There are many insecticide seed treatment combinations available on commercial field corn seed. Although there are only 4 main active insecticide ingredients involved (imidacloprid, thiamethoxam, clothianidin, and chlorantraniliprole), there are currently at least 20 different trade names with different combinations and amounts of active ingredient per seed. The chart provided here (see below) was created as a collaborative effort by corn entomologists from across the southeast. It shows the combination and rate of the active ingredients of each product and the relative efficacy against the most common soil pests. Because of the diversity of soil pests of corn in Virginia—depending on location, soil type, crop rotation system and history of pests—product selection should be made to fit each situation. This chart can be used to select the most effective product for the most common pests of a particular field. For example, if seed corn maggot has been a chronic pest, at least 8 products are ranked as Excellent (E rating on the chart) for controlling that pest—compared with only two products that provide Excellent control of wireworm. Hopefully this chart will be helpful when selecting the best insecticide seed treatments for next year’s field corn crop.
Category Archives: Field Corn
Field corn variety insecticide trait and herbicide tolerance chart
Field corn varieties provide a dizzying array of insect toxins—at least 14 different combinations by my count—that have very different degrees of efficacy against several corn pests. The chart provided here (see below) lists the current commercial varieties, the insect toxin combination they provide, and the relative efficacy of each against the most commonly encountered corn insect pests. The chart was created as a collaborative effort by corn entomologists from across the southeast, with guidance by two in particular, Kathy Flanders at Auburn University and Dave Buntin at University of Georgia. For our purposes in Virginia, I would pay the most attention to those varieties that provide Excellent (E rating on the chart) protection against corn earworm and fall armyworm, and if you are growing continuous corn, especially in the valley and piedmont regions, corn rootworm. The chart also provides the herbicide tolerance package of each variety, and the associated refuge requirement. Hopefully this chart will help you with your choice of seed in the next season.
Field corn insecticide trait and herbicide tolerance chart
Southern Rust in Corn – Update
Southern rust continues to be reported on corn in Virginia. Southern rust was first confirmed August 3 on corn samples from Chesapeake and Suffolk. Since then, reports of southern rust have been made from Sussex and Albermarle counties, and it is likely that the pathogen is throughout much of the state. Yield of corn at or near the dent stage is unlikely to be impacted by the disease, but late planted corn in fields with good yield potential (120 bu/ac +) may need to be protected with a foliar fungicide. Strobilurins are good preventative fungicides whereas triazoles are recommended once sporulation is observed in a field due to their curative activity. A combination fungicide is a good option as long as a strobilurin fungicide has not been applied previously. Wet, warm weather favors disease development. Once sporulation occurs, symptoms of rust are relatively obvious. Lesions start out as raised, blister-like pustules then break open to reveal orange spores. Samples of corn plants with symptoms of southern rust can be submitted to the disease clinic at the Virginia Tech Tidewater AREC (contact Dr. Hillary Mehl, hlmehl@vt.edu).
Southern Rust on Corn – Update August 5, 2014
Southern rust was confirmed August 3 on corn samples from Chesapeake and Suffolk. Yield of corn at or near the dent stage is unlikely to be impacted by the disease, but less mature corn in the region may need to be protected with a fungicide application. Strobilurins are good preventative fungicides whereas triazoles are recommended once sporulation is observed in a field due to their curative activity. A combination fungicide is a good option as long as a strobilurin fungicide has not been applied previously. Wet, warm weather favors disease development. Once sporulation occurs, symptoms of rust are relatively obvious. Lesions start out as raised, blister-like pustules then break open to reveal orange spores. Samples of corn plants with symptoms of southern rust can be submitted to the disease clinic at the Virginia Tech Tidewater AREC (contact Dr. Hillary Mehl, hlmehl@vt.edu).
Results of the Corn Earworm Survey in Virginia Field Corn—2014
Annually, we conduct a survey to estimate Helicoverpa zea (corn earworm) infestation levels in field corn in mid- to late July. Corn is considered a nursery crop for corn earworm, allowing the pest to complete a lifecycle and then move on to other crops such as soybean, cotton, and peanut in August. Over 30 years of data show that there is a linear correlation between the infestation level in corn and the amount of soybean acreage that gets treated with insecticide for this pest.
To conduct the survey this year, the number of corn earworms found in 50 ears of corn was recorded in 5 corn fields in each of 29 counties, totaling 7,250 ears and 145 fields sampled. When fields were known to contain Bt or non-Bt corn, this was noted. Otherwise, samples were considered to be random and assumed to be representative of the actual Bt/non-Bt composition in each county. Age of corn earworms, or if they had already exited the ears, was also recorded (data not shown). We greatly appreciate the help of Virginia Cooperative Extension Agriculture and Natural Resource (ANR) Agents, Virginia Tech faculty and staff, and volunteers in this effort. These cooperators are acknowledged in the attached Figure. We also would like to thank the many growers who graciously allowed us to inspect their fields for corn earworm.
Results of the survey are provided below (click on the Figure to enlarge it). Statewide, approximately 20% of ears were infested with corn earworm. For comparison, 18% of ears were infested in 2013, 30% in 2012, 33% in 2011; 40% in 2010; and 36% in 2009. Regional averages for 2014 were 6% infested ears in Northern counties, 4% in the Northern Neck, 18% in Mid-Eastern, 17% in South-Central, 30% in the Southeast, and 17% on the Eastern Shore.
