First-generation European Corn Borer Research Articles

European corn borer and its parasites overwintering abundance and damages on different corn FAO maturity groups

European corn borer (ECB) is one of the most significant maize pests in the world and also in Croatia. ECB causes yield reduction from 2 to 25%, even more in years favorable for its development. According to estimations, these losses are around 7%. About 90% of the hybrids had some resistance to whorl-leaf feeding (first-generation ECB) and 75% had some resistance to sheath and sheath-collar feeding (second-generation ECB). Along with resistance, modern maize hybrids possess certain level of tolerance. The main aim of this paper was to determine moth eclosion of the overwintering generation and presence of the parasites of ECB larvae during the overwintering as well as to estimate population density of ECB on maize growing area in Croatia. Also, we aimed to establish the differences among different maize FAO maturity groups in damage caused by ECB larvae. Estimated overwintering population was over 8,000 moths/ha i.e. more than 4 million larvae of first generation. During the overwintering four different parasites attacked the larvae. Two species belong to the order Hymenoptera (Cotesia marginiventris Cresson and Eriborus terebrans Gravenhorst) and two species belong to the order Diptera (Ramonda spathulata Fallen and Lydella thompsoni Herting). One caterpillar predator species Paragymnomerus spiricornis Spinola (Hymenopetra) overwinters in maize stalks as well. The highest attack of the first ECB generation was recorded on FAO maturity group 500. The damage from second ECB generation was the highest on FAO groups 400 and 500. The maize of the higher FAO groups has high and robust stems with large number of big leaves. That intensive vegetative growth is a biological characteristic that attracts first generation of ECB to intensifying egg lying. High population level of the first generation also leads to high level of second ECB generation which ultimately caused yield reduced on the hybrids of longer vegetation period (medium-late FAO maturity groups).

LARVAL FIRST GENERATION EUROPEAN CORN BORER AND CORN ROOTWORM CONTROL, 2001

LARVAL FIRST GENERATION EUROPEAN CORN BORER AND CORN ROOTWORM CONTROL, 2001

Quantitative Trait Loci for First- and Second-Generation European Corn Borer Resistance Derived from the Maize Inbred Mo47

European corn borer (ECB), Ostrinia nubilalis (Hübner), family Crambidae, order Lepidoptera, is a serious insect pest of maize (Zea mays L.) in the USA. Understanding the genetic basis for ECB resistance should increase the efficiency of breeding insect-resistant germplasm. The objectives of this study were to determine the number, genomic positions, and genetic effects of quantitative trait loci (QTL) conferring resistance to leaf feeding damage cause by first-generation ECB (1ECB, defined as the trait of leaf feeding damage) and stalk tunneling caused by second-generation ECB (2ECB, defined as the trait of stalk tunnel damage). The study included 244 F2:3 families derived from the cross of B73Ht (susceptible) × Mo47 (resistant). Inbred Mo47 represented a novel source of ECB resistance containing 50% tropical germplasm. The QTL analyses for three individual environments and combined across environments were performed by composite interval mapping using QTL Cartographer. Nine QTLs were identified for 1ECB on chromosomes 1 (three QTLs), 2, 4 (two QTLs), 5, 6, and 8, on the basis of data combined across environments. Seven QTLs for 2ECB were found on chromosomes 2, 5 (two QTLs), 6 (two QTLs), 8, and 9. Several of the QTLs detected are located in genomic regions reported for resistance to other stem borer pests of maize. Inconsistency of QTLs across environments complicates use of Mo47 for marker-assisted selection of ECB resistance.

