T heileria orientalis is a vector-borne hemoprotozoan that infects cattle and buffalo and is generally spread by ticks of the Haemaphysalis genus (1-3). Historically, this organism has been referred to as Theileria sergenti, Theileria buffeli, or the T. orientalis/T. sergenti/T. buffeli complex; however, the name T. sergenti is now considered invalid (4), and T. orientalis is commonly used to refer to all (5). From a clinical perspective, T. orientalis can cause anemia, lethargy, jaundice, fever, abortion, and mortality in cattle (6). Clinical infection can also result in decreased milk production in dairy cattle (7). T. orientalis is a conditional pathogen, and while pathogenic forms are largely limited to Eastern Asia and Australasia (5, 6, 8-10), it is frequently detected in asymptomatic animals; these benign forms are globally spread (5,(11)(12)(13)(14). Analysis of the most common genotyping locus (p32), encoding the variable major piroplasm surface protein (MPSP), currently identifies 11 distinct T. orientalis genotypes (13,15,16). Of these genotypes, type 2 (Ikeda) and to a lesser extent type 1 (Chitose) are typically found in association with clinical disease (6,9,10,(17)(18)(19)(20)(21)(22). The presence of pathogenic and benign forms of T. orientalis greatly complicates its clinical diagnosis, with standard blood film analysis unable to identify the pathogenic genotypes.Multiple conventional PCR (cPCR) assays have been published for the identification of T. orientalis in blood samples (9,21,23,24). The most commonly cited assays detect and genotype T. orientalis by amplifying unique regions of the MPSP gene (21). These assays use two universal primers to detect T. orientalis infection and specific forward primers to identify the Ikeda, Chitose, and Buffeli genotypes. While this method is highly sensitive and has been validated in prior studies (19,21), it is not multiplexed and is highly susceptible to PCR inhibitors (6), which are often found in nucleotide extractions obtained from blood (25,26). To overcome inhibition, undiluted and diluted nucleotide extracts can be examined in parallel to prevent false-negative results (6,19,27). However, if multiple reactions per sample are required to determine the presence of infection, the procedure becomes both expensive and time-consuming. Furthermore, cPCR does not give an accurate representation of parasite load and therefore cannot provide an indication of the severity of T. orientalis infection. A recently developed multiplexed tandem PCR (28) is able to discriminate between four genotypes of T. orientalis, but it is only semiquantitative and therefore cannot be used to define a clinical threshold.Hydrolysis probe quantitative PCR (qPCR) assays employ sequence-specific, fluorescently labeled probes attached to duplex-

SU MMARYIncreasing crop competitiveness using higher seeding rates is a possible technique for weed management in low input and organic farming systems or when herbicide resistance develops in weeds. A range of wheat seeding rates were sown and resulted in crop densities between 50-400 plants/m 2 (current recommendations are 100-150 plants/m 2 ) in the presence and absence of annual ryegrass (Lolium rigidum Gaud.) in three wheat cultivars at nine experiments in southern Australia. Wheat densities of at least 200 plants/m 2 were required to suppress L. rigidum and to a lesser extent increase crop yield across a wide range of environments (seasonal rainfall between 200-420 mm) and weed densities (50-450 L. rigidum plants/m 2 ). Doubling crop density of all cultivars from 100 to 200 plants/m 2 halved L. rigidum dry weight (averaged over all experiments) from 100 g/m 2 to about 50 g/m 2 . Higher crop densities gave diminishing marginal reductions in weed biomass, while cultivar differences in weed suppression were small. Grain yields ranged from 0 . 5 t/ha to over 5 t/ha depending on site and season. Maximum yields in the weed-free plots (averaged over environments and cultivars) were at 200 crop plants/m 2 , and yield declined only slightly by 4-5 % at densities up to 425 plants/m 2 . In the weedy plots grain yield continued to increase up to the highest density but at a slower rate. The percentage yield loss from weed competition was of a smaller magnitude than the suppression of L. rigidum by wheat. For example, 100 wheat plants/m 2 led to an average 23 % yield loss compared with 17 % at 200 plants/m 2 , and the probability of reduced crop grain size and increased proportion of small seeds was negligible at these densities. Cultivar differences in yield loss from weed competition were small compared with differences due to crop density. Adoption of higher wheat seed rates as part of integrated weed management is now strongly promoted to farmers.

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