Root-lesion Nematode Pratylenchus Penetrans Research Articles

Nematicidal Activity of Monoterpenoid Compounds against Economically Important Nematodes in Agriculture

The phase-out of increasing numbers of synthetic nematicides has prompted an urgent need for environmentally benign and effective products to protect crops from nematode damage. We tested a group of selected plant-origin monoterpenoid compounds for their nematicidal activities, and found some of them could be potent nematicides. Most of the monoterpenoids were more toxic than the commercial nematicide oxamyl (13.4% mortality at 250 μg/mL) against the soil saprophytic nematode Caenorhabditis elegans, among which carvacrol and thymol were the most potent (100% mortality at 250 μg/mL). (–)-Perillaldehyde, eugenol, geraniol and menthol were of moderate nematicidal activity at the same concentration, with mortality at 97%, 91%, 90% and 84%, respectively, against C. elegans. Nematicidal activity against the root lesion nematodes Pratylenchus penetrans was generally less potent, but citronellol, carvacrol and (–)-perillaldehyde were more toxic (mortality at 250 μg/mL were 87%, 78% and 56%, respectively) than oxamyl (50%). Thymol showed similar (50%) mortality to that of oxamyl.

ROTATION WITH TAGETES SP. FOR CONTROL OF ROOT-LESION NEMATODES AFFECTS FLUE-CURED TOBACCO GROWTH, YIELD, QUALITY, AND COST OF PRODUCTION

Abstract The root-lesion nematode (Pratylenchus penetrans) can cause significant reduction in tobacco yield and quality. This nematode also is a parasite of cereal rye (Secale cereale), which is a common rotation crop in tobacco areas. Row fumigation prior to transplanting tobacco in the spring is practiced by >95% of Ontario growers to control nematode populations. Planting of Tagetes sp. (marigold) also reduces nematode populations, and when used instead of rye as a rotation crop with tobacco, can provide an alternative to chemical fumigation. Field trials were conducted from 1996 to 1998 to compare the impacts of marigold rotation vs. a traditional fall rye rotation crop, with and without chemical fumigation, on flue-cured tobacco yield, quality, and cost of production. Both the marigold rotation and the non-fumigated rye rotation resulted in slightly less early season N available in the following tobacco crop year compared to the rye + fumigation check. Plant height in July and days to flowering, both...

Reduction of root-lesion nematodes (Pratylenchus penetrans) in tubers of potato (Solanum tuberosum) during cold storage

The effect of storage duration at low temperatures on numbers of the nematode Pratylenchus penetrans harbored within potato tubers of cvs. Superior, Monona, Saginaw, Saginaw Gold, Yukon Gold, and Kennebec were studied from 1992 to 1995. Numbers of P. penetrans in potato tubers held at 1-5?°C for 8 months decreased to nearly zero, regardless of cultivar. The number of nematodes decreased at different rates when stored at 3-5°C than when stored at 1-3°C and decreased most rapidly during the first 2 months of storage at 1-3°C; at 3-5°C storage, it took 4 months for the numbers to decrease substantially. The number of live nematodes in potato tubers after 8 months of storage below 5°C was too low to pose a significant threat at planting to already infested fields, but would still be a source of a new infestation.

Abstracts, British Columbia Regional Meeting, The Canadian Phytopathological Society, 1997

