THE BERTHA ARMYWORM, MAMESTRA CONFIGURATA (LEPIDOPTERA: NOCTUIDAE). ARTIFICIAL DIET AND REARING TECHNIQUE

1976 ◽  
Vol 108 (12) ◽  
pp. 1327-1338 ◽  
Author(s):  
G. E. Bucher ◽  
G. K. Bracken

AbstractA technique is described for rearing successive generations of the insect in numbers from 200 to 40,000 continuously without diapause. All components of the diet are commercially available and the principal ingredients are of plant origin. Survival at four stages of development is given and the causes of mortality are discussed. The per cent survival of insects from instar III to pupation times the percentage of perfect female pupae obtained at harvest gives a factor considered to be the best measure of the worth of an artificial diet. The variability of these statistics is shown by frequency distributions obtained in 50 independent tests of the diet. Overall survival of 84% times 73% perfect females gave a diet worth factor of 61. An analysis of rearing costs is presented. Although 15 continuous generations have been reared, egg production of the highly selected strain has not deteriorated.

1976 ◽  
Vol 108 (12) ◽  
pp. 1319-1326 ◽  
Author(s):  
Clyde G. Bailey

AbstractDifferential survival, growth, and egg production were obtained for the bertha armyworm, Mamestra configurata Wlk., feeding on four natural host plants and one artificial diet. Highest survival, growth, and egg production were obtained among insects reared on the artificial diet. Foliage of potato was the only food which appeared to lack the nutritive qualities essential for adequate survival, growth, and reproduction. Larvae reared on this plant consumed significantly less food, had a poorer survival, accumulated less reserves in the form of tissue growth, developed into smaller pupae, and produced adults that were less fecund than those reared on other foods. Despite these differences, the approximate digestibility (AD), the efficiency of conversion of ingested food to body tissue (ECI), and the efficiency of conversion of digested food to body substance (ECD) obtained for insects feeding on potato, were very similar to values obtained for insects which were reared on other plants. On each diet a linear relationship was obtained between food consumption and growth.


1982 ◽  
Vol 114 (12) ◽  
pp. 1191-1193
Author(s):  
R. P. Bodnaryk

During a study of the effects of insecticides on cyclic nucleotide metabolism it was observed that moths (Mamestra conjgurata Wlk.) treated with the pyrethroids permethrin and deltamethrin often had grossly bloated abdomens several hours after treatment.Two- to three-day-old moths were obtained from a laboratory culture of the bertha armyworm, M. configurata, reared on an artificial diet (Bucher and Bracken 1976). Initially, males and females were treated topically with insecticide in 5 μl of acetone applied to the thorax, head, or abdomen. Pyrethroid-treated moths developed abdominal bloat independent of the site of treatment, therefore the thorax was chosen for treatment. Treated moths were held at 20°C and examined twice daily for 3 days to determine the incidence of bloat and mortality.


1988 ◽  
Vol 120 (5) ◽  
pp. 401-413 ◽  
Author(s):  
W. J. Turnock

AbstractPopulations of larvae of the bertha armyworm, Mamestra configurata Wlk., in four physiographic regions of Manitoba showed similar trends over time: a decline from the outbreak of 1971–1972 to very low densities in 1975–1977, an increase to a peak during the years 1979–1981, and a subsequent decline. During the period of peak larval populations, brief (1 or 2 years) outbreaks [at least some fields with > 20 larvae per square metre) occurred at five locations in two regions, the Swan River Plain and the Valley River Plain, but not in the Western Uplands or the Manitoba Lowlands. In the first two regions, larval densities rose rapidly (from < 1.6 to > 13.8/m2) in 1 year. Although the general trend of population density was similar, there were differences in density among and within regions, and in the timing, severity, and duration of peak populations. Two parasitoids (Banchus flavescens Cress., Athrycia cinerea (Coq.)) and two pathogens (a nuclear polyhedrosis virus (NPV) and fungi of the Entomophthorales) occurred regularly in larval populations. Of these, B. flavescens had the highest constancy among collections and may help to keep bertha armyworm populations at low densities. NPV was rarely found among larvae from low-density populations but appeared in all populations that reached outbreak levels. No single biotic agent could be associated with the population declines because of multiple parasitism and the difficulty in partitioning mortality when only a single sample could be taken. The rapid increase of bertha armyworm larvae from very low to outbreak levels in 1 year will prevent predictions of outbreaks from being based on larval densities in the preceding year.


