جستجوی مقالات مرتبط با کلیدواژه « کیوی » در نشریات گروه « گیاهپزشکی »

The use of antifungal compounds such as essential oils for the preservation of natural fruits during the storage period has dramatically been rising. In this study, the individual essential oils of Marjoram (Origamum marjorana), wild mint (Mentha longifolia) and Summer savory (Satureja khuzistanica) were employed for the control of corruption of fruits during the storage period. In this study, the antifungal activity of essential oils was investigated on growth a specie of plant pathogenic fungus Botrytis cinerea on PDA medium and fruit tissues. Antifungal activities on PDA medium were measured by disk diffusion and volatile essential oil methods. To evaluate the effects of the essential oils on fungal growth in fruit tissue, the Kiwi were inoculated with 30 µl of spore suspension (106 spore/ml), and then fruits were sprayed with 4 and 20 µl/ml of the essential oils. Seven days after inoculation, fruits were evaluated in terms of pollution. To calculate the percentage of infected fruit was divided into eight parts and the number of infected fruit fungus pathogen contamination in 12.5% multiplication and percentages were calculated. Data were analyzed as a completely randomized design with three replications. Essential oils have showed significant inhibitory effect on fungus growth. The results showed that most inhibition of growth in a paper disk method was in order for fungus B. cinerea related to the essential oil of Summer savory 56.54 percent respectively and volatile essential oil methods was related to the essential oil of Summer savory was 55.97 percent respectively. The results inoculated of the fruit tissue with a spore suspension B. cinerea showed that respectively treatment (20µl/ml) of Marjoram (with 35.42% of disease) had the inhibitoriest effect against the pathogen.

In order to investigate the bacterial agents causing kiwifruit leaf spot disease in Iran, sampling performed in two consecutive years from the kiwifruit growing areas in the northern provinces. More than 400 bacterial strains isolated from the leaves of infected trees with various signs of leaf spot like brown angular spot, white spot with brown border, orange color spot and water soaking spot with yellow penumbra. 130 strains identified as pathogenic factors in different pathogenicity test. Among them, 25 strains were suspicious to have the Pseudomonas genus according to morphological properties such as color and shape of the colonis and studed from the phenotypic and molecular view point. All the strains had positive result through the hypersensitive reaction test in tobacco and geranium leaves, but during other phenotypic and molecular tests, they had different results. These tests proved that half of the strains in this study have the most similarity to P. syringae. Using two pairs of specific primers that designed based on the 16S-23S rRNA (ITS) sequence, by the name of PsaF1⁄R2 and PsaF3⁄R4, made it clear that strains: 20, 86, 101, 138, 132, 117, 194 and 230, are belonging to P. syringae pv. actinidiae. This experience that rpoD gene sequence of other 17 strains and its dissimilarity to any of the rpoD gene sequences, belonged to the species of genus Pseudomonas in the genebank, proves that these strains are unknown species of Pseudomonas, makes it necessary that determind the taxonomic status of these strains further investigations are required.

The mulberry scale pest Pseudoulacaspis pentagona (Targioni) (Hem.: Diaspididae) has entered Kiwi orchards causing worries to gardeners in recent years. The damages of this pest by feeding of both adults and nymphs from host plant sap, which weakens the plant and cause gradual death of the tree. In the current study, three geographical regions of Guilan province (i.e. west, east, and central) where the kiwi fruit is largely planted were selected. During 2015-2016 pest population changes and the rate of pest parasitism were studied. The results indicated variations in pest density in the studied areas. The spatial distribution pattern of nymphs and adults of these regions were aggregated and random. The highest pest density was recorded in 2015 from the east of Guilan (88.4 ± 14.25 adult scales in 10cm) while, 40.4 ± 4.09 and 77.8 ± 3.24 were recorded in 2016 and 2017 respectively. The Temperature fluctuations and parasitism by Encarsia berlesei Howard were found to be the limiting factors for pest activity. The presence of parasite was found to be remarkable in sampled areas. The highest number of parasitized was recorded in the third generation (38.78 parasited adult scales in 10 cm) from east Guilan in 2015. The annual parasitic activity rate of this parasitoid can be considered as one of the most important options in management of mulberry scale pest on the kiwi. The results could be improved and incorporated in management of this important pest.

Kiwifruit is an economically important fruit crop in the northern part of Iran. Identify the Kiwifruit fungal pathogens in Guilan province, 65 kiwifruit orchards were visited in 2008–2010. Leaves and fruits with disease symptoms were sampled and their fungal pathogens were isolated and purified on PDA and WA. Fungal species were determined morphologically according to the relevant literature. Fungi associated with leaf spots, blights and fruit rot symptoms with their prevalence rate were identified and determined in this study as follows: Alternaria alternata (45%), Diaporthe cf. actinidiae (25%), Colletotrichum gloeosporioides (12%), Botrytis cinerea (11%) and Pestalotiopsis longiseta (7%). The pathogenicity of all isolated fungi was proved on kiwifruit leaves (in vivo) and fruits (in vitro). The leaf spots caused by P. longiseta and D. cf. actinidiae were more severe followed by blight and curling of leaf margins. In all of the species, the disease was more severe in wounded than in unwounded leaves. Effect of leaf age was different. D. cf. actinidiae at stem end and B. cinerea at both stem and distal ends showed the highest level of fruit rot developments at 25±1°C and 0–1°C, respectively. Based on the results of this study, kiwifruit is reported as new host of C. gloeosporioides and D. cf. actinidiae in Iran and infections caused by all the species can be important on injured host tissues.