ANALYSIS OF MORTALITY IN THE APPLE MAGGOT, RHAGOLETIS POMONELLA (DIPTERA: TEPHRITIDAE), IN QUEBEC

1977 ◽  
Vol 109 (6) ◽  
pp. 769-788 ◽  
Author(s):  
P. J. Cameron ◽  
F. O. Morrison

AbstractLife tables were constructed for populations of R. pomonella (Walsh) in two abandoned, heavily infested apple orchards near Como, Quebec. All life stages were sampled and the results expressed in terms of the apple as a unit. Twenty-five life tables, each based on one tree, covered two successive generations on both early and late maturing varieties.Natality was of no value in predicting variation in numbers of emerging adults, whereas the early pupal stage estimates explained over 80% of the variation. Parasitism of larvae and pupae was more common than previously recorded but parasites were not significant in the population dynamics of their host. Nutritionally based larval mortality, predation on mature larvae and pupae, and movements of adults between trees were key factors in population variation. Early variety trees appeared to maintain apple maggot population levels. These results were supported by experimental studies on the effects of temperature treatments and predation on larval and pupal mortality.

1971 ◽  
Vol 60 (3) ◽  
pp. 399-407
Author(s):  
John B. Davies

One field and four laboratory trials were run to determine the reason for the success of 1–8% malathion in diesel oil in controlling Culicoides furens (Poey) in swamp mud in Jamaica. In the laboratory malathion and marine diesel oil (1:4000) was an effective larvicide for up to two days after application to the mud, but diesel oil alone gave only slight mortality even after six days. Judged by the emergence of adults, diesel oil gave 100% pupal mortality for five days and still showed some effect after four weeks; this effect was not improved by the addition of malathion. In the field, counts of emerging adults showed that diesel oil at 106–5 gal/acre gave 97–8% control of C. furens for up to eight weeks after application. It is concluded that, because of the possibility of pupicidal action, insecticides should be assessed on adult emergence rather than larval mortality.


2009 ◽  
Vol 100 (1) ◽  
pp. 87-97 ◽  
Author(s):  
W.H. Jenner ◽  
U. Kuhlmann ◽  
P.G. Mason ◽  
N. Cappuccino

AbstractLeek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae), is an invasive alien species in eastern Canada, the larvae of which mine the green tissues of Allium spp. This study was designed to construct and analyse life tables for leek moth within its native range. Stage-specific mortality rates were estimated for the third leek moth generation at three sites in Switzerland from 2004 to 2006 to identify some of the principle factors that inhibit leek moth population growth in areas of low pest density. The contribution of natural enemies to leek moth mortality was measured by comparing mortality on caged and uncaged leeks. Total pre-imaginal mortality on uncaged plants was 99.6%, 99.1% and 96.4% in 2004, 2005 and 2006, respectively. Variation in mortality was greater among years than among sites. Total larval mortality was greater than that in the eggs and pupae. This was due largely to the high mortality (up to 83.3%) of neonates during the brief period between egg hatch and establishment of the feeding mine. Leek moth pupal mortality was significantly greater on uncaged than on caged leeks, indicating an impact by natural enemies, and this pattern was consistent over all three years of study. In contrast, the other life stages did not show consistently higher mortality rates on uncaged plants. This observation suggests that the pupal stage may be particularly vulnerable to natural enemies and, therefore, may be the best target for classical biological control in Canada.


2019 ◽  
Vol 11 (16) ◽  
pp. 132
Author(s):  
Sandra M. Chaneiko ◽  
Andressa L. de Brida ◽  
Pedro G. Bassa ◽  
Marco H. F. Telles ◽  
Luana A. dos Santos ◽  
...  

Anastrepha fraterculus (Diptera: Tephritidae) is among the most important fruit pests in South America, and the use of entomopathogenic fungi is considered a promising alternative for its control. The objective of this work was to evaluate the pathogenicity of Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin on larvae and pupae of A. fraterculus, along with fungal effects on adult fly longevity. Fungal inoculations, fly larvae or pupae were placed in Petri dishes with 1 mL/plate, and the concentrations of 10, 15, 20 and 25 grams of commercial product/liter of water. Controls received water only. To evaluate the residual effect on adult flies, emerging adults were transferred to clean arenas and the adult longevity was monitored. Beauveria bassiana and M. anisopliae caused 93.3 and 96.7% larval mortality and 14.0 and 15.0% pupal mortality, respectively. The estimated LC50 and LC90 values were 22.56 and 40.87 g/L for B. bassiana, and of 23.45 and 42.02 g/L for M. anisopliae. Infected adult insects had shorter longevity than non-infected insects, with mean survival of 8.0 and 83.5 days for B. bassiana and M. anisopliae, respectively.


