Wilt Disease Complex caused by
Fusarium oxysporum f. sp. cubense (E. F. Smith) and
Ralstonia solanacearum (Smith) Yabuuchi et. al.
Using Chemical and Biological Elicitors
Resistance in plants has been reported to be inducible using biological and or chemical elicitors. Fusarium wilt and bacterial wilt diseases are two major diseases hampering abaca production in the Philippines. This study was conducted to evaluate the efficacy of biological and chemical eliciors of resistance to control wilt disease complex in abaca caused by Fusarium oxysporum f. sp. cubense (FOC) and Ralstonia solanacearum. Suspected biological elicitors (Fomes and Xanthomonas oryzae pv. oryzae or Xoo) and known chemical elicitors (Asprin or Acetyl Salicylic acid and Boost) were sprayed to the abaca tissue cultured seedlings at 15 days interval together with water and Nordox (fungicide with bactericidal activity) as checks. The sprayed seedlings were challenged by simultaneous inoculation with FOC and Ralstonia solanacearum. The parameters used to compare the treatments were: percent infected plants, disease severity rating, percent area of vascular discoloration and number of remaining live plants. Results show that Boost and Fomes resulted to an effective control of the wilt disease complex which were comparable or even better compared to Nordox, the fungicide check. Xoo and Acetyl Salicylic Acid on the other hand produced higher disease compared to the control. This study has demonstrated the potential of Fomes and Boost as biological and chemical elicitors of resistance, respectively in abaca which protected it from wilt disease complex.
Keywords: Abaca, SAR, chemical elicitors, biological elicitors, Fusarium wilt, Bacterial wilt
1 Student Researcher, VSU
2 Associate Professor, DPM, VSU and Research Adviser
Abaca (Musa textilis Nee) is indigenous to the Philippines, and is one of the major dollar earners of our country. Abaca plant has many slender stalks, upright and pointed leaves. It is harvested for its strong but flexible fiber usually called as Manila hemp used for making twines, ropes, cordage, pulp and specialty papers, fiber crafts, textile and fabrics. It is also one of the few cash crops that can grow with relatively little input compared to the other crops (FIDA, 2007).
Abaca has a high market potential but its production has been limited due to the occurrence of diseases, such as bunchy top, bacterial wilt and fusarium wilt which have taken their toll on many abaca farms. This devastation caused by viruses, bacterial wilt and fusarium wilt in abaca aggravates the farmers’ production problems. Fusarium wilt disease is caused Fusarium oxysporum f. sp. cubense (E. F. Smith) Snyd. And Hans. which is also referred to as Agent Green. This fungus does so by colonizing the water-conducting vessels (xylem) of the abaca plant resulting for a blockage and breakdown of xylem. Yellowing of the leaves, followed by drying and wilting and eventually plant death are the external symptoms of the disease. Most affected plants have discolored vascular bundles and eventually die before maturity thus, forcing the farmers to harvest the abaca plant prematurely.
Another equally important disease is the bacterial wilt disease. Bacterial wilt is caused by the bacteria Ralstonia solanacearum (Smith) Yabuuchi et al., 1995). The early symptoms of this disease include rusty brown streaks in the leaves which later turn blighted and water soaked and finally wilting of the whole plant. The internal symptoms are the vascular discoloration, water soaking and finally the rotting of pseudo- stem. Fusarium wilt...