scholarly journals Temperature Dependent Growth and Mortality of Agrotis segetum

Insects ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 7 ◽  
Author(s):  
Peter Esbjerg ◽  
Lene Sigsgaard
Keyword(s):  
Pheromone Trap ◽  
Agrotis Segetum ◽  
High Survival ◽  
Temperature Dependent ◽  
Larval Instars ◽  
Growth And Survival ◽  
Dry Conditions ◽  
Dependent Growth ◽  
Trap Catches ◽  
Nw Europe

From 1905 to present, cutworm outbreaks have caused substantial yield losses in North Western (NW) Europe. Early authors pointed to dry summers as the trigger; around 1980, the explanation was improved via modelling of historical data. The number of precipitation days and the July temperature proved to be important, and in experiments, moist soil caused considerable mortality. This information was used in preliminary forecasting with pheromone trap catches as biofix for estimations of occurrence and survival. As more precise information on temperature effects on growth and survival was needed, we performed experiments on growth and mortality effects on egg, all larval instars and pupae. We found clear positive relations between temperatures below 35 °C and development rates of eggs, all larval instars and pupae. Mortality was also affected, and low temperature caused pronounced mortality of young larvae. The severe mortality under cold, moist conditions versus high survival under warm, dry conditions may explain both the lack of relation between captures and injuries and the pronounced fluctuations of cutworm attacks in NW Europe reported from 1905 to present. These variations are likely to increase with the climate change and suggest a reanalysis of data on trap capture and injuries to improve decision support and sustainability in Integrated Pest Management.

The influence of behaviour modifying chemicals on mating success of the red bollworm Diparopsis castanea Hmps. (Lepidoptera, Noctuidae) in Malawi

1976 ◽  
Vol 66 (2) ◽  
pp. 279-300 ◽  
Author(s):  
R. J. Marks
Keyword(s):  
Sex Pheromone ◽  
Sexual Attraction ◽  
Practical Method ◽  
Pheromone Trap ◽  
Cotton Field ◽  
Field Cage ◽  
Synthetic Sex Pheromone ◽  
Trap Catches ◽  
First Time ◽  
Lepidoptera Noctuidae

AbstractThe synthetic sex pheromone (dicastalure) of the red bollworm of cotton, Diparopsis castanea Hmps., in Central and Southern Africa, and an inhibitor of male sexual attraction (trans-9-dodecenyl acetate,=IIA), were used in an enclosed 0·2 ha cotton field-cage to reduce successful female matings. Over one month dicastalure at 21·0 and 42·3 g/ha produced average reductions in mating of 47·9% and 72·5% respectively and 37·9 g IIA/ha produced an overall reduction in mating of 71·5%, or 79·5% in released moth populations, over the same period. The proportion of virgin females present in disruption situations was significantly greater than in untreated populations and was density-independent for moth populations of up to 2 200/ha. The proportion of fertile eggs in disruption situations was correspondingly reduced to 30·2% from an average of 67·9% in control cycles. Reduction in sex pheromone trap catches is an unsatisfactory indicator of the extent to which males are prevented from inseminating females and considerably over-estimates the true degree of disruption. This is the first time that a naturally occurring inhibitor has been used successfully to disrupt mating in a field population of insects and it indicates the potential of the method for the control of high density pest populations in cotton. However, use of polyethylene dispensing mechanisms similar to those used in the field-cage disruption experiments would be unsuitable as a practical method of dispensing behaviour modifying chemicals and it is suggested that, for suitably controlled release of such chemicals, currently available microencapsulation technology offers the best prospects.

scholarly journals THRESHOLD SIZE FOR FLOWERING IN DIFFERENT HABITATS: EFFECTS OF SIZE-DEPENDENT GROWTH AND SURVIVAL

Ecology ◽  
1997 ◽  
Vol 78 (7) ◽  
pp. 2118-2132 ◽  
Author(s):  
Renate A. Wesselingh ◽  
Peter G. L. Klinkhamer ◽  
Tom J. de Jong ◽  
Laurence A. Boorman
Keyword(s):  
Growth And Survival ◽  
Threshold Size ◽  
Size Dependent ◽  
Dependent Growth

