Prepared by the researcher : Elbasher Elkhalifa Elzain Elkhalifa- the researcher  in Head of Plant Protection Department- Ministry of Agriculture in White Nile State

Democratic Arab Center

Journal of Afro-Asian Studies : Seventeenth Issue – May 2023

A Periodical International Journal published by the “Democratic Arab Center” Germany – Berlin

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Abstract

To manage the disease, the study involved the investigation of the effect of different concentrations of natural products formulations and fungicide, Seed Star 42, on the incidence of the disease under natural infection conditions for two successive seasons. Three concentrations were tested from each of the natural products e.g. Neem oil, aqueous extracts of plants leaves of argel, Neem and usher plus mesquite plant fruits extract, as follow; 2.5, 5 and 10 ml/l and 25, 50 and 100% for each of the extracts respectively. This in addition to argel 5gm powder per hole and the fungicide seed star 42 at the rate of 5 gm/Kg seeds as seed dressing plus the control. The assessment of the treatments effects on the pathogen was recorded as percentage disease incidence.

The result showed an invariably high effect on disease incidence obtained by the concentrations of Neem oil at 5ml/l, argel at 5gm/hole and seed star 42 at 5 gm/Kg seeds which gave almost 100% disease control where the percent was 0.0, 0.0, 1.0 at the forth count respectively compared to control which was 16.33. It is noteworthy that those encouraging results were confirmed by the same experiment repeated the season after. However, the effect of Neem leaves extracts at the three concentrations, 25, 50 and 100% was the lowest in disease control, at the forth counts; 8.67, 9.67 and 10.33% respectively, compared to the other treatments and this was an indication of inefficacy. Beneficial effects expressed as reduction in percent of fruits infected were also recorded due to application of these three treatments. Apparently, there was also obtained a high yield gains in this study upon treatments of tomato with those three products. The yield was almost doubled by application of the forgoing products giving a total of 41.6, 46.0 and 36.0 Kg per treatment respectively compared to control 23.1 Kg.

The current results were considered promising and encouraging to carry out a photochemical analysis of Argel plant using different solvents so as to determine the bioactive ingredient in the plant. Obviously, the present study is presenting for the first in Sudan the highly effective method for control of early blight disease in tomato using argel powder at planting time.

Introduction

Tomato (Solanum lycopersicum L.(Synonoum  Lycopersicon esculentum (Mill) (Peralta et al., 2005), whichis believed to have originated in the coastal strip of western America (Papadopoulos,1991), is belonging to the important fruit vegetables for human nutrition ; Thus cultivated across all continents (Anon, 2009).

In the Sudan the tomato is considered as one of the major vegetable crops due to its economics and nutritional value and being one of the main cash vegetable crops. Total production in Sudan reached 529,200 tons in 2012 produced from 37,044 hectares and increased to 617,400 tons in 2016 produced from 46,746 hectares ((FAO, 2006, 2018). The crop is grown mainly to be used either fresh or cooked mixed with other vegetables. Tomato Lycopersicon esculentumL is a member of the family Solanaceae (Shread, 1966).  It was described by Hansen (2000) as an ancient vegetable crop which originated in Peru, South America. It was taken to Europe by the earlier invaders and from there to North and South America and the rest of the world.  In the Sudan it is the second most important vegetable crop of Onion it is produced in a wide area around large cities along the Nile and on seasonally flooded plains.

Objectives

Main objective:-

The main objective of this study is to improve tomato productivity by developing a package of integrated control measures that offer several options for farmers to manage early blight disease of tomato in White Nile State production areas.

Specific objectives are to:-

• Isolate and identify the genus Alternaria.
• Explore the antifungal potentials of different formulations of some higher plants and fungicide against infection of tomato plant under field conditions.

LITRATURE REVIEW

History of Early Blight Disease:

Early blight is the major fungal disease of tomato caused by the fungus Alternaria alternata.(Ellis and Martin, 1971). This disease, which in severe cases can lead to complete defoliation, is most damaging on tomato (Peralta etal., 2005)in regions with heavy rainfall, high humidity, and fairly high temperatures (24°–29°C). Epidemics can also occur in semi-arid climates where frequent and prolonged nightly dews occur (Rotem, 1994).

