scholarly journals Prevalence rates of Trichogramma evanescens (Westwood) in Ostrinia nubilalis (Hübner) population in the south of russia in 2013-2018

2020 ◽  
Vol 18 ◽  
pp. 00012
Author(s):  
Inna Grushevaya

The European corn borer Ostrinia nubilalis (Hübner) is a dangerous corn pest – a convenient object for studying population dynamics and assessing various pest mortality factors. The mortality of European corn borer’s eggs by the natural parasite population Trichogramma evanescens (Westwood) was estimated in 2013–2018 in the Gulkevichsky district of the Krasnodar Territory. Two generations of the European corn borer are developing in the Krasnodar Territory. Often pest’s first generation of is not infected with the parasite. When monitoring the abundance of the second generation, even in years with a low abundance of the European corn borer, infected phytophage eggs are found in the crops of grain corn. Infection of eggs of the second-generation European corn borer in 2013-2018 ranged from 0.26 to 69.55 eggs / m2, with an average of 37.53 eggs / m2.

1981 ◽  
Vol 113 (7) ◽  
pp. 585-591
Author(s):  
W. H. Foott ◽  
P. R. Timmins

AbstractA 5-year study of a bivoltine strain of the European corn borer, Ostrinia nubilalis (Hübner), showed that first-generation moths deposited more eggs on early-planted corn, whereas second-generation moths oviposited more frequently on late-planted corn. The second generation was much larger than the first generation and caused the greater reduction in yield, regardless of whether the yields were based on physiological losses or a combination of physiological losses and dropped ears. It was shown that delay of harvest beyond the time that moisture content of the corn was sufficiently low for machine harvesting could result in severe yield losses from broken stalks and dropped ears during autumn storms.


1979 ◽  
Vol 111 (3) ◽  
pp. 233-236 ◽  
Author(s):  
D. G. R. McLeod ◽  
C. Ritchot ◽  
T. Nagai

AbstractThere are now two strains of the European corn borer, Ostrinia nubilalis (Hübner), in Quebec. The strain normally found produces one generation while the more recently introduced strain produces two generations per year. Both strains have been characterized and compared with corn borer strains from Ontario and New York State. The two attributes of the recently introduced strain that promote the development of a second generation are (1) early emergence in the spring with less intense diapause and (2) a lower critical photoperiod for diapause induction. The latter characteristic allows pupation of first generation larvae. Field and laboratory tests on the pheromone response of adult male moths demonstrated that the origin of this recent introduction was New York State.


1988 ◽  
Vol 120 (10) ◽  
pp. 841-853 ◽  
Author(s):  
Dennis A. Lee

AbstractA combination of laboratory and field trials, from 1983 to 1985, were used to determine mortality factors affecting all life stages of Alberta populations of the European corn borer, Ostrinia nubilalis (Hübner), feeding on corn. The resulting life table demonstrated that greatest mortality occurred during the first and second larval instars (62.2%), when mature larvae are in diapause (69.5%), and from moth migration and loss in reproductive potential (70.3%). Stages where mortality was slight included the egg stage (11.7%), non-diapausing third- to fifth-instar larvae (2%), and pupae (10.4%).Laboratory trials showed that greater egg mortality occurred at relative humidities (RH) of 35 and 55% than at a RH of 75%. In the field, egg parasitism was nil, predation of early-instar larvae (5.2%) and diapausing larvae (6%) was low, and parasitoids were scarce (emerging from ca. 2% of pupae). Sustained periods of hot, dry weather with high moisture stress were related to mortality of both eggs and early-instar larvae. Death of early-instar larvae also was related to periods of rainy weather with low evaporation. The 64% non-diapause larval mortality was much lower than that reported elsewhere. The dramatic increase in the corn borer since its recent introduction to Alberta may be due to a lack of natural enemies, and because only non-resistant corn hybrids are grown.