Adaptations of Coleoptera to the marine environment. II. Observations on rove beetles (Staphylinidae) from rocky shores

1988 ◽  
Vol 66 (11) ◽  
pp. 2469-2474 ◽  
Author(s):  
Werner Topp ◽  
Richard A. Ring
Keyword(s):  
Oxygen Consumption ◽  
Spring Tide ◽  
Salinity Range ◽  
Laboratory Population ◽  
Rocky Shores ◽  
Temperature Dependent ◽  
Rove Beetles ◽  
Dry Conditions ◽  
Lethal Time ◽  
Rate Of Evaporation

Two common rove beetles inhabit the intertidal rocky shores of British Columbia: Liparocephalus cordicollis Le Conte and Diaulota densissima Casey. Liparocephalus cordicollis, the more abundant of the two, is a predator that feeds preferentially on small chironomid larvae. Adults and larvae of this species can withstand submergence in seawater at 10 °C for more than 2 weeks. Thus they are able to survive continuous inundation from one spring tide to the next, just above lowest tide levels. Adults of L. cordicollis are osmotic regulators and can stabilize their body weight at salinities varying from 2 to 45‰. Both of these staphylinid species respire above and below water. Oxygen consumption of L. cordicollis in air at 10 °C was 376 ± 59 μL O2∙g−1∙h−1, but when the beetles were immersed in seawater at the same temperature the respiration rate was reduced to 45 ± 8 μL O2∙g−1∙h−1. During submersion, temperature-dependent reactions were observed (Q10 = 2). Respiration was constant within the salinity range of 2–30‰, but at higher levels (45‰) oxygen consumption increased to 55 ± 5 μL∙g−1∙h−1. When L. cordicollis was exposed to warm, dry conditions (simulating low tide on a warm summer day) the rate of evaporation from the cuticle was very high, calculated at 175 μg H2O loss per cm2 body surface per hour per mm Hg saturation deficit. The LT50 (mean lethal time) for a laboratory population was 2.5 h at a vapor pressure deficit of 7 mm Hg. In the larvae of beetles of the two species, asynchrony of growth in the population occurs because submerged larvae stop feeding and growing. Consequently, the development of individuals living near the low tide line is protracted compared with that of individuals living in the midlittoral zone.

scholarly journals Growing Blackgum Whips in Ground Beds Increases Survival and Growth Following Transplanting to Field

2008 ◽  
Vol 26 (2) ◽  
pp. 105-108
Author(s):  
Daniel K. Struve
Keyword(s):  
Short Fiber ◽  
Pine Bark ◽  
Root Pruning ◽  
High Survival ◽  
Growth And Survival ◽  
Transplant Shock ◽  
Nyssa Sylvatica ◽  
Harvesting Process ◽  
Production Period ◽  
Field Plots

Abstract Difficult-to-transplant species can be produced in containers and transplanted with high survival. However, circling roots can develop even in containers designed to prevent root malformation, requiring root pruning before transplanting and this results in transplant shock. In order to determine the effect of different containers and substrates on whip growth and survival after transplanting, blackgum (Nyssa sylvatica Marsh.) whips were grown in four container types (Spinout®-treated plastic, tall or short fiber containers or in ground beds) and two substrates (pine bark: Com-Til™ and Haydite: Com-Til™). Container-grown whips were overwintered in unheated polyhouses; bed-grown were overwintered out-of-doors with no winter protection. Two year branched whips grown in Haydite: Com-Til™ were bare rooted and root pruned before transplanting. Whips grown in containers required root pruning to correct root malformation, while whips grown in pine bark: Com-Til™ in ground beds were root pruned as part of the harvesting process. Container and substrate treatment did not affect whip stem diameter, but whips grown in ground beds in pine bark: Com-Til™ were the tallest. Overwinter survival for container-grown whips ranged from 77 to 88% and averaged 85% for whips grown in ground beds. The percentage of whips reaching 1.2 m in height ranged from 53 to 97% for whips produced in tall fiber containers in Haydite: Com-Til™ substrate and in short fiber containers in Haydite: Com-Til™ substrate, respectively. Two years after whips were transplanted, survival averaged 98% (174 of 178). Two years after transplanting, whips produced in beds in pine bark: Com-Til™ substrate had the greatest caliper. Whips produced in ground beds in pine bark: Com-Til™ offer an acceptable alternative to container-produced blackgum whips; they had high overwintering and transplant survival; they were taller at the end of the two year whip production period, and two years after transplanting to field plots they had the largest trunk caliper.

