Branch cankers on citrus trees in Spain caused by Phytophthora citrophthora

Abstract

Considerable losses of citrus trees have been observed in the major citrus-growing areas of Spain. Samples were collected from 132 orchards, and isolations and pathogencity tests were conducted to determine the aetiology of a serious canker disease. Affected trees showed cankers on the scion that frequently began on the branches. Three Phytophthora species were identified based on their morphological, cultural, physiological and molecular profiles. Phytophthora citrophthora was the main species associated with this new syndrome in 114 orchards. Phytophthora nicotianae (syn. P. parasitica ) was isolated from nine orchards as the sole Phytophthora species and in coinfection with P. citrophthora from another nine orchards. Phytophthora citricola was isolated only from one orchard. In stem-inoculation studies conducted under greenhouse conditions, clementine mandarin cv. Hernandina and sweet orange cv. Navel Late were more susceptible to P. citrophthora than sour orange and Carrizo citrange rootstocks. Clementine cv. Hernandina was also highly susceptible in field inoculation experiments. In agreement with field surveys, clementine mandarin cultivars were the most affected, their rootstocks remaining healthy. Phytophthora citrophthora was found to be the predominant species in orchard soils; however, P. nicotianae was also isolated. This information changes the scenario of diseases caused by Phytophthora spp. in Spain and consequently, the present knowledge of epidemiology and the effectiveness of the current control measures should be reassessed.

First report of clementine trunk and branch canker caused by Phytopthora citrophthora in Tunisia

“…However, to the authors' knowledge, this is the first report of trunk and branch canker caused by P. citrophthora in Tunisia on clementine. This new syndrome was reported first in Spain in 2008 (Alvarez et al, 2008) and then in South Africa in 2010 (Schutte et al, 2010). This disease could have a high economic impact as clementine production increases in Tunisia.…”

Assessing and Measuring of Citrus gummosis (Phytophthora spp.) in Major Citrus Growing Areas of Ethiopia

“…Isolations from the bark of citrus tree revealed the presence of the fungus Phytophthora spp, the cause of citrus gummosis, affecting root crown and the branch. All thus features were also described by Farih, et al [19], Ali and canihos et al [20], Alvarez, et al [7]. isolated from citrus bark.…”

“…Alvarez et al [7] reported that the citrus Cankers were more frequent on scions than rootstocks 92·4 and 7·6% of respectively. The disease mainly affected mature citrus trees; Diseased trees showed cankers and gum exudations mainly on aboveunion parts, especially on the major limbs, whereas rootstocks generally remained healthy.…”

“…with the aim to develop eco-friendly and sustainable measures for their management is an integral part of this coordinated research effort. Foot rot and gummosis occur when Phytophthora propagules are splashed onto the trunk near ground level, infect wounds or growth cracks and produce lesions which extend down to the bud union and cause a twig dieback and if severe, trees may eventually die [7]. Few studies have suggested a possible mechanism of gummosis occurrence on citrus tree and as a cause of for citrus decline elsewhere in the world much work was not done in Ethiopia thus far on gummosis.…”

Phytophtho citophthrotrunk and branch canker on Clementine mandarins in the Western Cape province of South Africa

“…Gum exudation at the surface of the affected bark generally accompanies further development of the disease and extensive lateral invasion of the cambium through injuries or growth cracks results in girdling and weakening or death of the tree (Klotz & Calavan, 1969;Whiteside, 1971). Recently, P. citrophthora was identified to be the predominant species in orchard soils in Spain as well as the causal organism for branch cankers on Clementine mandarins (Alvarez et al, 2008). Fawcett (1936) described Phytophthora spp.…”