Stay on Your A Game to Conquer Corn Leaf Aphid

Corn leaf aphids on sweet corn
Photo courtesy of Bugwood.org

Pest Specs

The corn leaf aphid (Rhopalosiphum maidis Fitch) can be problem for Florida sweet corn growers. These aphids usually feed within the whorl of corn, and are most apparent at or just before tassel push. This pest sucks sap from plants and excrete a sticky sugary substance called “honeydew.” The honeydew can become moldy, giving the tops of the plants a black, sooty appearance.

Identification

The corn leaf aphid is a blue-green or gray, soft-bodied, spherical insect about the size of a pinhead (roughly 1/16 inch in length). The end of the abdomen and bases of cornicles are not reddish as in birdcherry aphids.

Nymphs resemble adults, except they are smaller and are sexually immature. Adults and nymphs often can be found clustered within the whorls or upper parts of corn plants over isolated or wide areas of a field.

Most corn leaf aphids are wingless. However, as populations increase, some develop delicate, filmy wings. These wings enable them to fly to uninfested plants to start new colonies. Winged females have a black head and thorax and a green abdomen.

Like other insects, aphids shed their skin as they grow. These numerous white-to-gray discarded skins give the appearance of a white mold or ash on leaf surfaces.

Heavily infested corn leaves may wilt, curl, and show yellow patches of discoloration. When tassels and silks are covered with honeydew, the pollination may be disrupted. Excessive feeding results in incomplete kernel development and/or barren ears. Aphids cause the greatest damage while feeding within the whorl where their presence is not usually apparent.

Heavy accumulation of honeydew on husks also can affect the marketability of ears.

The insect also acts as a vector of Maize dwarf mosaic virus.

Survival and Spread

The corn leaf aphid overwinters in the southern states and migrates northward in the summer. Aphids reproduce parthenogenetically — that is the female aphids do not need to mate with male aphids and give birth to live nymphs. The generation time is very short and overlaps. This so-called telescoping of generations enables rapid multiplication of corn leaf aphids in a short period of time. Initially, colonies of corn leaf aphid reproduce rapidly in corn whorls until tassel emergence, after which they move downward to the stalks and leaves. Winged forms known as alates are typically observed around tassel emergence and senescence.

Management Methods

Natural enemies may control these aphids under low pesticide input situations such as silage corn. However, in sweet corn, they appear at a time when pesticide use increases for armyworm, greatly reducing the potential control by predators and parasitoids.
Chemical control of this aphid is more effective when they are exposed on the emerging tassel. Several insecticides are available for corn leaf aphid control in sweet corn. They are more susceptible than birdcherry oat aphids to pesticides frequently used for armyworm control.
Make sure to consult UF/IFAS recommendations for currently labeled insecticides for corn leaf aphid control in Florida sweet corn.

Topics: ,

Leave a Reply

One comment on “Stay on Your A Game to Conquer Corn Leaf Aphid

  1. If you have aphids in your corn your nitrate levels are probably too high. You likely need one or more of the following to convert your nitrates to protein. Molybdenum, sulfur, or manganese. You can find out what your nitrate/protein balance is, as well as most other nutrient levels, with a plant sap analysis from Crop Health Labs. My favorite tool.