Effects of Peruvian Maize Extracts on Growth, Development, and Fecundity of the European Corn Borer

Twelve Peruvian maize, Zea mays, accessions were selected because of their relatively high level of field resistance to first-generation European corn borer (ECB), Ostrinia nubilalis, larval leaf-feeding. Water extracts of freeze-dried, powdered, leaf tissue were incorporated into a standard ECB diet, fed to larvae, and the effects on larval growth, development, and fecundity were measured. Larval and pupal weights were monitored as were the time elapsed in the larval, pupal, and adult stages. Adult fecundity and egg fertility were recorded. The experiment was a randomized block design (larvae and pupae) or a completely randomized design (adults) and analyzed with ANOVA (α = 0.05). Pairwise comparisons were made between groups of insects grown on diets containing extracts from the Peruvian lines, a standard diet, or diets containing extracts of a known susceptible inbred, and a known resistant inbred line. Survival was analyzed with a chi-squared test (α = 0.05). Two Peruvian accessions significantly reduced female larval and pupal weights, extended pupal and adult development time, and decreased survival of pupae and adults. Water extracts also had a pronounced impact on males; two accessions significantly reduced pupal weight and extended the time required to pupate, and one reduced male survival to adults. The results indicate that water-soluble factors from resistant Peruvian accessions inhibit the growth, developmental time, and survival of ECB. These resistance factors could be useful in the development of maize germplasm with insect-resistant traits.

Insecticide Rescue Treatments for Control of First-Generation European Corn Borer in South Dakota, 1997

Abstract Corn fields near New Holland and Letcher, South Dakota were used to evaluate planting-time and postemergence insecticides for controlling first-generation European corn borer, Ostrinia nubilalis Hubner, larvae. Preapplication counts (4 d before application) at Letcher indicated a uniform infestation of O. nubilalis larvae in 92.0% of plants sampled. Approximately 2.4 larvae (4.2, 62.5 and 33.3% were 1st, 2nd and 3rd instars, respectively) per plant were observed at this location. Similarly at New Holland a 90% infestation level (predominantly 1st and 2nd instars on the application date) existed, but the average number of larvae was estimated to be ~ 4-fold less than at Letcher). The at-planting-time treatment at New Holland occurred on 15 May and all whorl-treatments (approximately 1 week prior to tasseling) on 12 July (Letcher) and 15 July (New Holland). Insecticides were applied to single-row plots (16.4 cm by 30.5 m) in a randomized complete block design with 4 replicates. Granules were directed into corn plant’s whorl using a pneumatic applicator powered by a 3.5-horsepower engine mounted on a highboy. Noble metering units attached to a modified chain-driven apparatus regulated the amount of granules released into the pneumatic applicator. Liquid treatments were applied to corn plant whorls using a single-nozzle 3-gal. CO2-propelled backpack sprayer system. Approximately one month following insecticide applications (11 August), twenty corn stalks were randomly chosen from each plot. Each plant was split vertically and examined for O. nubilalis tunneling damage. The number and length of O. nubilalis cavities were analyzed using the ANOVA procedure with means being compared with the LSD.

Relation of European Corn Borer (Lepidoptera: Pyralidae) Leaf-Feeding Resistance and Dimboa Content in Maize

European corn borer, Ostrinia nubilalis (Hubner), is a major insect pest of maize, Zea mays L., in the northern Corn Belt, which affects production through physiological yield reduction and harvest losses. Four maize inbreds (two resistant [C131A and B75] and two susceptible [C103 and C121E] to first-generation European corn borer along with all possible F1s [6 eachl and F2s [6 each] plus the double crosses [15 each] from the F1s) were evaluated for resistance to leaf feeding by the European corn borer and 2, 4-dihydrox-7-methoxy-1, 4-henzoxazin-3-one (DIMBOA) concentration in the leaf tissue. The two objectives of our study were: (1) to compare the traditional visual leaf feeding rating scale to a chemical analysis of the concentration of DIMBOA and (2) to determine the concentration and persistence of DIMBOA among these genotypes in relation to resistance. The leaf-feeding resistant inbreds, C131A and B75, had initial ratings of 1.0 on a scale of 1–9 (1, highly resistant to 9, highly susceptible) and they had a concentration of DIMBOA of 704 and 433 μ g/g, respectively. The susceptible inbreds, C103 and C121E, had ratings of 7.5 and 3.8 and DIMBOA concentrations of 91 and 70 μ g/g, respectively. The resistant ratings of the F1S and F2S were generally related to their parentage. The resistant genotypes had higher levels of DIMBOA and this trait was expressed in the various crosses in an additive manner indicating that DIMBOA concentration is genetically determined. The leaf feeding ratings became higher and DIMBOA concentrations lower as the plant matured. The correlation ofleaf feeding rating and DIMBOA concentration was r = −0.40 62 d after planting, but 10 d later it dropped to r = −0.34; both are Significant negative correlations. No resistance was found by the time the inbreds and crosses were flowering.

