Observations from a $#%*! Growing Season: Notes on the ’04 Late-Season Crops

Sunflowers
The crop was planted at near normal timeframes compared to the five year average, but got delayed due to cool wet weather in mid-May. The weather that followed after planting had a huge impact on emerging plants and sunflowers up to the four-leaf stage.

This weather pattern set up a lot of sunflower acres for infection of downy mildew, both as primary and secondary infection. A number of seed companies beginning in 2005 will offer some new DM resistant hybrids, as well as the option of Cruiser supplemented with the seed treatment fungicide Dynasty (azoxystrobin) for downy mildew suppression in sunflower.

More acres were treated with seed insecticides like Cruiser and Concur in 2004 to deal with wireworm and other secondary insects. Stands were very good when these products were used to keep early insects under control. Later in the season, there were other insect issues, such as a high incidence of sunflower midge and seed weevils at around the reproductive stages. Also, there was a high number of sunflower maggots that seemed to cause some distortion of the heads this year when they appeared in high numbers. Banded sunflower moth also was a problem in areas that already got hit by sunflower midge.

Wet weather set in during the delayed pollination period, resulting in sclerotinia for many producers that seemed to get worse the further north and east you went in North Dakota.

Soybeans
This warm season crop had a rough start as cool wet conditions in mid-May caused delayed germination, reduced stands, and more issues with seedling diseases.  It was when they got into the ground that the weather delayed the emergence and issues like pythium, rhizoctonia, fusarium, and phytophthora started to show up. Seed treatments showed their benefit up to the 1st trifoliate stage of the crop as there was less loss due to diseases. Short rotations didn’t help in suppressing disease inoculum pressure.

Lack of heat and too much moisture caused some of the crop to seed out into June. One of the worst weed issues for a number of growers was volunteer Roundup Ready canola in the crop, particularly north. The weed emerged too early to use ALS or IMI chemistry, so there were many fields that had heavy pressure early on and with the moisture throughout the season, saw pressure after flowering started. Late applications of Raptor seemed to delay beans for a couple of days.

Some mid-season disease showed up this year in heavy abundance: brown spot and bacterial blight. Weather conditions were perfect for the infections and many acres showed symptoms at 1st-2nd trifoliate stage. After plants got to the V5+ stage, it wasn’t an issue for the rest of the season. There was also more Phytophthora that showed up this year as the year was very good for disease infections. Variety selection is very important when it comes to looking at soil types and disease pressure.

Nothing prepared anyone for the freeze of August 20 that in some cases ended the soybean crop in northern Minnesota and northeast N.D. Maturity played a large part in which varieties suffered most or not as bad. Early varieties did better than later, and solid seed was generally better than beans in rows. Bushy varieties held the frost away from most of the plant better than varieties with thinner stems and smaller leaves.

The weather did straighten out quite a bit and soybeans started some regrowth and actually had more blossoms again. With a very wet late August and early September, the next big issue was white mold that set in late and took a large bite out of some fields. Some fields were harvested with 40% dockage due to sclerotinia later on. Green regrowth, late bloom periods and wet weather for a long period of time contributed to this situation.

The only good thing that can be said for soybeans this year was the reduced presence of the soybean aphid. The potential was there for large damage as the crop was not as far along as it was the year before. There were some areas that had some activity, but overall the threat was very isolated.

Corn
For all the genetic diversity, hybrid characteristics and production practices that make corn what it is, the weather made everything else take a back seat. Planting progress started out very well but just like other crops, was delayed by cool, wet weather.

Corn sat in the ground for up to three weeks in some cases. This caused some issues with stands as heavy disease pressure from pythium, rhizoctonia,  and seedling blights set in to reduce initial planting populations. Wireworm also became a problem on acres that were not treated with Cruiser, Poncho or Concur. This insect will persist for a longer than normal period of time due to the cool weather during the growing season.  It also seems to be more of a problem in no-till fields.

Cool (heck, downright cold) weather made growers nervous about applying herbicides to a stressed crop. Corn that was normally five leaf and about eight inches tall was now only about four to five inches tall but still at the same leaf stage. The technology of herbicide-tolerant crops showed its value this year as Roundup Ready and Liberty Link corn were not affected by herbicide applications like some of the conventional programs.

Injury wasn’t as big as anticipated, but delaying the maturity of some conventional varieties with ALS chemistries in combination with plant growth regulators was observed. Like soybeans, one of the biggest weed issues this year was the pressure of volunteer glyphosate-tolerant canola in the corn crop in northern areas. Cloudy, cool, wet weather made for issues of using certain products to control the weeds.

There was corn that got froze off in mid-May but rebounded out of that, only to be behind for the rest of the season. There were many reports of purple corn due to phosphate deficiency symptoms, hybrid characteristics and wet seed beds. Also, nitrogen and sulfur were moved out of the root zone early in the season. So there was a lot of corn that was suffering from cold temperatures, lack of certain fertility requirements, slowly metabolizing herbicide applications, and poor root systems. Insects were not that big of an issue this year. Corn borer infestations were present in small numbers.

June-July temperatures didn’t fluctuate very much as the area kept falling behind in heat units. Then the unexpected August 20 hard freeze hit when a lot of corn was in the late watery to milk stage. This weather event doomed much of the crop in the northern part of the growing area and set the stage for low test weight corn. Some plants turned death white three days after this freeze while other varieties a couple of miles away seemed to handle it very well, so note the difference in hybrids.

After that hard frost, the weather actually became fairly decent considering the year. A good September helped with fill on the crop. The crop in the southern areas still had a chance to make a crop; but the northern portions the crop adjusters were waiting to see how many heat units were going to be compiled before the crop was to be adjusted.

The season ending killing frost occurred in the first week of October. A lot of corn north of Hwy 2 in N.D. did not make it. South of Highway 2, the crop was wet with harvest delays. Early maturities made corn in areas where later traditional hybrids are the norm. 

The abnormal growing season is sure to weigh on the minds of many growers as they figure their crop rotations and select hybrids for ’05.  That said, growers should also keep in mind that conditions were abnormal.  Go ahead and tweak your rotation and hybrid mix, but drastic changes might be unnecessary. If you want to sleep better in the next growing season, the best bet might be hedging your production with a few more acres of early-season crops and/or earlier-maturing hybrids.

Hanson, Devils Lake, N.D., is a regional agronomist with Agriliance.

Pinpointing ’04 Pest Problems

See maps indicating survey results for disease and insect pressure in North Dakota online at www.ag.ndsu.nodak.edu/ndipm.   The NDSU IPM web site features images of pest incidence and severity for various insects and diseases in wheat, barley, soybeans and sunflower.  Minnesota Department of Agriculture Pest Survey results can be found online at www.mda.state.mn.us/pestsurvey.