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Field and Forage Crops |
Unless we have an unexpected insect outbreak, this will be our last insect update for 2003. Spider mites have flared up in some widely scattered areas of the state this past week. For the most part, the recent cooler, wetter weather should help reduce the mite populations. Information on evaluating mite infestations late in the season is available on the Cotton Insect Corner web page.
With the exception of some bollworm, European corn borer and stink bug damage to bolls on very late cotton, most of our acreage should be free from further insect damage. Insect pests and their damage to our cotton crop appeared to be heavily impacted by weather this growing season. With planting and replanting dates all over the map, thrips control was variable, but in the end cotton plants showed very little difference where thrips control was good or poor. This is not typically the case in North Carolina.
Like this year's widely maturing and very well watered corn crop, the bollworm moth flight was spread over a prolonged period, and bollworm pressure varied greatly from one area to another. For many, this was a tough year to make insecticide treatment decisions. This seems to be confirmed by early returns from our damaged boll survey, with some Bollard and conventional cotton fields showing high boll damage.
Although stink bugs were generally kind to us this past growing season, plant bugs were another story. Plant bugs seemed to have benefitted from our very wet weather, with very high buildups in vegetation surrounding cotton fields. On the positive side, we can probably expect lower levels of plant bugs next season. However, odds are that stink bug levels will likely be higher in 2004, as was the case in 2000 and in 2001.
Unlike 2003, beet armyworms were at very low levels this growing season, while fall armyworms were widespread late in the season but at low levels. European corn borer moths and larvae were higher than in recent years, but were fortunately generally kind to cotton.
Cotton aphids occurred at moderate to high levels in scattered areas throughout the state again this year, but between aphid mummy parasites and the fungus, only scattered cotton fields reached treatable levels.
I have received a report of twolined spittlebug causing damage in bermudagrass in Wayne County. This is not usually a severe pest in North Carolina, but spittlebugs have been strong this year. Spittlebug damage can cause severe yellowing and some death among plants. I don't really have a threshold to offer. Some suggest 1 spittlebug per stem. Check your grass pastures. Cutting may be a solution this time around. Chemicals are an option and you can check the North Carolina Agricultural Chemicals Manual, but I would be patient and do some close monitoring this fall and again next spring, especially if we have a mild winter. Twolined spittlebug overwinters in the egg stage.
Fire ants love pastures. Pesticide labeling in pasture is tricky, however. The basic options are:
For a new note on Insects Found in Forage and Pasture, visit the following web site:
http://www.ces.ncsu.edu/depts/ent/notes/forage/past&for/past&for.html
We are seeing an increase in symptoms that may be from earlier infections of tomato spotted wilt virus. Overall the incidence has been much lower in 2003 than in 2002. Some plants are declining with symptoms that look similar to CBR. There are still plenty of worms in fields right now, but most are below thresholds and we certainly don't have a shortage of vines in most area.
Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Last modified on September 15, 2003 by Stephen J. Toth, Jr.