First-Generation European Corn Borer (Lepidoptera: Pyralidae) Response to Three Conservation Tillage Systems in Minnesota

Plant injury and densities of mature larvae by first-generation Ostnnja nubilalis (Hubner), European corn borer, were examined in chisel-plow, ridge-tillage, and notillage maize, Zea mays (L.). in southeastern Minnesota during 1985-1987. Tillage plots were split with and without terbufos application and with and without Bacjllus thurjngjensjs permethrin application in all combinations. Chisel-plow suffered greater plant injury than ridge-tillage or no-tillage, probably because oviposition was greater in chisel-plow. Ovipositing females were not responding primarily to plant height or developmental stage. Soil surface temperatures were higher in chisel-plow during the early evening when oviposition occurred, and we suggest microclimate influenced female oviposition. Larval density was highest in chisel-plow maize that received terbufos. We concluded that the risk of yield loss to first-generation O. nubllaljs in ridge-tillage and no-tillage maize did not exceed the risk of yield loss in chisel-plow maize.

Distributions Among S1Lines for European Corn Borer (Lepidoptera: Pyralidae) and Stalk Rot Resistance Ratings in Two Maize Synthetics Improved by Recurrent Selection

Four cycles of recurrent selection were used to reduce leaf-feeding damage caused by first-generation European corn borer (ECB), Ostrinia nubilalis Hubner, and pith decay associated with Diplodia, Diplodia maydis (Berkeley) Saccardo, stalk rot (DSR) in two maize, Zea mays L., synthetics, BSAA and BSBB. Recurrent selection was based on the evaluation of SI progenies. For this study, 100 unselected Illines from each of the original (CO) and improved (C4) populations of BSAA and BSBB were evaluated for ECB resistance, DSRresistance, and stalk rind puncture. The distributions of S,1 lines for the three traits and the genetic relationships among traits were evaluated to determine the effectiveness of the recurrent selection programs. The C4s of both synthetics were more resistant than the COs to ECB leaf feeding after artificial infestations, were more resistant to D5R after artificial inoculations, and possessed harder stalks. The differences between the CO and C4 means were highly significant (P < 0.01) in all instances. Reductions in genetic variation were observed in BSAA for ECB ratings and in BSBB for all three traits. The reductions in genetic variation were especially dramatic for ECB ratings, indicating that relatively few gene pairs were segregating for leaf-feeding resistance in BSAA and BSBB. Low and generally nonsignificant correlations between DSR ratings and rind puncture readings indicated that selection for both traits would be justified to improve field stalk lodging resistance.

Reaction of Two Maize Synthetics to Anthracnose Stalk Rot and Northern Corn Leaf Blight Following Recurrent Selection for Resistance to Diplodia Stalk Rot and European Corn Borer

Reaction of Two Maize Synthetics to Anthracnose Stalk Rot and Northern Corn Leaf Blight Following Recurrent Selection for Resistance to Diplodia Stalk Rot and European Corn Borer

Response of Two Maize Synthetics to Recurrent Selection for Resistance to First-Generation European Corn Borer (Lepidoptera: Pyralidae) and Diplodia Stalk Rot

