Abiotic Diseases of Olive

Abiotic Diseases of Olive

S.M. Sanzani, L. Schena, F. Nigro, V. Sergeeva, A. Ippolito and M.G. Salerno | View Article Several non-parasitic diseases are of primary significance for olive trees growing in the Mediterranean area and other warm-temperate regions of the world. As for other crops, they are generally poorly understood and often completely unrecognized, especially in olive which is considered a crop of marginal lands. The origin may rest with a lack/excess of essential nutrients or an excess of non-essential elements; it may be an unsatisfactory environment: too cold or hot, too wet or dry, or too windy; there may be unsuitable soil characteristics such as poor physical condition, water-logging, salinity, improper pH, and so on. Also pollution in the environment, spray and fire damage, and climatic extremes like lightning, hail, and snow can cause heavy losses to olive. This review focuses on the most important disorders of olive caused by environmental, physical, and chemical stresses that can affect the normal physiological processes in trees. An integrated view is utilized to highlight interactions with plant healthiness, production, and...
First report of anthracnose and fruit mummification of olive fruit

First report of anthracnose and fruit mummification of olive fruit

H. S. S. Duartea, P. G. C. Cabrala, O. L. Pereiraa, L. Zambolima, E. D. Gonc¸alvesb, J. Vieira Netob, E. M. Zambolima and V. Sergeeva | View Article The olive tree is an arboreal species belonging to the family Oleaceae with recognized importance in the production of olive oils and olives. In December 2008, typical lesions of anthracnose, with mature fruit mummification were observed in olive tree fields in Maria da Fe´ , in the state of Minas Gerais, Brazil. A fungus was isolated directly on potato dextrose agar (PDA) from conidia collected from pink to orange masses on infected fruit. A typical fruit sample was deposited in the local herbarium (VIC 31209). The isolate showed a pink colony on PDA, producing sporodochia with a mass of hyaline amerospores with pointed ends. Based on these morphological characteristics the fungus was identified as Colletotrichum acutatum, which has been reported to cause anthracnose on olives trees in other countries and most recently in Australia (Sergeeva et al., 2008). In Brazil, C. acutatum is reported to cause disease on fruit of apple, citrus, strawberry, peach, plum, nectarine, medlar, and on yerba-mate (Kimati et al.,...
Epidemiology, histopathology and aetiology of olive anthracnose

Epidemiology, histopathology and aetiology of olive anthracnose

P. Talhinhas, C. Mota-Capita˜o, S. Martins, A. P. Ramos, J. Neves-Martins, L. Guerra-Guimara˜es, V. Va´rzea, M. C. Silva, S. Sreenivasaprasad and H. Oliveira | View Article Anthracnose is an important disease affecting mature olive fruits, causing significant yield losses, and poor fruit and oil quality. In Portugal, high anthracnose incidence was recorded during 2003–2007 with 41%of 908 orchards surveyed displaying disease symptoms. In another 14% of the orchards, the pathogen was recorded in symptomless plants. Disease severity was on average 36%, frequently reaching 100%. In Portugal, anthracnose is endemic to neglected orchards of susceptible cultivars, but under favourable conditions it can also severely affect less susceptible...
Genetic variation in Spilocaea oleagina populations from New Zealand olive groves

Genetic variation in Spilocaea oleagina populations from New Zealand olive groves

Friday O. Obanor, Monika Walter, E. Eirian Jones, Judith Candy and Marlene V. Jasper | View Article Olive leaf spot caused by the fungus, Spilocaea oleagina, is the most important leaf disease of olives in many olive-growing regions worldwide with yield losses of up to 20%. The genetic structure of S. oleagina populations was investigated with universally primed-polymerase chain reaction (UP-PCR) techniques. Ninety-eight S. oleagina isolates were collected from 12 known and 4 unknown cultivars from olive groves in five New Zealand...
Morphology and phylogeny of Botryosphaeria dothidea causing fruit rot of olives

Morphology and phylogeny of Botryosphaeria dothidea causing fruit rot of olives

A.J.L. Phillips, I.C. Rumbos, A. Alves & A. Correia | View Article The taxonomic position of the causal agent of fruit rot of olives was determined from fresh collections of the fungus from central Greece. In culture it formed two types of conidia, namely fusiform, hyaline, aseptate conidia typical of the genus Fusicoccum, and dark-walled, ovoid, ellipsoid or fusiform, 1–2 septate conidia that are not typically observed in Fusicoccum. A phylogenetic analysis based on ITS and EF1-a sequences placed the fungus within the same clade as Fusicoccum aesculi, which is the anamorph of Botryosphaeria dothidea, and the type of the genus...
Sources of Variation in a Field Evaluation of Olive Leaf Spot

Sources of Variation in a Field Evaluation of Olive Leaf Spot

F.O. Obanor, M. Walter, E.E. Jones and M.V. Jaspers | View Article Incidence (% infected leaves) and severity (number of lesions/leaf) of olive leaf spot disease, caused by Spilocaea oleagina, were assessed every 2 weeks on 20 trees in a Canterbury olive grove for 12 weeks during summer 2003/04. All the trees were infected by olive leaf spot disease (OLS) and although disease incidence and severity varied between trees (P<0.001), it did not vary between branches over time (P=0.088). There was a strong correlation (R2=0.869) between disease incidence and severity. It was estimated that at least fi ve trees and 50 leaves/tree were required to correctly estimate the mean values of the parameters measured. Throughout the duration of the experiment, no new leaf lesions formed and although old lesions increased in size (P<0.001), spore numbers decreased from 5×104 to 1×102 conidia/cm2 of lesion and viability of conidia declined from 55 to...