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From: Stephen B. Bambara, Extension Entomologist
A televised plant disease and insect clinic is scheduled for 10:15 a.m. to 12:15 p.m. on Tuesday, June 6, 2006. This will be a joint Entomology and Plant Pathology program focusing on current insect and disease problems. Sites for the televised clinic will be North Carolina State University, Elizabeth City State University, Winston Salem State University, Hickory Metro Higher Education Center, University of North Carolina at Asheville, University of North Carolina at Charlotte, East Carolina University, North Carolina A&T State University, Duke University, Carteret Community College, University of North Carolina at Wilmington, Brunswick Community College, and Fayetteville State University.
For more information, contact Tom Creswell, Department of Plant Pathology, North Carolina State University (e-mail: Tom_Creswell@ncsu.edu; telephone: 919-513-1184).
From: Jack S. Bacheler, Extension Entomologist
In the past few days, some cotton has begun to grow out of further potential for thrips damage, finally getting beyond the “thrips-safe” 5 true leaf stage. Cotton planted approximately 2 to 2 ½ weeks ago also looks reasonably good, with both seed treatments and Temik holding well. Much of our crop, however, still looks “rough”, some having come through two and occasionally three foliar treatments for thrips.
A sample of 91 adult thrips, taken from a cotton field in Halifax County in which thrips control with multiple applications was poor, was identified as just over 94 percent western flower thrips. The sobering part of this high percentage of “westerns” was that the thrips levels were high as well – between 4 and 5 adults and over 8 immature thrips per plant. This (along with another sample) may help explain the control difficulties experienced over the past several weeks in many areas of the state. Although entomologists sometimes suggest using a one-half pound of active ingredient of either Orthene or Monitor for western flower thrips on cotton, little information is available from replicated tests. Bidrin, dimethoate or a pyrethroid insecticide is not likely the answer either. This species is very tolerant to insecticides. Hopefully, this battle with thrips will be behind us before long. In years past, thrips pressure (flying adults) often eases off substantially by the end of the first week in June. Let’s hope that is the case in 2006.
Be sure to check for the actual presence of immature thrips with a hand lens or beat several seedlings against a flat white surface. Remember, thrips-damaged leaves will not be looking much better even without thrips. The best indicator of whether plants are beginning to overcome thrips damage will be the presence of new straight shiny leaves in the bud area.
Although mite problems may not materialize in 2006, several factors suggest that this could be a banner year for this pest, at least by North Carolina standards. These factors are:
This would appear to be a good year to check cotton fields for symptoms of spider mite damage, most often recognized initially by yellowish leaf speckling, followed by bronzing or a purplish color, and finally the dropping of yellowing leaves. A hand lens is almost indispensable in looking for spider mites and their eggs on the inner mid veins on the undersides of speckled or purplish leaves.
As opposed to past years in which mite levels and their symptoms primarily showed up in cotton field edges and proceeded inward, in 2004 and in 2005 it was also common for mites to show up initially throughout cotton fields, particularly in reduced tillage situations.
We have had a few reports of grasshopper damage to seedlings, which seems to be more of a problem in hot, dry weather in scattered reduced till cotton fields, and two observations of slugs reducing stands in the lower areas of reduced till cotton fields. A medium rate of a pyrethroid insecticide usually controls the red-legged and differential grasshoppers common in North Carolina, though nymphs are easier to control than adults. Slugs cannot be controlled economically in cotton.
Producers, summer scouts, consultants, and industry personnel are welcome to attend the following cotton scouting schools in North Carolina. More schools will be scheduled and announced in future issues of the North Carolina Pest News.
Robeson, Hoke and Scotland Counties: Thursday, June 15 from 10 a.m. to 12:00 noon at the County Extension Center, 116 West Prospect Street, Raeford. Contact Keith Walters (telephone: 910-875-3461; e-mail: keith_walters@ncsu.edu) or David Morrison (telephone: 910-277-2422; e-mail: david_morrison@ncsu.edu) for details.
Northampton County: Thursday, July 20 from 9:30 to 11:30 a.m. at the County Administration Building, Jackson. Contact Craig Ellison (telephone: 252-534-2711; e-mail: craig_ellison@ncsu.edu) for details.
Halifax County: Thursday, July 20 from 1:30 to 3:30 p.m. at the Agricultural Building, Halifax. Contact Arthur Whitehead (telephone: 252- 583-5161; e-mail: arthur_whitehead@ncsu.edu) for details.
