Mild winter for bean leaf beetle

decrease font size  Resize text   increase font size       Printer-friendly version of this article Printer-friendly version of this article

click image to zoomFigure 1. Predicted overwintering mortality of bean leaf beetle based on accumulated subfreezing temperatures during the 2011-2012 winter (1 October 2011 – 8 March 2012). Most Iowa winters are harsh on overwintering bean leaf beetles. Typical statewide overwintering mortality ranges from 60-99 percent (see a 20-year historical record of predicted bean leaf beetle mortality in central Iowa.) A combination of cold winter temperatures and the high adoption of insecticidal seed treatments have drastically curbed bean leaf beetle populations throughout much of the state.

Bean leaf beetle adults are susceptible to cold weather and will die when the temperature is below -10 degrees C, but they have adapted to winter by protecting themselves in leaf litter and insulating snow cover. An overwintering survival model was developed by Lam and Pedigo from Iowa State University in 2000, and is helpful for predicting winter mortality based on accumulated subfreezing temperatures. Figure 1 is a map of predicted mortality in Iowa for the 2011-2012 winter.

click image to zoomFigure 2. Overwintering bean leaf beetles can defoliate young soybean plants and vector bean pod mottle virus. In general, Iowa experienced a warm winter, with predicted mortality ranging from 30-53 percent. The predicted mortality estimates are the lowest since the overwintering model was developed. Many areas in the state had less than normal accumulated snow cover, which could increase actual adult mortality. A recent ICM News article discusses the implications for warm winters, lack of snow cover and insect survival. 

Overwintering adults are strongly attracted to soybean and will move into fields with newly emerging plants (Fig. 2). Early-planted fields should be monitored closely this year, given the predicted likelihood of adult overwintering survival. Other fields of concern include food-grade soybean and seed fields where reductions in yield and seed quality can be significant. Information about managing bean leaf beetle and bean pod mottle virus is available on the Iowa State entomology website. 

Bean leaf beetle is easily disturbed and will drop from plants and seek shelter in soil cracks or under debris. Sampling early in the season requires you to be sneaky to estimate actual densities. Although overwintering beetles rarely cause economic damage, their presence may be an indicator of building first and second generations later in the season.


Buyers Guide

Doyle Equipment Manufacturing Co.
Doyle Equipment Manufacturing prides themselves as being “The King of the Rotary’s” with their Direct Drive Rotary Blend Systems. With numerous setup possibilities and sizes, ranging from a  more...
A.J. Sackett Sons & Company
Sackett Blend Towers feature the H.I.M, High Intensity Mixer, the next generation of blending and coating technology which supports Precision Fertilizer Blending®. Its unique design allows  more...
R&R Manufacturing Inc.
The R&R Minuteman Blend System is the original proven performer. Fast, precise blending with a compact foot print. Significantly lower horsepower requirement. Low inload height with large  more...
Junge Control Inc.
Junge Control Inc. creates state-of-the-art product blending and measuring solutions that allow you to totally maximize operating efficiency with amazing accuracy and repeatability, superior  more...
Yargus Manufacturing
The flagship blending system for the Layco product line is the fully automated Layco DW System™. The advanced technology of the Layco DW (Declining Weight) system results in a blending  more...
Yargus Manufacturing
The LAYCOTE™ Automated Coating System provides a new level of coating accuracy for a stand-alone coating system or for coating (impregnating) in an automated blending system. The unique  more...
John Deere
The DN345 Drawn Dry Spreader can carry more than 12 tons of fertilizer and 17.5 tons of lime. Designed to operate at field speeds up to 20 MPH with full loads and the G4 spreader uniformly  more...
Force Unlimited
The Pro-Force is a multi-purpose spreader with a wider apron and steeper sides. Our Pro-Force has the most aggressive 30” spinner on the market, and is capable of spreading higher rates of  more...
BBI Spreaders
MagnaSpread 2 & MagnaSpread 3 — With BBI’s patented multi-bin technology, these spreaders operate multiple hoppers guided by independent, variable-rate technology. These models are built on  more...


Comments (0) Leave a comment 

Name
e-Mail (required)
Location

Comment:

characters left


Tube Series (TS) Conveyors

USC’s Tube Series Conveyors combine the gentleness of the signature Seed Series with the traditional stability of a tube-style conveyor, ... Read More

View all Products in this segment

View All Buyers Guides

Feedback Form
Feedback Form