The genus Amblyseius (Acari: Phytoseiidae) in Greece, with the Description of a New Species

A nationwide survey on Phytoseiid mites in Greece revealed the occurrence of 19 species belonging to the Genus Amblyseius. A key and illustrations of all these species are given along with the synonyms, habitats and distribution data. A new species, A. makedonicus, found on Oryza saliva, is described.

Phomopsis oryzae-sativae. [Descriptions of Fungi and Bacteria].

A description is provided for Phomopsis oryzae-sativae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Oryza saliva. DISEASE: Collar rot of rice, appearing at the end of tillering stage. Visible symptoms are small dark brown lesions at the base of the auricle of the topmost fully expanded leaf. These lesions enlarge to cover the whole auricle and in the advanced stage lesions extend to the adjacent parts of the leaf sheath and leaf blade. Within 14 days the blade joint at the top of leaf sheath turns dark brown and then rots, causing the leaf blade to drop off (Kanjanasoon, 1962). GEOGRAPHICAL DISTRIBUTION: Asia (Thailand). TRANSMISSION: No studies reported. Conidia presumably dispersed by water splash.

Alternaria padwickii. [Distribution map].

A new distribution map is provided for Alternaria padwickii (Ganguly). M.B. Ellis. Hosts: Rice (Oryza saliva). Information is given on the geographical distribution in AFRICA, Egypt, Malagasy Republic, Nigeria, ASIA, Burma, Cambodia, China, India, Indonesia, Malaysia, Nepal, Pakistan, Philippines, Thailand, Vietnam, AUSTRALASIA & OCEANIA, Australia, Fiji, New Caledonia, Tahiti, SOUTH AMERICA, Surinam.

Xanthomonas oryzicola. [Descriptions of Fungi and Bacteria].

A description is provided for Xanthomonas oryzicola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Oryza saliva. Some weed species of Oryza have also been reported to be susceptible (45, i789). Weakly pathogenic to Leersia hexandra by artificial inoculation. DISEASE: Bacterial leaf streak of rice. Narrow, dark greenish, water-soaked streaks of various lengths appear between the veins. Minute amber droplets of bacterial exudate are commonly found on these lesions. Later the lesions extend and coalesce giving large brownish patches. In the late stages symptoms are difficult to distinguish from bacterial leaf blight. GEOGRAPHICAL DISTRIBUTION: Confined to tropical Asia. Reported from China, India, Philippines, Thailand and West Malaysia (CMI Map 463 and 49, 144).TRANSMISSION: The pathogen spreads within a crop in surface moisture and may enter the leaf through minor abrasions or stomata. Warm wet weather is favourable to both spread and development of the tisease. Introduction into new areas can occur in seed from infected plants (48, 1693).

Timing imbalance in the meiosis of the F1 hybrid Oryza sativa × O. australiensis

The meiosis in the F1 hybrid Oryza saliva × O. australiensis was studied. Contrary to the observations of Gopalakrishnan (1959), true allosyndetic bivalents were not found at metaphase I. The most frequent associations were non-chiasmatic, end-to-end pseudobivalents. Autosyndetic bivalents were recorded mostly in the complement belonging to O. sativa, which are distinguishable by their smallness and lighter staining. The meiotic cycle exhibits timing imbalance with earlier condensation, and possibly migration, of the univalents belonging to O. australiensis. The data on meiotic pairing in the F1 hybrid and the comparative morphology of O. sativa, O. officinalis and O. australiensis inicate that the last species is the most primitive member, having originated from the pre-Sativa and pre-Officinalis complex.