Studies of plant host preferences of the stem Nematodes, Ditylenchus Weischeri and D. Dipsaci
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Date
2016
Authors
Hajihassani, Abolfazl
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Abstract
The occurrence of D. weischeri Chizhov, Borisov & Subbotin, a newly described stem nematode species of creeping thistle (Cirsium arvense L.), and D. dipsaci (Kühn) Filipjev, a pest of garlic and quarantine parasitic species of many crops, has been reported in Canada. This research was conducted to determine if D. weischeri is a pest of agricultural crops, especially yellow pea (Pisum sativum L.) in the Canadian Prairies. Significant (P < 0.05) slight reproduction (1 < ratio of final to initial population < 2) of D. weischeri occurred on two (Agassiz and Golden) of five varieties of yellow pea examined. Other annual pulse and non-pulse crops, including common bean, chickpea, lentil, spring wheat, canola, and garlic were non-hosts for D. weischeri. Conversely, a range of reproduction responses to D. dipsaci was observed with all pulse crops being a host of the nematode. Ditylenchus weischeri was not a seed-borne parasite of yellow pea, unlike, D. dipsaci which was recovered from seed. Conversely, D. weischeri and not D. dipsaci was recovered from creeping thistle seeds. In callused carrot disks, with no addition of medium, an increase of 54 and 244 times the addition density of 80 nematodes was obtained for D. weischeri and D. dipsaci, respectively, after 90 days. Temperature had a significant influence on the development of D. weischeri and D. dipsaci in yellow pea. Development of D. weischeri did not proceed past adult stage at 17 and 22°C whereas a minimum generation time of 30 days was apparent at 27°C with the associated accumulated growing degree-days of 720 degree-days (above a base temperature of 3°C). The minimum generation time for D. dipsaci was 24, 18 and 22 days with 336, 342 and 528 degree-days at 17, 22 and 27°C, respectively. In field microplots, grain yield of yellow pea were not significantly affected by addition density of D. weischeri. At harvest, the total number of recovered nematodes per plant was not significantly different than the added at the start. The results of these studies confirm that D. weischeri is unlikely to be a pest of yellow pea for weather conditions of the Canadian Prairies.
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Keywords
Stem Nematodes, Host Prefernce, Biology, Yellow Pea