1983 ◽  
Vol 115 (8) ◽  
pp. 1039-1042 ◽  
Author(s):  
B. M. Hegdekar

AbstractThe critical photoperiod for diapause induction in pupae of Mamestra configurata Walker in Manitoba was 16 h 06 min at Glenlea (49°38′ N), 16 h 20 min at Grandview (51°10′ N), and 16 h 42 min at Birch River (52°24′ N). The differences in cirtical photoperiods observed at Glenlea and Grandview were not significant. At least two different photoperiods exist, one in the Glenlea and Grandview areas and the other in the Birch River area. In the laboratory, the critical photoperiod was 13.5 h when larvae were exposed to a daily fluctuating temperature regime of 12 h at 25 °C and 12 h at 10 °C. Longer critical photoperiods found for the field populations may be related to the relatively low ambient temperatures to which the larvae were exposed in field cages.


1986 ◽  
Vol 118 (12) ◽  
pp. 1221-1230 ◽  
Author(s):  
M.A. Howlader ◽  
G.H. Gerber

AbstractThe effects of age, egg development, and mating on calling behavior of the bertha armyworm, Mamestra configurata Walker, were studied at 20°C, 60% RH, and a 16-h L: 8-h D photoperiod. Most virgin females called and copulated for the first time during the second or third scotophase after emergence. The first copulation was 17.0 ± 0.2 h (mean±SE) long and was terminated within 1 h after lights off in the scotophase following the initiation of copulation. The ovaries contained the first chorionated eggs before the beginning of the second scotophase after emergence. The first egg laying occurred during the same scotophase in which the first copulation was terminated, i.e. scotophase three or four. Almost 75% of the eggs were laid by the end of the seventh scotophase after emergence. Mated females resumed calling after a refractory period of about 2 days. Once calling was resumed after copulation, most females laid eggs and called nightly, with egg laying occurring during the first 5–6 h and calling during the last 2–3 h of the scotophase. Mated females called for a shorter period during each scotophase than virgin females of the same age (1–3 h vs. 4–6 h). In virgin females, the diel periodicity of calling was advanced and the length of the daily calling period was increased with age until the seventh scotophase after emergence; thereafter, both remained relatively unchanged.


1972 ◽  
Vol 104 (11) ◽  
pp. 1745-1750 ◽  
Author(s):  
Y. W. Lee ◽  
R. J. Ford ◽  
H. McDonald ◽  
K. S. McKinlay ◽  
L. G. Putnam ◽  
...  

AbstractResidues of methomyl in rape plants and seed were determined after its application for bertha armyworm control. In one experiment application of 3 oz of methomyl per acre left 17 p.p.m. residue on the rape plants immediately after application. This level rapidly declined to 1.5, 1.0, 0.4, and 0.2 p.p.m. 1, 2, 5, and 9 days later, respectively, and no residue was detected (less than 0.02 p.p.m.) in seed harvested 22 days after application of the toxicant. Rape plant samples collected from several farms immediately after the application of 3 to 4 oz of methomyl per acre had 2.5 to 16 p.p.m. residues, indicating inefficient application of the insecticide in some cases. Analysis of rape seed samples collected from 36 farms showed little residue in three samples (0.02 to 0.03 p.p.m.) and none in 33, indicating that the use of methomyl for bertha armyworm control is not likely to contaminate rape seed with undesirable levels of residues.


Author(s):  
P. G. Mason ◽  
W. J. Turnock ◽  
M. A. Erlandson ◽  
U. Kuhlmann ◽  
L. Braun

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