Ustilago hordei; use of RAPD and AFLP technology for tagging and fingerprinting in smuts and other fungi. G. Bakkeren, D. Lin, N. Lee, M. Abdennabher, D. Gaudet, P. Thomas, D. Mills, C. A. Lévesque, and J. Kronstad. (G.B. and C.A.L.) Pacific Agri-Food Research Centre, Agriculture & Agri- Food Canada, Summerland, B.C. VOH 1Z0, (G.B., D.L., N.L., and J.K.) Biotechnology Laboratory, Departments of Microbiology and Immunology, and Plant Science, University of British Columbia, Vancouver, B.C. V6T 1Z3, (M.A. and D.M.) Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA 97331, (D.G.) Research Station, Agriculture & Agri-Food Canada, Lethbridge, Alberta, TIJ 4B1, (P.T.)Agriculture & Agri- Food Canada, Research Station Winnipeg, Manitoba, R3T 2M9. Tomato ringspot nepovirus protease demonstrates different level of tolerance to amino acid substitution at two polyprotein cleavage sites. K. Carrier and H. Sanfacon. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH 1Z0. Development of PCR primers specific for Pezicula malicorticis and P. perennans, fungal species associated with anthracnose and perennial cankers of apple and bull's eye rot of apple fruit. S. N. de Jong, C. A. L&vesque, and J. E. Rahe. Centre for Pest Management, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C. V5A 1S6, (C.A.L.) Pacific Agri-Food Research Centre, Agriculture and Agri- Food Canada, Summerland, B.C. VOH 1Z0. First record of Pythium paddicum isolated from turfgrass roots collected from a British Columbia golfcourse. R. C. Descalzo, I. W. Geere, G. Geere, and C.A. L&vesque. I.G. MicroMed Environmental Inc., 190-12860 Clarke Place, Richmond, B.C., V6V 2H1, (C.A.L.) Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH 1Z0. Control of the root lesion nematode Pratylenchus penetrans with antagonistic rhizobacteria. C. Hackenberg, T. Forge, A. Muehlchen, and T. Vrain. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH 120. A novel host-based identification and detection system using cranberry pathogens as a model. C. E. Harlton, Y. Ahn, and C. A. L&vesque. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH IZ The sexual stage of Pezicula malicorticis on anthracnose cankers. K. Jurkemikova and J. E. Rahe. Centre for Pest Management, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C. V5A 1S6. Development of commercial biocontrol products; synergy in action, "Mickey" a case study. M. Leggett. Philom Bios Inc., 318-111 Research Drive, Innovation Place, Saskatoon, Saskatchewan S7N 3R2. A survey of blueberry fruit rot in British Columbia — implications for management. L. Macdonald. B.C. Ministry of Agriculture, Fisheries and Food, 1767 Angus Campbell Road, Abbotsford, B.C. V3G2M3. Microbiological aspects of apple replant disease and the potential for control through the use of integrated management Strategies. M. Mazzola. USDA-ARS, Tree Fruit Research Lab, 1104 N. Western Ave., Wenatchee, WA 98801. Abiotic considerations for overcoming replant problems in high density orchard systems. G. H. Neilsen, E. J. Hogue, D. Neilsen, and B. J. Zebarth. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH Molecular approach to monitor a beneficial Penicillium species. D. O'Gorman, M. Leggett, and C. A. Lévesque Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH IZO; (M.L.) Philom Bios Inc., 318-111 Research Drive, Innovation Place. Saskatoon, Saskatchewan S7N 3R2. Development of fusarium crown and root rot, a new disease on greenhouse cucumbers in British Columbia. Z. K. Punja and K. Ng. Department of Biological Sciences, Centre for Pest Management, Simon Fraser University, Burnaby, B.C. V5A 1S6, and (K.N.), B.C. Ministry of Agriculture, Fisheries and Food, Abbotsford, B.C. V3G 2M3. Revisiting Pythium taxonomy, identification and ecology. A. Quail, C. Mayes, and C. A. Lévesque. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summer/and, B.C VOH1Z0. Geographic variation in the mitochondrial DNA of Chondrostereum purpureum . T. D. Ramsfield, Z. K. Punja, S. F. Shamoun, and W. E. Hintz. Centre for Pest Management, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C., V5A 1S6, (S.F.S.) Canadian Forest Service, Pacific Forestry Centre, 506 West Burnside Road, Victoria, B.C., V8Z 1M5, (W.E.H.) Biology Department, University of Victoria, Victoria, B.C. V8W3N5. Binding of cucumber necrosis virus to zoospores of its fungal vector in vitro. M. Robbins and D. Rochon. Department of Plant Science, University of British Columbia, Vancouver, B.C., V6T 2A2, and Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland, B.C. VOH IZ0. Latent infection of apples and stone fruit in British Columbia in 1997. P. Sholberg, K. Bedford, L. Lashuk, and P. Haag. Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland, B.C., VOH 1Z0.

