Tips To Stay On Top Of Corn Thrips

Identification
Grass thrips are orange or yellow, slender insects about 1/16 inch long. Adults have two pair of feather-like wings and are darker in color. Immature thrips are wingless, yellowish in color, and are most commonly found in whorls, tassels, ears, or on the underside of leaves. Both winged adults and immatures feed by penetrating leaf cells and sucking out their contents. Minute, longitudinal, whitish scars become so numerous that entire leaves may look grayish and desiccated. Most feeding takes place behind leaf sheaths in the whorl or on the underside of lower leaves.

Thrips are most noticeable and of greatest concern at two periods during the season: on young seedling plants and at ear formation. On young seedlings, their feeding makes the plants look stunted. A common sign of a heavy thrips infestation is distorted leaves that turn brownish around the edges and cup upward.

Damage is usually noticed only under extended periods of hot, dry weather conditions when plants are moisture-stressed. Gusty winds during these periods will further desiccate plant tissue and compound thrips injury. Usually the plants will outgrow the problem, just as they outgrow injury resulting from wind damage.

At ear formation, thrips and thrips injury to developing kernels provides entry for infection by Fusarium spp. and subsequent ear rot diseases from Fusarium and other organisms that can result in losses.

Survival And Spread

Adults emerge continuously throughout the warm months. Adults and immatures may be found in corn at any time during the growing season. Eggs are deposited in plant tissue and hatching occurs in about five days during the summer months; the immature stages take about five to seven days to complete development.

Management Methods

Treatment is usually not necessary on seedlings because vigorously growing plants with adequate soil moisture will recover from thrips injury. Thrips also might be beneficial at this time because of their role as mite predators. If dry conditions persist, plants are stressed, and thrips are present, treatment may be justified. Foliar insecticides are effective for suppression of thrips. No threshold has been established for damage from thrips at ear formation. Treating for thrips will probably not prevent spread of Fusarium ear rot diseases.

Minute pirate bugs (Orius tristicolor) play a major role in controlling thrips populations. Indiscriminate use of broad spectrum insecticides can wipe out the bugs and flare thrips populations.

Good field sanitation and the preservation of beneficial insects will help to manage thrips in an organically grown crop. Thrips populations often build up on weeds. Cultivating nearby weedy areas before corn emerges will reduce potential thrips problems when the weeds begin to dry out. Cultivating weedy areas after corn emergence may increase problems.
If control is necessary, consult UF/IFAS recommendations for currently labeled insecticides for thrips control in sweet corn.

Topics:

