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Fig. 1. Polyphasic approach to differentiate the six Meloidogyne species known to infect olive trees. The analysis combines the use of maximum parsimony (MP) analysis of internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA), esterase (Est.) phenotypes compared to that of M. javanica, and perineal patterns (PP) (see Table 1 for further details). DNA sequences were not available for M. lusitanica. P. penetrans and P. vulnus can be differ- entiated by phylogenetic analysis of se- quences of the D2-D3 expansion regions of 28S rRNA and 18S rRNA (92) as well as several differential morphological traits (20) such as (i) rounded spermatheca, post- vulval uterine sac 1 to 1.5 vulval body diameter long, and subcylindrical female tail in P penetrans, compared with (ii) oval spermatheca, postvulval uterine sac 2 vulval body diameter long, and conoid These nematodes are characterized by a cyst stage that allows them to survive in soil for several years in the absence of a The large populations of H. mediterra- nea found in orchard soils as well as the anatomical alterations in infected olive roots suggest that parasitism by this nema- tode may contribute to decline of olive seedlings in new plantations or olive nurs- eries (19,21). Although olive trees infected by H. mediterranea do not show any

Figure 1 Polyphasic approach to differentiate the six Meloidogyne species known to infect olive trees. The analysis combines the use of maximum parsimony (MP) analysis of internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA), esterase (Est.) phenotypes compared to that of M. javanica, and perineal patterns (PP) (see Table 1 for further details). DNA sequences were not available for M. lusitanica. P. penetrans and P. vulnus can be differ- entiated by phylogenetic analysis of se- quences of the D2-D3 expansion regions of 28S rRNA and 18S rRNA (92) as well as several differential morphological traits (20) such as (i) rounded spermatheca, post- vulval uterine sac 1 to 1.5 vulval body diameter long, and subcylindrical female tail in P penetrans, compared with (ii) oval spermatheca, postvulval uterine sac 2 vulval body diameter long, and conoid These nematodes are characterized by a cyst stage that allows them to survive in soil for several years in the absence of a The large populations of H. mediterra- nea found in orchard soils as well as the anatomical alterations in infected olive roots suggest that parasitism by this nema- tode may contribute to decline of olive seedlings in new plantations or olive nurs- eries (19,21). Although olive trees infected by H. mediterranea do not show any

Related Figures (20)

Importance of Olives and Their Associated Nematodes olive varieties are cultivated for oil extrac- tion. Olive oil has many favorable nutri- tional properties; as a result, consumption of olive oil is increasing worldwide, ex- tending the consumption area from the traditional one in the Mediterranean Basin (i.e., 77% of the world production area) to Australia, Canada, Japan, and the United States. Some olive varieties are specifically cultivated for direct consumption as table olives. crease yields while reducing the time for investment recovery. This model, broadly adopted in new olive-producing areas of the Southern Hemisphere and the Mediter- ranean Basin, creates an environment con- ducive to diseases caused by or involving nematodes. In Argentina, for example, Meloidogyne javanica (Treub, 1885) Chit- wood, 1949 was one of the main pathogens associated with a high incidence of “drying syndrome” in newly established olive or- chards (75). Similarly, estimates of olive losses in the United States due to Meloi- dogyne spp. and T. semipenetrans ranged from 5 to 10% (44). Nematode damage to olive is particularly evident in nurseries, where optimum irrigation practices favor root proliferation and increased nematode population growth that subsequently im- pacts adult trees (29,70). Olive trees (Olea europaea (L.) subsp. europaea (L.)) were among the first fruit trees cultivated and are among the most ancient crops in the Mediterranean Basin (103). Cultivated olive trees can be distin- guished from their wild relatives by larger fruits and higher oil content of the fleshy oil-containing mesocarp. The