1978 ◽  
Vol 110 (5) ◽  
pp. 487-493 ◽  
Author(s):  
W.M. Elliott ◽  
R.J. McClanahan ◽  
J. Founk

AbstractThe formation of a yellow band inside the stalk of each ovariole was a good indicator that a female European corn borer had laid eggs. The absence of these bands was less reliable as an indicator that no eggs had been laid, probably due to the time taken for the bands to form. The numbers of moths accumulating in a light trap over a week at Harrow, Ontario, and the numbers of females estimated to have laid eggs correlated significantly with the numbers of larvae developing in nearby green pepper plots 3, 4, and 5 weeks later during second generation flights. This enabled linear equations for forecasting pepper damage to be developed, in which the dissection data was more useful than the total moth catch alone.


1963 ◽  
Vol 95 (12) ◽  
pp. 1285-1292 ◽  
Author(s):  
C. A. Barlow

AbstractA method of forecasting the size of first-generation or summer infestations of Ostrinia nubilalis in Kent County, Ontario, is described. A function is derived from partial regression analysis relating the estimated size of the expected summer infestation to (1) the number of females caught in a light-trap during the first or spring flight, and (2) average rainfall per day during the first flight. The function explains 94% of the observed variation in estimated size of first-generation infestations in this area between 1947 and 1961. A means of categorizing the estimated size of the predicted infestation based on the frequency distribution of previously estimated infestations is also described. Methods of sampling and estimating population size and the applicability of the predictive equation to other environments are discussed.


1986 ◽  
Vol 118 (10) ◽  
pp. 943-956 ◽  
Author(s):  
Dennis A. Lee ◽  
John R. Spence

AbstractDifferences in phenology were observed between two populations of Ostrinia nubilalis (Hbn.) in Alberta. In the South Saskatchewan River valley, borers pupated and emerged 3–6 days earlier than on the plains. This was not simply a function of different microclimates because median pupation occurred at 331 degree-days (DD) for plains populations and at 490 DD for valley populations. First-generation flight extended from the last week in June until the 1st week in August. Flight peaks in 1983 occurred on 8 July in the valley and on 14 July on the plains. Flight was delayed in 1984 by cold nightly temperatures. In 1983 valley populations had a partial second generation, with a flight peak in late August. Mean pupal mass was significantly less for plains populations than valley populations. Transplant experiments demonstrated that these differences reflected mainly environmental influences. During spring 1984, mean larval mass in the two populations did not differ until early June, when both mean wet and dry mass of valley larvae increased significantly but those of plains larvae did not change. This variability of phenotypes contributes to the colonizing ability of the European corn borer.


Genetika ◽  
2020 ◽  
Vol 52 (1) ◽  
pp. 351-365
Author(s):  
Snezana Gosic-Dondo ◽  
Dragan Grcak ◽  
Milosav Grcak ◽  
Danijela Kondic ◽  
Djuradj Hajder ◽  
...  

The objective of the paper was to determine the effect of insecticides on the development of the European corn borer (Ostinia nubilalis Hbn) and the effect of damage in six maize hybrids of different maturity groups. The research involved the following hybrids: ZP 427, ZP 434, ZP 555, ZP 600, ZP 606 and ZP 666. In the field trial, insecticides were applied in two terms, during the flight of O. nubilalis first generation and during the flight of second O. nubilalis generation. We used Fobos EC insecticide and a combination of Match 050 EC + Nurelle D insecticides, whose active substances are different. The active substance in Fobos EC insecticide is bifenthrin 100 g l-1, in Match 050 EC lufenuron 50 g l-1 and, in Nurelle D insecticide, the active ingredient is a combination of chlorpyrifos 500 g l-1 and cypermethrin 50 g l-1. The damage inflicted on plants was assessed in July and September. Fobos insecticide had the best plant protection effect, after its use, the arithmetic mean of the total attack percentage of all hybrids was approximately 81.62% while in the control group, it was approximately 91.72%.


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