The disease was first described in New Jersey (U.S.A) in 1882 and later by. The most critical early work was that of Jones during the period 1891 – 1903 Until 1945 where extensive research on the disease was done Walker (1952). After that, many aspects of the disease were studied and showed that early blight is a very common disease of both Tomato and Potato. Fruits, roots and stems lesion on tomato were observed by Walker (1952). Paul grow, (2000) reported that Early blight pathogen was first described by Ellis and Martin in 1994 from dying Potato leaves and was called at that time Macrosporiumsolani. In spite of its name the disease may occur at any time during the growing season (Hansen, 2000). In contrast to name of early the blight could appear on maturity stage (Paul grow, 2000) .

Pathogen:

Neergaard (1945) reported that Alternaria spp. has large spores producing group of fungus and characterized by separate conidia borne singly on simple conidiophores..

Joly (1959) studied the morphological variations of Alternaria species and later during 1964 divided them in three sections and proposed a simple Keyfor identification and determination of the most common species. Furthermore, noticed that the conidia of Alternaria alternata are uniform, beaked, dark uniform, pale golden or olivaceous brown and smooth and usually 150-300 um in length and 15-19um thick in the broadest part, with 9-11transverse septa and 1-4 longitudinal or oblique septa, sometimes branched 2.5-5 um thick tapering gradually

Bose and Som (1986) observed  septets and the branched, light brown hyphae which turned darker with age. The conidiophores were short measuring 50-90 um long and dark color. The conidia were 120-296*12-20 um in size, beaked, uniform, dark color and borne singly. However, in culture they formed short chains. Singh (1987) reported that the conidia contained 5-10 transverse septa and 1-5 longitudinal septa. The mycelium was septets, branched, light brown hyphae which turned darker with age.

The role of Natural Products:

Neem (Azadirachta indica A. Juss):

Origin and Characteristics of Neem tree:

Neem tree was introduced to Sudan from India. The tree showed promising results in reducing as well as controlling some insects and disease. The most effective part of Neem is seeds and leaves from which powder is extracted and applied in various ways to infected plants (Ruskin, 1991).

Chemistry of Neem Tree:

All parts of A. Indica tree have been examined by many chemists who showed that Neem trees contain a number of chemicals and showed that Neem compound called “triterpenes” or ” Limonoids”. There are nearly about 100 proto limonoids or tetramer titer, pentanor titer penoidshexanor titer and some none titer penoids (Jones et. al., 1989).

Neem oil:

Neem oil is a vegetable oil pressed from the fruits and seeds of the Neem. (Azadirachta indica) is an ever green tree which is endemic to the Indian sub continent and has been introduced to many other areas in the tropics. It is the most important of the commercially available products of Neem for organic farming and medicines.

Toxicity of Neem oil:

The ingestion of Neem oil, even in small doses, is severely toxic and can induce metabolic acidosis seizures. This can also be associate d with allergic contact dermatitis. Formulations made of Neem oil also find wide usage as a biopesticides for organic farming , as it repels a wide variety of pests including the Mealy bug , beet army, worm, aphids,thrips, white flies, Locust and the Japanese beetle. Neem Oil also controls of black spots, powdery mildew, anthracnose, rust and Alternaria.

2.3.3 Mesquite(Prosopis juliflora):

Prosopis juliflora (SW) DC is an evergreen tree native to South America, Central America, and the Caribbean. In the United State of America, it is well known as Mesquite (Anderson, 2005). It is fast growing, Nitrogen- fixing, and tolerant to arid conditions and saline soils. In some circumstances Prosopis juliflora can provide a variety of valuable goods and services: fuel wood. Charcoal, animal feed, construction materials, soil conservation and rehabilitation of degraded and saline soils (Pasiecznik, 1999 and Pasieczniket,al., 2001). In the dry land of India, Prosopis juliflora is considered as one of the most valuable tree species (Pasiecznik, et.al. .2001).