Sweet Corn Stories
Sweet Corn
June 13, 2017
45 Years Ago, a Hard Freeze in June Killed an Entire Sweet Corn Crop
While late freezes aren’t uncommon, temps in the teens in mid-June are. That’s what happened to growers 45 years ago Read More
Corn leaf aphids on sweet corn
Sweet Corn
May 24, 2017
Stay on Your A Game to Conquer Corn Leaf Aphid
Learn how to identify, the survival and spread, as well as management methods for this vegetable pest. Read More
Sweet Corn
April 7, 2017
22 of the Latest Sweet Corn Varieties [slideshow]
Browse this slideshow for more information on 22 sweet corn varieties you need to know in 2017 from the nation’s leading seed Read More
Pest Control
March 22, 2017
Fear of GMOs is Impacting Quality Food Research [Opinion]
Perhaps the greatest threat to our industry is a public that values instinctual opinion over careful research and the findings of experts who have dedicated years to their field of study. Read More
Sweet Corn
March 13, 2017
DNA Study Gives Insight in how Corn Adapts to New Climates
A new study has mapped the close correlation between maize’s response to altitude and flowering triggers. Understanding how the two Read More
Cucurbits
December 20, 2016
3 New Fungicide Product Options for Vegetable Growers
Unique modes of action the main feature of modern chemistries. Read More
Profile shot of Clifton Seed's Aspire sweet corn
Sweet Corn
October 20, 2016
12 Sweet Corn Varieties Florida Growers Can Count On
Open your eyes and ears to the latest and greatest cultivars. Read More
farm labor pic for web
Labor
October 12, 2016
Labor Shortages Mean Lost Income
Agriculture is not a typical industry; fresh produce can't wait in the field for a crew to come and harvest it. Read More
Sweet Corn
October 11, 2016
Branch Farms Debuts ‘Sweet Emotion’ Sweet Corn 
New variety performs well in terms of taste, quality, and shelf life. Read More
Crop Protection
October 6, 2016
The Effects Of Poly-Coated Urea On Sweet Corn Production
Research compares the effects between poly-coated urea and regular urea on sweet corn growth. Read More
white grubs
Cucurbits
September 21, 2016
Don’t Let White Grubs Gobble Up Your Vegetable Crop
Learn how to identify, the survival and spread, as well as management methods for this pest. Read More
Sweet Corn
August 30, 2016
Abbott & Cobb Forms Licensing Agreement With Syngenta
The long-term agreement involves licensing Abbott & Cobb’s patented SuperSeedWare technology to Syngenta Seeds for use in sweet corn varieties.  Read More
Tar spot of corn
Disease Control
August 23, 2016
Florida Sweet Corn Has New Deadly Stalker In Tar Spot
Learn how to identify, the survival and spread, as well as management methods for this disease. Read More
Common smut of corn
Disease Control
July 19, 2016
Open Your Eyes To Common Smut In Sweet Corn
Learn how to identify, the survival and spread, as well as management methods for this formidable fungus. Read More
Insect Control
July 6, 2016
Miticide Label Now Includes Sweet Corn
Agri-Mek SC miticide/insecticide from Syngenta controls two spotted spider mites. Read More
The Latest
Insect Control
August 24, 2017
Stop Fall Armyworm from Getting the Drop…
Learn how to identify, the survival and spread, as well as management methods for this notorious pest. Read More
Sweet Corn
July 19, 2017
Variety Specs | Production Tips: Corn &#…
Each month, American Vegetable Grower® will offer growing tips on specific varieties, supplied by the breeder or distributor. This month, we’re offering Read More
Crop Protection
June 21, 2017
Early-Season Scouting Tips for Sweet Cor…
Black cutworm and true armyworm have been caught in relatively high numbers across the Midwest, including Michigan. Learn more about determining risk and scouting in your sweet corn plantings. Read More
Sweet Corn
June 13, 2017
45 Years Ago, a Hard Freeze in June Kill…
While late freezes aren’t uncommon, temps in the teens in mid-June are. That’s what happened to growers 45 years ago Read More
Sweet Corn
May 24, 2017
Stay on Your A Game to Conquer Corn Leaf…
Learn how to identify, the survival and spread, as well as management methods for this vegetable pest. Read More
Sweet Corn
April 7, 2017
22 of the Latest Sweet Corn Varieties [s…
Browse this slideshow for more information on 22 sweet corn varieties you need to know in 2017 from the nation’s leading seed Read More
Pest Control
March 22, 2017
Fear of GMOs is Impacting Quality Food R…
Perhaps the greatest threat to our industry is a public that values instinctual opinion over careful research and the findings of experts who have dedicated years to their field of study. Read More
Sweet Corn
March 13, 2017
DNA Study Gives Insight in how Corn Adap…
A new study has mapped the close correlation between maize’s response to altitude and flowering triggers. Understanding how the two Read More
Cucurbits
December 20, 2016
3 New Fungicide Product Options for Vege…
Unique modes of action the main feature of modern chemistries. Read More
Sweet Corn
October 20, 2016
12 Sweet Corn Varieties Florida Growers …
Open your eyes and ears to the latest and greatest cultivars. Read More
Labor
October 12, 2016
Labor Shortages Mean Lost Income
Agriculture is not a typical industry; fresh produce can't wait in the field for a crew to come and harvest it. Read More
Sweet Corn
October 11, 2016
Branch Farms Debuts ‘Sweet Emotion’ Swee…
New variety performs well in terms of taste, quality, and shelf life. Read More
Crop Protection
October 6, 2016
The Effects Of Poly-Coated Urea On Sweet…
Research compares the effects between poly-coated urea and regular urea on sweet corn growth. Read More
Cucurbits
September 21, 2016
Don’t Let White Grubs Gobble Up Yo…
Learn how to identify, the survival and spread, as well as management methods for this pest. Read More
Sweet Corn
August 30, 2016
Abbott & Cobb Forms Licensing Agreem…
The long-term agreement involves licensing Abbott & Cobb’s patented SuperSeedWare technology to Syngenta Seeds for use in sweet corn varieties.  Read More
Disease Control
August 23, 2016
Florida Sweet Corn Has New Deadly Stalke…
Learn how to identify, the survival and spread, as well as management methods for this disease. Read More
Disease Control
July 19, 2016
Open Your Eyes To Common Smut In Sweet C…
Learn how to identify, the survival and spread, as well as management methods for this formidable fungus. Read More
Insect Control
July 6, 2016
Miticide Label Now Includes Sweet Corn
Agri-Mek SC miticide/insecticide from Syngenta controls two spotted spider mites. Read More