Effects of Moisture during Starvation of Larvae of the Pale Western Cutworm, Agrotis orthogonia Morr. (Lepidoptera: Phalaenidae)

1957 ◽  
Vol 89 (10) ◽  
pp. 465-469 ◽  
Author(s):  
L. A. Jacobson ◽  
P. E. Blakeley

Larvae of the pale western cutworm, Agrotis orthogonia Morr., feed almost entirely below ground, attacking their food plants just below the soil surface. Larval movement and feeding usually occur at the interface between dry and moist soil. They can absorb moisture from the soil and also from the plants on which they are feeding.In a previous investigation, Jacobson (1952) found that mortality from starvation varied directly with temperature and inversely with the size of larvae when the relative humidity was kept near 100 per cent. This paper is a report on the role of moisture during starvation.

Author(s):  
Sina Shaffiee Haghshenas ◽  
Behrouz Pirouz ◽  
Sami Shaffiee Haghshenas ◽  
Behzad Pirouz ◽  
Patrizia Piro ◽  
...  

Nowadays, an infectious disease outbreak is considered one of the most destructive effects in the sustainable development process. The outbreak of new coronavirus (COVID-19) as an infectious disease showed that it has undesirable social, environmental, and economic impacts, and leads to serious challenges and threats. Additionally, investigating the prioritization parameters is of vital importance to reducing the negative impacts of this global crisis. Hence, the main aim of this study is to prioritize and analyze the role of certain environmental parameters. For this purpose, four cities in Italy were selected as a case study and some notable climate parameters—such as daily average temperature, relative humidity, wind speed—and an urban parameter, population density, were considered as input data set, with confirmed cases of COVID-19 being the output dataset. In this paper, two artificial intelligence techniques, including an artificial neural network (ANN) based on particle swarm optimization (PSO) algorithm and differential evolution (DE) algorithm, were used for prioritizing climate and urban parameters. The analysis is based on the feature selection process and then the obtained results from the proposed models compared to select the best one. Finally, the difference in cost function was about 0.0001 between the performances of the two models, hence, the two methods were not different in cost function, however, ANN-PSO was found to be better, because it reached to the desired precision level in lesser iterations than ANN-DE. In addition, the priority of two variables, urban parameter, and relative humidity, were the highest to predict the confirmed cases of COVID-19.


2016 ◽  
Vol 225 ◽  
pp. 96-108 ◽  
Author(s):  
I. Fratoddi ◽  
A. Bearzotti ◽  
I. Venditti ◽  
C. Cametti ◽  
M.V. Russo

1958 ◽  
Vol 90 (7) ◽  
pp. 439-440 ◽  
Author(s):  
A. M. Harper

Normally the sugar-beet root aphid, Pemphigus betae Doane, lives and feeds on sugar-beet roots below ground during the summer and fall. However, in many beet fields between Lethbridge and Monarch, Alberta, in September, 1956, a large number of these aphids were found on the soil surface and on the crowns and leaves of the plants. Many of the aphids had crawled up the plants and, even after death, remained clinging to the leaves (Fig. 1). This clinging reaction seemed similar to that of grasshoppers infected with Entomophthora grylli Fresen. Mr. R. B. Baird, Entomology Laboratory, Canada Department of Agriculture, Belleville, Ontario, identified the organism causing the disease destroying these aphids as Entomophthora aphidis Hoffm. This is the first record of this disease killing subterranean aphids in Canada. The only other reports of E. aphidis on root aphids are those of Maxson (1916) in Colorado and Charles (1941) in California. In Canada, it has been previously reported as a factor in control of the pea aphid, Acyrthosiphon pisum (Harr.), in the Annapolis Valley, Nova Scotia (MacLeod, 1953).


2016 ◽  
Vol 16 (2) ◽  
pp. 927-932 ◽  
Author(s):  
M. L. López ◽  
E. E. Ávila

Abstract. This study reports measurements of deposition-mode ice-nucleating particle (INP) concentrations at ground level during the period July–December 2014 in Córdoba, Argentina. Ambient air was sampled into a cloud chamber where the INP concentration was measured at a temperature of −25 °C and a 15 % supersaturation over ice. Measurements were performed on days with different thermodynamic conditions, including rainy days. The effect of the relative humidity at ground level (RHamb) on the INP concentration was analyzed. The number of INPs activated varied from 1 L−1 at RHamb of 25 % to 30 L−1 at RHamb of 90 %. In general, a linear trend between the INP concentration and the RHamb was found, suggesting that this variability must be related to the effectiveness of the aerosols acting as INPs. From the backward trajectories analysis, it was found that the link between INP concentration and RHamb is independent of the origin of the air masses. The role of biological INPs and nucleation occurring in pores and cavities was discussed as a possible mechanism to explain the increase of the INP concentration during high ambient relative humidity events. This work provides valuable measurements of deposition-mode INP concentrations from the Southern Hemisphere where INP data are sparse so far.


