Mild winter temperatures during the months of December, January and February indicate the potential for high populations of flea beetle in most regions of Missouri. In our model, the potential for flea beetle damage is calculated by adding together the average daily winter temperatures for the months of December, January and February. If the average monthly temperatures for these months add to less than 90 degrees Fahrenheit, then the risk of economic flea beetle infestations is low. If the total is between 90 degrees and 100 degrees, moderate flea beetle damage can be expected. Heavy damage is possible if the three monthly averages total 100 degrees or more. Data from the 17 Commercial Agricultural Weather Stations located around the state are summarized by regions of the state and specific counties in the following table. Average monthly temperatures are given in degrees Fahrenheit. The following information has been provided by Jim Jarman, regional agronomy specialist. My thanks to Jim for his efforts and contribution to the newsletter.

2006 Corn Flea Beetle Predictions Table 1 For Missouri

Table 1. The sums of average monthly Fahrenheit temperatures for December 2005, January and February 2006 are used to predict flea beetle survival in Missouri. The University Missouri Commercial Agriculture Automated Weather Station Network on the Agricultural Electronic Bulletin Board (AgEBB) provided high, low and average Fahrenheit temperatures.
County, University of Missouri Commercial Agriculture automated weather station location	Sum of average winter temperatures (Degrees Fahrenheit)
Northern Missouri Region Average Temperature	96.08
Atchison County, Graves Memorial Plots (3 miles north of Corning)	97.80
Gentry County, Hundley-Whaley Farm (Albany)	93.60
Linn County, Forage Systems Research Center (Linneus)	95.90
Knox County, Greenley Memorial Center (1 mile east of Novelty)	93.70
Buchanan County, Buchanan County Extension Center (St. Joseph)	99.40
Central Missouri Region Average Temperatures	104.44
Audrain County, 6 miles northwest of Auxvasse	101.60
Chariton County, 4 miles west of Brunswick	98.60
Boone County, South Farms (4 miles southeast of Columbia)	104.00
Boone County, Sanborn Field (University of Missouri)	107.30
Monroe County, Monroe City (Monroe City Airport)	103.40
Morgan County, Versailles R-II Outdoor Classroom	110.10
Pettis County, Green Ridge R-VIII School District	105.80
South West Missouri Region Temperature	112.30
Barton County, Lamar (Barton County Electrical Cooperative)	112.30
South Central (Ozark) Missouri Region Average Temperatures	106.10
Crawford County, Wurdack Farm (2 miles east of Cook Station)	109.90
Shannon County Alley Springs (Ozark National Scenic Riverways Network)	101.60
Shannon County Round Springs (Ozark National Scenic Riverways Network)	106.80
South East Missouri (Bootheel) Region Average Temperatures	119.36
Cape Girardeau County, Delta	112.00
Dunklin County, Cardwell	121.60
Dunklin County, Rice Farm (1 mile east of Glennonville)	119.80
Dunklin County, Rhodes Memorial Research Farm (north of Clarkton)	118.00
Mississippi County, (5 miles south of Charleston)	117.00
Pemiscot County, Delta Center (Portageville)	121.70
Pemiscot County, (6 miles west of Steele)	122.60
Pemiscot County, Lee Farm (5 miles southeast of Portageville, MO)	122.20

Biology/ Damage
Flea beetles are small, dark, jumping beetles which overwinter as adults. In early spring, they move to seedling corn and feed on plant foliage from the time of plant emergence through about the fourth-leaf stage of growth. Adult beetles strip the chlorophyll layer (green tissue) from the surface of seedling corn leaves resulting in the formation of "window panes" or translucent areas in leaf surfaces. Damage is often seen as translucent tracks or lines that run parallel to the veins of the corn leaf. Heavy flea beetle infestations cause plants to look "tattered" and wilted, similar to the type of injury caused to seedling corn when blasted by blowing sand. The most injurious flea beetle attacking corn is the corn or maize flea beetle. Typically, infestations are most severe in years where mild winters allow for increased survival of adults, and cool temperatures and drought conditions during spring result in slowed growth of corn plants. Flea beetles may transmit Stewart’s wilt (a bacterial wilt) to corn, although most field corn has resistance to this plant pathogen. The economic threshold for implementation of control methods for flea beetles in field corn is an average of five or more beetles per corn seedling up through the fourth-leaf stage of development. To scout for flea beetles, examine corn plants for feeding damage and determine the average number of flea beetles present per corn plant. This is most readily accomplished in the early morning or late afternoon by walking slowly through the field and counting beetles as they feed. Remember, flea beetles are easily recognized by their jumping ability similar to grasshoppers.

Management Options
Although the model predicts high populations of flea beetle for most areas of the state, a couple factors may limit flea beetle numbers in the 2006 season. First, adult beetle mortality may be higher than predicted due to several rapid changes in temperatures during winter months and this spring. A second factor may be that the widespread use of seed treatments for corn during the past few years may be suppressing flea beetle problems statewide, similar to what Bt corn has done to the European corn borer populations throughout the Midwest. Regardless of predictions and insecticide use, producers are encouraged to scout seedling corn for the presence of flea beetle this spring.

If an economic population is found, an effective management option for flea beetle is the use of foliar applied insecticide rescue treatments. Several insecticides are labeled for this use once the economic threshold has been reached or exceeded. Cruiser and Poncho seed treatments also provide good protection from this pest due to their systemic activity in seedling foliage.

First Capture Of Black Cutworm Moths
The first capture of BCW moths in central Missouri occurred in mid-March. Moth captures have been low since that time due to several days of cold temperatures and very high winds preventing moth movement over the landscape. Captures of moths are expected to increase over the next few days as warmer temperatures are predicted. Visit the IPM Web site at http://ipm.missouri.edu/pestmonitoring/blackcutworm/index. htm for additional information on black cutworm activity and predictions for first cutting of field corn by 4th instar larvae.

Insecticides And Rates Labeled For Flea Beetle Management Used As Rescue Treatment On Field Corn Include The Following:

Flea Beetles	Permethrin	Ambush*	6.4 to 12.8 fl oz	Over row	Treatment is justified when 5 or more beetles per plant are present or when seedling plants are being severely damage or killed and beetles are present.
	Esfenvalerate	Asana XL*	5.8 to 9.6 fl oz
	Cyfluthrin	Baythroid 2*	0.8 to 1.6 fl oz
	Bifenthrin	Capture 2EC*	2.1 to 6.4 fl oz
	Bifenthrin	Fanfare 2EC*	2.1 to 6.4 fl oz
	Chlorpyrifos	Lorsban 4E*	1 to 2 pt
	Zeta-cypermethrin	Mustang Max*	2.72 to 4 fl oz
	Chlorpyrifos	Nufos 4E*	1 to 2 pt
	Microencapsulated Methyl parathion	Penncap-M*	2 to 3 pt
	Permethrin	Pounce 3.2EC*	4 to 8 fl oz
	Gamma-cyhalothrin	Proaxis*	2.56 to 3.84 fl oz
	Carbaryl	Sevin XLR Plus	1 to 3 pt
	Lambda-cyhalothrin	Warrior*	2.56 to 3.84 fl oz
	* indicates restricted use pesticide (RUP)
Treatment is justified when five or more beetles per plant are present or when seedling plants are being severely damage or killed and beetles are present.
Be sure to read and follow all label directions, precautions, and restrictions.

Wayne Bailey
573-882-2838 office
or 573-864-9905 cell