edible oil and fruit products of cultivated olive trees are prized worldwide. Botanical studies of pollen grains, stones, and wood from ar- chaeological contexts indicate that the East Mediterranean (Israel) was the first area in which olive was domesticated (54). In the Mediterranean Basin, olive constitutes a complex of wild forms, weedy types, and cultivated varieties. Wild oleasters (Olea europaea (L.) subsp. sylvestris (Brot.)) occupy primary niches and occur in dis- turbed areas and in areas of abandoned cultivation (33). Cultivated olive is also grown extensively in the subtropical re- gions of Australia, southern Africa, and North and South America. More than 80% of 8 million hectares of olive grown world- wide in 2007 were located in Mediterra- nean countries, including North Africa. An additional 17% occur in the Middle East (Iraq, Iran, Jordan, and Syria), and less than 2% are found in the Americas (Argen- tina, Chile, Mexico, Peru, and the United States) (34). Olive crops are one of the most important sources of edible oil, and Olive trees serve as hosts to a large number of plant-parasitic nematodes, of which root-knot nematodes (Meloidogyne spp.), root-lesion nematodes (Pratylenchus spp.), spiral nematodes (Helicotylenchus spp.), and Mesocriconema xenoplax (Raski) Loof & De Grisse, 1989 are widely distributed (Table 1) (2,42,51,65,70,74). Conversely, limited distribution on olive has been reported for the citrus (Tylenchu- lus semipenetrans Cobb, 1913) and the cyst-forming (Heterodera mediterranea Vovlas, Inserra & Stone, 1981) nematodes (19,21,59). Of the endoparasitic nematodes (including Meloidogyne, Pratylenchus, Tylenchulus, and Heterodera), many are recognized as pathogenic to olive. The effects of parasitism by some nematodes on plant growth and yield result from dis- ruption of the normal process of plant root growth and function (40). Water stress and nutrient deficiencies occur as the plant root system fails to adequately explore and exploit the soil due to plant parasitic nema- tode attacks. Damage to established olive orchards by nematode parasitism may not be clearly perceived because olive is an extremely vigorous plant able to thrive in relatively dry areas, which may obscure expression of symptoms from nematode attacks. However, modern olive production is based largely on the establishment of new high-input orchards intended to in- The accurate and timely identification of plant-parasitic nematodes infecting crops is a prerequisite for designing effective management strategies. This is particularly relevant for olive trees because of the di- versity of pathogenic nematode genera and species in several growing areas (Table 1). A reliable identification allows distinction between pathogenic and nonpathogenic nematodes and exclusion of species under quarantine or regulatory strategies. Identi- fication of most nematodes is based on morphology and morphometric traits of adult females (20,40), but the task is hin- dered by the need for experienced diagnos- ticians to assess the intraspecific variability of morphological traits. To illustrate this point, the main comparative diagnostic traits of Meloidogyne spp. attacking olives are summarized (Table 2). The last few years have seen the development of reli- able diagnostic methods based on nucleic acid analyses, which have significantly improved and facilitated the routine identi- Corresponding author: P. Castillo, Research Scien- tist, Institute of Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), P.O. Box 4084, 14080 Cordoba, Spain E-mail: pcastillo @ias.csic.es
Importance of Olives and Their Associated Nematodes olive varieties are cultivated for oil extrac- tion. Olive oil has many favorable nutri- tional properties; as a result, consumption of olive oil is increasing worldwide, ex- tending the consumption area from the traditional one in the Mediterranean Basin (i.e., 77% of the world production area) to Australia, Canada, Japan, and the United States. Some olive varieties are specifically cultivated for direct consumption as table olives. crease yields while reducing the time for investment recovery. This model, broadly adopted in new olive-producing areas of the Southern Hemisphere and the Mediter- ranean Basin, creates an environment con- ducive to