Leaf Blight Tolerant Taro Variety Project

Table of Contents

Executive Summary

Hawaii Taro Statistics

Project Accomplishments


Leaf Blight Tolerant Taro Variety Project Goals

Taro Production Information
More Information on Taro Production

Dr. Uchida's Taro Pocket Rot Update

Palauan Taro Information
Photos of P1 and P10

Taste Test Sampling (Photos)

Evaluation of Leaf and Corm Taste Tests: On-Going

Palauan Trial Yield Data: On-Going

1996 Luau Trial (Unreplicated) Results

Huli Distribution Information

For Project Members:

Taro Project Baseline Form

Taro Huli Distribution/Adoption Evaluation Form

Taste Test Sampling Evaluation Form


Project 16-914
Leaf Blight Tolerant Taro Varieties: Promoting Grower Adoption and Food Processor Acceptance


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Taro BlightProject Title: Project 16-914   Final (Project Termination) Report

Leaf Blight Tolerant Taro Varieties: Promoting Grower Adoption and Food Processor Acceptance 

Project Investigators: R. Hamasaki, H. D. Sato, A. Arakaki, R. Shimabuku, S. Fukuda, D. Sato, R. Yoshino, and N. Kanehiro

Resource Persons: J. Silva (AGRN), and J. Uchida (PPTH)

Project Goal: Demonstrate to growers that phytophthora leaf blight can be managed using disease tolerant or resistant cultivars.

Executive Summary

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The statewide team of project investigators conducted various educational workshops, field demonstrations, and applied research projects. As a result of these educational activities, 685 growers and gardeners throughout the state learned about the management of taro leaf blight through the use of disease resistant taro varieties. A total of 150 of these growers became interested in this disease management strategy, secured planting material through the program, and conducted on-farm test plantings for evaluation. The project investigators also worked with 10 commercial taro processors across the state to evaluate and promote the blight resistant taro varieties for various uses such as table taro, chipping, luau (cooked taro leaves), and poi.

Impacts: After 2-3 years of on-farm evaluations and test marketing trials, 76 growers produced and marketed the disease resistant taro varieties on a regular basis. These varieties readily gained high acceptance for use as Polynesian table taro, have gained moderate adoption for use as luau, and their use as a blend in poi processing is slowly but steadily increasing. It is expected that the production and utilization of the disease resistant taro for Polynesian table taro, poi, and luau, will continue to increase steadily over the next 3 to 4 years. Growers now recognize the benefit of the inherent disease resistance to the taro leaf blight, the high plant vigor, and the high corm and leaf yield potential of the introduced taro varieties. The use of the disease resistant taro varieties is a non-chemical approach to managing the devastating taro leaf blight. The introduced taro varieties Ngesuas (P1) and Dirratengadik (P20) performed well overall.

  Farmers / Gardeners Processors
Island Number Reached # Conducted Test Planting Number Adopted # Firms Reached
Hawaii 60 28 6 2
Kauai 32 32 32 1
Maui 20 5 4 1
Molokai 200 20 3 0
Oahu 373 65 31 6
Total 685 150 76 10

Hawaii Taro Statistics

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Farm revenue from taro reached a record high in 1999, according to the Hawaii Agricultural Statistics Service. Hawaii taro production was estimated at 6.8 million pounds for 1999, up 13 percent from 1998 and the highest total since 1995. The combined farm price for poi and Chinese taro averaged 53 cents per pound in 1999, unchanged from the record high achieved in 1998. The boost in production, combined with steady farm prices, enabled taro farmers to post farm revenues of $3.6 million, up 13 percent from 1998 and a new record high. Poi taro acreage increased to 420 acres Statewide in 1999, up 5 percent from 1998. This was the most acreage in poi taro since 1979 when 405 acres were devoted to poi taro. Chinese taro totaled 80 acres, down 11 percent from 1998 (Hawaii Taro, Annual report of acreage, farm prices, marketings, and farm value, Hawaii Agricultural Statistics Service, May 8, 2000).

Some Project Accomplishments, By Island


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Background: In Hawaii, taro is a culturally significant, ethnic commodity having traditional uses in food products such as poi, kulolo, squid luau, and lau lau. Chinese taro (Bun Long) is prized in Chinese restaurants and is prepared in a variety of table taro dishes. Other popular uses include taro chips, specialty breads, pancakes, English muffins, garden burgers and other value-added products which are currently being market tested.

Activities: Activities conducted by Agent Dwight Sato included a field planting of Chinese taro (Cv. Bunlong) and five Palauan taro varieties (P1, P8, P10, P13, P20), a field trial for corm yield, trial for leaf yield, evaluations for suitability for table taro, poi processing, and chipping, distribution of planting material to growers for on-farm evaluations, and several educational events such as a poster presentation at the Hawaii Farm Bureau Convention.

Results: 60 growers learned about the management of taro leaf blight using the disease resistant varieties. 28 interested growers obtained planting material through the project and conducted on-farm evaluations. Currently, there are 4 growers producing and marketing the resistant taro for Polynesian table taro, 1 grower produces both poi taro and luau, and 1 grower produces only poi taro. At this time, there was no adoption by industry four using the Palauan taro varieties for chipping. Further work is required to promote market acceptance.


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Background: Kauai’s farmers produce about two-thirds of the state' s poi taro. In 1999, there were 65 farms (230 acres total) which produced 4.3 million pounds of taro for poi processing (Hawaii Agricultural Statistics Service, May 8, 2000).