Long-term evaluation of cover crop and strip-tillage on tomato yield, foliar diseases and nematode populations

A 6-yr (1987–1992) experiment, continuous on the same site, evaluated potential problems for yield, nematodes and diseases with tomatoes (Lycopersicon esculentum Mill.) grown in a strip-till system. Treatments consisted of conventional tillage (CT) and strip tillage (ST), rye (Secale cereale L.), wheat (Triticum aestivum L.) and perennial ryegrass (Lolium perenne L.) cover crops and a 2-yr rye-tomato rotation. Results of the first 5 yr indicated a decrease in tomato yield over time for both tillage treatments and cover crops. However, yield rebounded overall for treatments in 1992 with the highest yield in the rye-tomato rotation. We suspect this was a result of high populations of root-knot nematodes which collapsed over the winter of 1991/1992. Tomato yields were lower following wheat and perennial ryegrass than rye. In only 1 yr out of 6, strip-tillage reduced yield compared with conventional tillage. Bacterial speck/spot symptoms on foliage, although minor, were significantly greater in ST than in CT plots during the last 3 yr. No major trends in incidence and severity of bacterial and fungal diseases and of disorders of fruit were evident during the 5-yr period and neither fruit yield nor quality were significantly affected by these factors. Root-knot nematodes (Meloidogyne hapla Chitwood) were numerically less in the rye-tomato rotation than in other treatments; both root-knot and root lesion nematodes (Pratylenchus penetrans [Cobb]) tended to be less numerous under CT than under ST. Strip-tillage is feasible for machine harvest processing tomatoes. However, we are concerned about the tendency of tomatoes grown under reduced tillage to have lower yields than those grown under conventional tillage. More work is required on the interactions of cultivars, cover crops and nematodes in soil conservation systems. Key words: Tomato, bacterial speck/spot, foliar diseases, root-knot nematodes, root lesion nematodes, tillage

Relationships between soil penetration resistance and soif nematode burden in barley on Prince Edward Island

Fifty sloping fields of barley with different short-term cropping histories across Prince Edward Island were examined for variations in root-zone depth and the severity of soil parasitic nematodes as part of a wider study of relationships between cropping sequence, topographic position, soil physical conditions and crop performance. Root lesion nematode (Pratylenchus penetrans) density in the roots was significantly greater (13%) at foot slopes than at top slopes, and stunt nematode (Tylenchorhynchus spp.) was significantly greater (8%) at top slopes where the soil was drier. The density of stunt nematodes and root lesion nematodes in the soil was significantly greater (>15%) under miscellaneous cereals-barley sequences than under potato-barley or hay-barley, attributable to level of carryover. Root lesion nematode density in the roots was significantly greater (12%) under hay-barley than either of the other two sequences. This nematode also showed a strong tendency to increase in number with increasing root-zone depth, and may be explained on the basis that increased root-zone depth provides increased host root mass (substrate). Stunt nematodes, on the other hand, increased with decreasing root-zone depth and may be explained by the known propensity of these organisms for drier, shallower soil conditions.

Development of Potato Early Dying in Response to Infection by Two Pathotypes ofVerticillium dahliaeand Co-infection byPratylenchus penetrans

Verticillium dahliae isolates assigned to subgroups A and B of vegetative compatibility group 4 (VCG 4A and 4B) were tested for virulence to potato and ability to interact with the root-lesion nematode Pratylenchus penetrans in field microplot and greenhouse experiments. Microsclerotial inocula and the Verticillium-susceptible potato cultivar Superior were used. No differences in virulence were found between isolates from VCG 4A and 4B when plants were grown in soil infested with V. dahliae only. In contrast, plants grown in soil infested with V. dahliae isolates from VCG 4A plus P. penetrans exhibited higher disease severity and had lower tuber yields than plants grown in soil infested with V. dahliae isolates from VCG 4B plus P. penetrans [...]

