Soybean aphid numbers creep up

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

Soybean aphid numbers have crept up in some fields, especially in southwest Michigan. Also, there are reports in some fields in Ionia County. The aphids in the pictures I saw were fat, green, happy and concentrated on new growth (lots of nitrogen). In some fields, numbers were up to 200 to 300 on some plants. Aphid numbers remain low in the fields my lab samples at MSU and outlying farms in Montcalm and Saginaw counties, so the infestation is patchy. High numbers in some areas may be related to recent rain events, if winged aphids were carried from other locations and dropped in Michigan. But, some of the reports are from areas with sandy soil or low K, a predictable risk factor for soybean aphids.

The threshold for soybean aphids is 250 per plant (not on a single plant, the average across a field). In essence, if every plant has soybean aphids, with several-hundred concentrated on the new growth, that is 250. Note that 250 is simply a spray guide with a five- to seven-day lead time built in. Damage from soybean aphids does not actually start until there are more than 600 per plant (a very reliable, well-tested threshold).

If the soybeans are well into the R stages (R4-R5), the canopy is full and moisture is adequate, beans can easily handle the current levels of aphids and wouldn’t get sprayed unless numbers increase dramatically. Aphids living under a full canopy will eventually experience high humidity, and in the next few weeks, get infected with beneficial aphid-killing fungus. Also, there are a lot of beneficial insects in the fields we monitor and these will reduce infestations.

Beans that are younger (R1-R2), lack a canopy and need more rain are at most at risk now for yield loss.

Please only treat fields that really need to be sprayed. We do not need to flare spider mites in August.


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


Grain Storage Systems

Behlen Grain Storage Systems offers large capacity bins with diameters from 16’ to 157’ and capacities exceeding 1,500,000 bushels. All ... Read More

View all Products in this segment

View All Buyers Guides

Feedback Form
Feedback Form