MORTALITY IN LARVAE OF EUXOA MESSORIA (LEPIDOPTERA: NOCTUIDAE) COLLECTED FROM THE TOBACCO AREA OF ONTARIO

1971 ◽  
Vol 103 (6) ◽  
pp. 888-892 ◽  
Author(s):  
G. E. Bucher ◽  
H. H. Cheng
Keyword(s):  
Bacterial Infection ◽  
Fourth Instar ◽  
Stable Population ◽  
Virus Diseases ◽  
Adult Females ◽  
Causes Of Mortality ◽  
Trap Plants ◽  
Euxoa Messoria ◽  
Lepidoptera Noctuidae

AbstractLarvae of the dark-sided cutworm were collected from trap plants of tobacco set in a field of rye at Delhi, Ont., in 1969. They were reared individually to pupation to determine the degree of survival and the causes of mortality from the fourth instar to maturity. About 36% pupated and the greatest amount of mortality was caused by insect parasitism, a microsporidial disease, and bacterial infection. Fungus and virus diseases were virtually absent. As adult females are capable of laying a large number of eggs, mortality in eggs and young larvae must reach at least 98% to maintain a stable population. Introduction of virus pathogens to attack larvae might well be expected to result in regulating the population at a lower density.

The concentration of lamdacyhalothrin and its effect on the cutworm Agrotis segetum (Lepidoptera: Noctuidae)

1991 ◽  
Vol 81 (2) ◽  
pp. 143-145 ◽  
Author(s):  
B.W. Blair
Keyword(s):  
Fourth Instar ◽  
Synthetic Pyrethroid ◽  
Agrotis Segetum ◽  
Economic Plant ◽  
Initial Screening ◽  
Pest Damage ◽  
Plant Damage ◽  
Antifeedant Effect ◽  
Equivalent Rate ◽  
Lepidoptera Noctuidae

AbstractDuring initial screening of the synthetic pyrethroid lamdacyhalothrin (PP 321) at a concentration of 44 and 22 mg/l and applied as a 30 ml drench over each plant against third to fourth instar cutworms, Agrotis segetum (Denis & Schiffermüller) in microplots, few died but they did not damage the plants. Reducing the concentrations to 11 and 5.5 mg/l increased mortality and plant damage. When A. segetum were confined on soil treated with the insecticide at concentrations of 22, 11 and 5.5 mg/l and sprayed at an equivalent rate of 500 l/ha, they all died within one day. The higher concentrations appeared to have a repellent and/or antifeedant effect, and it has been possible to reduce the concentration of lamdacyhalothrin to 12.5 mg/l (≡5.6g a.i./ha) for the drench treatment without risking economic plant damage. For insecticides that have repellent and/or antifeedant properties, it should be possible to balance lower concentrations with adequate protection of plants from pest damage.

scholarly journals Reproductive potential of Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) in the laboratory: effect of multiple couples and the size

2016 ◽  
Vol 76 (2) ◽  
pp. 526-530 ◽  
Author(s):  
A. Specht ◽  
D. G. Montezano ◽  
D. R. Sosa-Gómez ◽  
S. V. Paula-Moraes ◽  
V. F. Roque-Specht ◽  
...  
Keyword(s):  
Reproductive Potential ◽  
Reproductive Parameters ◽  
Spodoptera Eridania ◽  
Adult Females ◽  
Controlled Conditions ◽  
Pupal Size ◽  
Lepidoptera Noctuidae

Abstract This study aimed to evaluate the effect of keeping three couples in the same cage, and the size of adults emerged from small, medium-sized and large pupae (278.67 mg; 333.20 mg and 381.58 mg, respectively), on the reproductive potential of S. eridania (Stoll, 1782) adults, under controlled conditions (25 ± 1 °C, 70% RH and 14 hour photophase). We evaluated the survival, number of copulations, fecundity and fertility of the adult females. The survival of females from these different pupal sizes did not differ statistically, but the survival of males from large pupae was statistically shorter than from small pupae. Fecundity differed significantly and correlated positively with size. The number of effective copulations (espematophores) and fertility did not vary significantly with pupal size. Our results emphasize the importance of indicating the number of copulations and the size of the insects when reproductive parameters are compared.

