John O'Sullivan

John O'Sullivan
Associate Professor (retired)



519-426-7127 x336



Simcoe Station



This research program is involved in weed and crop management for vegetable crops. Weed management research screens new herbicides and develops registrations of new weed control products for the vegetable industry. Studies emphasize integrated weed management that effectively control weeds for a wide range of vegetable crops with emphasis on reduced inputs for weed control. The goal of the weed management program is to provide cost effective, reliable and safe weed control recommendations for vegetable growers and give effective control and reduce the need for labor for weeding, producing higher yields in a sustainable production system. It aims to integrate new herbicide use with current control methods. The registration of new weed control products is of great significance to Ontario vegetable growers. New weed control products reduce the need for labor for hand hoeing and weeding and reduce the cost of production to the grower, resulting in improved competitiveness of this industry by providing more effective weed control. It provides vegetable growers access to newer, potentially safer and more effective herbicides with minimized impact on the environment. The program provides vegetable growers additional weed control options and encourages a more sustainable production system by utilizing environmental friendly herbicides in combination with a number of other methods of weed control.


Studies with new herbicide chemistry identifies cultivar tolerance of major vegetable crops to new herbicides such as sweet corn and also identifies the potential for damage to sensitive crops due to the persistence of these new, low use rate herbicides, in the rotation. There are also studies on the effect of different tillage systems on yield and quality of vegetable crops. This program aims at developing information that helps form a systems approach to vegetable production and demonstrates to growers that conservation tillage is economical and sustainable.

Studies on vegetable production and physiology include cultivar trials on vine crops such as processing cucumbers, pumpkins and melons, peppers and beets and the development of machine harvesting systems for processing cucumbers. This program's objectives are to maintain the vegetable industry in Ontario in a competitive position by recommending high yielding, disease resistance/tolerance cultivars with superior quality, adaptable to Ontario growing conditions and market acceptance and to promote management practices that produce maximum yields at minimum production costs. The program evaluates new harvesting technology for vegetable crops , especially cucumber harvesters. Cultivar evaluations are focused on providing the vegetable industry in Ontario with the best possible information on superior cultivars with market acceptance and adapted to this area. This enhances the competitiveness of the vegetable industry. A viable mechanical harvest system for processing cucumbers give growers and processors other options to produce this crop. This is important since the availability of reliable hand labor to harvest the crop is an ongoing problem. Mechanical harvesting reduces the cost of production and has possibilities for increased export of cucumbers. This program is staffed by myself and Bill Bouw, research technician.


Relevant Links:

Selected Publications:

O'Sullivan, J., R.J. Thomas, and W.J. Bouw. (1998). Tolerance of Sweet Corn (Zea Mays) cultivars to rimsulfuron. Weed Technol. 12:258-261.

O'Sullivan, J. and W.J. Bouw. (1998). Sensitivity of Processing Sweet Corn (Zea Mays) cultivars to nicosulfuron/runsulfuron. Can J. of Plant Sci. 71:151-154.

O'Sullivan, J. and W.J. Bouw. (1997). Effect of timing and adjuvants on the efficacy of reduced herbicides rates for Sweet Corn (Zea Mays). Weed Technology 11: 486-489.

O'Sullivan, J., R.A. Brammall, and W.J Bouw. (1995). Tolerance of Sweet Corn (Zea Mays) cultivars to nicosulfuron/runsulfuron. Weed Technology 9:58-62.

O'Sullivan, J. and W.J. Bouw. (1993). Reduced rates of postemergence herbicides for Sweet Corn (Zea Mays). Weed Technology 7:995-1000.

O'Sullivan, J. and W.J. Bouw. (1984). Pepper seed treatment for low temperature germination. Can J. of Pl.Sci. 64:387-393.

O'Sullivan, J. and H.T.M Colwell. (1980). Effect of harvest date on yield and grade distribution relationships for pickling cucumbers harvested once-over. J. Amer. Soc. Hort. Sci. 105:408-412.

O'Sullivan, J. (1980). Irrigation, spacing and nitrogen effects on yield and quality of pickling cucumbers grown for mechanical harvesting. Can. J. of Plant Sci. 60:923-928.

O'Sullivan, J. and A.A. Reyes. (1980). Effects of soil fumigation, rotation and nitrogen on yield, specific gravity, petiole NO2-N and Verticillium wilt of potatoes. J. Amer. Soc. Hort. Sci. 105:809-812.

Colwell, H.T.M. and J. O'Sulllivan. (1980). Economics of harvest timing for once-over harvesting of cucumbers. J. Amer. Soc. Hort Sci. 06:163-167.

Ennis, D.M. and J. O'Sullivan. (1979). Cucumber quality - a review. J. of Food Sci. 44(1):186-189, 197.

Ennis, D.M. and J. O'Sullivan. 1979. Sensory quality of cucumbers before brining. J. of Food Sci. 44(3):847-849.

O'Sullivan, J. (1979). Response of peppers to irrigation and nitrogen. Can. J. Pl. Sci. 59:1085-1091.

O'Sullivan, J. (1978). Effects of rotation and nitrogen on yield and quality of potatoes. Can. J. of Pl. Sci. 58:475-483.

O'Sullivan, J., W.H. Gabelman, and G.C. Gerloff. (1974). Variations in efficiency of nitrogen utilization in tomatoes (Lycopersicon esculentum Mill.) grown under nitrogen stress. J. Amer. Soc. Hort Sci. 99:543-547.