scholarly journals Location and Survival of Leaf-Associated Bacteria in Relation to Pathogenicity and Potential for Growth within the Leaf

1999 ◽  
Vol 65 (4) ◽  
pp. 1435-1443 ◽  
Author(s):  
M. Wilson ◽  
S. S. Hirano ◽  
S. E. Lindow
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Pathogens ◽  
Vacuum Infiltration ◽  
Associated Bacteria ◽  
Growth And Survival ◽  
Total Leaf ◽  
Spray Inoculation ◽  
Dry Conditions ◽  
Population Sizes ◽  
Better Than

ABSTRACT The growth and survival of pathogenic and nonpathogenicPseudomonas syringae strains and of the nonpathogenic species Pantoea agglomerans, Stenotrophomonas maltophilia, and Methylobacterium organophilum were compared in the phyllosphere of bean. In general, the plant pathogens survived better than the nonpathogens on leaves under environmental stress. The sizes of the total leaf-associated populations of the pathogenic P. syringae strains were greater than the sizes of the total leaf-associated populations of the nonpathogens under dry conditions but not under moist conditions. In these studies the surface sterilants hydrogen peroxide and UV irradiation were used to differentiate cells that were fully exposed on the surface from nonexposed cells that were in “protected sites” that were inaccessible to these agents. In general, the population sizes in protected sites increased with time after inoculation of plants. The proportion of bacteria on leaves that were in protected sites was generally greater for pathogens than for nonpathogens and was greater under dry conditions than under moist conditions. When organisms were vacuum infiltrated into leaves, the sizes of the nonexposed “internal” populations were greater for pathogenic P. syringae strains than for nonpathogenic P. syringaestrains. The sizes of the populations of the nonpathogenic species failed to increase or even decreased. The sizes of nonexposed populations following spray inoculation were correlated with the sizes of nonexposed, internal populations which developed after vacuum infiltration and incubation. While the sizes of the populations of the pathogenic P. syringae strains increased on leaves under dry conditions, the sizes of the populations of the nonpathogenic strains of P. syringae, P. agglomerans, andS. maltophilia decreased when the organisms were applied to plants. The sizes of the populations on dry leaves were also correlated with the sizes of the nonexposed populations that developed following vacuum infiltration. Although pathogenicity was not required for growth in the phyllosphere under high-relative-humidity conditions, pathogenicity apparently was involved in the ability to access and/or multiply in certain protected sites in the phyllosphere and in growth on dry leaves.

scholarly journals Flight initiation and flight activity in Prostephanus truncatus (Coleoptera: Bostrichidae)

1998 ◽  
Vol 88 (5) ◽  
pp. 545-552 ◽  
Author(s):  
D. Scholz ◽  
C. Borgemeister ◽  
R. H. Markham ◽  
H. M. Poehling
Keyword(s):  
Sex Ratios ◽  
Breeding Site ◽  
Pheromone Trap ◽  
Flight Activity ◽  
Prostephanus Truncatus ◽  
Pheromone Traps ◽  
Set Up ◽  
Trap Catches ◽  
Maize Cobs ◽  
Flight Initiation

