Estimation of european corn borer egg masses density by sampling of runs

1989 ◽  
Vol 31 (2) ◽  
pp. 289-304
Author(s):  
J. Vaillant ◽  
S. Derridj
1992 ◽  
Vol 27 (3) ◽  
pp. 239-250
Author(s):  
Clifford B. Keil ◽  
Christopher Tipping

Hybrid matings of two Ostrinia nubilalis (Hübner) (Lepidoptera: Pyralidae) colonies (N and O), established in the laboratory a year apart, demonstrated positive heterosis in the F1 generation as indicated by increases in pupal weight (6%), number of egg masses per female (65%) and number of eggs per female (77%) as compared to intra-colony crosses in mass matings. In contrast, pupation date, an indicator of development time, was intermediate in the hybrids relative to the parental colonies. There was also a 37% increase in the numbers of eggs/female and a 45% increase in egg masses/female in the hybrid parental cross. We investigated this stimulation of oviposition in single female, reciprocal crosses. Oviposition stimulation was directional with the cross of N colony males x O colony females exhibiting significantly higher numbers of total eggs/female and egg masses/female on a daily basis. Colony O females in this cross laid more large egg masses than females in other crosses. Data from individual female crosses demonstrated that egg production in hybrid mass mating experiments was consistent with random mating of males and females from both colonies.


1990 ◽  
Vol 122 (6) ◽  
pp. 1211-1220 ◽  
Author(s):  
P. Palaniswamy ◽  
B. Galka ◽  
B. Timlick

AbstractStudies were conducted from 1985 to 1988 in commercial corn fields distributed throughout the main corn growing areas of Manitoba to determine the distribution, phenology, and the level of infestation of the European corn borer, Ostrinia nubilalis (Hübner). Pheromone and blacklight traps were used to monitor the flight activity of European corn borer throughout the flight period. The level of European corn borer infestation was determined by sampling for egg masses, hatched egg masses, plants with egg masses, plants with shot holes, larvae, and stalk breakage. Results indicated that the European corn borer infestation occurred throughout the corn growing areas of Manitoba and that the population has declined from 1985 through 1988. Significant positive correlations existed among the number of egg masses, plants with egg masses, plants with shot holes, larvae per plant, and plants with broken stalks. Peak capture of moths in pheromone traps occurred well after peak oviposition, and 10–14 days after the peak blacklight trap capture. Blacklight trap catch, but not the pheromone trap catch, was positively correlated with egg mass density. Both blacklight and pheromone traps were equally efficient in determining the onset and the duration of European corn borer flight, although for initiating surveys of egg masses and shot hole damage, pheromone traps are recommended. In Manitoba, corn growers apply pesticides well before the recommended damage threshold is reached.


HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1336-1338 ◽  
Author(s):  
James D. Frantz ◽  
Jeffrey Gardner ◽  
Michael P. Hoffmann ◽  
Molly M. Jahn

A replicated greenhouse evaluation of a range of commercial and noncommercial (Capsicum spp.) accessions for resistance to european corn borer (ECB) [Ostrinia nubilalis (Hubner)] was conducted. Percentage of fruit damaged was observed among 29 accessions four weeks after plants were artificially infested with ECB egg masses. Small-fruited peppers generally showed lower levels of damage, while large-fruited peppers were the most susceptible. Genotypes with elongate fruit were less damaged than those with bell-shaped fruit. Resistance to fruit damage was also associated with increasing pungency level, with two notable exceptions. The pungent genotype `Large Red Thick Cayenne' was significantly more susceptible than many of the other pungent accessions tested. The relative susceptibility of this accession may be related to large fruit size. The nonpungent pepper `Corno di Toro' showed significantly lower percent fruit damage than other nonpungent peppers including `Banana Supreme' with roughly similar fruit size, ranking amidst highly pungent peppers such as `Red Scotch Bonnet'. These results confirm that resistance to ECB can be identified in nonpungent Capsicum genotypes and demonstrate that pungency is not always correlated with ECB damage. Reported sources of aphid resistance or tolerance showed good levels of ECB resistance, but interpretation of these results was confounded by the presence of pungency.


1995 ◽  
Vol 20 (1) ◽  
pp. 185-185
Author(s):  
John F. Witkowski

Abstract The cornfield was located in Cedar county, northwest of the town of Hartington, NE. Six black headed egg masses were infested onto 30 marked plants (3, ten plant subsamples) per treatment on 24 Jun. A Cessna 188 Ag Truck was used to make the applications on 30 Jun. Aerial treatments were flown on in a strip plot design. On 9 Aug, all artificially infested plants were dissected from tassel to ground and examined for borer cavities.