Four cycles of recurrent selection in two maize, Zea mays L., synthetics, BSAA and BSBB, were done to select for resistance to first-generation European corn borer (ECB), Ostrinia nubilalis Hubner, and Diplodia ( Diplodia maydis [Berkeley] Saccardo) stalk rot (DSR). Recurrent selection was based on the evaluation of SI lines. The original synthetics and four improved cycle populations of BSAA and BSBB were evaluated in multiple environments as populations per se, crosses between synthetics, and test crosses to a susceptible tester. Two cycles of recurrent selection in BSAA and three cycles in BSBB produced populations that were as resistant to leaf feeding by the ECB as the highly resistant single-cross check, B75 x CI31A, after which no further progress was made. The realized gain per cycle of selection for BSBB (be = -0.63 units on a 1-9 scale) was highly significant and of greater magnitude than for BSAA (be = -0.10 units, nonsignificant). In contrast, highly significant linear progress for DSR resistance was made through all four cycles of selection in both synthetics (be = -0.38 and -0.36 units for BSAA and BSBB, respectively, on a 1-6 scale). The level of resistance to ECB and DSR in the population crosses and test crosses suggests that the genes governing resistance to these two traits are acting in an additive manner. Selection for resistance to DSR and ECB was associated with improvement in stalk rind strength and decreases in the incidence of stalk lodging and natural stalk rot development. The results indicate that improved stand ability in environments conducive to stalk rot development may require selection for physical stalk strength as well as for resistance to stalk-rotting organisms.

First-Generation European Corn Borer Control in Field Corn, 1987

Abstract Seven insecticidal treatments were examined to determine their efficacy in controlling primarily first-generation (second-generation also evaluated) European corn borer (ECB) in conventionally planted field corn grown on the Vernon Delano Farm in Richmond County, Va. 'Pioneer 3389' corn was planted on a 36-inch row spacing on 28 Apr. Materials were applied either as foliar sprays or granular applications on 9 Jun. Foliar spray concentrates were applied with a CO2-powered compressed-air sprayer, using TeeJet AL8004 nozzels, at 32 psi that delivered 31.8 gal of finished formulation/acre. Granular insecticides were applied directly in the whorl by using a Spred-rite gravity flow granular applicator. Individual plots were 4 rows by 30 ft with 2-row borders and were arranged in a complete randomized block experimental design with 3 replications. Individual plots were evaluated 8 days after treatment and then periodically throughout the remainder of the growing season. All plants in 30 row-ft were inspected for the presence of ECB feeding damage, and 5 random plants/plot were split and observed for the presence of live ECB larvae on 22 Jun. Yield estimates were obtained by harvesting 1 of the 2 center rows of each plot. Yields were adjusted to 12% moisture.

First-Generation European Corn Borer Control Via Ground, Chemigation, and Aerial Applications, 1986

Abstract Studies I, II, and III were established in cornfields near Armour and Redfleld, S. Dak. Study IV was established in 2 adjacent fields near Chamberlain. Treatments in studies I and II were randomized in a complete block design with 3 replications and all treatments were ground applied in one-row plots (0.97-m centers), 30 m long. Applications were made on 25 Jun at Armour and on 1 Jul at Redfleld. The granular materials (Study I) were applied from a highboy in a 20-cm band over the whorl with a pneumatic applicator powered by a 3.5-horsepower engine. Granules were metered by Noble metring units driven via chain Irive by a 12 V DC motor. Liquid materials (Study II) were applied with a CO2 backpack sprayer with a hand-held wand. One 1.5 LE nozzle/row delivered 19.5 gal/acre at 15 psi and 3.5 mph. The treatments in Study III were applied through center pivot systems on 26 Jun (Armour) and 4 Jul (Redfleld). A Zimmatic low-pressure irrigation system delivering 0.25 inches of water was used at Armour, and a Valley low-pressure system delivering 0.20 inches of water was used at Redfleld. Treatments (not replicated) consisted of different sized wedges (6-40 acres) of the pivot circle. The treatments in Study IV were applied aerially with a fixed-wing aircraft on 26 Jun. All treatments were applied in 2 adjacent fields and analyzed as 2 replicates of a single experiment. Granular treatments were at least 2 aerial swath widths wide (27 m), and liquid treatments were a single swath in width (15 m). All treatments covered the entire length of the field (minimum 3 acres). Liquid treatments were applied using 3 gal/acre of carrier. Plots from all studies were evaluated 1 month after treatment. Studies I and II were evaluated by splitting stalks from 10 plants showing leaf feeding in each plot and rep. These plants were examined for European corn borer (ECB) cavities (2.5 cm of tunneling equals one cavitiy). Studies III and IV were evaluated by splitting 10 leaf-damaged plants for ECB navities in each of 5 areas within each treatment area.