2018 ◽  
Vol 36 (3) ◽  
pp. 353-356 ◽  
Author(s):  
Ewerton M Costa ◽  
Francisco EL Silva ◽  
Elton L Araujo

ABSTRACT The leafminer [Liriomyza sativae (Diptera: Agromyzidae)] is one of the main pests of melon crop (Cucumis melo) in the states of Rio Grande do Norte and Ceará. Thus, adopting strategies to control this destructive insect is essential. The aim of this study was to evaluate the effect of aqueous neem seed extract, applied to soil via irrigation, on leafminer larvae, in the melon crop. An experiment was conducted in greenhouse, in completely randomized design, consisting of five treatments (four doses of aqueous neem seed extract: 1; 3; 5 and 10 g/100 mL) and the control consisting only of distilled water and 10 replicates (melon plants). The treatments were applied in a single dose, via soil irrigation. In the first stage of the evaluation, 24 hours after application, the number of dead larvae per plant was counted. In the second step, pupal mortality was recorded. The total mortality was also calculated considering the number of larvae and the number of emerged adults. We verified that, increasing the concentration of aqueous neem seed extract, an increase in the larval and pupal mortality of the leafminer in melon crop was noticed. The concentration 10 g/100 mL presented the best results, resulting in 36.4% of larval mortality, 96.5% of pupal mortality and 96.8% of total mortality.


2011 ◽  
Vol 35 (6) ◽  
pp. 1149-1156 ◽  
Author(s):  
Viviane Santos ◽  
Alcides Moino Junior ◽  
Vanessa Andaló ◽  
Camila Costa Moreira ◽  
Ricardo Alves de Olinda

Entomopathogenic nematodes (EPNs) are used in biological control of soil insects and show promise in the control of D. speciosa. The objective of this work was to evaluate the potential of native and exotic entomopathogenic nematode isolates in the control of D. speciosa under laboratory and greenhouse conditions. Results showed that all of EPNs caused larval mortality. The most virulent were Heterorhabditis sp. RSC01 (94%), Steinernema glaseri (84%), Heterorhabditis sp. JPM04 (82%) and Heterorhabditis amazonensis RSC05 (78%). There was no effect of the Heterorhabditis sp. RSC01 and S. glaseri isolates on eggs. The maximum mortality of D. speciosa larvae by Heterorhabditis sp. RSC01 was observed at a concentration of 300 IJ/ insect, while by S. glaseri observed the highest mortality at the concentration of 200 IJ/ insect. The Heterorhabditis sp. RSC01 isolate caused over 80% pupal mortality at a concentration of 250 IJ/insect. The virulence of Heterorhabditis sp. RSC01 and S. glaseri was affected by temperature. The Heterorhabditis sp. RSC01 isolate caused reduction in larva survival under greenhouse conditions at all of the tested concentrations and there was no difference in mortality among different concentrations of infectid juveniles.


2012 ◽  
Vol 21 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Maria Alice Zacarias do Amaral ◽  
Márcia Cristina de Azevedo Prata ◽  
Erik Daemon ◽  
John Furlong

With the objective of encouraging the use of rabbits as alternative hosts for the cattle tick, four rabbits were infested on the ears and back. From the second day of infestation the developmental stages were observed. e duration of larval engorgement and changes were estimated between six and eight days in the region of the back and between 've and seven days in the pinna. e nymphal engorgement and changes occurred at approximately 10.80 ± 2.65 days in the dorsal and 11.00 ± 2.52 days in the ear, with the engorgement of adults and copulation occurring at 7.03 ± 2.45 days, on the dorsal region and 8.55 ± 1.82 days in the region of the pinna. e parasitic period ranged from 21 to 29 days (back) and from 23 to 30 days (pinna). e engorged females of the back and ear weighed on average 34.43 ± 18.73 and 36.30 ± 18.10 mg, respectively. e nutritional and reproductive e/ciency indexes were 17.38 ± 14.27 and 26.85 ± 17.13% (back) and 17.42 ± 12.22% and 30.70 ± 19.80% (pinna). Although not appropriate to maintain successive generations of Rhipicephalus (Boophilus) microplus, rabbits can be used for di:erent stages of engorgement of the ixodid, allowing experimental studies.