Prosopis spp is ever green leguminous trees or sharps. The genus comprises 44 species of which 40 are native to the Americas, of the remaining species 1929kdeziana,PAfricana is indigenous to Africa ,where is P kodzina , P farcta and P. cineraria  are  native  to middle east and Pakistan [ Borun and Messey ,1929  and Bukarat, 1976].Prosopis species grow in arrays of environment and are not restricted by soil type, pH, salinity or fertility [Sid Ahmed, 2005 and Babiker 2006]

The name Prosopis was selected by Linnaeus to describe the only species he was aware of P.spicigera in 1776.Felker, et. Al., (2003).  Stated that genus ProsopisLinnaeusBurkat is in the family Leguminous [Fabaceae], Sub family Mimosoidae. The placing of Prosopis in the wider taxonomy classification system given below based on.

Usher (Caltropis procera)

Sadana and Didwania(2015) studied the bio-efficacy of Calotropis procera and Eucalyptus obliqueextracts against Alternaria alternate under in vitro conditions. They found that fresh aqueous extract of at 15% was most effective which gave 88% percent inhibition of mycelia growth of Alternaria alternate estrain A1 followed by Calotropis procera.

Fungicide (Seed Star 42 WS)

Apron Star 42 WS is a new fungicide-insecticide that combines two active ingredients, namely thiamethoxam, metalaxylam (mefenoxam)azoxietrobin and difenoconazole (www.syngenta.com, 2006). The trade names include   Cruiser and Actara (Horii et.al. 2007).

MATERIALS AND METHODS

This study which conducted at White Nile State, that situated South of Khartoum State, between Latitudes (13 30 12 N) and Longitudes (33 30 31 E) aiming to improve tomato productivity at this State by developing a package of integrated control measures that offer several options for farmers to manage early blight disease of tomato.

Effect of aqueous extracts of natural products and fungicide on early blight disease:

Preparation of aqueous extracts:

The objective  of this experiment was to study the antifungal activities of plant extracts of leaves of Neem, Usher, Argel and the fruit of mesquite on the incidence of early blight disease on tomato under field conditions. The extracts from the four plants were tested for their effects on the incidence of the fungus. Aqueous extracts of each of the plant materials were prepared as recommended by Okigbo (2006). The leaves of Neem, Usher, Argel and the fruit of mesquite were first washed carefully, shade dried, ground into powder and stored in tightly covered glass jars wrapped with Aluminum foil until needed for preparation of extracts.

The obtained fine powder form different products were weighted separately and added to it equal amount of sterilized distilled water by volume into conical flask 250 ml and then placed in a shaker for 24 hrs. The mixture was then strained thorough a light cloth and then filtered through a WattmanNo1filter paper (24 cm). The stock solution was kept in the refrigerator at 4˚c for further work. Three concentrations (v/v) 100%, 50%, 25% were prepared by serial dilution with distilled water.

Field experiments:

The field experiment was conducted twice during seasons (2017/2018),.The experiments which were carried out during winter season were conducted in an area infested with early blight of tomato to ensure presence of high inoculums pressure. Land was prepared by proper plaguing and then divided in to 54 plots allocated to three replications each of 18 plots. The plot size was 3* 2.5 m containing two Mastaba each of 240*80 cm. Plots were arranged in a complete Randomized Block Design (CRBD) with three replicates.

Sowing of seeds:

Seeds of the tomato variety Strain B were sown directly in holes on the side of Mastaba, 20 cm between holes giving a total of thirty plants per plots. After irrigation, the plants were fertilized once by using Urea after 21 days after seeds germination at the rate of 40 kg urea / feddan.

Treatments:

Eighteen treatments were tested in this experiment which included; seed dressing by Seed Star 42 fungicide, Argel powder per holes at time of seeds sowing, Neem oil and aqueous extracts of leaves of, Neem, Usher, and Argelin addition to aqueous extract of fruits of mesquite and control. The treatments were assayed for their bioactivity against Alternaria spp. in tomato winter production season under field conditions.

With the exception of Argel powder which was applied at time of sowing at the rate of5g/ hole, the treatments were applied after appearance of first symptoms of Early Blight. The Neem oil was used at the concentrations of 10, 5 and 2.5 ml/ liter of water whereas aqueous extracts of leaves of Argel, Neem and Usher plus fruits of mesquite of 100, 50 and 25%. This was in addition to the Apron star fungicide at its standard rates of 5gm/1kg, seed dressing. Knapsack sprayer, 20 liter size was used for spraying. Application of treatments which started with the appearance of first symptom was repeated five times at ten days interval.

