1997-98 Canola Performance Tests

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

The Season

Georgia producers planted an estimated 5,000 acres of canola in 1997. Virtually all of the 1997-98 acreage was planted in the Coastal Plain region to laurate canola cultivars under identity preserved contract for Calgene Oils.

As the planting season approached, soil moisture levels statewide were extremely low due to a two month drought. A series of strong weather systems in October dumped large amounts of rainfall across the growing region and rapidly changed field conditions from too dry to too wet. Continued heavy rains resulted in poor emergence and severe stand problems in many early planted fields. Wet field conditions continued throughout the planting window making planting difficult. As a result, planted acres were severely reduced from earlier expectations.

Monthly rainfall amounts recorded at the five test locations during the 1997-98 growing season are presented in the table below. Rainfall amounts at all test locations were well above normal. The Coastal Plain region experienced a very wet growing season, with all test locations reporting rainfall amounts of 12 inches or more above normal.

1997-98 Rainfall1

Month Year Calhoun2 Griffin Midville Plains Tifton

---------------------------------------- inches -------------------------------------------      

October 1997 7.91 4.38 5.17 5.85 6.05
November 1997 2.97 4.17 4.35 7.96 5.71
December 1997 3.30 6.03 6.42 7.18 8.34
January 1998 4.45 5.82 4.79 5.31 5.26
February 1998 7.26 7.49 6.78 6.88 4.54
March 1998 5.54 4.95 7.04 7.32 8.06
April 1998 8.91 7.59 6.83 9.16 3.52
May 1998 2.85 2.30 2.90 4.31 2.44
June 1998 2.51 2.57 1.89 1.69 1.20
Total (9 months) 45.70  45.30  46.17  55.66  45.12 
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 1997-98 canola growing season in Georgia was characterized by a wet but mild winter followed by a hot and dry spring. A cold front in mid-March sent temperatures plunging into the teens over much of the state. Fortunately, the state's canola crop suffered only minor freeze damage. High temperatures combined with low soil moisture caused moderate to severe moisture stress on the crop during late seed fill. This reduced the crop's yield potential 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 half of the state's acreage required treatment for the green peach and/or the turnip aphid. Green peach aphids proved difficult to control and some fields required multiple treatments. Losses due to aphid infestations exceeded 10 percent in many production areas. Phoma blackleg, which emerged as a significant disease problem during the 1993-94 season, was noted at low levels in several production fields across south Georgia but caused little economic loss to the 1998 crop. Incidence of Sclerotinia sclerotiorum during the rosette stage was much lower than in recent years but later infections of Sclerotinia stalk rot were observed in many fields during seed fill. Damage from other pests was isolated and minimal.

Farmers reported yields ranging from 12 to 52 bushels per acre. Average yield for the 1997-98 Georgia canola crop is estimated at only 28 bushels per acre.