From: Stephen R. Koenning, Extension Plant Pathologist, and E. James Dunphy, Extension Agronomist
This spring, Asiatic soybean rust has been found overwintering on kudzu in Alabama and Florida. These are still isolated finds and pose little threat to North Carolina at this time. Thus far many kudzu sites in Georgia, where rust was found this winter, have been destroyed and repeat visits to these sites has found no infections on new foliage. Soybean rust has been “unofficially reported” in Mexico, but the government will not comment because of “Trade Issues”. Soybean harvest is underway in Mexico now, but Mexico as a source for soybean rust is more likely to influence the Midwest rather than North Carolina. The Soybean Rust Forecast Center will soon start, including this as a possible source of rust spores. Nevertheless, vigilance is the key word. Last year we gave soybean rust a 30 percent chance of causing yield loss in soybean. Based on the fact that soybean rust is likely surviving in more locations in 2006 than in 2005 and the relatively mild winter the chances of a rust epidemic seem greater. Thus far, however, dry weather has affected many of the locations where we know rust is alive and well, which has prevented spread. Currently, there is a moderate to severe drought in Florida, Mississippi and Louisiana, which may be inhibiting development of the fungus in many areas. Monitor the web sites and be informed! Having no loss from rust in 2005 does not mean we will not have a loss in 2006. Remember, rust most likely will have to arrive before or shortly after the initiation of flowering to cause severe yield losses and soybean should not be sprayed beyond R5.
Soybean rust was first observed in South America in 2001 in Paraguay. Since 2001 it has been found in Brazil, Bolivia, Argentina, Columbia, and Uruguay. By 2004, most soybean acreage in Brazil received multiples applications of fungicides. This past year the number of fungicide applications for soybean in South America ranged from less than one in Argentina to as many as five in parts of Brazil and Bolivia. Rust was relatively light in many areas of Brazil in 2005 and 2006 because of drought, whereas other areas with abundant rainfall saw severe pressure from rust. In parts of Brazil and Argentina fungicide applications started two to three weeks before flowering. Rust was widespread in Argentina in 2004 and 2005, but yield loss from rust was considered minimal, and Argentina had record soybean yields. Argentina was expecting severe rust in 2005 and 2006, because of a mild winter that resulted in large amounts of volunteer soybean that were infected with rust. Soybean rust, however, did not develop as anticipated in Argentina even in the northern states of Entre Rios and Missiones. There were periods of drought in southern Argentina that may have impeded development of rust there, but more than adequate rainfall occurred in northern areas. Some crop professionals suggest that variation in day/night temperatures south of Brazil impede rust development. The crop consultants in Argentina take a more conservative view on management of soybean rust. In general, their recommendation is to wait until rust is found before making fungicide applications.
From: Stephen B. Bambara, Extension Entomologist
You probably feel confident that you can identify a ladybeetle or a lacewing. But can you recognize them in their immature stages? Many gardeners spray or “squish” beneficial insects that they don't recognize.
The common green lacewing occurs throughout North America. The light green adult has long, slender antennae, golden eyes, and large, veined, gauze-like wings that are 1/2 to 1/3 inch in length. It is a slow-flying, nocturnal insect that feeds on nectar and pollen, and it emits a foul-smelling fluid from special glands, if captured. It sometimes appears at porch lights. The female lacewing usually lays eggs in groups on leaves. Each egg is held above the leaf surface on a slender stalk. A female lacewing can lay up to 300 eggs over a period of 3 to 4 weeks in a greenhouse, but individuals rarely survive that long in the field. Doodlebug-like larvae and adults consume soft-bodied insects such as aphids. Sometimes larvae will attach debris to their backs for camouflage.
Lady beetles, also known as ladybugs, come in varying patterns of spots. The larvae, however, resemble something entirely different. They have long, narrow bodies with ridges and tapered abdomens. They may be dark with bright coloration or even fluffy white. Pupae may be a bit more slug-like and may mistakenly appear to be sucking the juices out of the plant. Eggs are usually yellow, oval and stand on end in clusters of about a dozen.
Every year about this time someone reports seeing this “dis-Stink-tive” bug. Unfortunately it doesn't have a common name. The scientific name is Euthyrhynchus floridanus. The nymphs are metallic teal and red (image by James Ward). While the adults have a completely different pattern of black and orange. These predatory stink bugs are attractive and eat other insects in the garden.
Flatid planthopper activity will likely begin soon with nymphal feeding and fluffy waxy spots appearing on tender shoots of many plants such as hosta, crape myrtle, hydrangea, maple, etc. The diagnostic characteristic is that they JUMP when you touch the fluff. As the summer weeks pass, the fluffy mass will expand a little. Eventually, the adults will leave and the residue will be left behind. Usually there aren't that many over which to be concerned, but if washing them off with a hose does not disrupt them enough, insecticidal soap, or other suitable insecticide should be adequate.
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 June 5, 2006 by Stephen J. Toth, Jr.