Data Collection:

Disease symptoms were observed starting from appearance of the first symptom on leaves before each application of treatments and continued until the downfall of diseased leaves. In each count ten plants were randomly selected from the middle of each plot and the number of plants showing Alternaria leaf symptoms were counted and expressed as a percentage of the plants inspected. Similar data about percentage of diseased fruits was also obtained according to;

At harvest time, the total yield was calculated for each treatment including the untreated control (Sallam and Kamal, 2012)under field conditions.

Data analysis:

The obtained data were subject to analysis of variance for the randomized complete block design, using MStatC computer program. Means were separated by Duncan’s multiple range test at P = 0.05.

Results

The results of these studies are presented under the different parameters investigated. The results cover surveys of tomato commercial fields for occurrence and spread of early blight disease, isolation and identification of Alternaria alternata., effect of natural plants formulations and fungicide on control of the pathogen and evaluation of tomato varieties for resistance to the disease.

The effect of different concentrations of natural products formulations and fungicide on incidence of early blight disease in tomato plants under natural infection (forth count, season2017 – 2018)

Considering the past three counts, the data of the forth count sustained the same pattern where all treatments had reduced the disease incidence to a level lower than that of the control. Their scores on disease incidence were significantly high at P< 0.05 compared to control which was 16.33 percent. Among these treatments, that of Neem oil at 5 ml/l, Argall powder per hole, Argall leaves extracts 100% and fungicide ranked top in control of the disease. However, the data highlighted the remarkable control of early blight disease given by these treatments. Their score of disease control range from 0.0 percent with Neem oil at 5ml/l and Argall powder per hole to 0.33 and 1.0 percent with Argall leaves extract at 100%and fungicide respectively.

It is worthnoty that the efficacy of these four treatments in sustaining this very low disease incidence (0.0 to 1.0 percent) throughout the counting periods. However, the effect of other treatments e.g. that of mesquite and Neem leaves exhibited a successively reducing efficacy of disease control and buildup of early blight with plant again each count. The record of their disease incidence was ranging from 4.67 to 11.33 percent.

Table (1): The effect of different concentrations of natural products formulations and fungicide on incidence of early blight disease in tomato plants tested under natural infection (forth count, season2017 – 2018).

No significant differences between means with the same letter(s) within column at P= 0.05

The effect of different concentrations of natural products formulations and fungicide on incidence of early blight disease on tomato fruits under natural infection (first count, season2017 – 2018)

Table, 6 presents the incidence of early blight diseases on tomato fruits at harvest time. The data indicated clearly the influence of the four top ranked treatments; Neem oil at 5 ml/l, Argall powder per hole, Argall leaves extracts 100% and fungicide, in controlling the early blight disease in plant leaves was also continued to express their effect on control disease incidence on fruits of tomato at harvest. They significantly reduced the incidence of the disease giving 0.33 percent with Neem oil at 5 ml/l, Argall powder per hole, fungicide and 0.67 with Argall leaves extracts at 100% compared to control 3.67 %. The other treatments have had variable level of disease control ranging between 1.0 to 5.0 percent.

The effect of different concentrations of natural products formulations and fungicide on total weight of tomato fruits tested under natural infection (season2017 – 2018)

The effects of treatments on the total weight of tomato after four successive harvests are presented in Table 7. Treatments of Neem oil at 5 ml/l, argall powder per hole, extracts of leaves of Argall at all concentrations and fungicide scored the highest total weights of tomato, in evaluation of effect of treatments on yield, with significant difference from the control. Concerning the impact of other treatments on total weight, three of them were ranked second to the above mentioned treatments for total yield although the difference was not significant compared to those four treatments? It is noteworthy that in this investigation, all Argall treatments resulted in highest total weight compared to the control. However, the remaining treatments effect on yield was not significant where they gave total weight of tomato ranging from the lowest yield of 18.4 to 23.0 Kg per treatment compared to control 23.1kg.

Table (2) The effect of different concentrations of natural products formulations and fungicide on incidence of early blight disease on tomato fruits tested under natural infection (fife count, season2017 – 2018).

