Potato Root Eelworm Research Articles

End-to-end somatic association of chromosomes in the potato root eel-worm

End-to-end somatic association of chromosomes in the potato root eel-worm

Field resistance to late blight and potato root eelworm in group tuberosum dihaploids

An examination of the feasibility of obtaining dihaploids with high levels of field resistance to important potato pathogens, showed that dihaploids may be produced which are more resistant to late blight or to potato root eelworm pathotype E than are their tetraploid parents. The significance of this is discussed in relation to the possible types of gene action involved in conferring field resistance.

The multiplication of three pathotypes of the potato root eelworm on different potato varieties

In two pot experiments the pathotypes, AB and ABCD ofHeterodera rostochiensis multiplied at lower rates on the potato variety ‘Libertas’ than pathotype A. Pathotype ABCD multiplied at the same rate on a variety resistant against pathotype A as pathotype A on ‘Libertas’. Pathotype AB multiplied at a lower rate on Libertas and a variety resistant against A than A on ‘Libertas’. In a third experiment with the pathotypes A and ABCD and five potato varieties susceptible to all pathotypes, two varieties resistant to A and AB and three resistant to A significant differences between the rate of reproduction of the same pathotype on different susceptible varieties were found. The rate of reproduction of the pathotype ABCD on the varieties tested tended to be slightly lower than that of pathotype A on varieties susceptible to that pathotype.

The Plant Protection Service in the Netherlands

AbstractA survey is given of the history, the tasks and the organization of the Plant Protection Service in the Netherlands. Its activities encompass two major fields, concerning phytosanitary and phytopharmaceutical aspects.In the phytosanitary field, a distinction can be made between long‐term and short‐term phytosanitary policy, depending on whether one has to deal with existing and established pests or diseases, or with a suddenly arising plant health problem. Two examples are given as illustrations, viz. the approach followed in designing new regulations for controlling potato root eelworm, and the campaign against the recent outbreak of fireblight.A further outline is given on the activities of the Plant Protection Service in the pesticides field, on the responsibilities of the different Ministries concerned, and on the basic elements of pesticides legislation. The restrictions imposed on the use of persistent organochlorine insecticides and organomercury fungicides are summarized.Finally, it is emphasized that the problems of plant protection are becoming increasingly complex as a result of a developing antagonism between phytosanitary and phytopharmaceutical requirements, and of a potential antagonism between these two on the one hand and environmental demands on the other. This situation calls for an integrated approach in plant protection matters, and for an intensified international collaboration.

Resistance as a Means of Control of the Potato Root Eelworm

AbstractA survey of the resistance of wild potatoes to the potato root eelworm and the use made of this property in potato‐breeding is presented. Several biotypes of this parasite have been found to exist. The use of resistant varieties in the control of the potato root eelworm, in connection with other methods of control (crop rotation and soil disinfestation), is discussed.

An Integrated Approach in the Control of Potato Root Eelworm

AbstractDuring the last decade, new control possibilities for the potato root eelworm have come to the fore, namely resistant potato varieties and soil disinfection. These have led to an integrated approach to the control of the potato root eelworm in the Netherlands. For this purpose, a number of potato rotations, aiming at the prevention or elimination of non‐detectable populations of the potato root eelworm, are prescribed for non‐infested fields. These regulations allow the farmer to grow potatoes more frequently on non‐infested soils if he uses control measures (i.e. resistant potato varieties, soil disinfection). More stringent restrictions are in force for infested fields on which the growing of susceptible crops and propagation material is, of course, prohibited.

Crop Rotation and Soil Pathogens — Trends in Germany

AbstractThe need to cut costs has led to a simplification of crop rotation in several fields of plant cultivation. The results of Thormann, who has grown wheat continuously on parts of his farmland for 10 years, are discussed. Also, the preliminary results of our own experiments with increasing proportions of wheat and barley suggest that more wheat and barley may be cultivated in crop rotation than is allowed according to the conventional limits determined by the increase of foot rot diseases and cereal root eelworm. Even in successive crops of maize the problem of soil‐borne pathogens can be tackled: the spread of blister smut is stopped by the control of the frit fly and by selection of tolerant varieties; root and stem rots of maize are overcome by the selection of appropriate varieties, too. On the contrary, the potato root eelworm is a serious pest in all sites of intensive potato production. Only an integrated control including the use of resistant varieties and the application of nematicides gives success. Much research work has to be done mainly to get more information on the biotical defence mechanisms of the soil.

