scholarly journals Foliar Sprays of Bacillus Thuringiensis in Early Corn, 1996

1997 ◽  
Vol 22 (1) ◽  
pp. 122-123 ◽  
Author(s):  
Ruth V. Hazzard ◽  
Mark A. Mazzola
Keyword(s):  
New York ◽  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Corn Oil ◽  
Food Grade ◽  
Foliar Sprays

Abstract Sweet corn was planted 2 May in blocks of 4 rows by 25 feet. Each treatment was repeated 4 times in a RCB design. Blocks were separated by 15 feet. Insecticides were applied on 5, 11, and 18 Jul, beginning before tassels emerged. Biweekly treatments were also sprayed on 9, 16, and 22 Jul. ECB flights were monitored with two nylon Heliothis traps baited with a Trece’ pheromone lure (New York or Iowa strain). The CEW flight was monitored with a Heliothis trap with a Hereon Helicoverpa zea lure. Sprays were applied at 75 psi with a four row drop nozzle sprayer pulled (5 nozzles per row) behind a tractor. A hand held applicator delivered 0.5 ml per ear of a 1 ;20 mixture of Dipel ES and food-grade corn oil directly to the silks on 16 Jul. Plots were harvested on 29 Jul. Fifty ears per plot were rated for damage, and for presence of CEW and ECB. Two ratings are reported; Undamaged ears = no feeding on ear; undamaged kernels = no feeding on filled kernels, may have feeding on unfilled tip.

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 Optimum Timing of an Application of Corn Oil and Bacillus thuringiensis to Control Lepidopteran Pests in Sweet Corn

2004 ◽  
Vol 14 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Rosalind Cook ◽  
Anne Carter ◽  
Pamela Westgate ◽  
Ruth Hazzard
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
European Corn Borer ◽  
Sweet Corn ◽  
Corn Oil ◽  
Corn Earworm ◽  
Larval Feeding ◽  
Corn Borer ◽  
Late Planting ◽  
All Treatment

Corn oil and Bacillus thuringiensis ssp. kurstaki (Bt) applied directly into the silk channel of a corn ear has been shown to be an effective pesticide against corn earworm, Helicoverpa zea (CEW), and european corn borer, Ostrinia nubilalis (ECB). Field studies were conducted in 2000 and 2001 to determine the influence of application timing on ear quality at harvest. Two blocks of corn were planted during each year to observe treatment effects under varying populations of the two insect species. The treatment consisted of 0.5 mL (0.017 floz) of food grade corn oil containing a suspension of Bt at 0.08 g (0.003 oz) a.i. per ear applied directly into the silk channel at the husk opening. One treatment application was made on each silk day 3 through 11 from first silk; silk day 1 was the first day that 50% or more of ears had 2.5 cm (1 inch) of silk protruding from the husk. One treatment did not receive the oil + Bt suspension. All ears were harvested at milk stage, on silk day 25. The number of CEW larvae in treated ears increased with later application days in 2000, but not in 2001. Damage from larval feeding was mainly found near the tip of the ear, and damage ratings were lower compared to untreated ears for all treatment days for both plantings in 2000, and through application day 8 in the late planting of 2001. ECB larvae were reduced for all treatment days in both plantings in 2000 and the late planting of 2001. The percentage of ears rated as marketable (i.e., free of feeding damage) ranged from 71% to 100% in treated plots compared to 30% to 77% in the untreated plots. There was a linear decrease in marketability with later application days in two of the four plantings. The greatest decrease in marketability was after application day 7. Because the oil application affects kernel development at the tip, the length of ear with under-developed kernels, or cone tip, was measured. The number of ears with cone tip decreased linearly with the later application days in all plantings. There was 10% conetip or less after day 7 in 2000 and day 6 in 2001. The best combination of effective insect control resulting in the highest rates of marketable ears with the least degree of cone tip was achieved in this experiment by application of oil + Bt suspension on day 7. Year to year variation in the environment would suggest a range from day 6 to 8.

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.

Technology of production of biopesticides based on Bacillus thuringiensis

2021 ◽  
Vol 9 (16) ◽  
pp. 28-38
Author(s):  
Anatolii Bezusov ◽  
◽  
Valentyna Krutiakova ◽  
Olena Myroshnichenko ◽  
Nataliia Dotsenko ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Corn Oil ◽  
Raw Materials ◽  
Culture Fluid ◽  
Scientific Work ◽  
Insect Larvae ◽  
Effective Prevention ◽  
Research Results ◽  
Wide Range ◽  
Vegetable Raw Materials

Subject of research. Biopesticides are based on live cultures of specially selected beneficial microorganisms with controlled properties. They have a pronounced phytoprotective and stimulating effect, thus providing effective prevention and protection of plants from diseases. The obtained biological product increases productivity, improves the quality and structure of the crop, does not accumulate in plants, which allows to obtain environmentally friendly agricultural products and does not harm the environment. Among the large number of bacteria, as a source of microbiological insecticide is Bacillus thuringiensis, which infects lepidopteran pests and leads to their death. Preparations based on this strain are effective when used in low concentrations of solutions. The Bacillus thuringiensis strain produces several toxins with insecticidal action, including β-exotoxin and δ-endotoxin. Toxic effect is manifested and leads to paralysis of the intestinal tract of parasites. Preparations β-exotoxin and δ-endotoxin are obtained by culturing Bacillus thuringiensis bacteria in a liquid medium. The scientific work proposes a method of industrial production using by-products of vegetable raw materials, which makes it economically feasible to use such substrates. The purpose of the study is the development of technology, formulation of nutrient medium, process parameters for the cultivation of bacteria of the genus Bacillus thuringiensis and obtaining a culture fluid containing substances of the class of biopesticides. Methods. Standard and generally accepted methods of research of bioproducts in biotechnology. The formation of bioinsecticides was established by hydrolysis methods, followed by determination of the component of β-exotoxin – ribose, the formation of octagonal crystals of exotoxin – by microscopic method. Research results. Three variants of nutrient media, which include yeast-polysaccharide complex: corn flour, corn oil, yeast autolysate were developed. The parameters of the bacterial cultivation process were studied. The final product is a paste or powder with a titer of 35 .109 spores in 1 g of the bioproduct. Scope of research results. Microbiological preparations based on Bacillus thuringiensis are highly specific and act only on insect larvae from the classes Lepidoptera and Diptera. The resulting biopesticide can be used against pests of a wide range of vegetable and fruit crops.

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.

scholarly journals Common Receptor for Bacillus thuringiensis Toxins Cry1Ac, Cry1Fa, and Cry1Ja in Helicoverpa armigera, Helicoverpa zea, and Spodoptera exigua

2005 ◽  
Vol 71 (9) ◽  
pp. 5627-5629 ◽  
Author(s):  
Carmen Sara Hernández ◽  
Juan Ferré
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Helicoverpa Zea ◽  
Spodoptera Exigua ◽  
Cross Resistance ◽  
Binding Studies ◽  
Lepidopteran Species ◽  
Common Receptor ◽  
Binding Data ◽  
Helicoverpa Armígera

ABSTRACT Binding studies using 125I-Cry1Ac and biotinylated Cry1Fa toxins indicate the occurrence of a common receptor for Cry1Ac, Cry1Fa, and Cry1Ja in Helicoverpa armigera, Helicoverpa zea, and Spodoptera exigua. Our results, along with previous binding data and the observed cases of cross-resistance, suggest that this pattern seems to be widespread among lepidopteran species.

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