THE INFLUENCE OF POTATO CYST NEMATODE G. ROSTOCHIENSIS INFESTATION ON DIFFERENT POTATO CULTIVARS

The potato cyst nematode Globodera rostochiensis is one of the most serious pests of potato in Slovenia. Precise nematode identification and knowledge about potato cultivars, which are most suitable for growing in the Slovenian climate conditions and most resistant to G. rostochiensis, are necessary to develop an effective integrated pest control. Here we report the results of the influence of G. rostochiensis pathotype Ro1/4 on the yield of different potato cultivars: the susceptible cultivar Desiree, the resistant cultivars White Lady, Miranda, Aladin, Sante and Adora, and the clone KIS 94-1/5-14. The yield of cv. White Lady was the highest and that of susceptible cv. Desiree the lowest. The influence of several resistant and one susceptible potato cultivars on population dynamics of G. rostochiensis was also determined. The total number of cysts/100 cm3 and the number of eggs and juveniles per cyst increased in the susceptible cv. Desiree and decreased in the resistant cultivars White Lady, Sante and Adora

Comparison of aircraft-derived observations with in situ research aircraft measurements

Mode Selective Enhanced Surveillance (Mode-S EHS) reports are aircraft-based observations that have value in numerical weather prediction (NWP). These reports contain the aircraft's state vector in terms of its speed, direction, altitude and Mach number. Using the state vector, meteorological observations of temperature and horizontal wind can be derived. However, Mode-S EHS processing reduces the precision of the state vector from 16-bit to 10-bit binary representation. We use full precision data from research grade instruments, on-board the United Kingdom's Facility for Atmospheric Airborne Measurements, to emulate Mode-S EHS reports and to compare with derived observations. We aim to understand the observation errors due to the reduced precision of Mode-S EHS reports. We derive error models to estimate these observation errors. The temperature error increases from 1.25 K to 2.5 K between an altitude of 10 km and the surface due to its dependency on Mach number and also Mode-S EHS precision. For the cases studied, the zonal wind error is around 0.50 ms− 1 and the meridional wind error is 0.25 ms− 1. The wind is also subject to systematic errors that are directionally dependent. We conclude that Mode-S EHS derived horizontal winds are suitable for data assimilation in high-resolution NWP. Temperature reports may be usable when aggregated from multiple aircraft. While these reduced precision, high frequency data provide useful, albeit noisy, observations; direct reports of the higher precision data would be preferable

First Report of a Highly Damaged Potato Crop From Serbia Caused by Meloidogyne incognita

In 2014, a potato (Solanum tuberosum var. Kuroda) crop exhibiting 70% galling of tubers was observed in Bački Vinogradi, Vojvodina Province, Serbia. Potatoes had been grown every year for 5 years on this 1-ha site of sandy soil; tomatoes had been grown before that. In 2014, yield loss was observed for the first time at this location. Yield loss was approximately 20 tons/ha due to external galling and internal necrosis just below the skin, caused by an unknown root-knot nematode (Meloidogyne sp.). Galls were large, easily noticeable and scattered densely across the tuber surface. Adult females were visible just below the surface as white, pear-shaped bodies surrounded by a yellowish layer of host tissue. Symptoms of stunted and wilted plants were not detected despite heavy tuber infestation. The galls produced on potato tubers resembled damage caused by M. chitwoodi and M. fallax. Morphological characterization of female perineal patterns was analyzed on freshly isolated females (n = 30). Morphological identification of the species based on perineal patterns indicated the nematode was M. incognita. Species identification was further confirmed by isozyme phenotyping by esterase and malate dehydrogenase of 20 young egg-laying females (Strajnar et al. 2009). The isozyme patterns were I1 and N1, typical for M. incognita. Species identification was confirmed by mtDNA sequence analysis. A region of mtDNA was amplified with primers C2F3 and 1108 (Powers and Harris 1993), cloned, sequenced (GenBank Accession No. LN864824). Similarity of the sequence to other M. incognita sequences (99.9% identity) in GenBank and phylogenetic analysis confirmed the species identification. Meloidogyne incognita is globally the most rapidly spreading plant-parasitic nematode (Bebber et al. 2014), and is often referred to as one of the most damaging Meloidogyne species. It is found worldwide in tropical and subtropical regions as it prefers a warm habitat. In temperate regions, M. incognita is usually found in greenhouses. The investigation of distribution of Meloidogyne spp. in Serbia dates back to the 1980s (Jovičić and Grujičić 1986). During this intensive survey, widespread occurrence of M. incognita was observed, with M. incognita found in 18 localities. Meloidogyne incognita has been reported on tomatoes, cucumbers, and carnations in greenhouses and on field-grown tomatoes and peppers. Damage by M. incognita has only been reported on field-grown sunflower and tobacco plants. The severe damage reported here was a result of favorable conditions for this species leading to high infestation probably due to the combination of sandy soil and recently experienced warmer summers. There have been other reports of M. incognita found outside of greenhouses in open fields of temperate regions as well (Castillo and Jiménez-Díaz 2003). However, the severity of the damage from M. incognita observed on potato in the continental climate of the Balkan Peninsula has never been seen before. We anticipate that climate change and increased temperatures will result in significantly greater damage to potato by M. incognita in the future and may become an emerging problem for the Balkan Peninsula and other temperate regions of the world. bac

