The Bulletin Archives - Page 66 of 78

Wheat scab rearing its ugly “head” again in 2014

June 16, 2014
Aaron Hager

Head scab of wheat (a.k.a. Fusarium head blight) is showing up in the southern portion of Illinois. In many cases, incidence is moderate to high (over 50% of the heads affected). Affected wheat heads will appear “bleached” in color. Heads often are partially affected, with both healthy green and affected bleached areas being present in the same head. Although I have not been in all wheat production areas in the state, my general observations are that fields in southern Illinois (south of Interstate 70) range from a moderate to high incidence of scab. …

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University of Illinois to Offer Assistance Identifying Palmer Amaranth

June 16, 2014
Aaron Hager

Accurate identification of weedy Amaranthus species during early vegetative stages sometimes can be difficult. Differentiating between smooth pigweed and waterhemp is relatively easy since one species (smooth pigweed) has pubescence on the stem and leaves while the other does not. However, differentiating between waterhemp and Palmer amaranth during early vegetative stages can be much more difficult. To assist weed management practitioners in accurately identifying Palmer amaranth, we will accept tissue samples from suspected Palmer amaranth plants and use tools of molecular biology to identify whether the plant is Palmer amaranth or another species of Amaranthus. …

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Nitrogen in Late Spring 2014

June 13, 2014
Emerson Nafziger

The corn crop in Illinois is off to a good start in many fields, and in most areas is in the V5 to V8 growth stages, just starting its rapid growth phase. On average, the crop under good conditions will add some 200 lb of dry matter per acre per day over the next 80 days or so. It will take up 3-4 lb per day of nitrogen before pollination, after which the N uptake rate will slow.…

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Low Numbers of Soybean Aphids Found in Spring Survey

June 6, 2014
Michael Gray

Once again, Drs. Dave Voegtlin (retired entomologist, Illinois Natural History Survey) and Dave Hogg (Professor of Entomology, University of Wisconsin) conducted their annual spring survey of soybean aphids. From May 12-17, they looked for soybean aphids on the primary host — common buckthorn, Rhamnus cathartica. At some sampling locations, they also examined the glossy buckthorn, Frangula alnus. The overall assessment by these entomologists — there were fewer soybean aphids this spring as compared with the previous 2 years.…

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Western Corn Rootworm Hatch Underway Across Central Illinois

June 5, 2014
Michael Gray

Larry Bledsoe and his Purdue University entomology colleagues have a long tradition of being the first to report the annual hatch of western corn rootworm larvae. Larry indicated to me and some other entomologists that hatch began to occur on June 2 on one of the research farms near the Purdue University campus.
Provided below is a list (19 years) of western corn rootworm hatch dates (for central Illinois and central Indiana) taken from previous Pest Management and Crop Development Bulletin articles (since 1996) and based upon observations by Larry Bledsoe and other Purdue University entomologists.…

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Be Alert for Potato Leafhoppers in Alfalfa: New Pest Profile Published Recently

May 27, 2014
Michael Gray

Reports of potato leafhoppers in alfalfa typically begin to increase in late May and early June. Many entomologists consider potato leafhoppers to be the most significant economic insect threat to profitable alfalfa production. Recently a team of entomologists from the University of Wisconsin, the Illinois Natural History Survey, and the USDA ARS authored a peer-reviewed pest profile of potato leafhoppers. This profile offers up-to-date information on the biology, life cycle, injury, hosts, and management options for this key pest in alfalfa.…

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Soybean Injury from Soil-Applied Herbicides

May 20, 2014
Aaron Hager

Integrated weed management programs offer the greatest potential for long-term, sustainable solutions to weed populations demonstrating resistance to herbicides from multiple families. Soil-residual herbicides are important components of integrated weed management programs and provide several benefits, including reducing the intensity of selection for resistance to foliar-applied herbicides. Recent survey data indicate the percentage of Illinois soybean acres treated with soil-residual herbicides has increased during the past few years.
In the vast majority of instances, soil-applied herbicides control target weed species with little to no adverse effect on the crop. …

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Scattered Reports of Armyworms in Wheat Across Southern Illinois

May 20, 2014
Michael Gray

There have been scattered reports of armyworm infestations in southern Illinois wheat with some fields receiving an insecticide treatment. I encourage producers to review the biology, life cycle, and management information in the University of Illinois fact sheet on armyworms. With respect to economic thresholds, there is some variation from state to state. Provided below are thresholds from four land grant universities for consideration. They share some common features. If an insecticide rescue treatment is warranted,…

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Another Look at Soybean Planting Date

May 18, 2014
Emerson Nafziger

Soybean planting is off to a mediocre start in Illinois, with 26% of the crop planted by May 11, and limited progress with the rain of this past week. Planting will resume in some places this week, but other areas remain wet and it will take some time for soils to dry out. In comparison with recent history this is not yet a serious delay, but as time passes the delay will become a bigger concern.…

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It’s not too early to scout for Palmer amaranth

May 16, 2014
Aaron Hager

Planting progress may have been slowed by the recent precipitation, but weed emergence continues despite wet field conditions. Be aware that Palmer amaranth has begun to emerge. We scouted our Palmer amaranth field location west of Kankakee on May 8 and observed emerged Palmer amaranth plants (Figure 1).

We returned to the field on May 15 to find a very robust Palmer amaranth population (Figure 2). The largest Palmer amaranth plants found on May 15 were approximately 2 inches tall with 6 to 8 true leaves.…

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