MSc Final Oral Examination: Dennis Van Dyk


Interested Members of the University Community are invited to attend the Final Oral Examination for the Degree of Master of Science of  Dennis Van Dyk of the Department of Plant Agriculture.

Date: Friday, January 8th, 2021
Time:  11:00am

Method: Via Zoom videoconferencing - 
Meeting ID: 957 4252 7116
Passcode: 223551

Please contact Dennis at if you wish to be added to the list to attend the examination portion of the defense.

Thesis Title: Management and quantification of plant parasitic nematodes on carrots (Daucus carota subsp. sativus) in muck soils in Ontario

Advisory Committee 
Dr. Mary Ruth McDonald, Advisor
Dr. Katerina Jordan, Co-advisor
Dr. Sean Westerveld

Examination Committee
Dr. Manish Raizada, Chair
Dr. Mary Ruth McDonald
Dr. Sean Westerveld
Dr. Barry Micallef


Plant parasitic nematodes are a significant constraint to carrot production in Ontario, Canada. Growers need effective tools to control the primary plant pathogenic nematodes affecting carrots in Ontario, Meloidogyne spp. and Heterodera carotae. Growth room, microplot and field trials were conducted to evaluate new non-fumigant nematicides (abamectin, oleoresin of capsicum + AITC, spirotetramat, mustard seed meal, fluensulfone) and fumigants (chloropicrin, metam sodium, dazomet) for their efficacy against these plant parasitic nematodes. Abamectin and fluensulfone decreased nematode damage in growth room trials. Chloropicrin and metam sodium provided the most consistent control and increased carrot yields in field conditions. Two of the general methods to extract and quantify nematodes in soil samples were evaluated for the plant parasitic nematodes relevant to carrots. The Sugar Centrifugation method was effective for extracting both Meloidogyne and Heterodera spp. This research provides strategies to better manage plant parasitic nematodes in carrots grown in Ontario.