AbstractIn an outdoor experimental set-up, the number of Prostephanus truncatus (Horn) flying from maize cobs was recorded over 38 observation weeks. Flight activity in the field was recorded for 50 weeks with three pheromone traps, each placed at c. 100–300 m from the first experimental set-up. Multiple regression analyses revealed that both flight initiation and flight activity were partly influenced by mean temperatures, but were not directly related. Flight initiation was mainly dependent on population density. An additional experiment showed that sex ratios among pheromone trap catches were not correlated with the number of beetles caught; sex ratios were female-biased throughout the year. Seasonal fluctuations in flight activity recorded with pheromone traps are mainly dependent on changes in the number and sizes of beetle populations in a given area, as well as on breeding site availability and suitability.

KEX2 mutations suppress RNA polymerase II mutants and alter the temperature range of yeast cell growth

1989 ◽  
Vol 9 (6) ◽  
pp. 2341-2349
Author(s):  
C Martin ◽  
R A Young
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Single Gene ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Temperature Dependent ◽  
Growth Properties ◽  
Cold Sensitive ◽  
Dependent Growth ◽  
Kex2 Protease

Suppressors of a temperature-sensitive RNA polymerase II mutation were isolated to identify proteins that interact with RNA polymerase II in yeast cells. Ten independently isolated extragenic mutations that suppressed the temperature-sensitive mutation rpb1-1 and produced a cold-sensitive phenotype were all found to be alleles of a single gene, SRB1. An SRB1 partial deletion mutant was further investigated and found to exhibit several pleiotropic phenotypes. These included suppression of numerous temperature-sensitive RNA polymerase II mutations, alteration of the temperature growth range of cells containing wild-type RNA polymerase, and sterility of cells of alpha mating type. The ability of SRB1 mutations to suppress the temperature-sensitive phenotype of RNA polymerase II mutants did not extend to other temperature-sensitive mutants investigated. Isolation of the SRB1 gene revealed that SRB1 is KEX2. These results indicate that the KEX2 protease, whose only known substrates are hormone precursors, can have an important influence on RNA polymerase II and the temperature-dependent growth properties of yeast cells.

Pythium myriotylum is recovered most frequently from Pythium soft-rot infected ginger rhizomes in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Paul Daly ◽  
Yifan Chen ◽  
Qimeng Zhang ◽  
Hongli Zhu ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Severe Disease ◽  
Zingiber Officinale ◽  
Soft Rot ◽  
Temperature Dependent ◽  
Pythium Myriotylum ◽  
Disease Symptoms ◽  
Ginger Rhizome ◽  
Oomycete Pathogen ◽  
Dependent Growth ◽  
Pythium Soft Rot

Pythium soft rot is a major soil-borne disease of crops such as ginger (Zingiber officinale). Our objective was to identify which Pythium species were associated with Pythium soft-rot of ginger in China, where approximately 20% of global ginger production is from. Oomycetes infecting ginger rhizomes from seven provinces were investigated using two molecular markers, the internal transcribed spacer (ITS) and cytochrome c oxidase subunit II (CoxII). In total, 81 isolates were recovered and approximately 95% of the isolates were identified as Pythium myriotylum and the other isolates were identified as either P. aphanidermatum or P. graminicola. Notably, the P. myriotylum isolates from China did not contain the SNP in the CoxII sequence found previously in the P. myriotylum isolates infecting ginger in Australia. A subset of 36 of the isolates was analyzed repeatedly by temperature-dependent growth, severity of disease on ginger plants and aggressiveness of colonization of ginger rhizome sticks. In the pathogenicity assays, 32/36 of the isolates were able to significantly infect and cause severe disease symptoms on the ginger plants. A range of temperature-dependent growth, disease severity and aggressiveness in colonization was found with a significant moderate positive correlation between growth and aggressiveness of colonization of the ginger sticks. This study identified P. myriotylum as the major oomycete pathogen in China from infected ginger rhizomes and suggests that P. myriotylum should be a key target to control soft rot of ginger disease.

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