Infection of Second Stage Juveniles of Potato Cyst Nematodes By the Nematophagous Fungus Hirsutella Rhossiliensis in Dutch Potato Fields

Nematologica ◽  
1995 ◽  
Vol 41 (1-4) ◽  
pp. 617-627 ◽  
Author(s):  
Henk Velvis ◽  
Peter Kamp
Nematology ◽  
2015 ◽  
Vol 17 (9) ◽  
pp. 1105-1111 ◽  
Author(s):  
Vincas Būda ◽  
Rasa Čepulytė-Rakauskienė

Two behavioural assays were carried out: one on the attraction of potato cyst nematodes (PCN), Globodera rostochiensis and G. pallida, to solanaceae-specific secondary metabolite α-solanine, the other on the effect of ZnSO4 (a compound known to suppress chemoreceptors). The first assay demonstrated that α-solanine was attractive to second-stage juveniles (J2) of PCN; G. pallida was attracted to concentrations of 10−4 M and 10−5 M, whereas G. rostochiensis was attracted to 10−5 M. Globodera pallida reacted faster than G. rostochiensis to the same concentration of α-solanine. As α-solanine is produced by host plants of PCN, this compound is attributed to kairomones. The response to α-solanine of nematodes pre-exposed to a 3 mM ZnSO4 solution was significantly suppressed compared to that of water control. The effect was observed throughout the whole testing period (30 min). This is the first evidence that both α-solanine and ZnSO4 can affect the behaviour of hatched J2 of PCN.


Nematology ◽  
2003 ◽  
Vol 5 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Ken Devine ◽  
Peter Jones

AbstractThe behaviour of stimulated second stage juveniles (J2) (i.e., hatched in root leachate from potato cv. Cara) and unstimulated J2 (spontaneously hatched in water) of Globodera rostochiensis and G. pallida in response to fractionated and unfractionated potato root leachate (PRL) was investigated in attraction assays. In PRL, fractionated by combined ion-exchange-gel permeation chromatography on Sephadex G-10, three classes of semiochemicals with activity towards J2 were distinguished: i) chemoattractants; ii) chemostats, and iii) chemorepellents. The motility of PRL-hatched G. rostochiensis J2 in one fraction (12) at 10 days after their removal from the root leachate was significantly greater than that of water-hatched J2 apparently due to sensitisation of PRL-hatched J2. PRL-hatched J2 of G. pallida were attracted to different fractions than those of G. rostochiensis, whereas the water-hatched J2 from the two species were attracted to common fractions, indicating that sensitisation by exposure to PRL was species selective. The attraction of PRL-hatched PCN J2 to unfractionated PRL appeared to be dependent on the ratio of chemoattractant to chemorepellent semiochemicals in the leachate. For both species there was no detectable correlation between hatching activity and either attractiveness of root leachates from 12 potato genotypes or chemoattraction in PRL fractions, indicating that hatching factors were not active chemoattractants.


Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 216
Author(s):  
Aouicha Djebroune ◽  
Gahdab Chakali ◽  
Eugénia de Andrade ◽  
Maria João Camacho ◽  
Leidy Rusinque ◽  
...  

Morphological and molecular studies were conducted to characterize the specific identity of 36 isolates of potato cyst nematodes (PCNs) recovered from soil samples collected in several potato producing areas of Algeria. Morphometric data revealed that 44% of isolates contained Globodera pallida alone, 28% contained Globodera rostochiensis alone and 28% mixtures of the two species. Morphometric values of cysts and second-stage juveniles were generally distributed with slight differences in the expected ranges for both Globodera species. Inter- and intraspecific morphometric variability in nematode isolates was noted. Molecular analysis using conventional multiplex PCR with species-specific primers and TaqMan real-time PCR confirmed the morphological identification. In addition, the distribution of both potato cyst nematode species throughout various parts of the country was investigated. In the central areas, the isolates of G. pallida alone dominate, whereas isolates of G. rostochiensis alone are more frequent in the southern areas. In the eastern regions, mixed isolates are more representative. Most isolates examined in the western areas are mixtures of the two species or G. rostochiensis alone. Comparatively, G. pallida remains the most widely distributed species in its geographic range. This study confirms the presence of two PCN species, G. pallida and G. rostochiensis, in Algeria and provides additional information on their biogeographic distribution.


1989 ◽  
Vol 21 (8-9) ◽  
pp. 909-916
Author(s):  
A. M. Spaull ◽  
D. M. McCormack ◽  
E. B. Pike

Samples of sewage sludges, taken over a 12-month period from 9 Scottish sewage works, contained on average 0.24 cysts of Globodera spp. (potato cyst-nematodes) of which 11% were viable. The incidence was not significantly related to season or to the presence of vegetable-processing effluent. Exposure of cysts in sludge to mesophilic anaerobic digestion (35 °C, 30 min) cold anaerobic digestion (9 weeks), pasteurisation (70 °C, 30 min) and aerobic thermophilic digestion (60 °C, ld) reduced viability of eggs within the cysts by almost 100%. Sludges so treated can therefore be considered to be free from infection risk to potato crops, although the non-infective cysts may still be recovered. Treatment with lime at pH 11.5 (20 °C, 24 h), by aerobic stabilisation in an oxidation ditch (7 weeks) and by activated-sludge treatment (5d) did not reduced viability acceptably. Accelerated cold digestion did not reduce viability sufficiently after the usual 15 weeks but rendered eggs completely non-viable after 21 weeks. The results show that even sludge treated to destroy viable cysts should not be applied to land used for growing seed potatoes and subject to testing for freedom from infestation. Treatment destroying viability should increase the acceptability of sludge for ware potato growers, although the numbers of cysts applied in untreated sludge would be unlikely to increase significantly levels of cysts in soils already infested.


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 184
Author(s):  
John Wainer ◽  
Quang Dinh

The scope of this paper is limited to the taxonomy, detection, and reliable morphological and molecular identification of the potato cyst nematodes (PCN) Globodera pallida and G. rostochiensis. It describes the nomenclature, hosts, life cycle, pathotypes, and symptoms of the two species. It also provides detailed instructions for soil sampling and extraction of cysts from soil. The primary focus of the paper is the presentation of accurate and effective methods to identify the two principal PCN species.


2006 ◽  
Vol 80 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Dinka Grubišić ◽  
Ljerka Oštrec ◽  
Tanja Gotlin Čuljak ◽  
Sylvia Blümel

2009 ◽  
Vol 99 (12) ◽  
pp. 1387-1393 ◽  
Author(s):  
M. Hodda ◽  
D. C. Cook

Potato cyst nematodes (PCN) (Globodera spp.) are quarantine pests with serious potential economic consequences. Recent new detections in Australia, Canada, and the United States have focussed attention on the consequences of spread and economic justifications for alternative responses. Here, a full assessment of the economic impact of PCN spread from a small initial incursion is presented. Models linking spread, population growth, and economic impact are combined to estimate costs of spread without restriction in Australia. Because the characteristics of the Australian PCN populations are currently unknown, the known ranges of parameters were used to obtain cost scenarios, an approach which makes the model predictions applicable generally. Our analysis indicates that mean annual costs associated with spread of PCN would increase rapidly initially, associated with increased testing. Costs would then increase more slowly to peak at over AUD$20 million per year ≈10 years into the future. Afterward, this annual cost would decrease slightly due to discounting factors. Mean annual costs over 20 years were $18.7 million, with a 90% confidence interval between AUD$11.9 million and AUD$27.0 million. Thus, cumulative losses to Australian agriculture over 20 years may exceed $370 million without action to prevent spread of PCN and entry to new areas.


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