This survey is intended to be a representative sample, not a complete picture. We always recommend scouting individual fields to determine exactly what is happening in terms of corn earworm as well as other pests and crop problems. Also, please check the black light trap reports on the Virginia Ag Pest and Crop Advisory and other reports posted weekly to keep up-to-date on the insect pest situation.
Southern Rust on Corn in North Carolina – Update
Southern rust was confirmed on a sample from Camden County, NC on July 21. At this time, southern rust has NOT been reported in Virginia. Yield of corn at or near the dent stage is unlikely to be impacted by the disease, but less mature corn may need to be protected with a fungicide application. Contact your local extension office for recommendations if you suspect southern rust is in your area. Samples of corn plants with symptoms of southern rust should be submitted to your local extension office or the disease clinic at the Virginia Tech Tidewater AREC (contact Dr. Hillary Mehl, hlmehl@vt.edu). Typically the disease has little impact on Virginia corn since it arrives too late in the season to affect yield, but if southern rust is confirmed in Virginia prior to corn reaching the dent stage (R5), fungicide applications may be warranted. Updates will be provided as more information is obtained.
Southern Rust on Corn in North Carolina
Southern rust, a potentially devastating disease of corn, has been reported from several counties in North Carolina. At this time, southern rust has NOT been reported in Virginia. Samples of corn plants suspected to be infected with southern rust should be submitted to your local extension office or the disease clinic at the Virginia Tech Tidewater AREC (contact Dr. Hillary Mehl, hlmehl@vt.edu). Signs of the disease are pustules filled with powdery masses of orange spores (see attached photo). Typically the disease has little impact on Virginia corn since it arrives too late in the season to affect yield, but if southern rust is confirmed in Virginia prior to corn reaching the dent stage (R5), fungicide applications may be warranted. Updates will be provided as more information is obtained. Additional information: southern-rust-on-corn-jpg
Southern Rust on Corn in North Carolina
Southern rust, a potentially devastating disease of corn, has been reported from several counties in North Carolina. At this time, southern rust has NOT been reported in Virginia. Samples of corn plants suspected to be infected with southern rust should be submitted to your local extension office or the disease clinic at the Virginia Tech Tidewater AREC (contact Dr. Hillary Mehl). Signs of the disease are pustules filled with powdery masses of orange spores (see attached photo). Typically the disease has little impact on Virginia corn since it arrives too late in the season to affect yield, but if southern rust is confirmed in Virginia prior to corn reaching the dent stage (R5), fungicide applications may be warranted. Updates will be provided as more information is obtained.
Be careful if you are planning to tank mix Admire Pro with a starter/pop-up liquid fertilizer
Admire Pro applied as a liquid into the seed furrow is proving to be an excellent option for controlling thrips in cotton and peanuts. To increase efficiency, growers are beginning to look at the options for tank mixing other planting time products with the Admire Pro including different starter/pop-up liquid fertilizers. We have information that suggests that there are some combinations that are not working well.
For example, we did a field trial last summer and found that Admire Pro did NOT mix well with 10-34-0 (N-P-K). Where Ca(NO3)2 tank mixed with the Admire Pro with no problem and provided good seedling vigor and good thrips control, the 10-34-0 (N-P-K) Admire Pro tank mix did not. The Admire Pro 10-34-0 mix clotted up and caused clogginh of sprayer lines and nozzle screens. Not unpredictably, seedling vigor and thrips control were also compromised.
We recently had the same experience with a local grower. Before (thankfully) adding Admire Pro to a full load of 3-15-19, (N-P-K) starter/pop-up fertilizer we did a ‘jar’ test. We saw the same result as we did the previous summer in our field trial—that the Admire Pro clotted up in the jar and quickly precipitated out in whitish flakes to the bottom of the jar—not good.
We are beginning a project to evaluate other fertilizer products in lab ‘jar’ test mixes and will take some of these to the field this summer to look at how these mixes perform, both in terms of seedling growth enhancement and thrips control. In the meantime we STRONGLY recommend that if you are planning to tank mix Admire Pro with a starter/pop-up fertilizer that you do a ‘jar’ test to check for compatibility. And, based on our experiences, when filling the spray tank you should add the water first, then the fertilizer, then the Admire Pro last. Continual tank agitation may also be helpful to minimize the risk of any settling of the suspension.
Ames Herbert and Hunter Frame, VT, Tidewater AREC
Black light trap catches for week ending Sep. 5, 2013
Some of the higher corn earworm moth nightly averages were 37 (Dinwiddie-Old Hickory) and 66 per night (Charles City), but other reports were much lower (most were below 5 per night). Brown marmorated stink bug were caught in Petersburg (3.4 per night), Dinwiddie (1.1 per night in Old Hickory), and Warsaw (0.4 per night). Please click “More” for the complete tables. Thanks to the following for their reports this week: John Allison, Chris Drake, Mary Beahm, Scott Reiter, Mark Kraemer, Mike Parrish, and Ames Herbert and crew. Additional information: sep5blt-pdf