Progress 06/01/02 to 09/30/05
Outputs
The biocontrol fungus Septoria sp. was collected in Ecuador in 1998, and spore suspensions were applied to bush lantana in Kokee State Park, Kauai, in 1998-1999 by spraying to runoff. Subsequent inspections of the Park show a striking reduction in bush lantana biomass.
Impacts
Control of bush lantana in Kokee State Forest with a specific biocontrol fungus has made this site more accessible for hiking and opened up areas for growth of native flora, with none of the negative environmental effects associated with herbicide usage.
Publications
- Trujillo, E.E. 2005. History and success of plant pathogens for biological control of introduced weeds in Hawaii. Biological Control. 33:113-122.
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Progress 10/01/03 to 09/30/04
Outputs
Bush lantana sites at Puuwawa Forest Reserve, Hawaii were inoculated in March, 2004 with Septoria sp, cause of lantana leaf spots in Ecuador. Six weeks after inoculation symptoms of the disease were detected on inoculated plants. The disease could not be found six months later, after the sites had been under extreme drought. New cultures of the pathogen were destroyed by the lack of electricity at Manoa during the recent flood. Attempts at culturing this pathogen will be initiated when air-conditioning is reestablished at St. John. Septoria leaf spot of bush lantana is well established at Kokee State Park and the pathogen has reduced weed populations significantly.
Impacts
Effective biological control of bush lantana in Hawaii Forests will benefit native flora and will make hiking trails more accessible.
Publications
- No publications reported this period
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Progress 10/01/02 to 09/30/03
Outputs
Five forest sites infested with bush lantana were inoculated in the Island of Hawaii with Septoria sp. Inoculations were successful, but serious drought at Puuwaawaa Forest Reserve prevented disease epidemics and weed biomass reduction did not occur. Bush lantana weed population at Kokee State Park, Kauai has been reduced significantly by septoria leaf spot. Summer rains apparently favored epidemics of the disease. Bi-annual monitoring of 7 sites showed lantana biomass reduction of >95% at 3 sites and >50% at the other sites. Microscopic observations of leaf lesions showed more than 98% of the pycnidia that are produced on the diseased leaves occur on the upper leaf surface. Spore horns are noticeable on the surface when humidity is high. This pathogen, by producing its pycnidia on the upper leaf surface, facilitates spore dispersal.
Impacts
Effective biological control of bush lantana in Hawaii Forests will benefit native flora and will make hiking trails more accessible.
Publications
- No publications reported this period
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Progress 10/01/01 to 09/30/02
Outputs
The biological control fungus of bush lantana, Septoria sp, caused seriuos epidemics of the disease in many inoculated sites at Kokee State Park, Kauai during 2002. Symptoms of Septoria leaf spot of lantana were visible in all sites showing plant defoliation during the wet season. Pycnidia and spore horns of the pathogen were confirmed microscopically on infected leaf surfaces. These spores become air-born readily during foggy weather; fog apparently plays an important role in the distribution of this pathogen. Monitoring of inoculated lantana sites at Kokee showed epidemics of the disease occurring during November 2001 to May 2002. From May to September 2002 low rainfall at Kokee caused serious plant dieback and biomass reduction, at some sites was >80%. The pathogen has not been detected in other islands except for Kauai.
Impacts
Bush lantana biomass reductions is now visible at many heavily infected sites of Kokee State Park.
Publications
- Trujillo, E.E., Kadooka, C., Tanimoto, V., Bergfeld, S., Shishido, G. and Kawakami, G. 2001. Effective biomass reduction on the invasive weed species banana poka by Septoria leaf spot. Plant Dis. 85:357-361.
- Trujillo, E.E., Bergfeld, S. and Nelson, D. 2002. Septoria leaf spot of Banana poka induced by lei-inoculum in forest of Hawaii. Phytopathology. 92.
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