No significant differences between means with the same letter(s) within column at P= 0.05

Table (3) The effect of different concentrations of natural products formulations and fungicide on total weight of tomato fruits tested under natural infection after four harvests(first season 2017 – 2018)

No significant differences between means with the same letter(s) within column at P= 0.05

Recommendations

Based on the promising results obtained from application of natural product in addition to their safety the following investigations were recommended:-

• More research and investigation should be carried out to find the actual role of natural products on plants in relation to this early blight disease and other diseases.
• More emphasis on by-products is required particularly (Neem, Argall, Usher, and Mesquite) and others to find out the correlation between natural products and diseases control.

Discussion

The problem of the early blight disease control in tomato was seemed to be complicated by controversy around the geographical distribution and seasonal occurrence of the species of the genus Alternaria causing early blight in tomato (Giha, 1973: Pandeyet. al., 2003 and Reni and Roeland, 2006).Based on the foregoing, the rational of this study focused on the identity of the pathogen, prevalence of the fungus, quantification of losses caused by early blight disease and assessment of different components for management of the disease in order to develop an integrated disease control strategy.

However, although the use of chemicals has helped increase of yields obtained (Ali, 1996), but the worldwide trend towards environmentally-safe methods of plant diseases control have initiated the exploration of safe alternate products. However, Plants-derived compounds (photochemical) have been attracting much interest as natural alternatives to synthetic compounds.

In response to this, biofungicide or natural products emerged as promising alternatives in an attempt to modify this condition where some alternative methods of control have been adopted. This included, biofungicide or natural products which emerged as alternatives, e.g. Biological agents, Neem, Garlic, and few other plants proved to inhibit Early Blight in tomato and other plants diseases (Schmutterer, 2002; Prasad and Naik, 2003; Adandononet al., 2006 and Anjorinet. al., 2010)

Obviously, no single approach for Early blight disease control was proved to be effective and without drawback. Therefore, integrated management strategies are the only solution to maintain plant health.

Generally, the results of the experiments set up to determine the effect of different concentrations of natural products formulations and fungicide on total weight of tomato fruits under natural infection in this study revealed that all treatments (natural products and fungicide) have had positive effect in controlling early blight disease of tomato plant but their effects were variable. The variable effects of natural products and Apron  star 42 were also clearly observed on the different parts of the plants where the effects on the leaves were considerably higher as compared with those of the fruits. However, the most pronouncing effects on disease incidence were given by the natural products (Argall powder, Neem oil) and fungicide Seed star 42.

By far, the Argall powder at sowing time and Neem oil were the most predominant treatments among natural products. Results showed its highest significant antifungal activity against Alternaria alternata compared with other treatments this positive effect of the two components was observed on the different parts of the tomato crop. Similar results of Argel and Neem were also reported by Rous et al., (1980), Elhadiet, al., (1994), Abdel Moniem E. et, al., (2009). Likewise, results obtained, agreed that the treatment of tomato plants with Neem aqueous extracts reduced the percentage of Fusarium wilt disease incidence to the level of 25.5% and 27.8% after 6 weeks of infection respectively. Moreover, the promising effect of Neem products in controlling plant disease were also demonstrated by Schmutterer, (2002); Prasad and Naik, (2003); Adandononet, al., (2006) and Anjorinet. al., (2010)who reported the inhibitory effect of Neem as biofungicide.  Nevertheless, the results of testing natural products showed that there was increase in disease incidence and loss in yield with successive counts.

However, based on the results of this study, the minor insignificant difference between, natural products treatments (Argel and Neem oil) in controlling early blight disease in tomato plant, and chemical control (fungicide), in addition to the public attitude and environmental concerns towards the use of synthetic pesticides as well as the development of early blight disease strains resistant to different fungicides could reduce the appeal of chemicals and lead to the search of alternatively safe control methods.

Conclusions

1-Among all natural products and fungicide tested for controlling early blight disease in tomato, Argel and Neem products plus fungicide proved to be very effective in reducing the incidence of the disease.

2-The results indicated that the minor insignificant difference between natural products treatments (Argel and Neem oil) in controlling early blight disease in tomato in addition to environmental concerns and human health towards the use of synthetic pesticides could reduce the appeal of chemicals and lead to the search of alternatively safe control methods.

