Effect of environmental conditions on survival of soil-borne inoculum of Puccinia carthami Cda.

Inglés. The survival of teliospores of Puccinia carthami Cda. present in a field which had been planted with safflower for three years was studied in the laboratory. Soil samples were collected monthly from November 1988 to November 1989 and the variability of soil-borne inoculum of P. carthami was estimated as the percentage of infected seedlings. Also, rainfall, minimum and maximum temperatures and relative humidity were recorded monthly. The incidence and severity of rust was high during the first four months immediately after harvest of the safflower crop and progressively decreased with time. Although rust was not completely eliminated, it was markedly lower after a year. Probably control of rust results from unfavourable effects of environmental conditions on the viability of teliospores present in soil and on the safflower debris of the previous crop

Italiano. La sopravvivenza delle teleutospore di Puccinia carthami Cda. presenti inun terreno sottoposto a monocultura per tre anni, e stata studiata in laboratorio. Campioni di terreno sono stati prelevati mensilmente, durante il periodo novembre 1988 - novembre1989 e la vitalita dell'inoculo di P.carthami presente nel terreno e stata stimata come percentuale di piantine infette. Sono state inoltre rilevate mensilmente le precipitazioni, le temperature minime e massime e l'umidita relativa. L'incidenza e la gravita degli attacchi di ruggine era piu elevata nei primi quattro mesi successivi alla raccolta del cartamo e diminuiva progressivamente con il passare dei mesi. Sebbene il patogeno non sia stato completamente eliminato, dopoun anno l'incidenza della fitopatia era notevolmente piu bassa