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No. 07/May 11, 2001

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IN THIS ISSUE:
U.S. Drought Monitor
Recent rains in some areas of Illinois have alleviated concerns, at least for a while, about dry soil conditions. However, the weather in southern counties continues to be hot and dry, and the crops could use some rain.

The U.S. Drought Monitor Web site includes a map that delineates dry and droughty conditions throughout the United States. You might want to keep this Web site handy if you want to stay current with drought conditions.

Black Cutworm Captures Continue: Don't Delay Scouting Efforts in Central and Southern Illinois
Sporadic captures of black cutworm moths continue to be observed throughout the state of Illinois. Flights of black cutworms will continue to take place throughout the state. Late-planted and weedy fields will be the prime targets for egg-laying female moths. During the rush to get soybeans planted, don't neglect to scout cornfields that have emerging seedlings.

Armyworms in No-Till Corn, Wheat, and Pasture
Recent reports about armyworms causing damage in no-till corn and wheat have been numerous. Growers with grass pasture and grass hay fields need to look for armyworms right now before the damage gets out of hand. Lack of scouting may result in a significant lack of grass for livestock. Armyworms often cause significant damage seemingly overnight, so scouting is the only way to detect an infestation before it's too late.

Reports of White Grub and Grape Colaspis Damage
Grape colaspis larvae caused some significant damage over the past couple of years in fields of corn planted after soybean in west-central and western counties. This year will probably be the same. In addition, several cornfields have already been replanted as a result of white grub damage in Menard County near Greenview.

There are no rescue treatments for either white grubs or grape colaspis. After damage by these pests is discovered, the only reasonable response is to determine whether the current stand will provide the yield hoped for. If the plant population has been reduced substantially, replanting might be the right thing to do.

Grape Colaspis: A Quick Review
This article reviews some of what we know and some of what we don't know about grape colaspis. The following questions are discussed:

What types of fields are most susceptible to injury caused by grape colaspis?
What does injury caused by grape colaspis look like?
What do grape colaspis larvae look like?
What do we know about their life cycle?
Are any soil insecticides registered for control of grape colaspis larvae?
So what can be done if grape colaspis larvae are causing significant stand reduction?

Southern Corn Leaf Beetles Found in Lots of Fields
We have received numerous reports about the presence of southern corn leaf beetles throughout southern, western, and west-central Illinois since our first report of their presence, and they continue to cause significant damage in some fields throughout the affected area.

With black cutworms and other insect pests working in cornfields right now, proper diagnosis of the pest causing the damage is extremely important.

More European Corn Borer Moth Captures Reported in Southern Illinois
Ron Hines reported the capture of 13 European corn borer moths in a pheromone trap on May 8. Additional moths were caught in other pheromone traps. Ron indicated that these captures represent the greatest weekly totals in the last 4 years for his trapping location. Does this mean the first generation of European corn borers may cause more problems than anticipated? This article discusses the question.

Bean Leaf Beetles Will Converge on Early-Planted Soybean Fields
Bean leaf beetle adults can now be observed commonly throughout the state. The questions and answers in this article are intended to provide a brief review of the life cycle of bean leaf beetles and also to offer some insights on management strategies.

What's the best way to correctly identify bean leaf beetle adults?
Where do bean leaf beetles spend the winter?
When do bean leaf beetle adults abandon alfalfa?
Are bean leaf beetle larvae considered of any economic importance?
How many generations of bean leaf beetles occur in Illinois?
What are the suggested economic thresholds for bean leaf beetle adults on seedling soybeans?
Do bean leaf beetles vector the bean pod mottle virus?

First Soybean Aphids of the Season in Illinois
Two soybean aphids were found on a Rhamnus shrub in Kane County on May 7, 2001. This discovery answers one of the burning questions about this pest: Will soybean aphids survive the winter in Illinois?

Now the watch begins. Finding only two aphids doesn't mean that soybean aphids will become problematic in soybeans again this year. However, knowing that they're still present in the state at least gives us a "heads up."

Alfalfa Weevils and Biological Control Agents
Alfalfa weevils have done their damage to the first crop in southern Illinois, have caused significant damage to the first crop in some fields in central and western Illinois, and currently are present and causing injury in northern counties. Many growers were caught by surprise, as if the alfalfa weevil larvae appeared overnight. Obviously this underlines the importance of early and frequent scouting.

Alfalfa weevils will be present in some stage of development in most of Illinois throughout May, so keep your eye on them. However, as temperatures increase, the adults eventually leave alfalfa fields seeking shelter from the heat. The adults won't return to the alfalfa fields until the fall to begin the cycle all over again.

Potato Leafhoppers Can Be Found Statewide
On May 2, Dave Feltes reported his first observations of potato leafhoppers for the 2001 growing season, 3 weeks earlier than last year. Potato leafhoppers not only reduce yields but they also may have a significant negative effect on the nutritional quality of hay and also may impair the vigor of a stand. Growers should begin scouting alfalfa fields now and at least on a weekly basis throughout the growing season. Potato leafhoppers will be with us through the first several hard frosts.

This article discusses the following questions:

What do potato leafhoppers look like?
What kind of life cycle do leafhoppers have?
How do leafhoppers injure plants?
What's the best way to scout for potato leafhoppers?

Alfalfa Blotch Leafminer Confirmed in Will County
This year a survey effort was initiated to see whether the alfalfa blotch leafminer still is present in Illinois and, if so, where it occurs. Although we have not completed the survey, we have found adult alfalfa blotch leafminers (four per 100 sweeps) and a little pinhole injury in a field in Will County.

The alfalfa blotch leafminer is capable of becoming an economic problem, although the presence of natural enemies often keeps leafminer densities below economic levels. Knowing that it is present in Illinois alfalfa now, even in low numbers, will enable us to mount an educational campaign to alert producers and others about what to look for and when.

Virus Disease Risk in Early-Emerged Soybeans
Many pest species interact to cause larger problems than they would singly. The bean leaf beetle is one such pest. It not only causes physical damage to the plant by feasting on the leaves but can also transmit a viral plant disease called bean pod mottle virus (BPMV). First-emerged soybean fields are at a greater risk of BLB feeding than later-emerged fields. Consequently these fields are at greater risk of being infected with BPMV.

This article discusses the disease, its symptoms, its transmission, and its management.

Hophornbeam Copperleaf
This article examines the morphology and biology of hophornbeam copperleaf and proves suggestions for control.

Sidedress N Application
From a plant-growth viewpoint, sidedressing is the ideal time for N application. However, if not done correctly, it can cause seedling injury. This article compares the techniques available.

Regional Reports
Extension Center educators, Unit educators, and Unit assistants in northern, west-central, east-central, and southern Illinois prepare regional reports to provide more localized insight into pest situations and crop conditions in Illinois. The reports will keep you up to date on situations in field and forage crops as they develop throughout the season.

This week's issue includes reports from northern, southern, and west-central Illinois.



The Pest Management and Crop Development Bulletin
Executive Editor: Kevin Steffey, Extension Entomologist

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