Ecological Studies of the European Corn Borer (Lepidoptera: Pyralidae) in Boone County, Iowa

An ecological study of the European corn borer (ECB), Ostrinia nubilalis (Hbn.), was conducted in Boone County, Iowa, from 1950 through 1965. The average date of the beginning of first-generation pupation was 12 May, with completion 8 June. Moth flight usually began in late May, peaked during the 2nd and 3rd weeks of June, and ended in early July. First-generation oviposition was greatest during the last half of June. Most (69.0%) first-generation ECB eggs hatched; a significant number (25.5%) were lost, probably due to heavy rains and violent winds. Greatest total numbers of first-generation ECB egg masses and larvae occurred in maize planted 6–10 d after the first planting date. The average date of the beginning of second-generation pupation was 16 July, with the average completion 14 August. Peak second-generation moth flight was during the first half of August. Peak oviposition was in early to mid-August. Percentage of second-generation eggs missing was less than that of the first generation, probably because severe storms were less frequent during August than in June. Heavy second-generation infestations often occurred in early-planted maize; more than 65% of second-generation larvae were found in maize planted during the first 10 d of the planting period. Heaviest infestations were in maize planted 21–30 d after the first planting date. A small third-generation moth flight occurred in some years. Predators were much more numerous during the second-generation oviposition period than during the first-generation oviposition. More second-generation eggs were eaten by predators than were first-generation eggs. The most common parasitoid of the ECB was Lydella thompsoni Herting; this species was uncommon after 1959. Other parasitoids were recorded but were not numerous.

Control of First-generation European Corn Borer (Lepidoptera: Pyralidae) Larvae in Nebraska by Applying Insecticides by Center-pivot Irrigation Systems

In whorl-stage field corn, applications of chlorpyrifos 4 emulsifiable concentrate (EC), fenvalerate 2.4EC, and permethrin 3.2EC significantly reduced numbers of first generation European corn borer, Ostrinia nubilalis (Hubner), larvae compared with the untreated check when applied through circular overhead center-pivot irrigation systems with minimal irrigation water (0.58–0.86 cm). Only chlorpyrifos was evaluated all 3 years of the experiment (1982–84). Corn yields were taken in 1983 and all insecticide-treated plots showed significantly greater yields than the untreated check plot. Experiments conducted in 1983 with chlorpyrifos showed satisfactory efficacy when water rate was increased to 2 cm and when insecticide was prediluted to a ratio of 1 part chlorpyrifos/1 part oil/14 parts water to allow use of a high volume injector pump commonly used for fertigation.

Within-plant and Within-field Distribution of First-generation European Corn Borer (Lepidoptera: Pyralidae) Egg Masses on Field Corn in Virginia

The oviposition site selection by the European corn borer and the within-field pattern of egg mass distribution were studied on field corn in western Virginia. Nearly all egg masses were found on the lowest six leaves of the plant. The within-field distribution of egg masses was found to be a random distribution, as interpreted from the variance/ mean ratio, the method of Taylor and Green's coefficient of dispersion.