Reference

1- Abdel Moneim, E.; Wigdan, M.; Elzobair and Awad M. Abdelrahim, (2009).Antimicrobial activity of the Extract of Solenostemmaargel (Harjal) Plant.J.Sc.TechVol. 10(3). 2009.

2- Adandonon, T.A.; Aveling S.; Labuschagne N. and Tamo M. (2006).Biocontrol agents in combination with Moringaoleifera extract for integrated control of Sclerotium-caused cowpea damping-off and stem rot. European Journal of Plant Pathology 2006.

3- Ali, M. E. K. (1996). A review of wilt and root –rot diseases of food legumes. In production and important of cool-season food legumes. In the Sudan proceedings of the National Research Review workshop, (S.H Salih, O.A.A.Ageeb, M.C.Saxena, M.B.Soih, ed), Agricultural Research Corporation, Sudan /international Center for Agricultural Research in the Dry Areas, Syria/ Directorate General for international Cooperation, the Netherlands, 153-168.

      4- Anderson, S. (2005). Spread of the introduced tree species Prosopisjuliflora (SW) DC in the lake Barings area. Kenya, institution for Skoglif Vegetation Kologi, SLU (Swedish Agricultural University): UMEA, Sweden.

      5- Anjorin, T. S.;  Ikokoh, P. and Okolo, S. (2010). Mineral composition of Moringaoleifera leaves, pods and seeds from two regions in Abuja, Nigeria. Int. J. Agric. Biol., 12:431–434.

       6- Babiker, A. G. (2006). Mesquite (Prosopis spp.) in Sudan: history, distribution and control. In: Labrada R (ed.) Problems Posed by the Introduction of Prosopis spp. in Selected Countries. Plant Production and Protection Division, Food and Agricultural Organization of the United Nations  Rome, pp 11-2

       7- Bose, T. K. and Som, M.G. (1986). Vegetable Crops in India: Nayaprakash Publishing, Calcutta, PP.773.

      8- Brandoo, Filho.Jut.;Brinholi, O.; Bastos,and Andrade, J. M. (1996).Control of early blight (A.S) In potato (Solanum tuberosum L.) with fungicide  in irrigation system and conventional  spraying. Revista.UNIMAR.  18(3) 476-745.

       9- Broun, A. F. And Massey, R. E. (1929) Flora of the Sudan: Thomas Murby and CO., p 376

      10- Burkart, A.(1976) A monograph of the genus Prosopis (Leguminosaesubfam.Mimosoideae). Journal of the Arnold Arboretum 57:217-225

       11- Elhadi, F.K. A.; Hegazy, A. G.; Ata, N. and Enabawy, M.L. (1994).Studies for determining antimicrobial activity of Solenostemma argall. Science J., 14: 138-145.

      12- Ellis, M. B. (1971).Dematiaceoushyphomycetes. Common Wealth Mycological Institute, kew, surrey, England, PP 608.

       13- FAO, (2006). http://faostat.fao.org. Accessed 05/04/2008.

      14- FAOSTAT, (2018).Food and Agricultural Organization of the United Nations, statistic division on line available at http://faostat3 fao.org.

      15- Felker, P.; Grados, N.; Cruz, G. and Prokopiuk, D. (2003). Economic assessment of flour from Prosopisalba and P. pallida pods for human food applications. Journal of Arid Environment, 53:517-528

     16- Giha, O. H. (1973). Distribution and morphology of Alternaria tenuis associated with leaf spots in the Sudan. The British Mycological Society Transaction, 61: 2, pp 265-275.

     17- Hansen,M.A. (2000).Early Blight of tomatoes. Publication number: 50-708.

          18-  Horii, A.; Mccve, P. & Shetty, k. (2007). Enhancement of seed vigor following insecticide and phenol elector treatment.Bioresourse Technology 89:623-632.

   19- Joly, P. (1959).Morphological variations and the idea of species in the genus alterations. Bull. Soc. Mycol.FR., 75:149-158.

   20-   Jones, P.S.; lay, S.V.; Morgan, E.D.andSantafianos, D. (1989).The chemistry of Boca Raton.  C.R.C press 79-45.

