Report Of Dry Rot Research Articles

First Report of Dry Rot of Sweetpotato (Ipomoea batatas) Caused by Diaporthe batatas in Korea

First Report of Dry Rot of Sweetpotato (<i>Ipomoea batatas</i>) Caused by <i>Diaporthe batatas</i> in Korea

FIRST REPORT OF POSTHARVEST DRY ROT OF RAPHIA HOOKERI FRUITS CAUSED BY XYLARIA FEEJEENSIS

Raphia hookeri palm is cultivated in Nigeria and other parts of the world for its economic products ranging from building and construction materials to local beverage. The plant is propagated only by seed. R. hookeri-induced dry rot of palm fruits, a storage and field disease, was found to be associated with Xylaria feejeensis, Penicillium dierckxii, Botryodiplodia theobromae, Aspergillus niger and Trichoderma sp. A total of 309 seeds were examined and 17.48, 23.95 and 27.18% were found to be affected by the disease after two, four weeks and three months of storage, respectively. When healthy fruits were inoculated separately with the various fungi according to Oruade-Dimaro (1989) only X. feejeensis produced disease symptoms (dryness and flaky nature of the entire fruit, affecting the testa and embryo). Symptoms began with the growth of a mycelial mat on the fruit scales which gradually penetrated the mesocarp, forming a weft of mycelium surrounding it. The Commonwealth Mycological Institute (UK) confirmed the identity of the fungus by processing a partial ITS DNA sample of the organism followed by sequencing (IMI No. 501772). Analysis of the sequence showed top matches at >99% identity to the ITS sequences reported from X. feejeensis (Hsieh et al., 2010). This is apparently the first time that X. feejeensis has been isolated from Raphia palm and the first report of dry rot of Raphia palm fruit caused by X. feejeensis.

First Report of Dry Rot Caused by Fusarium oxysporum on Rose (Rosa spp.) in Brazil.

Roses are a high-value niche crop in the higher altitudes of northeastern Brazil. From July of 2007 and throughout 2008, severe stem rot and wilting of rose seedlings were observed in commercial fields in the São Benedito District, Ceará State, Brazil. Although economic losses due to the disease are unknown, it poses a threat to the growing rose industry in that region. Symptoms included leaf yellowing and abscission followed by plant collapse. Symptoms appeared earlier when grafted seedlings were produced during periods of high relative humidity (80 to 98%) and warm temperatures (20 to 31°C). In the laboratory, symptomatic seedlings were rinsed with distilled water, surface sterilized with 0.5% NaOCl, and incubated on PDA at 26 ± 2°C. Fusarium oxysporum was consistently isolated from infected scions and rootstocks. Identification of F. oxysporum was based on colony and conidia morphology obtained from single-spore colonies. Five 4-week-old rose ('Carola') seedlings were inoculated with a culture of fungus by spraying the needle-wounded scion with a spore suspension (1 × 105 CFU/ml). The spore suspension was obtained from a 1-week-old PDA culture incubated at 26 ± 2°C. Control seedlings were sprayed with sterile water. Inoculated seedlings were incubated for the first 48 h in a saturated humidity chamber. After 20 days at room temperature, the scion tissue of inoculated seedlings turned necrotic. Two symptomatic seedlings were placed in a saturated humidity chamber for 24 h to determine if fungal sporulation could be observed on the surface of the tissue. After 5 to 7 days, a white mycelium was observed over the necrotic tissue. Seedlings sprayed with sterile water remained symptomless. F. oxysporum was reisolated from symptomatic tissue. An isolate of F. oxyporum (No. 1484) was deposited in the Mycology Collection of Lavras (Minas Gerais State, Brazil). To our knowledge, this is the first report of F. oxysporum causing a disease on rose seedlings in Brazil.