Desiccation survival in the plant parasitic nematodes,Heterodera rostochiensisWollenweber andDitylenchus dipsaci(Kuhn) Filipjev

Using interference microscopy, it is shown that the free second-stage larva of the potato-root eelworm,Heterodera rostochiensis, takes up water at the same rate as one still inside the eggshell; the enclosed larva, however, loses water far less rapidly. It is considered that the shell, freely permeable to water when wet, becomes increasingly impermeable as it dries; the resulting reduction in the rate at which the enclosed larva dries, to which the cyst wall will also contribute, is thought to be of decisive importance for survival. Mechanisms of a similar kind probably operate in the fourth-stage larva of the narcissus strain ofD. dipsaci, both in the ‘eelworm wool’ aggregations and in the isolated individual larva. In the aggregations, nematodes on the outside of the mass died first: they also dry sooner. There is evidence that, in the isolated larva, a decrease in the perm eability of the drying cuticle slows the drying of deeper layers of the organism.

Influence of temperature on polyphenol oxidase activity in three species of Heterodea

1. 1. In the nematode genus Heterodera, the cyst wall is tanned by the activity of a polyphenol oxidase. 2. 2. In the potato root eelworm, H. rostochiensis, the enzyme is more active at low temperatures, including 0°C, than in either H. schachtii and H. avenae, the beet and cereal root eelworms. 3. 3. This may be correlated with the fact that the first species probably originated in the high Andean regions of S. America.

Emergence of Larvae From New Cysts of the Potato-Root Eelworm, Heterodera Rostochiensis

New brown and still yellow cysts of the potato-root eelworm were picked off the host plant at the same time. Both yellow-harvested and brown-harvested cysts were at once stimulated with a solution of a hatching concentrate. A high rate of emergence occurred from the yellow-harvested cysts but the rate was low from the cysts harvested when already brown. Since the yellow cysts turned brown after harvesting, the only apparent difference between the categories was their age. It is concluded therefore that the lack of response from the brown-harvested cysts indicates that a true dormancy develops during cyst maturation. This view is consistent with previous work with new brown cysts.

Effect of the Causal Fungus of Brown Root Rot of Tomatoes on the Hatch of the Potato Root Eelworm, Heterodera rostochiensis Woll

RECENT observations on the brown root rot complex of tomatoes caused Last and Ebben1 to support the view of Termohlen2 that a fungus which produces a grey sterile mycelium in culture is responsible for the brown root rot symptoms. Preliminary studies on the occurrence of potato root eel worm and the grey sterile fungus (GSF) on the roots of tomato revealed that the development of the nematode is adversely influenced by the presence of the fungus. It was thought that the restriction of the reproduction of the nematode could be caused by some substance (or substances) produced by the fungus and which affect the hatch of potato root eelworm, or its subsequent migration to and development in the host plant roots. An investigation of the former is reported here.

POTATO ROOT EELWORM AND TOMATO ROOTSTOCKS

Plant PathologyVolume 15, Issue 2 p. 76-85 POTATO ROOT EELWORM AND TOMATO ROOTSTOCKS C. W. Graham, C. W. Graham National Agricultural Advisory Service. ReadingSearch for more papers by this author C. W. Graham, C. W. Graham National Agricultural Advisory Service. ReadingSearch for more papers by this author First published: June 1966 https://doi.org/10.1111/j.1365-3059.1966.tb02801.xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume15, Issue2June 1966Pages 76-85 RelatedInformation

The hatching factor of the potato-root eelworm.

1. The hatching factor of the potato-root eelworm was concentrated from potato-root leachings by adsorption on charcoal. The crude material, extracted from charcoal with acetone, was purified by partition between ethyl acetate and m-potassium dihydrogen phosphate, and ethyl acetate and a solution of potassium metabisulphite (disulphite). Neutral material was removed by extraction from phosphate buffer at pH7.8. The yield of purified material, after chromatography on silica, DEAE-cellulose and Perlon columns, was 18mug./l. of potato-root leachings, and 0.04% by weight of the acetone-soluble material extracted from charcoal; 20% of the activity of the original potato-root leachings was recovered. 2. The purified material was a colourless gum. On paper chromatograms it gave a single weakly fluorescing spot, which reacted with 2,4-dinitrophenylhydrazine and aniline-xylose reagents. It was confirmed that the hatching factor is an acid, and it is inactivated at values above pH9. Other properties were a ready oxidation by permanganate and reaction with certain carbonyl reagents. Colour tests for alpha- and beta-unsaturated gamma-lactones were negative. The hatching factor showed no light-absorption maxima at wavelengths above 210mmu; absorption bands in the infrared region (670-4000cm.(-1)) are given. Our purified material, although a gum, gave a similar hatch to a ;crystalline' product at 640 times its concentration.

