Soybean aphid numbers are suddenly rising

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

It is late in the season but there is still one important insect pest to watch for in the next few weeks and that is the dreaded soybean aphid. There are several factors that could lead to a late outbreak:

1) The weather has been perfect for aphid development – temps in the low to mid-80's with relatively low humidity present ideal conditions for aphid reproduction. During our sweltering July aphids likely shut down for the most part, as they do not reproduce as rapidly at temperatures over 90,

2) There are many fields over threshold in northern Indiana and Michigan, and suction traps are capturing large numbers of winged aphids. Thanks to Dr. David Voegtlin, emeritus of the Illinois Natural History survey, we know that our Indiana suction traps (30' tall PVC tubes that suck in flying insects from overhead) have been starting to catch large numbers of migrating aphids. This is how the aphids colonize new areas and move away from areas that are too "crowded."

3) Many late-planted beans are still in vulnerable stages. Aphids will seek out the youngest beans they can find. These are the most nutritious for them, and the plants of course are most sensitive at these earlier development points. Southern Indiana producers, many of whom have many acres of late-planted beans, should be particularly vigilant.

Sampling: Count aphids, primarily on the undersides of leaves, on at least 20 plants in various areas of the field. When aphids are just beginning to colonize soybean plants, they will be concentrated on the most active growing points – the newest unrolled leaves and the developing pods. Shortcuts: if aphids are observed on the petioles and stems, that plant is over 250 aphids. If honeydew and sooty-mold are obvious as you walk the field, the threshold has been exceeded.

Aphid Number: Should you find an average of 250 or more aphids/plant during the pod and seed development stages (R3-R4), a treatment is justified. Threshold of ≥250 aphids/plant includes a week to get field sprayed. During the seed-fill stages (R5-R6), treatment is not as clear-cut. If aphid numbers are increasing and plants are under stress, however, a treatment is justified, see accompanying threshold graphic. Do NOT treat soybean beyond the R6 stage of growth, the plant is already beginning to senesce and any aphids that are there will not impact yield.


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 

e-Mail (required)


characters left

1325 Bushel Grain Cart

Equipped with a 22” computer balanced auger with 5/16” flighting,the unloading speed is 50% faster than smaller grain carts with ... Read More

View all Products in this segment

View All Buyers Guides

Feedback Form
Feedback Form