diseases caused by or involving nematodes. In Argentina, for example, Meloidogyne javanica (Treub, 1885) Chit- wood, 1949 was one of the main pathogens associated with a high incidence of “drying syndrome” in newly established olive or- chards (75). Similarly, estimates of olive losses in the United States due to Meloi- dogyne spp. and T. semipenetrans ranged from 5 to 10% (44). Nematode damage to olive is particularly evident in nurseries, where optimum irrigation practices favor root proliferation and increased nematode population growth that subsequently im- pacts adult trees (29,70). Olive trees (Olea europaea (L.) subsp. europaea (L.)) were among the first fruit trees cultivated and are among the most ancient crops in the Mediterranean Basin (103). Cultivated olive trees can be distin- guished from their wild relatives by larger fruits and higher oil content of the fleshy oil-containing mesocarp. The edible oil and fruit products of cultivated olive trees are prized worldwide. Botanical studies of pollen grains, stones, and wood from ar- chaeological contexts indicate that the East Mediterranean (Israel) was the first area in which olive was domesticated (54). In the Mediterranean Basin, olive constitutes a complex of wild forms, weedy types, and cultivated varieties. Wild oleasters (Olea europaea (L.) subsp. sylvestris (Brot.)) occupy primary niches and occur in dis- turbed areas and in areas of abandoned cultivation (33). Cultivated olive is also grown extensively in the subtropical re- gions of Australia, southern Africa, and North and South America. More than 80% of 8 million hectares of olive grown world- wide in 2007 were located in Mediterra- nean countries, including North Africa. An additional 17% occur in the Middle East (Iraq, Iran, Jordan, and Syria), and less than 2% are found in the Americas (Argen- tina, Chile, Mexico, Peru, and the United States) (34). Olive crops are one of the most important sources of edible oil, and Olive trees serve as hosts to a large number of plant-parasitic nematodes, of which root-knot nematodes (Meloidogyne spp.), root-lesion nematodes (Pratylenchus spp.), spiral nematodes (Helicotylenchus spp.), and Mesocriconema xenoplax (Raski) Loof & De Grisse, 1989 are widely distributed (Table 1) (2,42,51,65,70,74). Conversely, limited distribution on olive has been reported for the citrus (Tylenchu- lus semipenetrans Cobb, 1913) and the cyst-forming (Heterodera mediterranea Vovlas, Inserra & Stone, 1981) nematodes (19,21,59). Of the endoparasitic nematodes (including Meloidogyne, Pratylenchus, Tylenchulus, and Heterodera), many are recognized as pathogenic to olive. The effects of parasitism by some nematodes on plant growth and yield result from dis- ruption of the normal process of plant root growth and function (40). Water stress and nutrient deficiencies occur as the plant root system fails to adequately explore and exploit the soil due to plant parasitic nema- tode attacks. Damage to established olive orchards by nematode parasitism may not be clearly perceived because olive is an extremely vigorous plant able to thrive in relatively dry areas, which may obscure expression of symptoms from nematode attacks. However, modern olive production is based largely on the establishment of new high-input orchards intended to in- The accurate and timely identification of plant-parasitic nematodes infecting crops is a prerequisite for designing effective management strategies. This is particularly relevant for olive trees because of the di- versity of pathogenic nematode genera and species in several growing areas (Table 1). A reliable identification allows distinction between pathogenic and nonpathogenic nematodes and exclusion of species under quarantine or regulatory strategies. Identi- fication of most nematodes is based on morphology and morphometric traits of adult females (20,40), but the task is hin- dered by the need for experienced diagnos- ticians to assess the intraspecific variability of morphological traits. To illustrate this point, the main comparative diagnostic traits of Meloidogyne spp. attacking olives are summarized (Table 2). The last few years have seen the development of reli- able diagnostic methods based on nucleic acid analyses, which have significantly improved and facilitated the routine identi- Corresponding author: P. Castillo, Research Scien- tist, Institute of Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), P.O. Box 4084, 14080 Cordoba, Spain E-mail: pcastillo @ias.csic.es
