Yield and soil mapping were carried out in 2007 and 2008 in a 9.

Lodging lowers the productivity of sugarcane through a reduction in radiation use efficiency and stalk damage. However, there are few reports of experiments specifically designed to quantify effects of lodging in sugarcane. Efforts to model onset and progression of lodging, and the impact on crop productivity, have not been attempted. The objectives of this paper were to quantify effects of lodging on sugarcane and to develop modeling capability in terms of predicting lodging onset, progression and impact. Field experiments with irrigated ratoon crops were conducted at Pongola, South Africa. In one treatment the cane in each plot was allowed to grow through bamboo frames that prevented lodging. In the other treatment, the cane was not supported and could lodge at any stage. The degree of lodging was captured weekly by a rating that ranged from 1 to 9, where 1 = fully erect cane and 9 = completely lodged cane. At harvest estimated recoverable crystal percent (ERC %) of stalks and yield (cane and ERC) was measured for each plot. Lodging resulted in decreased ERC yields of up to 20.6%. An algorithm for simulating lodging when aboveground biomass (including rainfall and irrigation water retained on it) exceeds a variety-specific threshold, and which also considers wind speed and soil water content, was evaluated for predicting the extent and impact of lodging in the Pongola experiments, as well as for four deficit irrigation treatments of a field experiment conducted in Komatipoort, South Africa. The study showed that the onset of lodging was simulated reasonably well for various soil/crop/atmospheric conditions, while the extent of lodging at harvest was simulated very accurately for all crops.Simulated lodging was primarily driven by crop size and lodging events were triggered by rainfall that added weight to the aerial mass of the crop, and reduced the anchoring ability of the soil through saturation of the top soil. More accurate simulation of lodging, and its impacts on yield, will improve the accuracy of yield predictions by crop models, increasing 2 their value in applications such as crop forecasting, climate change studies and exploring crop improvement and management options.

Tomato yellow leaf curl is one of the most devastating virus diseases of tomato (Lycopersicon esculentum Mill) crops worldwide. Several whitefly-transmitted viruses are associated with the disease and all are assigned to the genus Begomovirus, family Geminiviridae. In Greece, Tomato yellow leaf curl virus (TYLCV) was first reported to infect greenhouse and open-field tomatoes in 2000 (2). During 2006, a survey was conducted in the southwestern part of Peloponnese (mainland) within the areas of Kyparissia and Filiatra (Perfecture of Messinia) to identify the prevalence and natural hosts of the disease. During this survey, yellow mosaic, severe leaf curling, and leaf crumple symptoms were observed in greenhouse bean plants (Phaseolus vulgaris) that were cultivated together with tomatoes showing typical TYLCV symptoms. In all affected greenhouses, the incidence of the disease ranged from 1 to 5% in beans and 90 to 100% in tomato plants. Both bean and tomato plants were highly infested with Bemisia tabaci (Gennadius) populations and produced unmarketable fruits. Twenty-four symptomatic bean plants were collected from four greenhouses that tested positive by triple-antibody sandwich-ELISA using TYLCV-specific antibodies purchased from NEOGEN, EUROPE, Ltd. DNA was extracted from all infected bean plants, and a 580-bp fragment of the coat protein gene was amplified by PCR using the TY(+)/TY(-) primer pair (1). Amplified fragments were then analyzed by restriction fragment length polymorphism with Ava II cutter enzyme. Two DNA fragments of 277 and 302 bp in agarose gels were produced from all isolates and the restriction pattern corresponded to TYLCV. The amplified DNA from four infected bean plants was cloned and sequenced. All four sequences were 100% identical (EMBL Accession No. AM418398) and showed 99% nucleotide identity to a TYLCV isolate from Italy (EMBL Accession No. DQ144621). To our knowledge, this is the first report of TYLCV infection of P. vulgaris, which is an important commercial crop in Messinia, Greece. Within the last decade, TYLCV has emerged as an important pathogen for several cultivated plants in many regions and different TYLCV variants have been reported to infect P. vulgaris (3). Bean is often used as an intercrop between tomato crops, and thus, infected plants may serve as a potential reservoir for virus survival and spread (4). References: (1) G. P. Accotto et al. Eur. J. Plant Pathol. 106:179, 2000. (2) A. D. Avgelis et al. Plant Dis. 85:678, 2001. (3) J. Morris et al. EPPO Bull. 32:41, 2002. (4) J. Navas-Castillo et al. Plant Dis. 83:29, 1999.

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The invasive pest of the tomato crops, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), soon after its establishment became a major problem of outdoor and greenhouse tomato crops across the Mediterranean countries. The pre-plant release of the predator Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae) has been found to substantially contribute to its establishment on the crop and efficient control of T. absoluta in greenhouses. The aim of the current study was to assess whether the pre-plant release of N. tenuis could contribute to its earlier establishment. It was concluded that the release of N. tenuis in the nursery contributed substantially in the earlier increase of its numbers in the field in comparison to the control plots. The native populations of M. pygmaeus appeared on the tomato plants before the native populations of N. tenuis. Thus, the conservation of both predators should be taken into consideration in the integrated management strategies against T. absoluta. Therefore, the application of this method in open field tomato crop enhances the earlier establishment of N. tenuis and should be further evaluated in the control of T. absoluta.

The objective of this study was to develop a basic variety selection decision support system (DSS) based on industry legalities, varietal characteristics and structured genotype-by-environment (G × E) analyses. Trial data extracted from a variety trial database at the South African Sugarcane Research Institute (SASRI) were categorized into different regions, harvest ages (12, 18, 24 months) and harvest seasons (early, mid, late season harvests). Restricted maximum likelihood analyses were conducted regionally to determine varietal adaptability to different harvest ages and seasons. Highly significant variety × harvest age and variety × season interactions allowed for the appropriate categorization of varieties. Varietal adaptability to different yield potential conditions was determined using the sites regression technique, and varietal adaptability was interpreted from the slope of the regression curves. The analysed data were used to create simplistic 'yes/no' spreadsheets, which were housed within a relational database. A web interface linked to the database allows users to specify characteristics of their production environment. The system then selects appropriate varieties that conform to specified criteria and eliminates non-compliers in a stepwise approach. The system was subsequently validated against expert extension specialist opinion and acceptable performance was observed.

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