Plant Disease ◽  
2005 ◽  
Vol 89 (11) ◽  
pp. 1241-1241 ◽  
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
M. L. Gullino

Several species of Diplotaxis (D. tenuifolia, D. erucoides, and D. muralis), known as wild or sand rocket, are widely cultivated in Italy. Rocket is used in Mediterranean cuisine as salad, a component of packaged salad products, and as a garnish for food. In winter 2003, a severe disease was observed on D. tenuifolia grown in unheated glasshouses on commercial farms near Albenga in northern Italy. Initial symptoms included stem necrosis at the soil level and darkening of leaves. As stem necrosis progressed, infected plants wilted and died. Wilt, characterized by the presence of soft and watery tissues, occurred within a few days on young plants. The disease was extremely severe in the presence of high relative humidity and mild temperature (15°C). Necrotic tissues became covered with white mycelium that produced dark sclerotia. Diseased stem tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 ppm streptomycin sulfate. Sclerotinia sclerotiorum (1) was consistently recovered from infected stem pieces. Sclerotia observed on infected plants measured 1.23 to 3.00 × 1.40 to 5.38 mm (average 2.10 × 2.85 mm). Sclerotia produced on PDA measured 1.00 to 4.28 × 1.00 to 6.01 mm (average 2.38 × 3.23 mm). Pathogenicity of three isolates obtained from infected plants was confirmed by inoculating 30-day-old plants of D. tenuifolia grown in 18-cm-diameter pots in a glasshouse. Inoculum, 2 g per pot of wheat kernels infested with mycelium and sclerotia of each isolate, was placed on the soil surface around the base of each plant. Three replicates of five pots each were used per isolate. Noninoculated plants served as controls. The inoculation trial was repeated once. All plants were kept at temperatures ranging between 10 and 26°C (average 15°C) with an average relative humidity of 80% and were watered as needed. Inoculated plants developed symptoms of leaf yellowing within 12 days, soon followed by the appearance of white mycelium and sclerotia, and eventually wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from inoculated plants. To our knowledge, this is the first report of infection of D. tenuifolia by S. sclerotiorum in Italy as well as worldwide. The disease currently has been observed in the Liguria Region but not yet in other areas where sand rocket is cultivated. The economic importance of this disease for the crop can be considered medium at the moment, but is expected to increase in the future. Reference: (1) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift, 75, 1949.


2017 ◽  
Author(s):  
Sergio M. Vicente-Serrano ◽  
Raquel Nieto ◽  
Luis Gimeno ◽  
Cesar Azorin-Molina ◽  
Anita Drumond ◽  
...  

Abstract. We analyzed changes in surface relative humidity (RH) at the global scale from 1979 to 2014 using both observations and ERA-Interim dataset. We compared the variability and trends of RH with those of land evapotranspiration and ocean evaporation in moisture source areas across a range of selected regions worldwide. The sources of moisture for each particular region were identified by integrating different observational data and model outputs into a lagrangian approach. The aim was to account for the possible role of changes in air temperature over land, in comparison to sea surface temperature (SST), on RH variability. Results demonstrate a strong agreement between the interannual variability of RH and the interannual variability of precipitation and land evapotranspiration in regions with continentally-originated humidity. In contrast, albeit with the dominant positive trend of air temperature/SST ratio in the majority of the analyzed regions, the interannual variability of RH in the target regions did not show any significant correlation with this ratio over the source regions. Also, we did not find any significant association between the interannual variability of oceanic evaporation in the oceanic humidity source regions and RH in the target regions. Our findings stress the need for further investigation of the role of both dynamic and radiative factors in the evolution of RH over continental regions at different spatial scales.


2019 ◽  
Vol 55 (No. 4) ◽  
pp. 242-253 ◽  
Author(s):  
Anamarija Jagodič ◽  
Stanislav Trdan ◽  
Žiga Laznik

Plants under herbivore attack emit mixtures of volatiles that can attract the natural enemies of the herbivores. Entomopathogenic nematodes (EPNs) are organisms that can be used in the biological control of insect pests. Recent studies have shown that the movement of EPNs is associated with the detection of chemical stimuli from the environment. To date, several compounds that are responsible for the mediation in below ground multitrophic interactions have been identified. In the review, we discuss the use of EPNs in agriculture, the role of belowground volatiles and their use in plant protection programmes.


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