Lidar measurements of Bora wind effects on aerosol loading

The Vipava valley in Slovenia is well known for the appearance of strong, gusty North-East Bora winds, which occur as a result of air flows over an adjacent orographic barrier. There are three revealing wind directions within the valley which were found to give rise to specific types of atmospheric structures. These structures were investigated using a Mie scattering lidar operating at 1064 nm, which provided high temporal and spatial resolution backscatter data on aerosols, which were used as tracers for atmospheric flows. Wind properties were monitored at the bottom of the valley and at the rim of the barrier using two ultrasonic anemometers. Twelve time periods between February and April 2015 were selected when lidar data was available. The periods were classified according to the wind speed and direction and investigated in terms of appearance of atmospheric structures. In two periods with strong or moderate Bora, periodic atmospheric structures in the lidar data were observed at heights above the mountain barrier and are believed to be Kelvin–Helmholtz waves, induced by wind shear. No temporal correlation was found between these structures and wind gusts at the ground level. The influence of the wind on the height of the planetary boundary layer was studied as well. In periods with low wind speeds, the vertical evolution of the planetary boundary layer was found to be governed by solar radiation and clouds. In periods with strong or moderate Bora wind, convection within the planetary boundary layer was found to be much weaker due to strong turbulence close to the ground, which inhibited mixing through the entire layer

Modeling the ocean and atmosphere during an extreme bora event in northern Adriatic using one-way and two-way atmosphere-ocean coupling

We have studied the performances of (a) a two-way coupled atmosphere-ocean modeling system and (b) one-way coupled ocean model (forced by the atmosphere model), as compared to the available in situ measurements during and after a strong Adriatic bora wind event in February 2012, which led to extreme air-sea interactions. The simulations span the period between January and March 2012. The models used were ALADIN (Aire Limiteé Adaptation dynamique Développement InterNational) (4.4 km resolution) on the atmosphere side and an Adriatic setup of Princeton ocean model (POM) (130 × 130 angular resolution) on the ocean side. The atmosphere-ocean coupling was implemented using the OASIS3-MCT model coupling toolkit. Two-way coupling ocean feedback to the atmosphere is limited to sea surface temperature. We have compared modeled atmosphere-ocean fluxes and sea temperatures from both setups to platform and CTD (conductivity, temperature, and depth) measurements from three locations in the northern Adriatic. We present objective verification of 2 m atmosphere temperature forecasts using mean bias and standard deviation of errors scores from 23 meteorological stations in the eastern part of Italy. We show that turbulent fluxes from both setups differ up to 20 % during the bora but not significantly before and after the event. When compared to observations, two-way coupling ocean temperatures exhibit a 4 times lower root mean square error (RMSE) than those from one-way coupled system. Two-way coupling improves sensible heat fluxes at all stations but does not improve latent heat loss. The spatial average of the two-way coupled atmosphere component is up to 0.3 °C colder than the one-way coupled setup, which is an improvement for prognostic lead times up to 20 h. Daily spatial average of the standard deviation of air temperature errors shows 0.15 °C improvement in the case of coupled system compared to the uncoupled. Coupled and uncoupled circulations in the northern Adriatic are predominantly wind-driven and show no significant mesoscale differences. © 2016 Author(s)

Modeling the ocean and atmosphere during an extreme bora event in northern Adriatic using one-way and two-way atmosphere–ocean coupling

We have studied the performances of (a) a two-way coupled atmosphere–ocean modeling system and (b) one-way coupled ocean model (forced by the atmosphere model), as compared to the available in situ measurements during and after a strong Adriatic bora wind event in February 2012, which led to extreme air–sea interactions. The simulations span the period between January and March 2012. The models used were ALADIN (Aire Limitée Adaptation dynamique Développement InterNational) (4.4 km resolution) on the atmosphere side and an Adriatic setup of Princeton ocean model (POM) (1°∕30 × 1°∕30 angular resolution) on the ocean side. The atmosphere–ocean coupling was implemented using the OASIS3-MCT model coupling toolkit. Two-way coupling ocean feedback to the atmosphere is limited to sea surface temperature. We have compared modeled atmosphere–ocean fluxes and sea temperatures from both setups to platform and CTD (conductivity, temperature, and depth) measurements from three locations in the northern Adriatic. We present objective verification of 2 m atmosphere temperature forecasts using mean bias and standard deviation of errors scores from 23 meteorological stations in the eastern part of Italy. We show that turbulent fluxes from both setups differ up to 20 % during the bora but not significantly before and after the event. When compared to observations, two-way coupling ocean temperatures exhibit a 4 times lower root mean square error (RMSE) than those from one-way coupled system. Two-way coupling improves sensible heat fluxes at all stations but does not improve latent heat loss. The spatial average of the two-way coupled atmosphere component is up to 0.3 °C colder than the one-way coupled setup, which is an improvement for prognostic lead times up to 20 h. Daily spatial average of the standard deviation of air temperature errors shows 0.15 °C improvement in the case of coupled system compared to the uncoupled. Coupled and uncoupled circulations in the northern Adriatic are predominantly wind-driven and show no significant mesoscale differences

Rotational and divergent kinetic energy in the mesoscale model ALADIN

Kinetic energy spectra from the mesoscale numerical weather prediction (NWP) model ALADIN with horizontal resolution 4.4 km are split into divergent and rotational components which are then compared at horizontal scales below 300 km and various vertical levels. It is shown that about 50% of kinetic energy in the free troposphere in ALADIN is divergent energy. The percentage increases towards 70% near the surface and in the upper troposphere towards 100 hPa. The maximal percentage of divergent energy is found at stratospheric levels around 100 hPa and at scales below 100 km which are not represented by the global models. At all levels, the divergent energy spectra are characterised by shallower slopes than the rotational energy spectra, and the difference increases as horizontal scales become larger. A very similar vertical distribution of divergent energy is obtained by using the standard ALADIN approach for the computation of spectra based on the extension zone and by applying detrending approach commonly used in mesoscale NWP community