Pratylenchus penetrans(root lesion nematode)—cause of patch chlorosis ofPinus radiataseedlings

Summary The root lesion nematode Pratylenchus penetrans was recovered from the roots of stunted, chlorotic, wilting and recently dead Pinus radiata seedlings growing in a forest nursery located on deep sands in south-western Victoria adjacent to the South Australian border. Although specimens of the genus Pratylenchus were recovered from P. radiata nursery soils in this region about 20 years ago, this is the first record of the species P. penetrans parasitising P. radiata in Australia. Greenhouse and phytotron tests showed that P. penetrans could, by itself, cause the disease symptoms observed in the nursery and that other soil pathogens, which produce similar symptoms, contributed insignificantly. P. penetrans was controlled by a single application of readily available proprietary brands of either liquid or granular nematicides shortly after seedling germination. A 10–15% improvement in seedling height was obtained even in healthy-looking seedlings infested with nematodes.

SCREENING RYE CULTIVARS AND BREEDING LINES FOR RESISTANCE TO THE ROOT-LESION NEMATODE PRATYLENCHUS PENETRANS

In greenhouse pot tests, 66 cultivars and breeding lines of rye (Secale cereale L.) were screened for resistance to the root-lesion nematode (Pratylenchus penetrans Cobb). Ten cultivars and breeding lines supported less reproduction of the nematode than did Tetra Petkus, the standard cultivar used in rotation with flue-cured tobacco in southwestern Ontario.

Problems in tree replacement. III.* The effects of cultural practices and soil fumigation on root-lesion nematodes and on the growth of apple replants

The growth of replant apple trees cv. Delicious was much less in field plots after a mixture of cover crops, including rye cv. Black Winter and lupin cv. New Zealand Blue, had been grown for 16 months than where the land had been left to volunteer weeds or kept free of plant growth. In a subsequent glasshouse experiment, growing rye or blue lupin in old orchard soil before planting apple seedlings caused severe stunting. In a field trial, soil fumigation with dichloropropene-dichloropropane (DD) before planting increased the first season's shoot growth of apple trees cv. Delicious after rye cv. Black Winter by 79% and after lupin cv. New Zealand Blue by 60%. Trees grew well after prairie grass cv. Priebe or oats cv. Saia, increases due to fumigation being 4.0 and 4.5% respectively. In a glasshouse experiment rye and blue lupin were shown to be much better hosts for the root-lesion nematode Pratylenchus penetrans than prairie grass or oats. A survey of Queensland apple orchards indicated that Pratylenchus penetvans and another species previously identified as Pratylenchus coffeae often occurred together. In a glasshouse experiment the addition of large numbers of P. penetrans to soil severely stunted apple seedlings cv. Granny Smith, whereas the other Pratylenchus species had little effect. ________________ *Part II, J. Aust. Inst. Agric. Sci., 20: 234 (1954).

EFFECTS OF DEEP FUMIGATION ON PRATYLENCHUS PENETRANS, FLUE-CURED TOBACCO, AND SOIL NITRATE CONTENT

Row applications of Telone (1,3-dichloropropene and related chlorinated C3 hydrocarbons), at 45 and 90 liters/ha were injected 15, 30, and 45 cm below the soil surface and ridged up an additional 15 cm. Telone, at 90 liters/ha injected at 15 cm, gave the best control of the root-lesion nematode Pratylenchus penetrans (Cobb) Filip. and Stek. 1941, in the top 0–20 cm of soil. The degree of nematode control in the top 20 cm of soil was inversely correlated with injection depth. Though the degree of nematode control with 45 liters/ha of Telone at 30 cm was considerably less in the 0–20-cm soil layer than with the 90-liter rate at the 15-cm depth, the yields of flue-cured tobacco were about equal for both treatments. Good control of nematodes in the 20–40-cm soil layer was obtained with both rates of Telone regardless of injection depth. At the recommended rate of 90 liters/ha there appeared to be no advantage to injecting Telone deeper than 15 cm. Where no Telone was applied, the levels of NO−3-N in the soil in June were higher, and yields of tobacco tended to be lower.

