PMID- 30823253
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20191120
IS  - 0191-2917 (Print)
IS  - 0191-2917 (Linking)
VI  - 86
IP  - 6
DP  - 2002 Jun
TI  - Pathogens Associated with Necrosis of Cactus Pear Cladodes in South Africa.
PG  - 693
LID - 10.1094/PDIS.2002.86.6.693D [doi]
AB  - The commercial cultivation of spineless cactus (Opuntia ficus-indica (L.) Miller) 
      for its fruit is a relatively recent undertaking in South Africa but has been 
      shown to possess huge export potential. To date, only one fungal pathogen, 
      Didymosphaeria opulenta (De Not.) Sacc., has been officially reported on the 
      genus Opuntia in South Africa, but the report is from O. stricta Haw. and not O. 
      ficus-indica (1). The need for research on diseases of O. ficus-indica in South 
      Africa has recently become important since local growers are increasingly 
      reporting disease-related yield losses. Surveys conducted over a period of 3 
      years indicated that stems or cladodes are particularly prone to various forms of 
      tissue necrosis, caused primarily by three fungi, which can ultimately lead to 
      death of entire cladodes. Alternaria tenuissima was isolated from a dry 
      superficial necrosis of the cuticle and underlying tissue as much as 3 mm deep. 
      Symptoms include small chlorotic spots on the cuticle, which coalesce to form 
      raised gray scabs. Fusarium sporotrichoides was isolated more commonly from dry 
      necrotic lesions that were darker, larger, and less superficial, sometimes 
      extending through the tissue to the opposite side of the cladode. Lasiodiplodia 
      theobromae (teleomorph Botryosphaeria rhodina) was isolated from roundish black 
      cankers (15 to 50 mm diameter) on cladodes and characterized by black gum 
      exudation from the perimeter of the canker. Pycnidia were often evident on the 
      surface of the canker. The fulfillment of Koch's postulates demonstrated that an 
      isolate of each respective species was very aggressive in colonizing cladodes 
      following artificial inoculations in the glasshouse. Mean lesion diameters 
      measuring 15, 27, and 44 mm for A. tenuissima, F. sporotrichoides, and L. 
      theobromae, respectively, were recorded 14 days after inserting wooden toothpick 
      tips that had been colonized by the three pathogens into each of five cladodes of 
      18-month-old potted plants of O. ficus-indica (cv. Morado). Alternaria sp. and B. 
      rhodina have been reported on Opuntia sp. in the United States (2), but no 
      records of the above three fungi occurring on O. ficus-indica were found. 
      References: (1) P. W. Crous et al. Phytopathogenic Fungi from South Africa. 
      University of Stellenbosch, Department of Plant Pathology Press, Stellenbosch, 
      South Africa, 2000. (2) D. F. Farr et al. Fungi on Plants and Plant Products in 
      the United States. The American Phytopathological Society, St. Paul, MN, 1989.
FAU - Swart, W J
AU  - Swart WJ
AD  - Department of Plant Sciences, University of the Free State, P.O. Box 339, 
      Bloemfontein 9300, South Africa.
FAU - Kriel, W-M
AU  - Kriel WM
AD  - Department of Plant Sciences, University of the Free State, P.O. Box 339, 
      Bloemfontein 9300, South Africa.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Plant Dis
JT  - Plant disease
JID - 9882809
EDAT- 2002/06/01 00:00
MHDA- 2002/06/01 00:01
CRDT- 2019/03/03 06:00
PHST- 2019/03/03 06:00 [entrez]
PHST- 2002/06/01 00:00 [pubmed]
PHST- 2002/06/01 00:01 [medline]
AID - 10.1094/PDIS.2002.86.6.693D [doi]
PST - ppublish
SO  - Plant Dis. 2002 Jun;86(6):693. doi: 10.1094/PDIS.2002.86.6.693D.