Leave a Reply

Insect Control Stories
Biocontrols Conference
September 11, 2017
The Grower’s Take: Citrus, HLB, and Biological Control
Uncle Matt’s Organic orange juice brand has enjoyed steady growth since its 2002 inception. The brand’s success is due to Read More
Insect Control
September 6, 2017
Vegetable Pest Populations Can Soar in High Tunnels, Study Shows
High tunnels alone are not enough to control pest populations, the study shows. To control pest levels, growers need to take other steps that allow ventilation while screening crops, and supporting natural predators. Read More
Biocontrols Conference
September 1, 2017
Dispelling the Rumors: Using Biologicals and Biochemicals in IPM Programs
Whether you’re a grower, packer, processor, or retailer, you have experienced the dramatic shift in consumer preference for sustainable practices Read More
fall armyworm
Insect Control
August 24, 2017
Stop Fall Armyworm from Getting the Drop on Your Sweet Corn Crop
Learn how to identify, the survival and spread, as well as management methods for this notorious pest. Read More
Insect Control
August 22, 2017
Stink Bug Threatens High-Dollar Crops in California
While populations are low, it appears invasive pest has recently stumbled upon the state’s peaches and almonds. Read More
a freshly picked avocado cradled in hand
Crop Protection
August 3, 2017
Can Avocados Be Saved from Deadly Laurel Wilt Disease?
Scientists from Florida and California are on the case and collaborating. Read More
sprayer nozzles
Biocontrols Conference
July 31, 2017
11 New Biocontrol Products You Need to Know
One of the highlights of the Biocontrols Conference & Expo Series is getting an early look at some of the Read More
Diamondback-Moth-adult-Stormy-Sparks
Crop Protection
July 25, 2017
Vegetable Field Scouting Guide: Diamondback Moth
Due diligence is needed to help take down this pest of biblical proportions. Read More
Fruits
July 14, 2017
Brown Marmorated Stink Bug Predator Egg Mass Found
Samuri wasp parasitized egg mass found in Southern New Jersey peach orchard. Read More
Beet-armyworms-on-a-tomato-plant
Citrus
July 12, 2017
Tomato Pests Can Be Induced to Cannibalism, New Study Shows
The University of Wisconsin's John Orrock says when beet armyworms are exposed to concentrations of methyl jasmonate, they will abandon eating tomatoes — and start eating one another. Read More
darkwinged fungus gnat larvae
Fruits
July 12, 2017
How to Deal with Annoying Fungus Gnats on the Farm
Learn how to identify, the survival and spread, as well as management methods for this insect pest. Read More
Close-up of mature diamondback moth
Insect Control
July 7, 2017
Can Genetic Engineering Put an End to Diamondback Moth Plague?
USDA OKs field release of pest with self-limiting gene at Cornell research farm. Read More
Crop Protection
June 25, 2017
Study Suggests Closer-Proximity Lures Help Increase Insect Pest Catches
Research shows single-trap locations are not as effective as those kept close together. Read More
Crop Protection
June 21, 2017
Early-Season Scouting Tips for Sweet Corn Growers
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
Illustration of CRISPR-Cas9
Citrus
June 15, 2017
Make Way for Life-Saving Science on Your Farm [opinion]
While nature always finds a way to adapt, science continues to find other ways to cope. Read More
The Latest
Insect Control
September 25, 2017
Prevent Sweet Potato Weevil From Giving …
Learn how to identify, the survival and spread, as well as management methods for this insect pest. Read More
Insect Control
September 20, 2017
Whitefly Troubles Go From Bad to Worse i…
Growers should have a plan for managing the pest from beginning to end of season. Read More
Biocontrols Conference
September 13, 2017
Get Better Results From Your Biopesticid…
Softer crop protection programs are becoming a must in specialty crop production. Growers who aren’t learning more about their options Read More
Biocontrols Conference
September 11, 2017
The Grower’s Take: Citrus, HLB, and Biol…
Uncle Matt’s Organic orange juice brand has enjoyed steady growth since its 2002 inception. The brand’s success is due to Read More
Insect Control
September 6, 2017
Vegetable Pest Populations Can Soar in H…
High tunnels alone are not enough to control pest populations, the study shows. To control pest levels, growers need to take other steps that allow ventilation while screening crops, and supporting natural predators. Read More
Biocontrols Conference
September 1, 2017
Dispelling the Rumors: Using Biologicals…
Whether you’re a grower, packer, processor, or retailer, you have experienced the dramatic shift in consumer preference for sustainable practices Read More
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
Insect Control
August 22, 2017
Stink Bug Threatens High-Dollar Crops in…
While populations are low, it appears invasive pest has recently stumbled upon the state’s peaches and almonds. Read More
Crop Protection
August 3, 2017
Can Avocados Be Saved from Deadly Laurel…
Scientists from Florida and California are on the case and collaborating. Read More
Biocontrols Conference
July 31, 2017
11 New Biocontrol Products You Need to K…
One of the highlights of the Biocontrols Conference & Expo Series is getting an early look at some of the Read More
Crop Protection
July 25, 2017
Vegetable Field Scouting Guide: Diamondb…
Due diligence is needed to help take down this pest of biblical proportions. Read More
Fruits
July 14, 2017
Brown Marmorated Stink Bug Predator Egg …
Samuri wasp parasitized egg mass found in Southern New Jersey peach orchard. Read More
Citrus
July 12, 2017
Tomato Pests Can Be Induced to Cannibali…
The University of Wisconsin's John Orrock says when beet armyworms are exposed to concentrations of methyl jasmonate, they will abandon eating tomatoes — and start eating one another. Read More
Fruits
July 12, 2017
How to Deal with Annoying Fungus Gnats o…
Learn how to identify, the survival and spread, as well as management methods for this insect pest. Read More
Insect Control
July 7, 2017
Can Genetic Engineering Put an End to Di…
USDA OKs field release of pest with self-limiting gene at Cornell research farm. Read More
Crop Protection
June 25, 2017
Study Suggests Closer-Proximity Lures He…
Research shows single-trap locations are not as effective as those kept close together. 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
Citrus
June 15, 2017
Make Way for Life-Saving Science on Your…
While nature always finds a way to adapt, science continues to find other ways to cope. Read More