Host Flowers Research Articles

In-Flight Assessment of Host and Nonhost Odors by Alfalfa Seed Chalcid (Hymenoptera: Eurytomidae)

The alfalfa seed chalcid, Bruchophagus roddi (Gussakovsky), is a host-specific insect that lays eggs in the developing seeds of alfalfa. In laboratory bioassay, females made in-flight evaluations of olfactory stimuli that emanated from an array of host and nonhost flowers. The outcome of choice tests depended on pretest conditions that varied in sequence and time of exposure to host and nonhost plants. Specific flight and landing behavior was elicited or inhibited by conditions that prevailed before the choice test. When females were confronted with a choice of different species of legume flowers (including alfalfa), they made more in-flight visits to the species to which they were exposed just prior to the test. Then, after in-flight evaluation of test flowers at close range, females made more landings on alfalfa. In addition, females made about the same number of direct landings on host and nonhost alike but without close-range evaluation of the flowers.

Alternaria dianthi . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Alternaria dianthi . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Dianthus spp., and other members of the Caryophyllaceae including Gypsophila and Saponaria spp. It is occasionally reported from other plants (e.g. Hibiscus esculentus (51, 1025; 42, 655)). DISEASE: Carnation blight. The fungus causes yellowing and necrosis of the host tissue, initially killing the leaves but in severe infections, also the stem and eventually the whole plant. The fungus can persist in the soil, from where it can attack seedlings, usually destroying them rapidly. It also infects the host's flowers, seed capsules and seeds. GEOGRAPHICAL DISTRIBUTION: Africa: Egypt, Malawi, Morocco, Mozambique, South Africa, Tanzania, Zambia, Zimbabwe. Asia: Cyprus, India, Japan, Malaysia, Taiwan, Thailand, Turkey, USSR (Armenia, Republic of Georgia). Australasia & Oceania: Australia (New South Wales, Queensland, South Australia), New Zealand, USA (Hawaii). Europe: Austria, Bulgaria, Czechoslovakia, Denmark, France, Germany, Hungary, Italy, The Netherlands, Norway, Poland, Romania, Spain Sweden, UK, Yugoslavia. North America: Bermuda, Canada, Jamaica, Panama, Puerto Rico, USA. South America: Brazil, Uruguay. TRANSMISSION: Successful growth and sporulation of the fungus requires warm moist conditions (optimal mycelial growth is at ca 20°C), although mycelium can survive at 0°C. Transmission of conidia is usually via wind, seeds or soil. A damp leaf surface is essential for infection.