Plant Parasitic Nematodes Associated with Citrus Trees and Reaction of Two Citrus Cultivars to Tylenchulus semipenetrans in Northern Egypt (original) (raw)
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AimsCitrus plants are hosts of numerous plant-parasitic nematodes (PPNs), which are microscopic organisms and hidden enemies for plants. Among the PPNs, the citrus root nematode, Tylenchulus semipenetrans, causes significant damage to citrus plantations in the world. Understanding the citrus nematode population, precise nematode identification, host preference among the citrus species, and damage threshold level are crucially important to control T. semipenetrans. Although some studies have been conducted, minutiae about citrus plant-nematode interactions, nematodes density, and molecular nematode identification have not been well understood. MethodsThis study aimed to reveal nematode identification using molecular and morphological methods, host-nematode interactions, host (citrus species) preference, damage of economic threshold (ET), and economic-injury level (EIL). Therefore, citrus plantations of different provinces located in the Mediterranean region of Turkey were investigate...
Managing nematodes in Egyptian citrus orchards
Bulletin of the National Research Centre
Backed by its Mediterranean climate, fertile soils, cheap labor, and geographic location, Egypt ranks high among citrus producer countries. These factors can collectively offer early fruiting and long harvest season, good quality, low production costs, and closeness of export markets. However, citrus trees are attacked by many plant-parasitic nematode species in Egypt and abroad; all but one, the citrus nematode Tylenchulus semipenetrans, of which are of limited distribution. Tylenchulus semipenetrans impacts the size and quality of citrus yields differently under various conditions, but guidelines have been published to help interpret soil sample results. Other species such as migratory endoparasites (lesion nematodes), sedentary endoparasites (root-knot nematodes), and several species of ectoparasitic nematodes (spiral and stunt nematodes) can damage citrus in Egypt. Yet, due to their limited distribution and very low population densities in citrus orchards, their damaging level i...
PATHOGENICITY OF CITRUS NEMATODE (TYLENCHULUS SEMIPENETRANS) ON CITRUS JAMBHIRI
Citrus nematode (Tylenchulus semipenetrans) causes severe damage to citrus. In the present study the relationship between different initial densities of T. semipenetrans and reduction in growth parameters of Citrus jambhiri and nematode infestations was examined in pot experiment under greenhouse conditions using completely randomized design. Seedlings of C. jambhiri were inoculated with T. semipenetrans at the rate of 0, 1,000, 2,000, 4,000 and 8,000 second stage juveniles/pot in the greenhouse. Data were collected on fresh and dry weights of the shoot and root, shoot length, nematode populations in the roots and soil and reproduction factor. All the data were subjected to analysis of variance and means were compared by Duncan's Multiple Range Test at 5%. The relationships between number of galls and growth variables and nematode infestations were determined using regression analysis. It was observed that all the inoculum densities caused reductions in growth parameters and were found directly proportional to the inoculum density. Similarly, a direct relationship was observed between root and soil populations of the nematode and inoculum levels. On the other hand, the nematode build up was the maximum at lower inoculum level and an inverse relationship was observed between reproduction factor and inoculum densities of the nematode.
Life
Plant-parasitic nematodes (PPNs) are found in citrus plantations throughout the world, but they are considered to be the most problematic pest in Morocco. Citrus fruit quality and yield have been adversely affected by PPNs. Due to data unavailability of nematodes associated with citrus, a detailed survey was conducted in the main citrus-growing regions of Morocco during 2020–2021 to assess the occurrence, distribution, and diversity of PPNs associated with rhizospheres of citrus trees. In addition, some soil properties have also been assessed for their impact on soil properties. Plant-parasitic nematode diversity was calculated using two ecological indexes, the Shannon diversity index (H′) and the Evenness index (E). The collected soil and root samples were analyzed, and eleven genera and ten species of plant-parasitic nematodes were identified. The results show that the most predominant PPN species were Tylenchulus semipenetrans (88%), Helicotylenchus spp. (75%), Pratylenchus spp. ...
