatching (96%) and larval mortality (99%) and (100%), respectively in water and methanol extract @ 10% concentration after 72 hours exposure time. Similarities between Ward’s cluster analysis of hatching egg and larval mortality in water and methanol extract of different seaweeds showed significant difference. Methanol extract was more effective as compared to water extract. In conclusion, use of seaweeds is positive sign against harmful microorganisms which are responsible for
considerable losses in agriculture yield.

As the use of nematicides is becoming prohibitive in many countries due to their detrimental consequences, the management of plant parasitic nematodes using nanoparticles can be one of the important alternatives. In the present study, the nematicidal activity of silver nanoparticles (AgNP) was investigated against the most destructive root-knot nematode (Meloidogyne incognita). The maximum mortality of juveniles was recorded at a concentration of 100 mg/ml followed by 75 mg/ml of AgNP. The minimum mortality was recorded with 25 mg/ml of AgNP. With the increase in concentration, there was a corresponding increase in the mortality of juveniles showing a direct relationship between mortality and concentration of nanoparticles. The effect of time on mortality was also found significant. With the increase in time, there was a corresponding increase in mortality and the relationship was found to be directly proportional. Similarly, the maximum hatching inhibition of M. incognita eggs was recorded at a concentration of 100 mg/ml of nanoparticles followed by 75 mg/ml of AgNP. The minimum inhibition was recorded with 25 mg/ml of AgNP. It was found that with the an increase in concentration, there was a corresponding increase in hatching inhibition showing direct relationship between hatching inhibition and concentrations of the nanoparticles. Similarly, the maximum hatching inhibitions were recorded after 6 th day followed by 5 th day. The hatching inhibition was found directly proportional to time duration as it increased with an increase in number of days. It is concluded from the present study that AgNP possess nematicidal activity against root-knot nematodes and can act as an alternative to high-risk synthetic nematicides or inconsistent biological control agents without causing any phytotoxicity.

The experiments were conducted under both greenhouse and field conditions to determine seasonal fluctuation, inoculum levels of the root-knot nematode, Meloidogyne incognita and application of some bioagents to control this nematode on cassava. Seasonal fluctuation of the root knot nematode Meloidogyne incognita were studied on two cassava cultivars (Brasilia and Endonisy) during the period from January to December 2008. Results reveal that M. incognita population fluctuated in soil of two cassava cultivars (Brasilia and Endonisy) increased from 420 individuals per 250 g. soil in Brasilia cultivar and from 180 individuals per 250 g. soil in Endonisy cultivar as the initial population in January 2008 to 3220 or 2100 individuals per 250 g. soil in August 2008 and then declined down to 640 or 420 individuals / 250 g. soil in December 2008 where soil temperature reached 17± 4ºC, respectively. Results showed that Brasilia cultivar was more susceptible than Endonisy cultivar. Nematode population increased during July, August and September in the two cultivars and then nematode population decreased to from November to December. Two cultivars of cassava were examined for their relative susceptibility to the infection with M. incognita. Brasilia cultivar was more susceptible than Endonisy to the root knot nematode. The nematode population in 250g soil and in root (number of developmental stages, females, egg masses number and eggs/ egg mass) were significantly higher on Brasilia as compared to the same criteria on Endonisy cultivars. Also data indicated decreasing % of fresh weight of the whole plant in cultivar Brasilia at inoculum 3000 where the percentage of decrease reached (88.6%) while, in cultivar Endonisy at inoculum 1000 was (26.2%). Five treatments (Psudomonas fluorescens, Trichoderma viridi, Bacillus thurngenthis, DiTera; Myrothecium verrucaria and Nemathoren were evaluated to control M. incognita. Using Nemathoren (10%) and Myrothecium verrucaria specially at the highest concentration performed the highest decrease in both soil. and root (developmental stages, females, egg-mass and number of eggs/ egg-mass) comparing with the other treatments. Psudomonas fluorescens and Bacillus thurngenthis occupied the intermediate rank in reducing the nematode populations, whereas Trichoderma viridi resulted the lowest number of nematode populations in both soil and roots. The results expressed as increasing % over control. Data indicated percent increase of fresh weight of the whole plant were greatly improved in both treatments of Nemathoren(10%G) and Myrothecium verrucaria at the highest concentration where the percentage of increase reached (87.2, 72.1%) respectively while, the treatment of Trichoderma viridi was (42.5%)at the lowest concentration. Also data showed a positive correlation between the amounts of total or reducing sugars and concentration of the used treatments. Amounts of phenols increasing the concentrations of the treatments. Amounts of total amion acids were decreased by increasing the concentration of the used treatments.