Heterodera Latipons on Barley in Jordan

A survey of major barley-growing areas in Jordan was conducted to determine the prevalence and degree of infestation of the Mediterranean cereal cyst nematode (MCCN) Heterodera latipons. The nematode was found in several locations in the northern and southern Mediterranean and the eastern desert areas of Jordan, but it was not detected in the northern Jordan valley and the southern desert areas. In those areas where the cyst nematode occurred, the incidence varied between areas from 30 to 100%. The degree of infestation varied from moderate to very severe. Infestation was most severe in the fields of the Northern Mediterranean area. The MCCN completed one life cycle per growing season. Studies on three isolates of the nematode from three areas, Ar-Ramtha, Madaba, and Al- Karak, revealed that the morphometrics varied little among these isolates. These three isolates as a whole varied in their virulence to two commonly used barley cultivars, Rum and Acsade 106, being more virulent on cv. Rum than on cv. Acsade 106. However, the isolates also varied among each other in their virulence to the same cultivar, Ar-Ramtha being the most virulent on cv. Rum, Madaba the most virulent on cv. Acsade 106

Effect of plant eztracts and essential oils on root-knot nematode

The nematicidal activity of methanolic extracts (20 µg ml-1) from twenty Jordanian plant species against two species of root-knot nematodes in vitro was evaluated. Whole-plant extract of Hypericum androsaemum showed the highest activity (11% mortality) against Meloidogyne javanica after 24 h of incubation. However, leaf extract of Origanum syriacum also increased M. javanica mortality markedly a day later, reaching 59 and 82% after 48 and 72 h of exposure respectively. Against M. incognita the response of leaf extracts was somewhat different, with leaf extract of Artemisia herba alba the most effective causing 22, 51, 54% mortality after 24, 48 and 72 h of exposure respectively. With a tenfold concentration (200 µg ml-1) of those plant extracts thought to contain volatile oils, the secondstage juveniles (J2) mortality of both nematodes increased after 24 and 72 h of incubation. Nematicidal tests of some volatile oils that are active ingredients of the plants tested revealed that geraniol, thymol, and camphor were the most effective against M. javanica J2s, with 91, 60, 56% mortality respectively after 72 h of exposure. Cineole, menthol, and pinene were not effective against this nematode. Against M. incognita J2s, the most effective oil components were carvacol, thymol, and geraniol, with mortalities of 100, 90, and 74% respectively after 72 h of exposure. Cineole was the least effective against M. incognita

A Valid and Reliable Instrument for Cognitive Complexity Rating Assignment of Chemistry Exam Items

The design and use of a valid and reliable instrument for the assignment of cognitive complexity ratings to chemistry exam items is described in this paper. Use of such an instrument provides a simple method to quantify the cognitive demands of chemistry exam items. Instrument validity was established in two different ways: statistically significant correlations between expert-based cognitive complexity ratings and student performance (as measured through statistical difficulty of items), and statistically significant correlations between expert-based cognitive complexity ratings and student mental effort ratings. Key benefits associated with instrument use include an enhanced understanding of the cognitive complexity of chemistry assessment tasks and as a means for characterizing exam content for the measurement of cognitive development

Root‐lesion nematodes of potato: current status of diagnostics, pathogenicity and management

Root‐lesion nematodes of the genus Pratylenchus are migratory endoparasites with worldwide economic impact on several important crops including potato, where certain species like P. penetrans, P. neglectus and P. scribneri reduce the yield and quality of potato tubers. Morphological identification of Pratylenchus spp. is challenging, and recent advancements in molecular techniques provide robust and rapid diagnostics to differentiate species without need of specialist skills. However, the fact that molecular diagnostics are not available for all Pratylenchus species means that there are limitations in worldwide application. In general, root‐lesion nematodes are difficult to manage once introduced into agricultural land and damage can be related to pathogenicity and population densities. In addition, root‐lesion nematodes interact with fungi such as V. dahliae, resulting in disease complexes that enhance the damage inflicted on the potato crop. Management interventions are often focused on limiting nematode reproduction before planting crops and include the application of nematicides, and cultural practices such as crop rotation, cover crops, biofumigation, and biological control. Understanding the limitations of the available crop protection strategies is important and there are many gaps for further study. This review discusses the status of the diagnosis, distribution, pathogenicity and management of the main species of root‐lesion nematodes, reported to infect potatoes worldwide, and highlights areas for potential future research

Efficacy of <em>Bacillus thuringiensis jordanica</em> against <em>Meloidogyne javanica</em> Infecting Tomato

A local strain of Bacillus thuringiensis jordanica (Btj), serotype H71, was evaluated for its efficacy in controlling Meloidogyne javanica attacking tomato. Glasshouse experiments were conducted using a soil drench of the bacterium applied one week before transplanting the tomato seedlings to the soil. Results showed a reduction in tomato root galling by 51–59% when M. javanica eggs or second stage juveniles (J2) were used as inoculum respectively. Single (14 days) and double (14 and 7 days) applications of Btj before plantation, both achieved a significant reduction in root galling. A field trial also showed that Btj, alone or in combination with peptone, significantly reduced root galling