CUTWORMS (LEPIDOPTERA: NOCTUIDAE) OF TOBACCO IN NOVA SCOTIA: II. FALL RYE AND WINTER FALLOW EFFECTS ON A FIELD POPULATION

1974 ◽  
Vol 106 (1) ◽  
pp. 73-77
Author(s):  
H. B. Specht
Keyword(s):  
Nova Scotia ◽  
Winter Rye ◽  
Tobacco Plants ◽  
Peridroma Saucia ◽  
Cultural Methods ◽  
Variegated Cutworm ◽  
Euxoa Messoria ◽  
Field Plots ◽  
Lepidoptera Noctuidae ◽  
Winter Fallow

AbstractTwice as many larvae of the dark-sided cutworm, Euxoa messoria Harr., were found in rye fall-seeded tobacco field plots than in winter-fallowed tobacco field plots. There were corresponding differences in numbers of injured tobacco plants. Cutworm aggregations were more prominent in the winter rye than in the winter fallowed area of the tobacco field with low populations of dark-sided cutworms.Larvae of the variegated cutworm, Peridroma saucia Hbn., appeared 2 to 4 weeks later than dark-sided cutworm larvae and winter cultural methods had little effect on their numbers.

ASSESSMENT OF TOBACCO LOSSES CAUSED BY THE DARK-SIDED CUTWORM, EUXOA MESSORIA (LEPIDOPTERA: NOCTUIDAE), DELHI, ONTARIO

1971 ◽  
Vol 103 (4) ◽  
pp. 534-541 ◽  
Author(s):  
H. H. Cheng
Keyword(s):  
Population Density ◽  
Tobacco Plant ◽  
New Method ◽  
Crop Losses ◽  
Euxoa Messoria ◽  
Average Current ◽  
Lepidoptera Noctuidae

AbstractIntensive studies on the damage and losses of flue-cured tobacco caused by the dark-sided cutworm, Euxoa messoria (Harris), were carried out in the field at Delhi, Ont., during 1967 and 1968. A new method for estimating the accurate tobacco crop losses is illustrated. Assessment of damage of the tobacco plant and the population density in relation to the yield are described. The yield was significantly related, negatively, to the dark-sided cutworm density, and was reduced in the cutworm-damaged blocks in comparison with the yield in the undamaged check blocks. Assessment of average losses caused by the species was 17% of marketable tobacco, which, based on the average current prices, would amount to 200 dollars per acre or approximately 25 million dollars over the country as a whole every year.

Predation of Corn Earworm (Lepidoptera: Noctuidae) Eggs and Young Larvae by Orius insidiosus (Say) (Heteroptera: Anthocoridae) on Grain Sorghum in a Greenhouse

1994 ◽  
Vol 29 (1) ◽  
pp. 10-17 ◽  
Author(s):  
D. A. Jacobson ◽  
T. J. Kring
Keyword(s):  
Larval Density ◽  
Grain Sorghum ◽  
Corn Earworm ◽  
Fourth Instar ◽  
The Other ◽  
Orius Insidiosus ◽  
First Instar ◽  
Egg Density ◽  
Lepidoptera Noctuidae ◽  
Individual Adult

Individual adult, fourth- and second-instar Orius insidiosus (Say) were caged for 24 h on branches of grain sorghum panicles with combinations of 0, 2, or 4 corn earworm eggs and 0, 2, or 4 first instar earworms, excepting 0 eggs and 0 larvae. Individual adult O. insidiosus also were caged for 24 h with 2 second-instar corn earworms. In cages with corn earworm eggs and first instars, predation by all stages of O. insidiosus on one stage of corn earworm was not significantly influenced by the number of the other stage available. The number of corn earworm eggs shriveled or missing, indicative of predation by O. insidiosus, was highest for cages with O. insidiosus adults (65% for either egg density). In cages with fourth-instar O. insidiosus, the percentage of corn earworm egg shriveled or missing was 45% with 2 eggs available and 32% with 4 eggs available. At all densities of eggs, the number of eggs shriveled or missing in cages with second-instar O. insidiosus was not significantly higher than in control cages. The number of first-instar corn earworms shriveled or missing was highest with fourth-instar O. insidiosus (≈ 52% loss at either larval density). Approximately 47% of larvae at both densities were shriveled or missing in cages with adult O. insidiosus. As was the case with eggs, the number of corn earworm larvae shriveled or missing in cages with second-instar O. insidiosus was not significantly different from that for the controls. Predation on second-instar corn earworms by adult O. insidiosus was not significant.

