Survey of organic sweet corn growers identifies corn earworm prevalence, management and opportunities for plant breeding

2020 ◽  
pp. 1-4
Author(s):  
Virginia M. Moore ◽  
William F. Tracy
Keyword(s):  
Plant Breeding ◽  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Insect Pest ◽  
Corn Earworm ◽  
Management Options ◽  
Current Management ◽  
Corn Production ◽  
Resistant Varieties ◽  
The U.S

Abstract Corn earworm (Helicoverpa zea) is one of the most important pests in organic sweet corn (Zea mays) production. Breeding of corn earworm-resistant varieties has been identified as a potential approach to deal with this pest, but it is critical that plant breeding efforts reflect the contexts and needs of organic producers who might eventually adopt earworm-resistant varieties. In November–December 2017, we surveyed organic sweet corn producers in the U.S. to learn about impacts of corn earworm on organic sweet corn production, how producers are currently managing the pest and opportunities for plant breeding to reduce its overall impact. The survey confirmed that corn earworm is the most challenging insect pest for organic sweet corn producers, that current management options remain limited and that earworm-resistant varieties could improve the ability of growers to consistently produce damage-free sweet corn and to improve the value of sweet corn within organic operations.

scholarly journals Combining Ability of Husk Extension, Maysin Content, and Corn Earworm Resistance

2021 ◽  
Vol 146 (1) ◽  
pp. 14-23
Author(s):  
Virginia M. Moore ◽  
William F. Tracy
Keyword(s):  
Zea Mays ◽  
Combining Ability ◽  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Corn Earworm ◽  
Management Options ◽  
Mating Design ◽  
Cultivar Development ◽  
Factorial Mating ◽  
Factorial Mating Design

Corn earworm (Helicoverpa zea) is a destructive pest with limited management options in sweet corn (Zea mays) production. Increased husk extension and the presence of the C-glycosyl flavone maysin are two proposed mechanisms for improving corn earworm resistance in corn cultivars. A factorial mating design was conducted to test hybrid combinations of sweet corn inbreds with long husks and/or maysin to identify candidates for future cultivar development. The mating design had seven male parents, including three commercial sweet corn inbreds (Wh9261, We11401, and Wt1001) and four inbreds selected for maysin content (Maysin1, 2, 3, and 4), and five female parents, including two commercial sweet corn inbreds (Ia453su and Ia5125su) and three inbreds with long, thick, tight husks (A684su, A685su, and A686su). Hybrids were evaluated for ear length, husk length, maysin content, and corn earworm resistance at six environments in 2016 and 2017. Relationships between husk extension, maysin, and corn earworm resistance were inconsistent, but five inbreds produced hybrids with significantly lower corn earworm infestation and/or damage, demonstrating potential to confer resistance to the corn earworm.

scholarly journals Occurrence and Ear Damage of Helicoverpa zea on Transgenic Bacillus thuringiensis Maize in the Field in Texas, U.S. and Its Susceptibility to Vip3A Protein

Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 102 ◽  
Author(s):  
Fei Yang ◽  
José C. Santiago González ◽  
Jayme Williams ◽  
Donald C. Cook ◽  
Ryan T. Gilreath ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
Sustainable Use ◽  
Leaf Tissue ◽  
Corn Earworm ◽  
Laboratory Population ◽  
Bt Maize ◽  
Cry Proteins ◽  
Damage Area ◽  
The U.S

