Factors Affecting Infection and Disease Development on Olive Leaves

Factors Affecting Infection and Disease Development on Olive Leaves

José R. Viruega, Luis F. Roca, Juan Moral, and Antonio Trapero | View Article Infection and development of olive scab disease, caused by Fusicladium oleagineum, were evaluated on detached leaves and potted plants of the susceptible cultivar Picual in growth chambers and a shadehouse. An inoculum dose of 1 × 105 conidia per ml was selected from a range of densities tested, and it was used for all experiments. Infection occurred from 5 to 25°C, and disease severity was the greatest at ~20°C for wetness durations of 12 to 24 h and at ~15°C for longer durations. Based on a generalized form of the Analytis Beta model, the optimum temperature and minimum wetness duration for infection were 15.5°C and 11.9 h. Dry periods ≤78 h immediately after inoculation did not reduce disease incidence but did reduce disease...
Evaluation of the Incidence and Severity of Olive Leaf Spot

Evaluation of the Incidence and Severity of Olive Leaf Spot

Mazen Salman, Abd-Almonem Hawamda, Ahmad Al-Ashqar Amarni, Mahmoud Rahil, Hajaj Hajjeh, Basel Natsheh, Ruba Abuamsha | View Article Olive Leaf Spot (OLS) is found in many parts of the world and cause readuced growth and yield in olive trees. In this study, investigations were carried out to measure the incidence (% infected leaves) and severity (number of lesions/leaf) of OLS in olive growing regions in Palestine, including the regions of Hebron, Bethlehem, Tulkarm, Salfit, Jenin, Nablus, Ramallah and Qalqilyah. OLS was found in all study areas with significantly higher percent incidences in Jenin and Nablus (67.16% ± 18.16% and 46.06% ± 23.70%, respectively). OLS was more severe in Nablus, Qalqilyah, Jenin and Tulkarm (severity grade 3.0 – 3.7). Analysis indicate that there is a positive correlation (R2 = 0.597) between dis-ease incidence and severity. OLS appeared to be particularly severe on trees that were growing in regions with higher annual rainfall. The correlation between severity and rainfall was positive (R2 =...
Plant sanitation

Plant sanitation

Vera Sergeeva | View Article A number of growers have queried how disease spreads to isolated groves, and asked for advice on establishing a new olive grove with fewer pests and disease problems into the future. This article provides some general rules and practices to prevent the introduction and/or spreading of pests and...
Disease resistance and adaptability of olive cultivars

Disease resistance and adaptability of olive cultivars

Vera Sergeeva | View Article Olives are extensively cultivated in the world and the industry continues to expand in many countries. Approximately 11 million hectares are under olive cultivation, comprising an estimated 600 varieties. New types of olive trees have been created over the years, both by adaptation to different climates and multiplication methods. Climate is the most important limiting factor in the distribution of olives, as temperature controls growth, reproduction and development of diseases and pests. Environmental factors also play an important role in managing diseases and...
Factors Affecting Infection and Disease Development on Olive Leaves Inoculated with Fusicladium oleagineum

Factors Affecting Infection and Disease Development on Olive Leaves Inoculated with Fusicladium oleagineum

José R. Viruega, Luis F. Roca, Juan Moral, and Antonio Trapero | View Article Infection and development of olive scab disease, caused by Fusicladium oleagineum, were evaluated on detached leaves and potted plants of the susceptible cultivar Picual in growth chambers and a shadehouse. An inoculum dose of 1 × 105 conidia per ml was selected from a range of densities tested, and it was used for all experiments. Infection occurred from 5 to 25°C, and disease severity was the greatest at ~20°C for wetness durations of 12 to 24 h and at ~15°C for longer durations. Based on a generalized form of the Analytis Beta model, the optimum temperature and minimum wetness duration for infection were 15.5°C and 11.9 h. Dry periods ≤78 h immediately after inoculation did not reduce disease incidence but did reduce disease...
What is effective against anthracnose?

What is effective against anthracnose?

Vera Sergeeva | View Article What do we know about anthracnose? What do we want to know about the disease that would help us to control it? What are the most important steps to improve anthracnose control? A disease is a condition in a plant that affects the plant’s normal functioning or development. For a disease to occur, three conditions must be met. Firstly, a pathogen has to be present on or in the plant. Secondly, there needs to be suitable environmental conditions for the pathogen. Thirdly, the plant must be susceptible to the...
Differentiation of olive Colletotrichum gloeosporioides populations

Differentiation of olive Colletotrichum gloeosporioides populations

S. J. Sanei and S. E. Razavi | View Article Twenty five isolates of Colletotrichum gloeosporioides obtained from fruits of olive, apple and citrus trees from different regions of Golestan province, northern Iran. Results from cross-inoculation experiments showed a great variability in pathogenicity among the isolates examined. They were investigated using complementation tests with nitrate-non-utilizing (Nit) mutants to know their vegetative compatibility. Among 250 chlorate-resistant sectors obtained, only 187 were Nit mutants. Three types of Nit mutants were obtained (Nit1, Nit3 and NitM) on the basis of the fungal phenotype. Nit1 mutants were the most frequent (71.6%), followed by NitM (16.6%) and Nit3 (11.8%). Based on their ability to form heterokaryons, all olive pathogenic isolates were grouped into two vegetative compatibility groups (VCG). This is a good indication of the homogeneity of the olive C. gloeosporioides population. The results might also suggest the absence of a relationship between pathogenicity of strains on apple and...
Differentiation of olive Colletotrichum gloeosporioides populations

Differentiation of olive Colletotrichum gloeosporioides populations

S. J. Sanei and S. E. Razavi | View Article Twenty five isolates of Colletotrichum gloeosporioides obtained from fruits of olive, apple and citrus trees from different regions of Golestan province, northern Iran. Results from cross-inoculation experiments showed a great variability in pathogenicity among the isolates examined. They were investigated using complementation tests with nitrate-non-utilizing (Nit) mutants to know their vegetative compatibility. Among 250 chlorate-resistant sectors obtained, only 187 were Nit mutants. Three types of Nit mutants were obtained (Nit1, Nit3 and NitM) on the basis of the fungal...
Biological pest control

Biological pest control

Vera Sergeeva | View Article Biological and non-chemical plant protection is important worldwide as an alternative to the use of conventional chemical pesticides. Biological pest control is the use of natural organisms as an alternative to, or in conjunction with, pesticides. It has become well established within protected crops and some field crops around the world. The biological control of pests relies on predation, parasitism or other natural mechanisms. It can be an important component of integrated pest management (IPM) programs. The use of biological control methods can reduce spraying costs and lead to a reduction in the potential for pesticide...