CHEMICAL CONTROL OF POTATO ROOT EELWORM IN GLASSHOUSE SOILS USING DAZOMET

Plant PathologyVolume 14, Issue 3 p. 101-104 CHEMICAL CONTROL OF POTATO ROOT EELWORM IN GLASSHOUSE SOILS USING DAZOMET T. Glyn Davies, T. Glyn Davies National Agricultural Advisory Service, BangorSearch for more papers by this author T. Glyn Davies, T. Glyn Davies National Agricultural Advisory Service, BangorSearch for more papers by this author First published: September 1965 https://doi.org/10.1111/j.1365-3059.1965.tb00288.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume14, Issue3September 1965Pages 101-104 RelatedInformation

THE EFFECT OF CHEMICAL SOIL STERILANTS AND AN ORGANOPHOSPHATE COMPOUND ON POTATO ROOT EELWORM

Plant PathologyVolume 14, Issue 2 p. 89-91 THE EFFECT OF CHEMICAL SOIL STERILANTS AND AN ORGANOPHOSPHATE COMPOUND ON POTATO ROOT EELWORM Serfiah Lewis, Serfiah Lewis National Agricultural Advisory Service, CardiffSearch for more papers by this author Serfiah Lewis, Serfiah Lewis National Agricultural Advisory Service, CardiffSearch for more papers by this author First published: June 1965 https://doi.org/10.1111/j.1365-3059.1965.tb00284.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume14, Issue2June 1965Pages 89-91 RelatedInformation

Cytological Differences in Root Cells of Susceptible and Resistant Potato Varieties Invaded By Potato Root Eelworm (Heterodera Rostochiensis Woll.) Larvae

In roots of potato plants susceptible to potato root eelworm (Heterodera rostochiensis Woll.) the cells lying close to nematode larvae showed a much more dense appearance of the cytoplasm than roots not invaded by nematodes. The vacuoles of these cells showed a tendency of changing their shape and numbers, while starch grains in leucoplasts were much smaller and chondriosomes gradually decomposed. In roots of resistant plants no changes in cytoplasma and vacuoles could be found; starch grains were much greater and chondriosomes showed a tendency to decompose to a lesser degree than in susceptible plants.

:The hydrogen ion concentration inside the cyst of the potato-root eelworm during hatching with some observations on the rate of movement of solutions into and out of the cyst

:The hydrogen ion concentration inside the cyst of the potato-root eelworm during hatching with some observations on the rate of movement of solutions into and out of the cyst

CONTROL OF POTATO ROOT EELWORM IN A LINCOLNSHIRE FEN SOIL

CONTROL OF POTATO ROOT EELWORM IN A LINCOLNSHIRE FEN SOIL

The prospects of controlling potato sickness by growing resistant varieties

A description is given of the situation in the Netherlands with respect to the races of the potato-root eelworm which can be differentiated with the genes in the resistant material bred from S. andigenum CPC 1673, S. kurtzianum and S. vernei. An explanation is given of the mechanism of the change of an eelworm population. Up to this moment no genes for resistance have been found whose effect is not eliminated by the development of new races of the parasite.

THE USE OF METHAM‐SODIUM AND D‐D AGAINST POTATO ROOT EELWORM IN COMMERCIAL GLASSHOUSES

Plant PathologyVolume 13, Issue 3 p. 121-125 THE USE OF METHAM-SODIUM AND D-D AGAINST POTATO ROOT EELWORM IN COMMERCIAL GLASSHOUSES W. H. Golightly, W. H. Golightly National Agricultural Advisory Service Newcastle-upon-Tyne, Shardlow and ReadingSearch for more papers by this authorC. T. Guile, C. T. Guile National Agricultural Advisory Service Newcastle-upon-Tyne, Shardlow and ReadingSearch for more papers by this authorC. W. Graham, C. W. Graham National Agricultural Advisory Service Newcastle-upon-Tyne, Shardlow and ReadingSearch for more papers by this author W. H. Golightly, W. H. Golightly National Agricultural Advisory Service Newcastle-upon-Tyne, Shardlow and ReadingSearch for more papers by this authorC. T. Guile, C. T. Guile National Agricultural Advisory Service Newcastle-upon-Tyne, Shardlow and ReadingSearch for more papers by this authorC. W. Graham, C. W. Graham National Agricultural Advisory Service Newcastle-upon-Tyne, Shardlow and ReadingSearch for more papers by this author First published: September 1964 https://doi.org/10.1111/j.1365-3059.1964.tb00914.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume13, Issue3September 1964Pages 121-125 RelatedInformation