A PHENOLOGY MODEL AND FIELD EVALUATION OF BEAUVERIA BASSIANA (BALS.) VUILLEMIN (DEUTEROMYCOTINA: HYPHOMYCETES) MYCOSIS OF THE EUROPEAN CORN BORER, OSTRINIA NUBILALIS (HBN.) (LEPIDOPTERA: PYRALIDAE)

1988 ◽  
Vol 120 (2) ◽  
pp. 133-144 ◽  
Author(s):  
Ziding Feng ◽  
Raymond I. Carruthers ◽  
Timothy S. Larkin ◽  
Donald W. Roberts
Keyword(s):  
Beauveria Bassiana ◽  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
Larval Mortality ◽  
Field Evaluation ◽  
Time Model ◽  
Corn Borer ◽  
Corn Borers ◽  
Phenology Model ◽  
Validation Experiments

AbstractA simulation model was developed to predict the timing of European corn borer, Ostrinia nubilalis (Hbn.), larval mortality following exposure to Beauveria bassiana (Bals.) Vuillemin conidia. Model response was compared with laboratory and field data collected specifically for model validation. In laboratory validation experiments, four conidial doses of a B. bassiana isolate collected from the People’s Republic of China were applied to European corn borer larvae which were then incubated at fluctuating temperatures. Simulation results compared favorably with fungal development and mycosis under laboratory conditions. Field validation experiments showed that applications of B. bassiana to European corn borer neonates in whorl-stage corn resulted in mortality levels over 60% when conidia and European corn borers were placed on the plants on the same day. When B. bassiana conidia were placed on plants prior to European corn borers, mortality decreased linearly with time. Model predictions of the timing of European corn borer mortality were found to be accurate when B. bassiana conidia were placed on corn plants at the same time or prior to European corn borers. When European corn borers were placed on plants prior to conidia, the model underestimated the time to European corn borer death. Lack of model fit in this situation is thought to be due to delayed host and pathogen interactions on the corn plant rather than poor prediction of the physiological development of the disease.

FACTORS AFFECTING MORTALITY OF THE EUROPEAN CORN BORER, OSTRINIA NUBILALIS (HÜBNER), IN ALBERTA

1988 ◽  
Vol 120 (10) ◽  
pp. 841-853 ◽  
Author(s):  
Dennis A. Lee
Keyword(s):  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
Larval Mortality ◽  
Reproductive Potential ◽  
Moisture Stress ◽  
Mortality Factors ◽  
Corn Borer ◽  
Factors Affecting ◽  
Rainy Weather ◽  
Early Instar

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.

DEVELOPMENTAL ADAPTATION OF THE EUROPEAN CORN BORER (OSTRINIA NUBILALIS HÜBNER) IN ALBERTA

1987 ◽  
Vol 119 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Dennis A. Lee ◽  
John R. Spence
Keyword(s):  
United States ◽  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
The United States ◽  
Life Stages ◽  
Corn Borer ◽  
Corn Borers ◽  
Developmental Thresholds ◽  
Temperature Thresholds ◽  
Higher Temperature

AbstractTemperature effects on development were studied for two Alberta populations of Ostrinia nubilalis (Hübner), from the South Saskatchewan River valley and the surrounding plains. Lower developmental thresholds for all life stages of both Alberta populations were determined by linear regression. Thresholds for the egg stage were significantly less for plains borers (9.5°C) than for valley borers (10.8°C), and about 2°C lower than for corn borers from the United States. Thresholds in Alberta populations for the 4th (15.3°C) and 5th (14.0°C, plains) instars, and for post-diapause pupation (12.8°C), were much higher than in populations from the United States. Higher temperature thresholds delay development in Alberta populations, thus reducing midsummer pupation. Valley populations developed significantly faster than plains populations during egg development, during the prepupal period of the 5th instar, and during post-diapause pupation. These results explain why valley populations have a partial second generation in some years.

GENETICS OF DIAPAUSE INDUCTION AND TERMINATION IN THE EUROPEAN CORN BORER, OSTRINIA NUBILALIS (LEPIDOPTERA: PYRALIDAE), IN SOUTHWESTERN ONTARIO

1978 ◽  
Vol 110 (12) ◽  
pp. 1351-1353 ◽  
Author(s):  
D. G. R. McLeod
Keyword(s):  
Growth Rate ◽  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
Diapause Induction ◽  
Corn Borer ◽  
Female Sex ◽  
Corn Borers ◽  
Lepidoptera Pyralidae ◽  
Male Sex ◽  
Diapause Incidence

AbstractGrowth rate, diapause incidence, and diapause intensity were different in two strains of corn borers found in southwestern Ontario. Crosses between these two strains demonstrated that growth rate was female sex linked while diapause incidence was male sex linked. The effect of these two characteristics on hybridization is discussed.

The impact of predation by red-winged blackbirds on European corn borer populations

1981 ◽  
Vol 59 (8) ◽  
pp. 1535-1538 ◽  
Author(s):  
Barry E. Bendell ◽  
Patrick J. Weatherhead ◽  
Robin K. Stewart
Keyword(s):  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
Agelaius Phoeniceus ◽  
Population Estimates ◽  
Corn Borer ◽  
Corn Borers ◽  
Late Fall ◽  
Lepidoptera Pyralidae ◽  
The Impact

Population estimates of the European corn borer (Ostrinia nubilalis Lepidoptera: Pyralidae) were significantly positively correlated with distance from a blackbird roost near Beauharnois, Quebec. Gullet contents of male red-winged blackbirds (Agelaius phoeniceus) indicated that corn borers were consumed, particularly in the late fall. This predation appears to be responsible for lowering corn borer populations in standing corn the following year. It was estimated that the benefit provided by red-winged blackbirds through predation on com borers compensated for approximately 20% of the damage the birds did to standing corn.