“ Data from the following references: 2,11,12,20—22,26,28,36,37,39,42,50,51,59,64,65,70,73,74,79,80,93,95,96. Table 1. Plant-parasitic nematodes associated with olive trees*
“ Data from the following references: 2,11,12,20—22,26,28,36,37,39,42,50,51,59,64,65,70,73,74,79,80,93,95,96. Table 1. Plant-parasitic nematodes associated with olive trees*
Root-knot nematodes, Meloidogyne spp., are among the most damaging plant pathogens worldwide (40). Meloidogyne species known to damage olive trees are well adapted to temperate and subtropical areas and include Meloidogyne arenaria (Neal, 1889) Chitwood, 1949; Meloi- dogyne baetica Castillo, Vovlas, Subbotin interactions that occur between some nematodes and Verticillium wilt of olive caused by the soilborne fungus Verticillium dahliae Kleb. Finally, we propose effective measures for nematode management in olive nurseries, which are of paramount
Root-knot nematodes, Meloidogyne spp., are among the most damaging plant pathogens worldwide (40). Meloidogyne species known to damage olive trees are well adapted to temperate and subtropical areas and include Meloidogyne arenaria (Neal, 1889) Chitwood, 1949; Meloi- dogyne baetica Castillo, Vovlas, Subbotin interactions that occur between some nematodes and Verticillium wilt of olive caused by the soilborne fungus Verticillium dahliae Kleb. Finally, we propose effective measures for nematode management in olive nurseries, which are of paramount
@ All measurements are in micrometers unless otherwise stated. b EP/ST = excretory pore to female anterior end/female stylet length. ° Isozyme phenotypes used are defined by Esbenshade and Triantaphyllou (32). Table 2. Differential morphological traits among Meloidogyne species infecting olive trees*
@ All measurements are in micrometers unless otherwise stated. b EP/ST = excretory pore to female anterior end/female stylet length. ° Isozyme phenotypes used are defined by Esbenshade and Triantaphyllou (32). Table 2. Differential morphological traits among Meloidogyne species infecting olive trees*
Fig. 2. A, Olive root system severely infected with root-knot nematodes; note small galls. B, Root galls caused by Meloidogyne javanica. C, Details of adult Meloidogyne incognita female (N) and egg mass (em). D and E, Details of typical galled olive root tip due to infec- tion by Meloidogyne spp. F, Detail of Meloidogyne spp. egg mass stained with phloxine B. ectoparasitic nematodes attack olive: the citrus biotype of the citrus nematode Ty- lenchulus semipenetrans infects olive trees in California, Chile, and Italy (52,59); Gracilacus peratica (Fig. 10) and Ogma rhombosquamatum (Mehta & Raski, 1971) Andrassy, 1979 were observed feeding on olive roots (280 to 360 nematodes/g fresh
Fig. 2. A, Olive root system severely infected with root-knot nematodes; note small galls. B, Root galls caused by Meloidogyne javanica. C, Details of adult Meloidogyne incognita female (N) and egg mass (em). D and E, Details of typical galled olive root tip due to infec- tion by Meloidogyne spp. F, Detail of Meloidogyne spp. egg mass stained with phloxine B. ectoparasitic nematodes attack olive: the citrus biotype of the citrus nematode Ty- lenchulus semipenetrans infects olive trees in California, Chile, and Italy (52,59); Gracilacus peratica (Fig. 10) and Ogma rhombosquamatum (Mehta & Raski, 1971) Andrassy, 1979 were observed feeding on olive roots (280 to 360 nematodes/g fresh
Fig. 3. Cross section of a young olive root (cv. Arbequina) infected by Meloidogyne arenaria. A, Detail of the lip region of an adult female (N) showing the stylet (st), me- dian bulb (mb), and induced giant cells (gc) with hypertrophied nuclei (hn). B, Detail of a feeding site showing xylem (xy) and giant cells with hypertrophied nuclei.
Fig. 3. Cross section of a young olive root (cv. Arbequina) infected by Meloidogyne arenaria. A, Detail of the lip region of an adult female (N) showing the stylet (st), me- dian bulb (mb), and induced giant cells (gc) with hypertrophied nuclei (hn). B, Detail of a feeding site showing xylem (xy) and giant cells with hypertrophied nuclei.