1986 ◽  
Vol 15 (3) ◽  
pp. 501-506 ◽  
Author(s):  
A. M. Shelton ◽  
J. P. Nyrop ◽  
A. Seaman ◽  
R. E. Foster

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Aleksandar Ivezić ◽  
Paul F. Rugman-Jones ◽  
Branislav Trudić

Abstract Background The European corn borer (ECB), Ostrinia nubilalis (Hübner, 1796) (Lepidoptera: Crambidae), is the major pest of maize (Zea mays Linnaeus, 1753) in Serbia. One potential method for managing this pest is the augmentative release of naturally occuring egg parasitoids of the genus Trichogramma. The first step in this process is accurately identifying the naturally occuring species and estimating their natural distribution and abundance. Molecular identification, based on differences in DNA sequences, has commonly been employed for the identification of Trichogramma species. A simple, quick, and accurate molecular assay is urgently required for the identification of two common Trichogramma species, associated with ECB in Serbia: T. brassicae Bezdenko, 1968 and Trichogramma evanescens Westwood, 1833. Such an assay will facilitate an expansive survey of resident populations of Trichogramma associated with ECB across agricultural growing regions of Vojvodina province. Results A species-specific multiplex PCR assay for the 2 species was developed and validated that assay using a sample of 79 parasitoid wasps reared from ECB egg masses collected from sample sites across Vojvodina province. Trichogramma brassicae was confirmed as the dominant egg parasitoid of ECB in this region, accounting for 77 of the 79 wasps (97.47%). The remaining 2 were confirmed as T. evanescens. Trichogramma brassicae was detected at all 12 sample sites, while T. evanescens was detected at only 2 plots, Mokrin and Nakovo. Conclusions The species-specific multiplex PCR assay presented herein can provide the basis of a quick, cheap, and reliable means for identifying the species of Trichogramma that parasitize ECB egg masses in Serbia. Two currently documented species, T. brassicae and T. evanescens, are readily diagnosed by the size of the PCR product they produce in the assay. Any additional species are expected to not produce a band of a diagnostic size. Such species would subsequently be identified by sequencing, which may also allow them to be promptly incorporated into a revised assay.


2018 ◽  
Vol 61 (6) ◽  
pp. 1867-1879
Author(s):  
Ariane Dionne ◽  
Mohamed Khelifi ◽  
Silvia Todorova ◽  
Guy Boivin

Abstract. Sweet corn requires many insecticide applications to control its main pest: the European corn borer () (Lepidoptera: Crambidae). The use of is an effective biological alternative to control the European corn borer in sweet corn. However, manual introduction at large scale of using Trichocards is time-consuming. Mechanized introduction of using a boom sprayer is an innovative and advantageous solution. The objective of this study was to design and test a boom sprayer to spray (Hymenoptera: Trichogrammatidae) in sweet corn canopy under real field conditions. parasitized eggs were sprayed at a rate of 800,000 individuals ha-1 using a boom sprayer designed at the Department of Soils and Agri-Food Engineering of Université Laval, Québec, Canada. parasitized eggs were also introduced at a rate of 500,000 individuals ha-1 using Trichocards. Overall, eight releases were made during the 2016 season. Field trial results showed a 17.22% emergence rate reduction of in the sprayed plots compared to Trichocards. Total fecundity and longevity of sprayed females were not negatively affected by spraying; indicating that spraying did not have any negative impact on their quality. The parasitism rates observed on natural egg masses of and on sentinel egg masses of were comparable for both methods. At harvest, sprayed and Trichocards treatments resulted in adequate control of the European corn borer. Obtained results also showed that spraying was 1.7 times faster than the manual introduction of Trichocards. Overall, the results indicate that spraying is a promising technique for an efficient and viable introduction of parasitized eggs. However, more research is recommended to further optimize the spraying parameters. The spraying system successfully used in sweet corn could also be used in corn production and adapted to other crops such as pepper, beans, and potatoes to control the European corn borer. Keywords: Biological control, European corn borer, Ostrinia nubilalis, Trichogramma, Trichogramma ostriniae, Sweet corn, Corn production, Spraying, Boom sprayer, Beneficial insects, Trichocards.


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