Time filter

Source Type

Agapiou A.,Cyprus University of Technology | Hadjimitsis D.G.,Cyprus University of Technology | Georgopoulos A.,National and Kapodistrian University of Athens | Themistocleous K.,Cyprus University of Technology | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering

Earth observation techniques intended for archaeological research, such as satellite images and ground geophysical surveys are well established in the literature. In contrast, low altitude airborne systems for supporting archaeological research are still very limited. The "ICAROS" project, funded by the Cyprus Research Promotion Foundation, aims to develop an airborne system for archaeological investigations. The system will incorporate both a GER 1500 field spectroradiometer and NIR camera in a balloon system operated from the ground. The GER 1500 field spectroradiometer has the capability to record reflectance values from 400 nm up to 1050 nm (blue/green/red and NIR band). The Field of View (FOV) of the instrument is 4° while a calibrated spectralon panel will be used in order to minimize illumination errors during the data collection. Existing atmospheric conditions will be monitored using sun-photometer and meteorological station. The overall methodology of the project and the preliminary results from different cases studies in Cyprus are presented and discussed in this paper. Some practical problems are also discussed and the overall results are compared with satellite and ground measurements. Spectroradiometric measurements and NIR images will be taken from different heights from the balloon system. The results will be compared with different satellite images. © 2012 SPIE. Source

Kumar C.S.,Indian International Crops Research Institute for the Semi Arid Tropics | Ranga Rao G.V.,Indian International Crops Research Institute for the Semi Arid Tropics | Sireesha K.,Agricultural Research Institute ARI | Kumar P.L.,International Institute Of Tropical Agriculture
Indian Journal of Virology

Baculoviruses were isolated from three major lepidopteran pests, Helicoverpa armigera, Spodoptera litura and Amsacta albistriga in the semi-arid tropics during natural epizootic conditions at ICRISAT fields, Patancheru, Andhra Pradesh, India. Biological, morphological and biochemical analysis identified these isolates as Nucleopolyhedroviruses (NPVs). Scanning electron microscopy of the occlusion bodies (OBs) purified from diseased larvae revealed polyhedral particles of size approximately 0.5-2.5 lm [Helicoverpa armigera Nucleopolyhedrovirus (HearNPV)], 0.9-2.92 lm [Spodoptera litura Nucleopolyhedrovirus (SpltNPV)] and 1.0-2.0 μm [Amsacta albistriga Nucleopolyhedrovirus (AmalNPV)] in diameter. Transmission electron microscopy of thin sections of OBs of the three isolates revealed up to 5-8 multiple bacilliform shaped particles packaged within a single viral envelope. The dimensions of these particles were 277.7 × 41.6 nm for HearNPV, 285.7 × 34.2 nm for SpltNPV and 228.5 × 22.8 nm for AmalNPV. Each of HearNPV and AmalNPV contained up to 6 nucleocapsids and SpltNPV contained up to 7 nucleocapsids per envelope. The estimated molecular weights of the purified OB (polyhedrin) protein of the three NPVs were 31.29-31.67 kDa. Virus yield (OBs/larva) was 5.18 ± 0.45 9 10 9 for HearNPV, 5.73 ± 0.17 × 10 9 for SpltNPV and 7.90 ± 0.54 × 10 9 for AmalNPV. The LC 50 values of various NPVs against 2nd and 3rd instar larvae indicated 2.30 × 10 4 and 1.5 × 10 5 OBs/ml for HearNPV, 3.5 × 10 4 and 2.4 × 10 5 OBs/ml for SpltNPV and 5.6 × 10 4 and 3.96 × 10 5 OBs/ml for AmalNPV. The lethal time required to cause 50% mortality (LT 50) for these three species were also defined. This study has shown that the NPVs infecting three major lepidopteran pests in India are multiple NPVs, and they have good potential to use as biocontrol agents against these important pests. © Indian Virological Society 2011. Source

Stavrinides M.C.,University of California at Berkeley | Stavrinides M.C.,Cyprus University of Technology | Stavrinides M.C.,Agricultural Research Institute ARI | Mills N.J.,University of California at Berkeley