Fig. 4. Aboveground symptoms of olive plant cv. Arbequina infected by Meloi- dogyne arenaria (right) showing a dis- tinct yellowing in uppermost leaves. Uninoculated control to the left. Xiphinema and Longidorus nematodes cause damage to olive by feeding on un- modified plant root cells. However, some species are also capable of transmitting viruses, leading to diseases in a wide range of fruit and vegetable crops (58). Olive is reported as a natural host of nepoviruses
Fig. 4. Aboveground symptoms of olive plant cv. Arbequina infected by Meloi- dogyne arenaria (right) showing a dis- tinct yellowing in uppermost leaves. Uninoculated control to the left. Xiphinema and Longidorus nematodes cause damage to olive by feeding on un- modified plant root cells. However, some species are also capable of transmitting viruses, leading to diseases in a wide range of fruit and vegetable crops (58). Olive is reported as a natural host of nepoviruses
Fig. 5. Relationships between relative shoot length olive cv. FS 17 and rootstock DA 12 | and initial population density (Pi) of Meloidogyne javanica. Abbreviations: m = mini- mum value of relative shoot length (relative length at very large Pi values; T = toler- ance limit.
Fig. 5. Relationships between relative shoot length olive cv. FS 17 and rootstock DA 12 | and initial population density (Pi) of Meloidogyne javanica. Abbreviations: m = mini- mum value of relative shoot length (relative length at very large Pi values; T = toler- ance limit.
Fig. 6. Micrographs of the root-lesion nematode Pratylenchus vulnus. A, Whole body of female and male. B, Female anterior region showing stylet (st), dorsal pharyngeal gland outlet (dgo), and excretory pore (pe). C, Detail of lip region. D, Female vulval region showing postvulval uterine sac (PUS). E and F, Female tails. G, Male tail. (Scale bars: A = 100 pm; B to G = 10 to pm) Soil disinfestation with fumigants prior to planting is a nematode control strategy broadly used in some fruit crops. For par- ticular crops, soil disinfestation may even The list of NFNs includes a series of or- ganophosphate and carbamate products that display a certain degree of insecticidal and acaricidal effects as well. In Spain, the official list of authorized NFNs pesticides includes ethoprophos, fosthiazate, fenami- phos, and oxamyl, but none are registered for use in olive (61). A similar situation, in which a certain number of specific nemati- cides are registered but none of them for
Fig. 6. Micrographs of the root-lesion nematode Pratylenchus vulnus. A, Whole body of female and male. B, Female anterior region showing stylet (st), dorsal pharyngeal gland outlet (dgo), and excretory pore (pe). C, Detail of lip region. D, Female vulval region showing postvulval uterine sac (PUS). E and F, Female tails. G, Male tail. (Scale bars: A = 100 pm; B to G = 10 to pm) Soil disinfestation with fumigants prior to planting is a nematode control strategy broadly used in some fruit crops. For par- ticular crops, soil disinfestation may even The list of NFNs includes a series of or- ganophosphate and carbamate products that display a certain degree of insecticidal and acaricidal effects as well. In Spain, the official list of authorized NFNs pesticides includes ethoprophos, fosthiazate, fenami- phos, and oxamyl, but none are registered for use in olive (61). A similar situation, in which a certain number of specific nemati- cides are registered but none of them for
Fig. 7. Natural infections of olive trees cv. Manzanilla by Heterodera mediterranea. A to C, Partially embedded second- (Jz) and third/fourth- (J3.4) stage juveniles and young cyst (arrow) in young olive roots. D, A mature female showing large gelatinous matrix with eggs. E and F, Cross sections of olive roots infected by H. mediterranea, showing a syncytium involving endodermal and pericycle cells (deeper stain). G, Magnification of a stelar syncytium showing fused syncytial cells and stelar distortion due to their expansion.
