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The Study on Strawberry Wilt Disease and Detection of Fusarium Pathogen in the Orchards
Strawberry,wilt disease,Fusarium oxysporum,detection,fungicide,
|Publication Year :||2013|
|Abstract:||草莓Fragaria ananassa屬薔薇科 (Rosaceae) 多年生草本經濟作物，是深受消費者喜愛的多年生草本溫帶水果。近年來在苗栗大湖地區已發生草莓幼苗大量死亡萎凋之嚴重疾病，田間亦可發現植株生長不良、具大小葉之萎凋病罹病株。故能造成草莓植株萎凋的病害除炭疽病、疫病及腐黴病菌外，已增加由Fusarium oxysporum 造成之草莓萎凋病。
Strawberry, Fragaria ananassa，is a very important fruit crop and is a perennial herbaceous plants. In recent years, a new wilt disease of strawberry was found in Miaoli country, Taiwan. The wilt strawberry grew poorly and showed uneven growth leaves in the field. Because Colletotrichum spp., Phytophthroa spp. and Pythium spp. can also cause the wilt or dead of strawberry, the role of Fusarium pathogen needs to be elucidated.
The strawberry wilt disease is a soilborne disease with a great loss potential for strawberry industry. This research is aimed to elucidate the role of suspect Fusarium oxysporum associated with this disease and to develop rapid detecting techniques for this pathogen. The Fusarium selective media were screened and compared for the ability to differentially identify the pathogen with cultural characteristic.
The Result showed that on K2 medium strawberry fusarial wilt pathogen developed a distinguished radiated colony with brush-like edge. Using this technique, we surveyed 8 field sites and detected many diseased seedlings together with soil. Results showed that this could only be detected in diseased crown tissue and residual roots from a strawberry orchard in Dahu, Miaoli country. No pathogenic Fusarium oxysporum was detected from the roots and soil collected from other region.
As preview reports showed that the pathogenicity test of strawberry wilt pathogen takes over two months, we designed a hot growth shelter for enhancing the wilt disease development. Three inoculation experiments were then conducted to associate the pathogen detected by the selective medium and the wilt disease. The results showed that dipping the root in conidial suspension followed by incubation in hot growth shelter can induce the disease in 2 weeks. When inoculated with a mycelia disc in the stem, only some seedlings developed symptoms and disease is not so severe. Inoculation in hydroponic system showed that no strawberry developed the symptom.
To understand the physiological characteristics of the pathogenic Fusarium oxysporum, we conducted some physiological studies. Results showed that the pathogen grows normally at between 25 to 30℃, and at pH from 6 to 9. Illuminating the colony can increase the production of macroconidia of this Fusarium pathogen.
Currently, no perfect control strategy has been established for strawberry wilt disease. Therefore we have selected and treated some chemical fungicide for controlling this disease. Results showed that both 53% thiabendazole + oxine-copper and 30% triflumizole wettable powder can inhibit the mycelial growth of this pathogen on PDA.
All the above results suggested that at present the detail infection process of this disease is still not clear. The internal symptoms on crown and root are not obvious. The pathogen density in the diseased strawberry are found to be very low. Their survival, transmission and disease ecology are not clear. The correlation with other pathogen including anthracnose, and phytophthora are not known. These indicate that a lot of research needed to be done in the future.
|Appears in Collections:||植物醫學碩士學位學程|
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