The corn earworm, Helicoverpa zea (Boddie), is a major pest of Bacillus thuringiensis (Bt) maize and cotton in the U.S.. Reduced efficacy of Bt plants expressing Cry1 and Cry2 against H. zea has been reported in some areas of the U.S.. In this study, we evaluated the occurrence and ear damage of H. zea on transgenic Bt maize expressing Cry proteins or a combination of Vip3A and Cry proteins in the field in Texas in 2018. We found that the occurrence of H. zea larvae and the viable kernel damage area on the ear were not different between non-Bt maize and Bt maize expressing Cry1A.105+Cry2Ab2 and Cry1Ab+Cry1F proteins. A total of 67.5% of the pyramided Bt maize expressing Cry1Ab+Cry1F+Vip3A was damaged by 2nd–4th instar larvae of H. zea. Diet bioassays showed that the resistance ratio against Vip3Aa51 for H. zea obtained from Cry1Ab+Cry1F+Vip3A maize was 20.4 compared to a field population collected from Cry1F+Cry1A.105+Cry2Ab2 maize. Leaf tissue bioassays showed that 7-day survivorship on WideStrike3 (Cry1F+Cry1Ac+Vip3A) cotton leaves was significantly higher for the H. zea population collected from Cry1Ab+Cry1F+Vip3A maize than for a Bt-susceptible laboratory population. The results generated from this study suggest that H. zea has evolved practical resistance to Cry1 and Cry2 proteins. Therefore, it is crucial to ensure the sustainable use of the Vip3A technology in Bt maize and cotton.

Ear Pests and Damage to Organic, Conventional and Bt-Protected Sweet Corn Grown in Central Kentucky

2009 ◽  
Vol 44 (4) ◽  
pp. 383-390
Author(s):  
John D. Sedlacek ◽  
Karen L. Friley ◽  
Steve L. Hillman
Keyword(s):  
Helicoverpa Zea ◽  
European Corn Borer ◽  
Sweet Corn ◽  
Crop Protection ◽  
Fall Armyworm ◽  
Corn Earworm ◽  
Genetically Engineered ◽  
Corn Borer ◽  
Sap Beetles ◽  
Southwestern Corn Borer

Sweet corn (Zea mays L. var. rugosa) was grown in replicated plots in 2004 and 2006 using organic, conventional, and genetically-engineered (Bt) production practices. Organic plots were treated with Entrust® (Dow AgroSciences LLC, Indianapolis, IN) whereas conventional and Bt sweet corn plots were treated with Warrior® (Syngenta Crop Protection, Inc., Greensboro, NC). All plots were treated once at silk emergence. Organic and conventional plots were treated again 1 wk later. Twenty-five ears were harvested from row centers in each treatment subplot to quantify ear pests and assess ear damage. The highest number of corn earworm, Helicoverpa zea (Boddie), larvae were found on organically-grown sweet corn. European corn borer, Ostrinia nubilalis (Hübner); southwestern corn borer, Diatraea grandiosella Dyar; and fall armyworm, Spodoptera frugiperda (J.E. Smith), larvae were not found as frequently. Neither corn earworm nor European corn borer larvae were found on Bt sweet corn ears. Sap beetles, Carpophilus lugubris Murray, were found on all 3 types of sweet corn. Organically and conventionally-grown sweet corn had a greater number of tip-damaged ears and numbers of damaged kernels per ear than Bt sweet corn. Ear length and weight were the same for all 3 types of sweet corn. Based on the information generated in this study, growing late-planted sweet corn organically or conventionally on a large commercial scale with a limited spray program and without using other types of ear pest management does not appear to be a practical or profitable option in central Kentucky.

scholarly journals Phytotoxicity and Pollination Disorders in Sweet Corn Due to Direct-silk Applications of Materials Used for Alternative Corn Earworm Control

2007 ◽  
Vol 17 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Tori Lee Jackson ◽  
Mark G. Hutton ◽  
David T. Handley
Keyword(s):  
New England ◽  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Corn Oil ◽  
Corn Earworm ◽  
Soy Oil ◽  
Conventional Management ◽  
Repeated Applications ◽  
Materials Used ◽  
Significant Injury