Fig. 7. Natural infections of olive trees cv. Manzanilla by Heterodera mediterranea. A to C, Partially embedded second- (Jz) and third/fourth- (J3.4) stage juveniles and young cyst (arrow) in young olive roots. D, A mature female showing large gelatinous matrix with eggs. E and F, Cross sections of olive roots infected by H. mediterranea, showing a syncytium involving endodermal and pericycle cells (deeper stain). G, Magnification of a stelar syncytium showing fused syncytial cells and stelar distortion due to their expansion.
Fig. 8. Cumulative egg hatch of Heterodera mediterranea incubated at 20°C in olive root exudates for 22 days. Abbreviations: SDDW = sterile deionized distilled water; P- Un = undiluted root exudates from olive planting stock cv. Picual; P-1:1, P-1:2 = root exudates from olive planting stock cv. Picual diluted, respectively, 1:1 or 1:2 with SDDW; Ar-Un = undiluted root exudates from olive planting stock cv. Arbequina; Ar-1:1, Ar-1:2 = root exudates from olive planting stock cv. Arbequina diluted, respectively, 1:1 or 1:2 with SDDW.
Fig. 8. Cumulative egg hatch of Heterodera mediterranea incubated at 20°C in olive root exudates for 22 days. Abbreviations: SDDW = sterile deionized distilled water; P- Un = undiluted root exudates from olive planting stock cv. Picual; P-1:1, P-1:2 = root exudates from olive planting stock cv. Picual diluted, respectively, 1:1 or 1:2 with SDDW; Ar-Un = undiluted root exudates from olive planting stock cv. Arbequina; Ar-1:1, Ar-1:2 = root exudates from olive planting stock cv. Arbequina diluted, respectively, 1:1 or 1:2 with SDDW.
Fig. 9. Reniform nematodes infecting olive trees. A to E, Rotylenchulus macrosoma. A, Micrograph of whole body of female. B, Nematode female attached to a root of wild olive. C to E, Cross sections of olive roots infected by R. macrosoma showing feeding cells (fc) and the stelar syncytium (S) with hypertrophied nuclei (hn), stelar distortion and compressed xylem elements (xy). F to I, Rotylenchulus macrodoratus. F, Micrograph of whole body of female. G, Scanning electron micrograph of a nematode female parasi- tizing an olive root (v = vulva). H, Detail of vulval region showing an egg outside. I, Cross section of an olive root showing enlarged uninucleate stelar or cortical “nurse cell” (gc).
Fig. 9. Reniform nematodes infecting olive trees. A to E, Rotylenchulus macrosoma. A, Micrograph of whole body of female. B, Nematode female attached to a root of wild olive. C to E, Cross sections of olive roots infected by R. macrosoma showing feeding cells (fc) and the stelar syncytium (S) with hypertrophied nuclei (hn), stelar distortion and compressed xylem elements (xy). F to I, Rotylenchulus macrodoratus. F, Micrograph of whole body of female. G, Scanning electron micrograph of a nematode female parasi- tizing an olive root (v = vulva). H, Detail of vulval region showing an egg outside. I, Cross section of an olive root showing enlarged uninucleate stelar or cortical “nurse cell” (gc).
Fig. 10. A, Colonies of mature females (N) of Gracilacus peratica (red-stained with acid fuchsin) infecting olive (cv. Coratina) feeder roots. B, Cross section of an olive feeder root showing the feeding tube in a nematode-infected cortical cell (arrow).
Fig. 10. A, Colonies of mature females (N) of Gracilacus peratica (red-stained with acid fuchsin) infecting olive (cv. Coratina) feeder roots. B, Cross section of an olive feeder root showing the feeding tube in a nematode-infected cortical cell (arrow).