The Auk ◽  
2005 ◽  
Vol 122 (3) ◽  
pp. 902-914 ◽  
Author(s):  
Laura R. Nagy ◽  
Richard T. Holmes

AbstractIndividuals within a population vary in important fitness components, such as reproductive success. In general, females can maximize the number of young they produce by altering either the number of young per breeding attempt or the number of breeding attempts per season. In short-lived species, and especially in small passerine birds, number of breeding attempts per season varies markedly among individuals. Here, we evaluated factors influencing whether female Blackthroated Blue Warblers (Dendroica caerulescens) initiated additional nests after a successful breeding attempt (i.e. double-brooded). The percentage of females that laid a second clutch after successfully fledging a first brood ranged from 0 to 87% and averaged 53% (n = 7 years). Multiple logistic regression and AICc model selection indicated that double-brooded females bred in territories with greater food availability and produced heavier nestlings than single-brooded females. Female age, male age, date of first breeding attempt, and number of young in the first clutch were not included in the best-fit model. Older females, however, produced heavier fledglings, and females mated to older males occurred on territories with greater food availability, indicating that age contributed to individual variation in reproductive output. Because the proportion of females that produce multiple broods within a season can have a substantial effect on the annual fecundity of a population, variation among females and among the territories they occupy (i.e. habitat quality) are key factors influencing population dynamics in this and other multibrooded, shortlived species.Poner Nidadas Dobles o No? Variación Individual en el Esfuerzo Reproductivo en Dendroica caerulescens


1967 ◽  
Vol 45 (4) ◽  
pp. 539-578 ◽  
Author(s):  
T. Burnett

Three populations of the greenhouse whitefly, Trialeurodes vaporariorum, and its chalcid parasite Encarsia formosa were propagated each year for three consecutive years on tomato plants in the greenhouse. The abundance of the host and parasite species fluctuated either with peaks of increasing amplitude, with peaks of decreasing amplitude, or with irregular peaks. The dominant process in the interaction was the occurrence of two qualitatively different types of host larval mortality: (a) parasitization, and (b) almost immediate killing after attack by adult parasites. Fluctuations in host and parasite abundance resulted from the almost immediate killing of small host larvae and the death of the short-lived adult parasites. The parasite population tended to destroy similar percentages of host populations of different densities but host mortality was also related to the age structure of the host population. Variation in host reproduction, caused by differences in rearing temperature and by seasonal variation in the physical environment, influenced host and parasite densities.


1978 ◽  
Vol 68 (1) ◽  
pp. 57-64 ◽  
Author(s):  
R. M. Perrin

AbstractIn studies in Nigeria, survival and weight increase of the larvae of Cydia ptychora (Meyr.) were affected by the variety of cowpea (Vigna unguiculata) on which they fed. The weights of fifth-instar larvae immediately prior to pupation and the amount of fresh food ingested were similar on three varieties when loose seeds were fed, but in a more natural situation, larvae appeared to face a manoeuvrability problem in small pods, which resulted in reduced weight gain. Differences in weight due to diet were less pronounced in emerging adults. Larval mortality was greatest on two varieties with large pods and may have been related to the nutritional quality of mature seeds or the presence of toxic chemicals. Some first-instar larvae died during the pod-boring process, particularly in the variety Vita-5. Two known susceptible varieties produced a moderate-to-small degree of mortality and large females. Significantly greater weight was attained when larvae fed for five days on 10-day-old seed followed by 15-day-old seed, or on 15-day-old seed throughout, than on 15-day-old seed followed by dried seed, or on 10-day-old seed throughout. Ovipositing females seemingly select pods of an age that minimises exposure of young larvae to drying or fully dried seed, which is a relatively unsuitable diet.


2018 ◽  
Vol 40 ◽  
pp. 02049
Author(s):  
Chanjoo Lee ◽  
Donggu Kim ◽  
Sungjung Kim ◽  
Un Ji ◽  
Jihyun Kim ◽  
...  

Vegetation is one of the key factors in river management where environmental aspects as well as flood protection should be taken into consideration. Because of this, numerous studies have been done including experiments and hydrodynamic modelling. Because most of experimental studies were made in indoor laboratory flumes with artificial trees, there are still limitations in transfer of their result to actual channels. REC (River Experiment Center) of Korea has been operating three real-scale, nature-like outdoor experimental channels. In a straight channel, several 4x2 m actual willow patches were planted and have been grown last three years for studies on flow vegetation interaction. A set of intensive flow measurement was made around the first upstream willow patch using ADVs together with measurement of vegetation properties. The experiments were made under several different depth conditions simulating snow-melt and flash-flood. Distribution of flow around and through the patch was characterized along with vertical profiles. The results of the experiment enhance understanding on interaction of flow and actual vegetation in a natural channel and may also provide information on flow resistance used for hydrodynamic modelling and validation.


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