On the incubation period of Puccinia horiana

Abstract

In his experiments Yamada (1955) found an incubation period of about 10 days for Puccinia horiana P. Henn. At a temperature of 15 ~ ~ Stahl (1964) found a period of 12 days, while Stark and Stach (1965) concluded that this time can vary from at least 10 days to 8 weeks 1. Little being known about the time of incubation in various conditions, the authors decided to do the pilot experiments reported below. Chrysanthemum plants of cv. 'Indianapolis White G 4' were inoculated on July 13, 1966, by spraying with a mixer-made suspension of sporulating lesions (Zandvoort et al., 1968). Immediately following inoculation the plants were placed in a glasshouse with a minimum temperature of 12 ~ ~ and a maximum temperature of 25 ~ ~ During the first 24 h after inoculation the plants were placed under a black polythene plastic foil. The sixth day after the inoculation the first symptoms of P. horiana became visible. In another experiment, plants of cv. 'Indianapolis White G 4' were inoculated on 27 June by spraying with a mixer-made suspension of spores. The treated plants were placed in glasshouses at four temperatures ranging from 10~ to 30~ For each temperature treatment 20 plants were used. Fig. 1 indicates that the time of incubation was shorter than 12 days at 17~ and 21 ~ 13 days at 10~ while at 30~ no symptoms became visible during 29 days. The development of the fungus at 10~ is definitely slower than 17~ or 21 ~ The number of infected leaves after 29 days suggests an optimal infection at 17 ~ At the field inspection done by the Plant Protection Service we commonly found new infections about 2-4 weeks after the destruction of infected plants, which is an indication for an incubation period of at least the mentioned time. An interesting indicacation of a very prolonged incubation period was found on one well isolated plot. Cuttings, rooted at an infected nursery where the temperature was over 30~ for several hours during some days of the rooting period, had been planted there about 17 June, 1966. After planting in the field there were several days with a high relative humidity and a temperature of 10~176On 5 August many necrotic spots and only one withered teleutosorus were found. One week later, fresh teleutosori were observed on ca. 2 ~ of the plants.

Rapidly expanding host range for Puccinia psidii sensu lato in Australia

“…Similar observations have been made for chrysanthemum white rust (P. horiana), which has an infection period of approx. one week under optimum conditions but up to eight weeks under sub-optimum conditions (Zandvoort et al 1968). This has implications for myrtle rust surveillance and domestic quarantine, as the time from infection to observation of symptoms is significantly greater during cooler temperatures.…”

Identification and characterization of pathotypes in Puccinia horiana, a rust pathogen of Chrysanthemum x morifolium

“…Under these conditions, symptoms appear 7-10 days post infection as chlorotic spots that develop teliospores after 14-18 days. Leaf wetness and a high relative humidity are essential for basidiospore formation, survival, and infection (Firman and Martin 1968;Zandvoort et al 1968).…”

Aplikasi Biofungisida Berbahan Aktif Corynebacterium sp. Ramah Lingkungan dalam Pengendalian Penyakit Karat Putih pada Krisan

“…Pustul karat putih akan muncul dalam kurun waktu 5 -13 hari setelah infeksi (15) . Pengamatan intensitas serangan penyakit karat baik pada percobaan super impose pada 63 HST disajikan pada Tabel 2.…”