Effects of combining Beauveria bassiana and Nosema pyrausta on the mortality of Ostrinia nubilalis

2010 ◽  
Vol 5 (4) ◽  
pp. 472-480 ◽  
Author(s):  
Khaled Abdel Rahman ◽  
Marek Barta ◽  
Ľudovít Cagáň
Keyword(s):  
Beauveria Bassiana ◽  
Ostrinia Nubilalis ◽  
Egg Production ◽  
European Corn Borer ◽  
Fourth Instar ◽  
Combined Effects ◽  
High Concentration ◽  
Corn Borer ◽  
First Instar ◽  
Fungus Beauveria Bassiana

AbstractWe tested the combined effect of the fungus Beauveria bassiana and the microsporidium Nosema pyrausta on the European corn borer larvae, Ostrinia nubilalis, in the laboratory. The first instar of O. nubilalis larvae was the most sensitive to the B. bassiana infection followed by the fifth, second, third, and fourth instar (LC50s were 4.91, 6.67, 7.13, 9.15, and 6.51 × 105 conidia/ml for the first to fifth instars, respectively). Mortality of each instar increases positively with concentration of conidia. When B. bassiana and N. pyrausta were used in combination, mortality increased significantly in all instars. Relative to the B. bassiana treatment alone, the B. bassiana + N. pyrausta treatment decreased the LC50s by 42.16%, 37.63%, 21.60%, 27.11%, and 33.95% for the first to fifth instars, respectively. The combined effects of the two pathogens were mostly additive. However, at the two highest concentrations the pathogens interacted synergistically in the first and second instar. Individuals that survived the B. bassiana and B. bassiana + N. pyrausta treatments and developed into adults had significantly shorter lifespans and females oviposited fewer eggs than non-exposed insects. The effects on the longevity and the egg production were most pronounced at high concentration of B. bassiana conidia.

POSTMATING AGE ESTIMATES FOR FEMALE EUROPEAN CORN BORER MOTHS, OSTRINIA NUBILALIS (LEPIDOPTERA: PYRALIDAE), USING TIME-RELATED CHANGES IN SPERMATOPHORES

1979 ◽  
Vol 111 (12) ◽  
pp. 1325-1335 ◽  
Author(s):  
W. M. Elliott ◽  
V. A. Dirks
Keyword(s):  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
Second Generation ◽  
Light Trap ◽  
Age Groups ◽  
Volume Depletion ◽  
Corn Borer ◽  
Corn Borers ◽  
Lepidoptera Pyralidae ◽  
Modal Values

AbstractThe spermatophores in mated female European corn borers, Ostrinia nubilalis (Hübner), were shown to lose volume (depletion), change colour, and retract their spiral stalks over a period of about 7 days in such a way that postmating age could be estimated from their appearance. Colour changes and stalk retraction occurred more slowly in females that laid fertile eggs than in those that did not, but depletion occurred at the same rate. The average postmating age was estimated as 5.2, 6.3, 3.9, and 2.6 days for small light trap catches of first generation females in 1974, 1975, 1976, and 1977 and 4.4, 3.9, and 3.2 days for larger catches of second generation females in 1974, 1975, and 1977. Catches did not show decreasing numbers in successive age groups but tended to show modal values at < 1 day and at 4–6 days with only 1% living > 7 days. Redistribution of the moths from the date of capture back to the date of mating tended to give a unimodal curve of numbers on time in the 1975 second generation but not in 1974 or 1977. The unimodal curve of redistributed moths in 1975 was significantly different from a normal distribution. The redistribution showed that 58% of the moths mated within the heat unit interval when the second generation was expected to emerge, whereas only 38% of the actual catches occurred in this interval. Redistribution also showed that mating probably occurred even on cold nights when few moths were trapped, and conversely that on some warm nights with large catches most of the moths had mated on earlier nights.

SOME FACTORS INFLUENCING PHEROMONE TRAP CATCHES OF THE EUROPEAN CORN BORER, OSTRINIA NUBILALIS (LEPIDOPTERA: PYRALIDAE)

1978 ◽  
Vol 110 (1) ◽  
pp. 51-55 ◽  
Author(s):  
D. G. R. McLeod ◽  
A. N. Starratt
Keyword(s):  
Ostrinia Nubilalis ◽  
European Corn Borer ◽  
Pheromone Trap ◽  
Pheromone Traps ◽  
Rapid Loss ◽  
Corn Borer ◽  
Corn Borers ◽  
Factors Influencing ◽  
Lepidoptera Pyralidae ◽  
Trap Catches

AbstractA study was made of the reason for the fairly rapid loss of attractancy of pheromone traps for the European corn borer, Ostrinia nubilalis (Hübner). This loss in attractancy appeared to be attributable mainly to formation of an inhibitory or repellent substance(s). Although traps with a suspended pheromone dispenser were significantly more attractive than traps with the dispenser placed in contact with the adhesive, they still became relatively unattractive to male corn borers within approximately 1 week.

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