Performance of Maize Inbred Line B86 in Hybrid Combinations: Resistance to First- and Second-generation European Corn Borers (Lepidoptera: Pyralidae)

Inbred line B86 was crossed with nine dent maize, Zea mays L., inbred lines. The nine lines, plus B86 and a check inbred line, and the nine single crosses, plus a single-cross check, were planted in a modified randomized block design during 4 years, with six replications each year. First-generation European corn borer (ECB), Ostrinia nubilalis Hübner, test plots were separate from the second-generation ECB test plots (two hills of three plants for each plot in each experiment). Plants in the first-generation tests were infested during the midwhorl stage of plant development, whereas plants in the second-generation tests were infested during an thesis. Plants in each test were infested with 12 egg masses (300 eggs) per plant in six applications of two masses, spaced 1 day apart. Leaf feeding damage in the first-generation tests and sheath-collar feeding damage and stalk damage in the second-generation tests were determined. B86 was resistant to first- and second-generation ECB; in combination with several susceptible inbred lines, B86 resistance showed variable levels of partial dominance for resistance to leaf feeding by first-generation ECB and for sheath-collar and stalk feeding resistance by second-generation ECB.

European Corn Borer (Lepidoptera: Pyralidae): Rate of First-Generation Larval Mortality in Sorghum Hybrids Compared with Inbred Lines of Maize During the Whorl Stage of Plant Development

The rate of first-generation European corn borer (ECB), Ostrinia nubilalis Hubner, larval survival on four sorghum, Sorghum bicolor (L.) Moench, hybrids, and two inbred lines of maize, Zea mays L., was determined by dissecting plants 3, 6, 9, 12, and 15 days after egg hatch. Infestations with ca. 200 eggs per plant were made during the mid whorl stage of plant development. Larval survival was much greater on a susceptible maize inbred line (B73) at all dissection intervals than was larval survival on four sorghum hybrids (P846, P8475, P8680, P8324) and on a resistant inbred line of maize (B85). Larval mortality was rapid on four sorghum hybrids within 6 days after egg hatch, but was not as rapid on the four sorghum hybrids as was larval mortality on a resistant maize inbred within 6 days after egg hatch. Feeding sites were determined for 22,827 first-generation larvae. Most larvae fed on leaf tissue in the moist area deep in the whorl of sorghum and maize plants through 9 days after egg hatch. Resistance in sorghum to first-generation O. nubilalis, therefore, is resistance to leaf feeding—i.e., antibiosis against first and second instars and is similar to first-generation resistance in maize.

Minimization of Insecticide Treatment for First-Generation European Corn Borer (Lepidoptera: Pyralidae) Control in Sweet Corn1

Field trials during 1979–1981 were conducted on sweet corn to determine the efficacy of granular whorl treatments against first-generation Ostrinia nubilalis (Hübner). Results showed that, when European corn borer infestation pressure was minimal to moderate, a single granular application compared favorably with multiple foliar sprays of the standard treatment, but supplemental sprays were necessary under high infestation conditions. An action threshold was utilized advantageously to determine the opportune time for granular treatment and the necessity for supplemental sprays. It was concluded that utilization of granular whorl treatment and effectively reduce the number of “hectare treatments” and could fit well into sweet corn pest management programs.

Granulated Insecticides for Control of Some Corn Pests1

From 1961 through 1963, 4 experiments were conducted using granulated insecticides for control of various corn pests. In 1961 granules were applied to corn in the pretassel stage for control of second-generation European corn borer, Ostrinia nubilalis (Hubner). Applications of DDT, Zinophos ( O,O -diethyl O -2-pyrazinyl phosphorothioate), Kepone® (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one), and carbophenothion were effective in reducing stalk infestation at harvest. While these same insecticides did not produce a statistically significant reduction of ear infestation, there did appear to be a reduction of ear infestation by European corn borer. In 1961, 1962, and 1963 granulated systemic insecticides were distributed in the furrow with the seed at planting time. In 1961 Di-Syston® ( O-O -diethyl S-[2- (cthylthio) ethyl] phosphorodithioate) increased stand as a result of seed-corn maggot ( Hylemya cilicrura (Rondani)) control. In 1962 Zinophos and phorate were apparently phytotoxic, but phorate did reduce infestation of first-generation European corn borer in the plants in the whorl stage. In the 1963 experiment the significant observations were that phorate apparently was phytotoxic in that it reduced stand. Bayer 25141 ( O,O -diethyl O-p- (methylsulfinyl) -phenyl phosphorothioate) also caused a reduction in stand, which was significantly reflected in a reduction in yield.