Pulsed Odors from Maize or Spinach Elicit Orientation in European Corn Borer Neonate Larvae

Abstract Corn was planted at the University of Illinois Cruse Farm, Champaign, Illinois, on 24 May. The experimental design was a split plot with natural or manual infestation of ECB as the main plots and 5 different B/-corn hybrids and their non-Br isolines as the subplots. Each plot was 4 rows (30-inch) wide X 40 ft long with 35 plants per row (after thinning). Treatments were replicated 5 times. Manual ECB infestations to simulate the first-generation were made on 3 and 6 July at the V7 corn leaf stage by releasing approximately 50 neonate larvae in corn grit into the whorls of corn plants using a ‘bazooka’ applicator. Manual ECB infestations to simulate the second-generation were made at corn anthesis on 7 Aug by applying approximately 25 neonate larvae in corn grit to the leaf exiles above and below the ear node. On 8 Aug, 25 neonate larvae were applied to the ear node and the second leaf axil above the ear node. All manual infestations were made to all plants (70 total) in the middle 2 rows of each plot. On 31 Jul, 20 consecutive plants were rated for leaf feeding by first generation larvae by using the 1 to 10 Guthrie scale. On 9 and lOOct, 15 consecutive plants from 1 of the middle 2 rows were split with a corn knife for evaluation. The number of plants with cavities and the total length of cavities per plant were recorded. Also, the number of live larvae per plant was recorded. The mean percentage of plants with cavities, the mean length of stalk tunneling (in inches) per plant and the mean number of live larvae were determined for each plot. ECB damage to the ear and shank were analyzed separately from the stalk damage data. An ear rating scale of 1 to 3 was used, with 1 being tip damage only, 2 being side damage only, and 3 being tip + side damage on the same ear. Shelled grain weights (yields) were taken from the 15 dissected plants, corrected to 15.5% moisture, and added to the machine harvested weights (moisture corrected) for the remaining plants of the middle 2 rows in each plot.

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SWEET CORN EAR RESISTANCE TO THE EUROPEAN CORN BORER (Ostrinia nubilalis, Hubner) AND ITS RESPONSE IN SINGLE CROSSES.

HortScience ◽

10.21273/hortsci.27.6.645f ◽

1992 ◽

Vol 27 (6) ◽

pp. 645f-645

Author(s):

Mary S. Joyce ◽

Dave W. Davis

Keyword(s):

Ostrinia Nubilalis ◽

European Corn Borer ◽

Sweet Corn ◽

Corn Hybrids ◽

Corn Borer ◽

Breeding Lines ◽

Corn Breeding ◽

Resistant Lines ◽

Additive Gene ◽

Neonate Larvae

Development of sweet corn hybrids having resistance to ear feeding by the European corn borer (ECB) (Ostrinia nubilalis, Hübner) would save growers millions of dollars annually. Sweet corn breeding lines have been developed which show resistance to ear feeding. To determine whether resistance in these lines was heritable, testcrosses were made between 6 resistant lines and 2 susceptible inbreds. The testcrosses, resistant lines, susceptible inbreds, and Jubilee, a standard susceptible hybrid, were planted in randomized complete blocks replicated 8 times at each of 2 locations. Primary ears were infested, on the ear tip, at mid-silk (R3) with approximately 50 neonate larvae and were evaluated for damage 25 - 30 days later using a 9 point scale. The resistant parents and their testcrosses had 15% to 64% more resistant ears (less than 1% kernel damage at the tip only) than Jubilee. The inbreds and their commercial hybrid did not differ in resistance from Jubilee. Resistance to ECB appears to be polygenic and it has been suggested that some level of non-additive gene action is important. While the specific traits responsible for ear resistance are not known, the resistance of the breeding lines was transmitted to the testcrosses.

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BT Corn Performance Against First- and Second-Generation Infestations of European Corn Borer, 1997

Arthropod Management Tests ◽

10.1093/amt/23.1.374 ◽

1998 ◽

Vol 23 (1) ◽

pp. 374-375

Author(s):

K. R. Ostlie ◽

K. M. Helgeson

Keyword(s):