Fig. 12. Conical piles of soil 80 cm high and with a base diameter of 1 m solarized for 3 weeks in July at Cordoba, southern Spain, for disinfestation from Meloidogyne incog- nita eggs and Jz placed in nylon bags at a depth of 20 and 40 cm inside a pile. Fig. 11. A, Micrograph of female whole body of Helicotylenchus oleae. B to F, Cross sections of olive roots infected by H. oleae. B and E, Details of a coiled nematode specimen (N) in the root cortex (CO). C, D, and F, Details of the lip regions of H. oleae (N) penetrating cell walls in the cortex of olive feeder roots (st = stylet; hn = hypertrophic cell nucleus).
Fig. 12. Conical piles of soil 80 cm high and with a base diameter of 1 m solarized for 3 weeks in July at Cordoba, southern Spain, for disinfestation from Meloidogyne incog- nita eggs and Jz placed in nylon bags at a depth of 20 and 40 cm inside a pile. Fig. 11. A, Micrograph of female whole body of Helicotylenchus oleae. B to F, Cross sections of olive roots infected by H. oleae. B and E, Details of a coiled nematode specimen (N) in the root cortex (CO). C, D, and F, Details of the lip regions of H. oleae (N) penetrating cell walls in the cortex of olive feeder roots (st = stylet; hn = hypertrophic cell nucleus).
Fig. 13. Relationship between final nematode population of Meloidogyne incognita race 1 on olive planting stocks cv. Picual and the rate of dry cork compost amending a potting mixture (0, 25, 50, 75, and 100%). Each point rep- resents the average of two trials. Lines represent the predicted function calcu- lated by fitting the expanded negative exponential model to data.
Fig. 13. Relationship between final nematode population of Meloidogyne incognita race 1 on olive planting stocks cv. Picual and the rate of dry cork compost amending a potting mixture (0, 25, 50, 75, and 100%). Each point rep- resents the average of two trials. Lines represent the predicted function calcu- lated by fitting the expanded negative exponential model to data.
Fig. 14. View of an olive orchard in southern Spain showing different crucifer species used as cover vegetation for preventing soil erosion, improving soil structure and fertility, increasing water infiltration, and reducing surface runoff. The removal of many nematicides from the market due to environmental and hu- Miscellaneous. Covering orchard soil with permanent vegetation is becoming one of the most commonly used orchard management systems for preventing soil erosion, improving soil structure and fertil- ity, increasing water infiltration, and reduc- ing surface runoff (16,35). Plant covers are usually natural flora, and their species composition is therefore fortuitous. How- ever, orchard soil can also be covered with specifically selected crop species (24) or the natural flora can be managed by use of adequate herbicide treatment (81). Some plant species used as cover crops or exist- M. incognita and R. reniformis (4). Culti- vars Meashon and Tofany were found to be resistant to M. incognita but moderately susceptible to R. reniformis, while culti- vars Manzanillo and Egazi were moder- ately susceptible to M. incognita but toler- ant of R. reniformis, and cultivars Hamed and Bekwal were susceptible to both nematode species (4). Similarly, screening of olive cultivars most commonly used in Italy for resistance against root-knot nema- todes showed that cultivar Coratina is re- sistant to M. incognita and M. javanica, whereas cultivars Leccino and Yusti are resistant to M. javanica and moderately susceptible to M. incognita (86). Other cultivars (Cima di Bitonto, Cellina di Nardo, Frantoio, and FS 17) were shown to be moderately susceptible to M. incog- nita (86), whereas the rootstock DA 12 1
Fig. 14. View of an olive orchard in southern Spain showing different crucifer species used as cover vegetation for preventing soil erosion, improving soil structure and fertility, increasing water infiltration, and reducing surface runoff. The removal of many nematicides from the market due to environmental and hu- Miscellaneous. Covering orchard soil with permanent vegetation is becoming one of the most commonly used orchard management systems for preventing soil erosion, improving soil structure and fertil- ity, increasing water infiltration, and reduc- ing surface runoff (16,35). Plant covers are usually natural flora, and their species composition is therefore