Corn earworm [CEW (Helicoverpa zea)] is one of the most important pests of sweet corn (Zea mays) in New England. Conventional management of this pest is achieved through repeated applications of chemical insecticides through the silking period. Organic growers, however, have few alternatives to prevent CEW infestation. Technology first developed in the 1930s and 1940s, using applications of mineral oil directly into the silk channel with an eyedropper, has been further researched in recent years using vegetable oils with and without pesticides, but pollination problems associated with these treatments have been observed. Several materials were evaluated for efficacy in controlling CEW populations and for phytotoxicity to the developing ear. Materials evaluated were corn oil, soy oil, carrageenan, corn oil mixed with Bacillus thuringiensis ssp. kurstaki (Bt), soy oil mixed with Bt, and carrageenan mixed with Bt. All treatments were compared with an untreated control. Treatments provided a range of 33% to 50% control of CEW infestation. The oil and Bt combinations provided some reduction in infestation compared with the untreated controls (33% vs. 100% infestation), but this level of control was inadequate for all wholesale markets and most direct markets. Additionally, oil-based treatments also caused significant injury to developing ears by reducing pollination quality, impacting the development of the kernels at the ear tip. This condition referred to as “cone-tip” is of concern since it may decrease marketability. The percent unmarketable ears due to cone-tips ranged from 0% to 13% for the untreated and carrageenan-based treatments. From 12% to 42% of ears were unmarketable due to the soy oil treatments. Corn oil treatments caused 10% to 50% cone-tips.

scholarly journals 429 Production of Fresh Baby Corn

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 518C-518
Author(s):  
C.A. Miles
Keyword(s):  
Sweet Corn ◽  
Row Spacing ◽  
Close Monitoring ◽  
Kernel Size ◽  
Corn Production ◽  
Field Corn ◽  
Length Width ◽  
Western Washington ◽  
Market Criteria ◽  
The U.S

Fresh baby corn is an ideal niche market crop. It is easy to produce and is growing in popularity in the U.S. In 1997 and 1998, we tested 10 corn varieties to determine suitability for fresh baby-corn production in western Washington. By harvesting ears 1 to 3 days after silk emergence, baby corn can be produced from many common sweet corn varieties, including `Kandy King', `Bodacious', `Tendertreat', and `Custer'. Ear quality characteristics such as length, width, and kernel size and appearance of these common sweet corn varieties were as good as for the variety Baby Corn, a specialty variety produced exclusively for baby corn. The corn variety GH2283, produced in the U.S. for sale of seed to Asia for baby-corn production, produced the best-quality baby corn ears in our trial. Using an in-row spacing of 2 inches, ears of baby corn can be harvested for 4 to 6 weeks, depending on variety, from a single planting. Market criteria for baby corn are 2 to 4 inches long and 1/3 to 2/3 inch in diameter at the butt end. Delaying harvest of sweet corn varieties for 3 days resulted in ears that were too large for baby corn. Field corn varieties in this trial required close monitoring to meet size criteria and delaying harvest 1 to 2 days resulted in ears that were too large. Harvest of baby corn is all by hand and height of the ear on the plant significantly affects ease of harvest, where dwarf varieties are the least easy to harvest.

Field Bioassay of Pheromone Lures and Trap Designs for Monitoring Adult Corn Earworm (Lepidoptera: Noctuidae) in Sweet Corn in Southern New England

1920 ◽  
Vol 17 (3) ◽  
pp. 1833-1836
Author(s):  
Norman L. Gauthier ◽  
Patrick A. Logan ◽  
Lisa A. Tewksbury ◽  
Craig F. Hollingsworth ◽  
Donald C. Weber ◽  
...  
Keyword(s):  
New England ◽  
Rhode Island ◽  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Corn Earworm ◽  
Reference Standards ◽  
Fresh Market ◽  
Field Bioassay ◽  
Southern New England ◽  
Lepidoptera Noctuidae

