Agricultural Research Institute ARI

Morogoro, Tanzania

Agricultural Research Institute ARI

Morogoro, Tanzania
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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 | Year: 2011

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.


Nawaz K.,University of Gujrat | Hussain K.,University of Gujrat | Choudary N.,University of Gujrat | Majeed A.,University of Gujrat | And 7 more authors.
African Journal of Microbiology Research | Year: 2011

This review aims to elaborate the potential applications of various biological agents in decontamination of agricultural soils, which have been polluted with continuous and higher doses of pesticides through process of biodegradation. Biodegradation is an eco friendly, cost effective, highly efficient approach and can be considered as a superior alternative to physical and chemical methods which are not only technically laborious and costly; also are not sufficient to completely degrade organic toxins. Development of experimental conditions in which all congruent biological agents are applied concurrently may be a promising strategy to enhance biodegradation and subsequently biodegradation. Much work remains to be done in carrying out field studies based on laboratory-scale results/experiments using plant-associated endophytic and rhizospheric bacteria to degrade a wide range of toxic organic compounds of concern in environmental soil before commercially viable systems. ©2011 Academic Journals.


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 | Year: 2010

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.


Papayiannis L.C.,Agricultural Research Institute ARI | Harkou I.S.,Agricultural Research Institute ARI | Markou Y.M.,Agricultural Research Institute ARI | Demetriou C.N.,Aristotle University of Thessaloniki | Katis N.I.,Aristotle University of Thessaloniki
Journal of Virological Methods | Year: 2011

Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV) (genus: Crinivirus, family: Closteroviridae) are two emergent whitefly-transmitted viruses that have been associated with yellowing symptoms of tomato crops during the last two decades. A real-time, one-step reverse transcription (RT) TaqMan ® polymerase chain reaction (PCR) assay was developed and optimized for the multiplex detection of TICV, ToCV and an internal control of mitochondrion cytochrome oxidase subunit I (mtCOXI) gene from plants. The plant mtCOXI assay can be used as an internal control in at least 77 plant species from 28 different families. The one-step RT TaqMan PCR assay successfully detected and discriminated the two virus species in infected tomato plants, other host plants and their whitefly vectors. In direct comparison, the assay was approximately 10,000-fold and 100-fold more sensitive than conventional one-step RT-PCR and two-step nested RT-PCR, respectively. The increased sensitivity allowed the use of alternative template preparation methods that do not require RNA purification. The assay can be performed either by the direct addition of crude plant extract into the real-time reaction mixture or alternatively, the sap extract can be blotted on a positively charged nylon membrane, eluted and added in the reaction mixture. The developed assay allows the simple, fast and cost-effective testing of a large number of samples and can be easily applied in surveys and certification schemes. © 2011 Elsevier B.V.


Papayiannis L.C.,Agricultural Research Institute ARI
Journal of Virological Methods | Year: 2014

Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd) are two important viroids known to infect several plant species worldwide. In this study, a real-time reverse transcription (RT) TaqMan polymerase chain reaction (PCR) assay was developed and optimized for the simultaneous detection of CEVd and HSVd. The assay's analytical and diagnostic sensitivity and specificity were evaluated using reference isolates. Two different RNA extraction methods and one rapid crude template preparation procedure were compared in terms of extraction purity and efficiency for PCR applications. Extraction method Q included a commercially available kit, whereas method C was a modified chloroform-phase extraction in house protocol. Procedure S involved blotting the sap extract on a positively charged nylon membrane and elution. The multiplex RT-TaqMan PCR assay successfully discriminated the two viroid species from all reference samples and its recorded diagnostic sensitivity (Dse) and specificity (Dsp) was 100%. On the contrary, in conventional RT-PCR tests, the overall Dse and Dsp were lower and estimated at 94 and 95% for CEVd, and 97 and 98% for HSVd, respectively. In a direct comparison, the developed assay presented 1000-fold more analytical sensitivity. Spectrophotometric results showed that RNA extraction methods Q and C, yielded the purest RNA, and gave the lowest mean Ct values. Alternative template preparation method S resulted in Ct values statistically similar to those obtained with methods Q to C when tested by RT-TaqMan PCR. The developed assay, using crude template preparation S, allows the simple, accurate and cost-effective testing of a large number of plant samples, and can be applied in surveys and certification schemes. © 2013 Elsevier B.V.


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 | Year: 2012

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.


Upadhyaya H.D.,Indian International Crops Research Institute for the Semi Arid Tropics | Sarma N.D.R.K.,Agricultural Research Station | Ravishankar C.R.,Zonal Agricultural Research Station | Albrecht T.,University of Hohenheim | And 12 more authors.
Crop Science | Year: 2010

Finger millet [Eleusine coracana (L.) Gaertn.], among small millets, is the most important food crop in some parts of Asia and Africa. The grains are a rich source of protein, fiber, minerals, and vitamins. A core collection of 622 accessions was developed. The aim of this study was to develop a mini-core collection using multilocational evaluation data of the core collection. Six hundred and twenty-two accessions together with six controls (four common and two location-specific) were evaluated for 20 morphological descriptors at five agroecologically diverse locations in India during the 2008 rainy season. The experiment was conducted in α design with two replications at Patancheru and in augmented design with one of the six controls repeated after every nine-test entry at other locations. The hierarchical cluster analysis of data using phenotypic distances resulted in 40 clusters. From each cluster, ~10% or a minimum of 1 accession was selected to form a mini-core, which was comprised of 80 accessions. The comparison of means, variances, frequency distribution, Shannon-Weaver diversity index (H'), and phenotypic correlations revealed that the mini-core captured the entire diversity of the core collection. This mini-core collection is an ideal pool of diverse germplasm for identifying new sources of variation and enhancing the genetic potential of finger millet. © Crop Science Society of America.


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
BioControl | Year: 2011

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).


Stavrinides M.C.,Agricultural Research Institute ARI
Phytoparasitica | Year: 2010

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.


PubMed | Agricultural Research Institute ARI
Type: | Journal: Journal of virological methods | Year: 2013

Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd) are two important viroids known to infect several plant species worldwide. In this study, a real-time reverse transcription (RT) TaqMan polymerase chain reaction (PCR) assay was developed and optimized for the simultaneous detection of CEVd and HSVd. The assays analytical and diagnostic sensitivity and specificity were evaluated using reference isolates. Two different RNA extraction methods and one rapid crude template preparation procedure were compared in terms of extraction purity and efficiency for PCR applications. Extraction method Q included a commercially available kit, whereas method C was a modified chloroform-phase extraction in house protocol. Procedure S involved blotting the sap extract on a positively charged nylon membrane and elution. The multiplex RT-TaqMan PCR assay successfully discriminated the two viroid species from all reference samples and its recorded diagnostic sensitivity (Dse) and specificity (Dsp) was 100%. On the contrary, in conventional RT-PCR tests, the overall Dse and Dsp were lower and estimated at 94 and 95% for CEVd, and 97 and 98% for HSVd, respectively. In a direct comparison, the developed assay presented 1000-fold more analytical sensitivity. Spectrophotometric results showed that RNA extraction methods Q and C, yielded the purest RNA, and gave the lowest mean Ct values. Alternative template preparation method S resulted in Ct values statistically similar to those obtained with methods Q to C when tested by RT-TaqMan PCR. The developed assay, using crude template preparation S, allows the simple, accurate and cost-effective testing of a large number of plant samples, and can be applied in surveys and certification schemes.

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