fortuitous. How- ever, orchard soil can also be covered with specifically selected crop species (24) or the natural flora can be managed by use of adequate herbicide treatment (81). Some plant species used as cover crops or exist- M. incognita and R. reniformis (4). Culti- vars Meashon and Tofany were found to be resistant to M. incognita but moderately susceptible to R. reniformis, while culti- vars Manzanillo and Egazi were moder- ately susceptible to M. incognita but toler- ant of R. reniformis, and cultivars Hamed and Bekwal were susceptible to both nematode species (4). Similarly, screening of olive cultivars most commonly used in Italy for resistance against root-knot nema- todes showed that cultivar Coratina is re- sistant to M. incognita and M. javanica, whereas cultivars Leccino and Yusti are resistant to M. javanica and moderately susceptible to M. incognita (86). Other cultivars (Cima di Bitonto, Cellina di Nardo, Frantoio, and FS 17) were shown to be moderately susceptible to M. incog- nita (86), whereas the rootstock DA 12 1
Fig. 15. Effects of in vitro treatment of Pratylenchus vulnus specimens with hot water at 25 to 55°C for 1 to 15 min. A, Percent mortality after treatment over time. B, Relationship between nematode mortality (%) and time of exposure at 40 and 45°C.
Fig. 15. Effects of in vitro treatment of Pratylenchus vulnus specimens with hot water at 25 to 55°C for 1 to 15 min. A, Percent mortality after treatment over time. B, Relationship between nematode mortality (%) and time of exposure at 40 and 45°C.
Dr. Castillo is a research scientist of nematology at the Institute of Sustainable Agriculture of the Spanish National Research Council at Cordoba, southern Spain. He received his B.S. (1984) and Ph.D. (1988) from University of Granada (Spain). His research focuses primarily on plant-nematode and nematode-—soilborne fungi interactions, as well as diagnosis of nematode dis- eases, host-parasite relationships, and nematode control by means of strategies compatible with sustainable agri- culture. He has contributed to plant nematology with numerous research articles, and he recently coauthored two comprehensive books on the spiral nematode genus Rotylenchus and the root-lesion nematode genus Pratylenchus. neering and a Ph.D. degree in plant pathology from the University of Cordoba in 1995 and 1999, respectively. She was a postdoctoral Fulbright scholar at the USDA- ARS, Washington State University, Pullman, USA in 2000 and 2001, and research scientist and assistant professor at the University of Cordoba from 2002 to 2007. Her research activity focuses on population biology of soil- borne plant pathogens and rhizosphere biocontrol agents, defining the biogeography, genetic diversity, biology, and ecology of phytopathogenic fungi, plant parasitic nema- todes, and plant-associated rhizosphere bacteria with potential as biocontrol agents.
Dr. Castillo is a research scientist of nematology at the Institute of Sustainable Agriculture of the Spanish National Research Council at Cordoba, southern Spain. He received his B.S. (1984) and Ph.D. (1988) from University of Granada (Spain). His research focuses primarily on plant-nematode and nematode-—soilborne fungi interactions, as well as diagnosis of nematode dis- eases, host-parasite relationships, and nematode control by means of strategies compatible with sustainable agri- culture. He has contributed to plant nematology with numerous research articles, and he recently coauthored two comprehensive books on the spiral nematode genus Rotylenchus and the root-lesion nematode genus Pratylenchus. neering and a Ph.D. degree in plant pathology from the University of Cordoba in 1995 and 1999, respectively. She was a postdoctoral Fulbright scholar at the USDA- ARS, Washington State University, Pullman, USA in 2000 and 2001, and research scientist and assistant professor at the University of Cordoba from 2002 to 2007. Her research activity focuses on population biology of soil- borne plant pathogens and rhizosphere biocontrol agents, defining the biogeography, genetic diversity, biology, and ecology of phytopathogenic fungi, plant parasitic nema- todes, and plant-associated rhizosphere bacteria with potential as biocontrol agents.
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MicrobiologyPlant BiologyOlive Tree
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