Susceptibility of three citrus rootstocks towards Phytophthora cactorum, P. citrophthora, P. parasitica and P. citricola.

摘要

The susceptibility of the citrus rootstocks sour orange, Carrizo citrange, and Swingle citrumelo to Phytophthora cactorum, P. citrophthora, P. parasitica and P. citricola was evaluated. All experiments were conducted in May-June and September-October 2004 in Greece. Apart from P. cactorum isolates, all others used were pathogenic on citrus rootstocks with similar virulence. In laboratory experiments, the susceptibility of citrus rootstocks did not differ. In field experiments, significant differences were found in the virulence of the isolates. The isolates 1263 (P. parasitica) and PI7 (P. parasitica) were the most virulent. No significant difference was observed among the isolates PI7 (P. parasitica), 1267 (P. citrophthora) and 1262 (P. citrophthora). The length of necrosis caused from the isolate PI4 (P. citricola) was least. The susceptibility of rootstocks differed from isolate to isolate. Generally, the rootstock Swingle citrumelo was the most resistant. No significant differences were found between the rootstocks sour orange and Carrizo citrange.