  21- Neergard, P (1945). Danish species of Alternaria and Stemphylium Taxonomy, Parasitism, Economic significance.Einarmunksgaard, Copenhagen.

  22- Okigbo, R.N. and Ogbonnaya (2006).Antifungal effects of two tropical plantleafextracts, Ocimum gratissimumandAframomummelegueta), on post harvest yam (Dioscoreaspp) rot. African Journal of biotechnology, 5:727-731.

   23-Pandey, K. K.; Pandey, P. K.; Kalloo, G. and Banerjee, M. K. (2003).Resistance to early   blight of tomato with respect to various parameters of disease epidemics. Journal of General   Plant Pathology, 69: 364-371.

    24- Papadopoulos, A.P. (1991). Growing Greenhouse Tomatoes in Soil and in Soilless Media. Agriculture   Canada   Publication   186/E,   Communications   Branch,   Agriculture Canada, Ottawa, Canada.

   25- Pasiecznik, N. (1999). Prosopis, pest or providence, weed or wonder Tree? European tropical forest Research Network newsletter 28: 12-14.

   26- Pasiecznik, N. P.; Felker, P.J. C. and Harris (2001) . The Prosopisjuliflora, Prosopis pallid complex: A monograph.HDRA, convent, UK.

    27-    Paul, Grow.(2000). Definition of tomato early blight, seen via net.

   28-  Peralta, I.E.; Knapp, S. and Spooner, D.M. (2005).New species of wild tomatoes (Sola, in I life, R.(2005). Collecting and recording fungi. British Mycological Society Recording Network (BMSRN). Section Lycopersicon: Solanaceae) from Northern Peru”.Sys.Bot., 30, 424-434, (2005).

   29-  Prasad, Y. and Naik, M. (2003). Evaluation of genotype, fungicides and plant extracts against early blight of tomato caused by Alternaria alternata. Indian Journal of plant Protection, 31: 49-53.

   30-  Reni, C. and Roeland E., (2006). Tomato early blight (Alternaria alternata) the pathogen, genetics, and breeding for resistance. Journal of General Plant Pathology, 72 (6): 335-347.

  31- Roos, S. A.; Medgalla, S. E.; Dishay, D. W. and Awad, A. H. (1980). Studies for determining antibiotic substances in some Egyptian plants: Screening for antimicrobial activities. Fitoterapia, 5: 303-308.

  32- Rotem J. 1994. The Genus Alternaria; Biology, Epidemiology and Pathogen city .American Phytopathological Society Press, St. Paul, Minnesota, 326 pp.

  33-    Ruskin, F. R. (1991). Neem, a tree for solving global problem. Report of an ADHOC panel of the Barrdon Science and Technology for International Development, National research Council,4:6082.

  34-  Sadana, D. and Didwania, N. (2015). Bio efficacy of fungicides and plant extracts against Alternaria alternata causing early blight of Tomato. International conference on plant, Marine and Environmental Sciences (PMES, – 2015) . Kuala Lumpur (Malaysia). Pp. 38 – 42.

 35- Saha, P. and Das, S. (2012). Assessment of yield loss due to early blight (Alternaria alternata) of tomato .Indian Journal of Plant Protection. 40(3): 195-198.

   36-   Schumtterer, H. (2002).The Neem tree: source of unique natural product for integrated pest management medicine, industry and other purpose. (Hardcover) 2^nd Edition, Weinheim, Germany: VCH verlagsgesllschaft. ISBN3-527-200546.

    37-  Sidahmed,O.A. A.(2005).Field control of the white scale insect, Palatoriablanchardii (Targ) (Homoptera ; Diaspididae) with aqueous extracts of Argel (Solenostemma argall ) (Del.) Hayne. M .Sc. Thesis, Sudan University of Science and Technology.

   38-   Singh, R.S.(1987).Diseases of vegetable crops. Oxford and IBH Pub .Co.Pvt. Ltd, New Delhi, Bombay, Calcutta. PP. 419.

   39-   Walke , J. C. (1952). Disease of vegetable crops 1st Edition. MC Grow Hill Book Company, Inc. Pp529.