Four commercial pheromones attractive to Helicoverpa zea (Boddie) were used as baits in four insect traps to attract moths in fresh market sweet corn. Moth catches were monitored for 10 wk in nine sites in Connecticut, Massachusetts, and Rhode Island. Zealure attracted twice as many moths as Scentry's corn earworm lure and nine times as many as Pherocon's corn earworm lure. Consep Membrane's Biolure attracted few moths. Hartstack traps caught three times more moths than Heliothis net traps and 15 times more than Multi-pher or International Pheromone Systems traps. Results suggest the need for reference standards in management programs that use pheromones to monitor corn earworm populations.

scholarly journals Direct Silk Applications of Corn Oil and Bacillus thuringiensis as a Barrier to Corn Earworm Larvae in Sweet Corn

2003 ◽  
Vol 13 (3) ◽  
pp. 509-514 ◽  
Author(s):  
Rosalind Cook ◽  
Anne Carter ◽  
Pam Westgate ◽  
Ruth Hazzard
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Corn Oil ◽  
Field Studies ◽  
Corn Earworm ◽  
Untreated Plot ◽  
Promising Alternative ◽  
First Instar ◽  
Almost All

Field studies were conducted in 2000 and 2001 to rate the efficacy and longevity of four pesticide treatments against corn earworm (Helicoverpa zea) larvae (CEW) in sweet corn (Zea mays). The four treatments used were 1) corn oil, 2) Bacillus thuringiensis ssp. kurstaki (Bt), 3) oil + Bt, and 4) an untreated plot. All treatments were applied on silk day 5. Silk day 1 was the first day that more than 50% of the ears had 2.5 cm (1 inch) or more silks emerging from the husk using a hand-held pump applicator. Two first-instar CEW larvae were placed directly into silk channel of selected ears on 6 different days (days 3, 6, 9, 12, 15, and 18 after first silk). The same six ears were then harvested 4 days later. Untreated ears had more live CEW and higher levels of feeding damage than the other three treatments ears for all harvest days in both years. The number of CEW found per ear was lower when Bt was included in the treatment. The use of corn oil gave the lowest damage ratings on almost all harvest days in both years. Treatments which contained oil had the highest number of marketable ears in both years, but also the highest percentage of underdeveloped kernels at the tip of the ear (6% to 9%). The oil and Bt treatments appeared to control CEW for at least 17 days, from silking through maturity. This treatment regime appears to be a promising alternative for growers to conventional pest management methods.

scholarly journals Pest Management Needs and Limitations for Corn Earworm (Lepidoptera: Noctuidae), an Emergent Key Pest of Hemp in the United States

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kadie E Britt ◽  
Thomas P Kuhar ◽  
Whitney Cranshaw ◽  
Christopher T McCullough ◽  
Sally V Taylor ◽  
...  
Keyword(s):  
United States ◽  
World War Ii ◽  
Pest Management ◽  
Helicoverpa Zea ◽  
Cannabis Sativa ◽  
Insect Pest ◽  
The United States ◽  
Corn Earworm ◽  
Minimal Risk ◽  
Lepidoptera Noctuidae

Abstract Corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), has emerged as an injurious insect pest to hemp, Cannabis sativa L., a crop newly reintroduced to the United States. Growing hemp presents a potential alternative economic opportunity for farmers but can be challenging with a market that is unstable and just developing. One of the most notable production challenges is managing corn earworm, an insect pest that is particularly damaging when it feeds on flower buds produced in cannabinoid varieties, creating extensive bud tunneling and wounds that allow entry of pathogens that can aid development and presence of bud rot. Damage to seeds is of lesser concern in hemp cultivars grown for grain and minimal risk is associated with hemp grown for fiber. Our ability to research hemp has only recently been allowed as production was largely suspended following World War II and, as such, there has been limited opportunity to develop information for empirically-based pest management recommendations. Further complicating development of integrated pest management (IPM) strategies are regulatory challenges associated with providing registration support to add hemp to pesticide labels, as it was not formally recognized as a crop by U.S. regulatory agencies until late 2019. Research needs and challenges to develop effective IPM programs for corn earworm on hemp are discussed here.