SOIL FUMIGATION FOR CONTROL OF VERTICILLIUM WILT OF EGGPLANT

Fumigation of Fox sandy loam field soils naturally infested with Verticillium dahliae delayed the onset and reduced the final incidence of Verticillium wilt of eggplant. Fumigation resulted in greater plant growth and concomitant increases in yield. Vorlex and EP-201 applied at 561.6 l./ha gave similar control of wilt and yield increases. Fumigation with Vorlex gave best control of wilt in 1964 and 1965, years in which the upper 15 cm of soil contained uniformly high moisture at the time of treatment. Vorlex applied at 561.6 l./ha reduced root populations of the root-lesion nematode Pratylenchus penetrans to considerably lower levels than Telone at 449.3 l./ha. Vapam was not as effective in controlling wilt as either Vorlex or EP-300, though like EP-300 it caused no early retardation of growth of eggplant. Yield increases from fumigation varied from year to year and ranged from 5 to more than 100 times yields from untreated soils. Soil fumigation in eggplant culture promises to be practical in southwestern Ontario where Verticillium wilt is serious.

THE INFLUENCE OF SPRING AND FALL APPLICATION OF NEMATICIDES ON PRATYLENCHUS PENETRANS AND QUALITY OF FLUE-CURED TOBACCO GROWN WITH VARIOUS FORMS OF NITROGEN

Field experiments were conducted to determine the effect of two chlorinated hydrocarbon nematicides on control of the root lesion nematode Pratylenchus penetrans (Cobb) and on the yield and quality of flue-cured tobacco. The nematode was effectively controlled with a spring or fall application of either D-D or Telone. Fall application resulted in an increase in total nitrogen and total alkaloids and a decrease in reducing sugars and ethanol extractables in the cured tobacco leaf, effects which are associated with low quality. Evidence indicated that fall fumigation inhibited the nitrification of ammonium nitrogen fertilizer applied to the rye straw in the summer preceding the tobacco crop. Excessive amounts of mineral nitrogen became available to the tobacco plant during its growing season. Spring application increased the chlorine content of the leaf but had no other adverse effects on chemical composition.

THE PATHOGENICITY OF PRATYLENCHUS PENETRANS TO CELERY

Celery seedlings, grown aseptically in silica sand with plant nutrients, were inoculated with surface-sterilized specimens of the root lesion nematode Pratylenchus penetrans (Cobb, 1917) Filip. & Stek., 1941. The reactions of invaded roots were studied microscopically. The epidermis, cortex, and endodermis of young celery roots showed different degrees of discoloration after invasion of P. penetrans, with the endodermis most severely affected. Pratylenchus penetrans was a primary parasite and pathogen of celery.

Studies On the Host-Parasite Relations of Pratylenchus Penetrans (Cobb) To Apple Seedlings

A technique is described for the inoculation, under aseptic conditions, of apple seedlings with the root lesion nematode Pratylenchus penetrans (Cobb, 1917) Filip. & Stek., 1941. Under these conditions apple feeder roots (i.e. those without secondary thickening) react to nematode invasion by a rapid discolouration of the outermost, (i.e. epidermis and hypodermis) and innermost, (i.e. inner cortex and endodermis) cortical tissues, but show little or no reaction in the intervening cortical parenchyma. This response is compared with that of peach roots, in which all the cortical tissues are readily discoloured by this nematode. Histochemical tests suggest that sensitivity to P. penetrans is correlated with the presence and concentration of phenolic substances in the various tissues of these two hosts.