Ontario Field Crop Report – July 13, 2022

Spring canola across the province is currently at or beyond full bloom. Observations from around the province at this stage are that spring canola is looking better overall than it has in recent years, particularly in Timiskaming District where the majority of the crop is grown. Little to no swede midge damage was observed in Timiskaming District prior to bolting.

Winter canola harvest has begun in southern regions. Many winter canola fields were terminated in late spring because of poor overwinter survival while some were retained but with lower yield expectations. However, with high prices the winter crop is proving profitable and there are certainly fields that promise to have strong yields.

Spring Canola

Fungicide application for white mould prevention has a strong return on investment in canola (both winter and spring types) because wet and humid conditions persist within the dense canopy, even in warm and sunny conditions. White mould spores colonize flower tissue, and the disease enters other healthy plant tissues when infected flower petals land on leaves or stems. Most spring canola is now beyond the 50% bloom stage, so the window to apply fungicide has closed. Significant flower petal drop has already occurred at 50% bloom, and white mould infection at later growth stages is less likely to cause significant yield loss. Fungicide applications beyond 50% bloom are also off-label, and this application timing may be within the pre-harvest interval.

Beyond 50% bloom, there usually are no management interventions until harvest time. It is very difficult to walk in canola fields during pod fill, but during late bloom stages and early pod fill it may be beneficial to check for insects. Late infections of cabbage seedpod weevil can result in holes chewed in pods (Figure 1.) which will increase the risk of shatter losses towards the end of the season. Being aware of holes in pods can inform harvest management decisions, including which fields to prioritize for prompt harvesting.

Diamondback moth larvae (Figure 2.) are another pest to watch. In late June, some fields in Timiskaming District were observed to have diamondback moth larvae present, but not at threshold levels. The larvae will feed on the exterior of pods when leaf tissue senesces, or when there is less leaf tissue due to plant stress or lack of moisture. It is difficult to effectively scout for this pest and determine if it is at threshold. The threshold is 200-300 larvae per square meter. One method is to count all the larvae on plants within a square foot, also counting any that fall to the ground. It may help to squish them as you count them. Then multiply the number of larvae by 10 to get the number per square meter. This method simplifies scouting somewhat but is not supported by all entomologists. A sweep net cannot be used to accurately scout for this pest. The Canola Watch article “Diamondback moth larvae: Common questions” can be consulted for more information.

Winter Canola

Harvest has begun on some fields in Essex and Chatham-Kent counties but is 2 or 3 weeks away in regions further north. Crops that were less healthy coming out of winter may have advanced more quickly through to maturity. Canola will dry down naturally in time, and pre-harvest herbicides are not required. Where fields are patchy and weed pressure is high, there may be value in applying a herbicide to control weeds. Herbicide applications have the added benefit of drying down plant stems faster than natural drying, but they will not speed the time to full seed colour change and maturity. Pre-harvest herbicide use may bring more value where there is an intention to plant double-crop soybeans.

Pre-harvest herbicide options include glyphosate, glyphosate plus Eragon, or Reglone. Herbicide application will help dry down plant stems, increasing ease of harvest, but note that where plant stems are very thick because of low populations or seeding on wide rows there could still be green in the stems at harvest. Reglone must have Agral 90 included in the tank. It is a true desiccant and is faster acting than the other options. There is a risk of shatter loss if there are harvest delays after Reglone application, especially if there is adverse weather such as hail, and heavy rain or wind. Performance of Reglone will be best if you spray in the evening allowing the plant to take up the herbicide, prior to a warm, sunny day. It should be applied when 80-90% of seeds have turned from green to brown-black.

Glyphosate and glyphosate plus Eragon are slower acting; harvest may be 2 or 3 weeks after application. Merge is required where Eragon is used. Eragon tends to work best when applied during warm, sunny days.  These products are applied when 65-75% of seeds have turned from green to brown-black.

Canola must be delivered to end users at 10% seed moisture or below. On a hot, sunny day, moisture can drop a couple percent through the day, so it may be possible to start harvest around 11% or 12% moisture. Canola must also be delivered with less than 2% green seed. The first seeds to change colour are at the bottom of the main stem. The last seeds to change colour are at the tips of the secondary branches.

Weather Data – July 4 – 10 2022

Location	Year	Highest Temp (°C)	Lowest Temp (°C)	Rain (mm)	Rain (mm) April 1st	GDD 0C April 1st	GDD 5C April 1st	CHU May 1st
Harrow	2022	31.4	17.4	7.5	217	1438	990	1459
	2021	32.6	11.8	11.2	253	1559	1072	1514
	10 YR Avg. (2011-20)	28.6	16.5	36.2	327	1527	1025	1576
Ridgetown	2022	30.5	16.4	4.3	181	1342	902	1333
	2021	31.9	8.7	32.4	272	1464	986	1424
	10 YR Avg. (2011-20)	29.4	14.3	25.6	266	1431	934	1462
London	2022	28.9	13.4	7.6	198	1295	860	1277
	2021	31.1	13.5	27.0	240	1457	983	1398
	10 YR Avg. (2011-20)	29.1	14.6	25.0	292	1408	915	1442
Brantford	2022	29.4	11.7	6.8	187	1292	851	1239
	2021	30.6	13.4	20.0	225	1441	966	1386
Welland	2022	27.8	12.6	1.9	193	1335	885	1317
	2021	29.1	12.5	66.1	195	1431	952	1378
	10 YR Avg. (2011-20)	28.6	15.2	11.2	281	1411	916	1444
Elora	2022	26.1	10.2	10.9	178	1181	753	1132
	2021	29.6	9.7	14.7	182	1313	848	1258
	10 YR Avg. (2011-20)	28.1	12.5	24.7	291	1257	776	1275
Mount Forest	2022	25.5	11.3	7.0	195	1181	759	1152
	2021	30.0	8.7	23.2	197	1319	857	1263
	10 YR Avg. (2011-20)	27.8	13.0	23.5	285	1238	765	1269
Peterborough	2022	24.7	6.5	6.2	219	1183	741	1155
	2021	29.2	10.3	67.5	229	1300	824	1237
	10 YR Avg. (2011-20)	28.8	12.4	9.7	258	1273	792	1281
Kemptville	2022	26.5	12.8	7.7	314	1280	818	1262
	2021	30.0	10.5	15.9	188	1417	935	1324
	10 YR Avg. (2011-20)	29.8	14.4	16.7	279	1336	856	1363
Earlton	2022	26.0	7.3	7.9	199	1051	657	1085
	2021	28.7	5.6	3.8	220	1215	758	1131
	10 YR Avg. (2011-20)	28.4	11.0	19.4	235	1033	636	1098
Sudbury	2022	22.5	10.2	12.1	208	1048	645	1066
	2021	27.3	10.1	2.1	200	1222	766	1157
	10 YR Avg. (2011-20)	28.2	12.1	24.0	264	1117	697	1178
Thunder Bay	2022	22.5	7.6	8.2	352	843	477	824
	2021	32.1	1.6	0.0	203	1095	652	1051
	10 YR Avg. (2011-20)	27.8	10.4	20.5	261	952	544	965
Fort Frances	2022	23.6	12.2	11.8	389	903	539	937
	2021	32.8	4.4	1.1	155	1166	718	1156
	10 YR Avg. (2011-20)	27.9	10.9	25.5	251	1071	645	1115