Survival, Development, and Fecundity of the Pale Western Cutworm, Agrotis orthogonia Morr. (Lepidoptera: Noctuidae), After Starvation

1960 ◽  
Vol 92 (3) ◽  
pp. 184-188 ◽  
Author(s):  
L. A. Jacobson ◽  
P. E. Blakeley
Keyword(s):  
Food Supply ◽  
Fourth Instar ◽  
Feeding Period ◽  
Pupal Size ◽  
Lepidoptera Noctuidae

Larvae of the pale western cutworm, Agrotis orthogonia Morr., may be starved in the field by planned control (Seamans and Rock, 1945) or elimination of their food supply as a result of their own depredation. Starvation may occur at any time during the feeding period. Some effects of starvation on mortality, particularly in the early instars, have been reported (Jacobson, 1952). Larvae that were fed only two hours each day had an additional instar, developed more slowly, and were smaller (McGinnis and Kasting, 1959). Starvation during the fourth instar when the larvae were fed on various foods resulted in smaller pupae, and the size and fecundity of females were directly associated with pupal size (Jacobson and Blakeley, 1958).

Keys to the adult females and fourth-instar larvae of the mosquitoes of Iran (Diptera: Culicidae)

Zootaxa ◽  
2009 ◽  
Vol 2078 (1) ◽  
pp. 1-33 ◽  
Author(s):  
SHAHYAD AZARI-HAMIDIAN ◽  
RALF E. HARBACH
Keyword(s):  
Aedes Albopictus ◽  
Fourth Instar ◽  
Museum Collections ◽  
Adult Females ◽  
Taxonomic Keys

Taxonomic keys are provided for the identification of the adult females and fourth-instar larvae of Iranian mosquitoes (Diptera: Culicidae), which include 64 species and three subspecies belonging to seven genera. The keys also include 12 species recorded in old literature that have not been collected recently, but are known to occur elsewhere in southwestern Asia. Aedes albopictus (Skuse) is not known to occur in Iran, but it is included in the keys because it has been established in many countries in the region during recent decades, and it is medically important. Newly recorded species, new characters, drawings illustrating characters used in the keys, and some notes are included to aid the identification of the species. The keys are based on recently collected specimens and museum collections, as well as taxonomic literature.

LABORATORY STUDIES OF SPRAY DEPOSITS ON THE MIGRATORY GRASSHOPPER (MELANOPLUS SANGUINIPES) (ORTHOPTERA: ACRIDIDAE)

1974 ◽  
Vol 106 (10) ◽  
pp. 1103-1108 ◽  
Author(s):  
K. S. McKinlay
Keyword(s):  
Target Surface ◽  
Fourth Instar ◽  
Unit Weight ◽  
Melanoplus Sanguinipes ◽  
Adult Males ◽  
Laboratory Studies ◽  
Adult Females ◽  
Linear Dimensions ◽  
Insecticide Sprays

AbstractHydraulic, fan-spray nozzles (Teejet 650067) at 50.8 cm (20 in.) spacing, 55.9 cm (22 in.) above the target surface, and operating at 2.8 kg/cm2 (40 p.s.i.) produced very uneven coverage when applying aqueous sprays containing uranine. Deposits immediately below the nozzles were 2 to 3 times more than those between nozzles.Deposits on grasshoppers (Melanoplus sanguinipes F.) were directly proportional to their plan area. Since this area increases as the square of the linear dimensions and weight increases as the cube, second instar grasshoppers collected twice as much spray/unit weight as fourth instar nymphs and 3 times as much as adult females. These differences were reflected in the mortality caused by insecticide sprays. A spray applying dimethoate at 140 g/ha (2 oz/ac) in 39.3 l./ha (3.5 Imp. g.p.a.) killed 90% of second instar nymphs but only 14% of adult males.

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