Evidence for Decreasing Helicoverpa zea Susceptibility to Pyrethroid Insecticides in the Midwestern United States

2007 ◽  
Vol 8 (1) ◽  
pp. 57 ◽  
Author(s):  
W. D. Hutchison ◽  
E. C. Burkness ◽  
B. Jensen ◽  
B. R. Leonard ◽  
J. Temple ◽  
...  
Keyword(s):  
United States ◽  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Survival Rates ◽  
Field Tests ◽  
Corn Earworm ◽  
High Survival ◽  
Vegetable Crops ◽  
Pyrethroid Insecticides ◽  
Midwestern United States

The corn earworm (CEW), Helicoverpa zea (Boddie), is a highly mobile pest of numerous field and vegetable crops in much of North America. In the Midwestern United States, CEW is a voracious pest of several high-value vegetable crops, including sweet corn, tomatoes, and snap beans, and seed corn grown for the field corn industry. Historically, synthetic pyrethroid insecticides have been cost-effective and have provided excellent control of CEW, with control of larvae in sweet corn exceeding 90%. However, since 2000 pyrethroids have only provided 35 to 45% control in field tests conducted in the Midwest, as indicated by small-plot sweet corn efficacy trials. During 2005, the four most commonly used pyrethroids averaged only 19.3 to 37.3% control of CEW (mean of 5 trials in Minnesota, Wisconsin, Illinois, and Indiana). In addition, the survival of moths exposed to the standard pyrethroid, cypermethrin, using the Adult Vial Test (AVT), indicated high survival rates (44 to 66% at 5 μg cypermethrin and up to 45% survival at 10 μg). These levels are similar to, or higher than recent AVT results from Louisiana and Texas. These states reflect two possible “source” regions of late-season CEW that likely migrate north to the Midwestern states each summer. These results, including the stability of resistance each year in the Midwest, are discussed within the context of developing and expanding a North American resistance monitoring and management network. Accepted for publication 3 June 2007. Published 19 July 2007.

scholarly journals Maize silk antibiotic polyphenol compounds and molecular genetic improvement of resistance to corn earworm (Helicoverpa zea Boddie) in sh2 sweet corn

2010 ◽  
Vol 1 (1) ◽  
pp. 3 ◽  
Author(s):  
Baozhu Guo ◽  
Ana Butrón ◽  
Brian T. Scully
Keyword(s):  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Gene Action ◽  
Molecular Genetic ◽  
Pleiotropic Effect ◽  
Corn Earworm ◽  
Critical Factors ◽  
Polyphenol Compounds ◽  
Field Corn ◽  
Antibiotic Compounds

The flavor of sh2 super-sweet corn is preferred by consumers. Unfortunately, sh2 sweet corn has little genetic variation for insect resistance. In this paper we review the functions of two loci, p1 and a1. The P1 allele has a major role in sh2 sweet corn resistance to corn earworm, an allele that was lost in historical selection because of its pleiotropic effect on undesirable cob color and silk browning. The P1 allele has significant effects on biosyntheses of silk antibiotic compounds, maysin, apimaysin, methoxymaysin, and chlorogenic acid. The effect of a1 shows gene action for lowered maysin and significant epistatic action with p1. The dominant functional allele A1 causes anthocyanin pigments in aleurone, plant, and pericarp tissues; the recessive a1 allele causes absence of pigment in these tissues. If silk browning and cob color are critical factors for maysin production but lack the customer’s preference, then separating red cob and browning silk, which are controlled by the P1 allele, may be difficult if not impossible. One high silk maysin sh2 sweet corn germ­plasm, shrunken Zapalote Chico, has been released. There is some field corn germplasm with p1-wwr alleles, but the amount of antibiotic flavones and their potential as a donor need further investigation.

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