The Georgia Agricultural Experiment Station
College of Agricultural and Environmental Sciences
The University of Georgia

Research Report Number 660
August 1999



1998-99 Canola Performance Tests


Edited by J. LaDon Day, Paul L. Raymer, and Anton E. Coy


The Season


     Georgia producers planted an estimated 1,500 acres of canola in 1998. Virtually all of the 1998-99 acreage was planted in the Coastal Plain region to traditional commodity canola cultivars. This production was stimulated by contract offers from two local oilseed crushers.

     Extremely dry weather persisted throughout the planting season. This greatly reduced the amount of canola actually planted from earlier expectations and also adversely affected stand establishment of the limited acreage that was planted. Monthly rainfall amounts recorded at the five test locations during the 1998-99 growing season are presented in the table below. Rainfall amounts at all test locations were well below normal.


1998-99 Rainfall1
Month Year Calhoun2 Griffin Midville Plains Tifton
  ----------------------------------- inches -----------------------------------
 
October 1998 2.47 0.45 1.14 0.22 0.03
November 1998 3.87 1.94 0.60 0.95 1.27
December 1998 6.33 1.95 1.95 1.28 1.60
January 1999 5.67 4.48 3.11 5.81 4.46
February 1999 3.01 2.19 2.49 2.62 1.73
March 1999 3.24 3.11 1.57 2.42 1.13
April 1999 2.14 1.53 2.75 2.65 2.07
May 1999 4.70 2.56 1.62 2.45 2.14
June 1999 4.85 6.76 2.87 3.30 7.57
 
Total (9 months) 36.28 24.97 18.10 21.70 22.00
 
Normal (9 months) 41.90 37.68 32.11 36.27 32.51
1.  Data collected by Dr. G. Hoogenboom, Georgia Station, Griffin, GA.
2.  Floyd County location.

     Overall, the 1998-99 canola growing season in Georgia was very dry with mild winter temperatures. The relatively dry winter was followed by an extremely dry spring. High temperatures during flowering and seed fill combined with low soil moisture caused moderate to severe moisture stress on the crop throughout seed fill. This reduced crop yields and the total oil content of harvested seeds throughout most of south Georgia.

     The mild winter favored development of aphids which became a significant problem in most south Georgia production fields. More than eighty percent of the state's acreage required treatment for the green peach and/or the turnip aphid. Excellent scouting and timely treatment provided effective aphid control and crop losses due to aphids were negligible. Phoma blackleg, which emerged as a significant disease problem during the 1993-94 season, caused little on no economic loss during the 1998-99 season. Blackleg was observed in only two fields at very low infestation levels. Incidence of Sclerotinia sclerotiorum during the rosette stage was much lower than in recent years but later infections of Sclerotinia stalk rot were widespread. Sclerotinia stalk rot levels ranged from 6 to 42% in infected fields and caused an estimated 10 percent crop loss. Damage from other pests was isolated and minimal.

     Farmers reported yields ranging from 20 to 68 bushels per acre. Average yield for the 1998-99 Georgia canola crop was estimated at 37 bushels per acre.