European Corn Borer ◽

First Generation ◽

Second Generation ◽

Egg Laying ◽

Row Spacing ◽

Corn Hybrids ◽

Corn Borer ◽

Leaf Injury ◽

First And Second Generation ◽

Neonate Larvae

Abstract Six transgenic corn hybrids expressing insecticidal proteins produced by genes from Bacillus thuringiensis (Bt) were evaluated at the Rosemount Experiment Station in separate experiments that targeted first and second generations. The hybrids representing 5 different insertion events, and their non-Bt isolines were evaluated in a RCB design with tour replications. Test hybrids were planted in the center 2 rows of a 4-row plot (22 ft long, 30-inch row spacing). Border rows were planted to NK 4640Bt to preclude inter-plot movement of larvae. Plots were planted on 21 May using a cone planter and thinned to 30,000 plants/A. In view of extensive natural first generation infestation, the second-generation experiment was treated with Warrier 1 E (zeta cypermethrin) @ 3.8 fl oz/acre on 15 Jul. In each plot, 15 consecutive plants were tested for Bt expression and non-expressers were rogued on 29 Jul. The plants intended for first generation evaluation were infested at the V6 with neonate larvae in grits deposited in the whorl on 14 Jul. Heavy natural egg laying from second generation eliminated the need for manually infesting second-generation plots. First generation evaluations included: number and length of tunnels on 21 Aug and % of plants with leaf injury and a leaf injury rating on 24 Sep. On 9 Oct the second generation measurements were recorded: number of overwintering larvae, tunnel number and length, and shank and ear damage.

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European Corn Borer Control with Microbial and Pyrethroid Insecticides on Pre-Tassel Sweet Corn, 1993

Arthropod Management Tests ◽

10.1093/amt/19.1.90a ◽

1994 ◽

Vol 19 (1) ◽

pp. 90-90

Author(s):

W. D. Hutchison ◽

D. W. Bartels ◽

P. C. Bolin

Keyword(s):

European Corn Borer ◽

Sweet Corn ◽

Block Design ◽

Soil Surface ◽

University Of Minnesota ◽

Corn Borer ◽

Pyrethroid Insecticides ◽

Randomized Complete Block Design ◽

The University ◽

Neonate Larvae

Abstract This test was conducted on the University of Minnesota, Rosemount Experiment Station in corn planted 1 Jun. Plots consisted of single rows on 30" centers, 30 ft in length, and separated by untreated border rows and 4 ft alleys between replicates. Treatments were arranged in a randomized complete block design with 4 replications. All plots were infested 27 Jul with approximately 25 neonate larvae/plant; larvae were applied to the whorl using ‘bazooka’ applicators. Plant growth stage at the time of infestation was primarily VI2-V13 and 95% pre-tassel (i.e., green tassel visible within the whorl). A single application of each treatment was made 4 Aug; the majority of larvae were second-instars. A medium-clearance Spirit sprayer was used to apply all materials. Liquid formulations were applied with one TX-10 nozzle/row at 40 psi, for a final spray volume of 30 gal/acre. Granular formulations were applied using a Gandy applicator. For all materials, applicator ground speed averaged 2 mph, wind speed 2 mph and ambient temperature 59°F. All treatments were evaluated 23 Aug by dissecting 5 plants per plot, from the tassel to the soil surface.

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Transmittibility of Ear Resistance to European Corn Borer in Sweet Corn Testcrosses and Resistance Stability

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.120.1.107 ◽

1995 ◽

Vol 120 (1) ◽

pp. 107-111 ◽

Cited By ~ 5

Author(s):

Mary S. Joyce ◽

David W. Davis

Keyword(s):

European Corn Borer ◽

Sweet Corn ◽

Channel Length ◽

Resistance Level ◽

Corn Borer ◽

Resistant Parent ◽

Breeding Lines ◽

Neonate Larvae ◽

Resistance Stability ◽

The Relationship

Concern over insecticide usage for control of European corn borer (Ostrinia nubilalis Hübner) in sweet corn (Zea mays L.) in recent years has increased the need for genetic control. Our objectives were to determine the degree of ear feeding resistance transmitted by resistant breeding lines to testcrosses and to investigate the relationship between resistance and both ear silk channel length, and infestation level. Testcrosses averaged 35% acceptable ears compared to 7%. for two commercial control hybrids and 45% for the lines per se when artificially infested at the ear tip at mid-silk at two locations. Generally, resistance in the testcrosses was closer to the resistance level of the resistant parent, indicating good combining ability for resistance. Heterosis above the resistant parent was found in 8 of 12 testcrosses. Across entries, ears having relatively longer silk channel length tended to have less damage but the relationship was not strong (r2 = 0.24, P < 0.01). When silk channels were artificially shortened at infestation, resistance levels were lower, but five of seven lines had a higher proportion of acceptable ears than did the control hybrid. Across increasing levels of infestation from 50 to 200 neonate larvae per ear eight of nine lines had higher resistance (P < 0.05) than the control.

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