We evaluated the influence of temperature on demographic parameters of two common vineyard pests, the Pacific spider mite, Tetranychus pacificus McGregor, and the Willamette spider mite, Eotetranychus willamettei (McGregor) (Acari: Tetranychidae). Additionally, we investigated the effects of temperature on their shared predator, the western predatory mite, Galendromus occidentalis (Nesbitt) (Acari: Phytoseiidae). The intrinsic rate of increase (r m) was higher for T. pacificus than E. willamettei at 15 and 28°C, but similar at 22°C.G. occidentalis achieved a higher r m than T. pacificus from 15 to 28°C, but the difference was significant only at 22°C. At 34°C, the r m for both T. pacificus and G. occidentalis was negative, while E. willamettei did not develop at this temperature. Prey species did not affect demographic parameters of G. occidentalis. These results suggest that higher temperatures favor T. pacificus over the less damaging E. willamettei, and may also reduce the effectiveness of G. occidentalis. © 2010 The Author(s). Source

The purpose of this study was to determine the effects of the timing and rate of release on the population growth of Phytoseiulus persimilis (Acari: Phytoseiidae) reared on bean plants infested with two-spotted spider mite (TSM), Tetranychus urticae (Acari: Tetranychidae). Dwarf bean plants were infested with TSM and 20 P. persimilis females were introduced on each plant 3, 6, 9 and 12 days following TSM infestation. In another experiment, female P. persimilis were introduced at the rates of 5, 10 and 20 per plant 6 days after TSM infestation. The maximum per capita net population growth (MCPG) of P. persimilis was estimated as the maximum number of mobile stages observed on a plant during the course of the experiment divided by the initial number of females released on that plant. Both the timing and rate of release had a significant effect on the MCPG of P. persimilis. Releasing 20 P. persimilis on day nine resulted in an MCPG of 2.97, whereas releases on day 3, 6 or 12 resulted in MCPG values of less than 1.7. In the rate of release experiment, the highest MCPG (4.4) occurred when five female P. persimilis were released per plant, whereas releasing 10 and 20 predatory mites per plant led to MCPG values of 2.71 and 1.66, respectively. The findings indicate that the productivity of a P. persimilis rearing system may be significantly improved through optimization of the timing and/or rate of release. © 2010 Springer Science+Business Media BV. Source

Stavrinides M.C.,University of California at Berkeley | Stavrinides M.C.,Agricultural Research Institute ARI | Lara J.R.,University of California at Riverside | Mills N.J.,University of California at Berkeley
Biological Control

We studied the effects of temperatures from 10 to 40. °C on development of the Pacific spider mite, Tetranychus pacificus (McGregor), and the Willamette spider mite, Eotetranychus willamettei McGregor (Acari: Tetranychidae), feeding on grape foliage. In addition, we investigated the influence of temperatures from 10 to 37. °C on development of the western predatory mite, Galendromus occidentalis (Nesbitt) (Acari: Phytoseiidae), feeding on T. pacificus and evaluated the suitability of E. willamettei as prey for the predatory mite at 28. °C. Using a non-linear development rate model we estimated that the lower threshold for development of the three mites lay around 10. °C. T. pacificus was the most heat-resistant, with its upper threshold for development at 40.3. °C, followed by G. occidentalis at 37.1. °C and E. willamettei at 31.0. °C. T. pacificus developed significantly more rapidly than E. willamettei above 22.8. °C, whereas G. occidentalis developed significantly faster than either spider mite from approximately 11 to 36. °C. G. occidentalis developed 5% faster when feeding on E. willamettei than T. pacificus at 28. °C. These results confirm field observations linking E. willamettei damage to cooler, coastal vineyards and early in the season in inland vineyards, and T. pacificus infestations to hot vineyards in inland and coastal areas. Although T. pacificus seems to be more heat tolerant than G. occidentalis, additional information on temperature effects on adult life history details of the two mites is needed to fully evaluate G. occidentalis performance at high temperatures. © 2010 Elsevier Inc. Source

Discover hidden collaborations