2019
A systemic investigation was conducted on February, 2018 to assess the diversity and community structure of plant parasitic nematodes from the soil rhizosphere of ten different citrus species grown at Citrus Research Station, Tinsukia, Assam. Four major plant parasitic nematode species viz., Tylenchulus semipenetrans, Helicotylenchus dihystera, Hoplolaimus indicus and Tylenchorhynchus spp were found prevalent in the rhizosphere of ten different citrus species. In addition to these, several dorylaimid, rhabditid and predatory nematodes were also encountered. Amongst the plant parasitic nematodes, T. semipenetrans was highly abundant (100%) followed by H. dihystera (80%), Tylenchorhynchus spp. (70%) and H. indicus (50%). Among, different citrus species, a higher population of T. semipenetrans was encountered on rough lemon and least number was encountered on trifoliate orange.
2011
This study aimed to determine resistance level of some citrus cultivars to the citrus nematode (Tylenchulus semipenetrans Cobb). Number of T. semipenetrans female penetrated per cm root not significantly different on all citrus cultivar. Number T. semipenetrans female per cm root on all citrus cultivar was < 1 nematode per cm root. This fact showed that Citrus jambhiri, C. reticulate, C. aurantium, C. nobilis, C. medica, C. macrocarpa, and C. hystryx ABC showed resistant reaction on T. Semipenetrans.
This investigation was planned to check the association of plant parasitic nematodes with fruit trees. Both root and soil samples were collected from fruit trees grown in campus and field areas of University of Agriculture Faisalabad, Pakistan. The plant parasitic nematodes were isolated and then identified. Their number of juveniles in roots and soil samples were calculated. Population density and prevalence of all the nematodes isolated was also determined. Out of total 83 samples of fruit trees, root knot nematode (genus Meloidogyne) was observed in 59 samples, lesion nematode (genus Pratylenchus) in 39, spiral nematodes (genus Helicotylenchus) in 30 samples and reniform nematode (genus Rotylenchulus) in 15 samples of twelve different fruit trees. The prevalence of root knot nematode in apple, peach and olive and of dagger nematode (genus Xiphinema) in apple, grapes, peach, blueberries and olive was calculated100%. Population density of root knot nematode was found 100% in both root and soil samples of peach followed by Helicotylenchus with 61% and 65% population densities in root and soil samples of blueberry respectively.
The problems of citrus nematode (Ty/enchulus semipenetran$ C,.abb)in orchards and nurseries of mandarin orange in Darjee1ing hills have been studies during 1988 to 1991. This nematode could be isolated from the infested roo1s and rootzonesoil and the slow decline symptoms could be reproduced in orange through seedling soil inoculation. Citrus nematode occured in all the orchards swveyed but Its incidence differed with respect to the season of observation and physiological condition of the plan1s. The population was high during March-April and low during November-December under Darjee1ing condition. All the common citrus species tested excluding trifoliate orange (poncirus trifoliata) were found to be susceptible to this nematode. Infested seedlings have been found to be an important means of spread which could be controlled by treating the r001s with 200 ppm of thimet (10 g) or nemacur (10 g) for 30 minutes. Nematode population in an orchard may be reduced by applying furadan (3 g) or thimet at the rate of 100 g/tree twice in a year Growing annuals, particularly cabbage, cauliflower, aster, zinnia and marigold etc. in the orchards reduced the nematode population both on the feeder roo1s and in rootzone soil.
Plant Parasitic Nematodes: A Major Constraint in Fruit Production
Nematodes - Recent Advances, Management and New Perspectives, 2022
The plant parasitic nematodes are one of the major limiting factors in fruit trees specially in citrus, banana, papaya, jackfruit, guava etc. The root knot nematodes are the major problem amongst all those nematodes infecting on these trees. Besides, directly causing a huge losses, they are also inviting the secondary plant pathogens, like fungi, bacteria, viruses etc. amongst which, the wilt fungus, Fusarium species increase the severity of the diseases. This complex disease is becoming much severe in banana and guava recent years. In citrus also, the citrus nematodes, Tylenchulus semipenetrans, is causing havoc by slow decline disease and it is becoming a major problem in horticultural nurseries because these nurseries are a hot spot of citrus nematodes. So, unknowingly these nematodes get spread to different places. The management of these nematodes by simple, cheap and eco friendly methods, is very important as it will decrease the monetary pressure on cultivators as well as it ...