Phomopsis asparagi. [Descriptions of Fungi and Bacteria].

A description is provided for Phomopsis asparagi. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Asparagus officinalis, A. plumosus, A. verticillatus. DISEASE: Stem blight of Asparagus species. The first symptom is a discolouration of the stem tissue followed by the appearance of brown, elliptical lesions. As infection progresses the affected areas become shrivelled and turn into well defined spots surrounded by dark brown margins. The centre of these spots become ashy-white with numerous immersed pycnidial conidiomata which later become erumpent. As disease advances the growth of the lateral branches is frequently arrested. All parts of the plant except the berries are susceptible to infection. In severe cases needles turn yellow, the plants are partially or completely defoliated and finally wither (16, 12; 55, 2446; 67, 1628). GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia), Asia (India, China-Shanghai, Malaysia, Pakistan, Siberia, Taiwan); Europe (France, Germany, Italy, Spain, Yugoslavia); North America (Eastern U.S.A., Alabama, Arkansas, New Jersey). TRANSMISSION: Through plant debris in soil (67, 4258; Kheswalla, 1936). Infection occurs rapidly through wounds. It has been found that conidia are discharged from pycnidial conidiomata by immersion in water, spraying with water and saturated high humidity. Longevity of conidial ooze was affected by spore cone., and undiluted spore ooze retained 41% germination after desiccation for 1 month (67, 4259). Survival of conidia in soil is affected by temperature and moisture. It has been reported that all conidia were destroyed after exposure to 35°C for 2 d; only 14% remained viable after 30 d at 10°C. At 28°C, conidia survived longer in dry than in wet soil. The fungus survived on infected stems buried in the soil during ploughing or in the ground for 3-4 months. On diseased stems at soil surface the pathogen survived > 6 months (67, 4258).