Activities: Planting material of Palauan taro cultivars (P1 and P20) were distributed to members of the Kauai Taro Growers Association on March 18-19, 1998. Investigators involved were Dr. Eduardo Trujillo, Agent Roy Yamakawa, and Dr. Arnold Hara. Dr. Hara subjected the huli to hot water disinfestation treatment according to the protocol he developed for the taro root aphid. A total of 32 farms planted at least one of the Palauan taro cultivars. A total of 1,205 P1 huli and 345 P20 huli was distributed.

Observations: Agent Roy Yamakawa conducted a field assessment with two of the cooperators. The taro was planted on 3/20/98 and harvested on 3/8/99. Overall the P1 and P20 cultivars were much more vigorous and higher yielding than the traditional Hawaiian taro varieties. A field assessment with two growers provided an indication that the Palauan taro varieties may also be less prone to taro pocket rot and soft rot. The investigator and cooperating growers also observed that the Palauan taro varieties had a longer harvest window than Lehua and could be left in the field much longer when matured. One commercial poi processor indicated that the P1 and P20 cultivars produce a light colored poi and strongly preferred the standard Lehua cultivars. A cooperator found that P1 and P20 were highly suitable for Tongan table taro preferences.

Adoption: Essentially all of the original 32 growers continue to grow at least one of the Palauan varieties for commerce. It is estimated that the disease resistant Palauan taro now comprises about 2 - 3 percent of the taro processed for poi and its use may increase to 15-20 percent in 3 to 4 years. In general, Lehua is the preferred variety for poi processing although some people feel that the Palauan taro varieties are also suitable. Vigor, high yield, and disease resistance are attributes of the test varieties and its use as a component (blend) in poi is proving to be highly beneficial. The disease resistant taro varieties were also highly acceptable for Polynesian table taro on Kauai.


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Activities: Agent Robin Shimabuku conducted an on-farm field trial in Keanae to evaluate the top five leaf blight tolerant Palauan varieties for wetland luau production. He also conducted an on-farm trial to evaluate the taro for poi processing when grown under wetland conditions in Waihee.

Results: 20 taro growers learned how to manage the taro leaf blight by using disease resistant taro varieties. 5 of the growers cooperated with on-farm evaluations. A total of 4 commercial growers now produce and market the resistant taro varieties for luau and poi processing on a regular basis. More growers have expressed an interest to adopt the disease resistant varieties.

Observations: The growers like the P1, P5, P7, P8, P10, and P20 varieties which they have adopted. The P7 variety is especially prized for poi processing. During the months of December through March when the taro leaf blight is severe, the use of the Palauan taro varieties have allowed the Keanae growers to harvest approximately 90% of the taro leaves for luau sales as compared to less than 25% recovery for the industry standard Bunlong. These growers can now also harvest the leaves from poi taro paddies. They feel that this practice does not seriously affect the quality or yield of the resultant corms as would be the case with other taro varieties. The use of the Palauan taro varieties has also reduced the production time by several months. In Keanae, growers are now able to harvest the Palauan taro within 6 to 9 months as compared to the 9 to 14 months required for the industry standard Maui Lehua variety.


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Background: Phytophthora leaf blight and nematodes caused significant taro crop losses on Molokai. Although research work with the selected Palauan taro varieties has demonstrated their resistance to the taro leaf blight, no work had been done to evaluate these varieties for resistance to root knot nematodes (Meloidogyne javanica).

Activities: Agent Alton Arakaki coordinated an applied research field trial with the objectives to, 1) demonstrate Phytophthora resistance of Palauan taro varieties for Molokai taro growers and, 2) evaluate the Palauan taro varieties for possible resistance to root knot nematode infection. 15 Palauan taro varieties were tested in the trial including P numbers 1,2,3, 4, 5, 6, 7, 8, 10, 12, 13, 15, 16, 19 and 20 and Bunlong was used for the control. At annual taro field days, growers learned the results of the nematode/blight evaluation trial, received training on sound taro production practices, and interested growers received taro and planting material for on-farm evaluations. Corms from the trial were provided to S. Fukuda, R. Hamasaki, R.Yoshino and N. Kanehiro for their poi quality evaluation and taste test on Oahu at a statewide taro meeting held at the Queen Liluokalani Children’s Center in Honolulu.

Results: Nematode aspect: All the taro varieties in the trial became infected with root knot nematodes. The average number of eggs per gram of roots for Bunlong, the control variety, was 4989.7 eggs/ gram. The nematode infection rate for Palauan varieties ranged from 573.72 to 5545.1 eggs/ gram of roots. Although there seemed to be wide variances in the number of eggs found the taro roots, statistical analysis did not show any significant differences in the numbers.

Taro corm yields (Makua): The plant population of the Palauan taro variety trial was 8,712 plants per acre. The corm yield (main corm only) ranged from 10,382 to 25,483 pounds per acre.

Adoption: More than 800 Palauan taro huli were distributed to 20 participants for grower evaluation at their own farms/gardens. At least 3 gardeners use the Palauan taro varieties for luau. There is commercial interest growing the disease resistant taro for the Polynesian table taro market.


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Oahu Project personnel contacted 373 growers and gardeners through workshops, demonstrations, farm visits, and other activities involving the disease tolerant taro varieties. Fifteen farms produce the blight resistant Palauan taro varieties on Oahu. A total of 6 commercial taro processors (laulau and poi) were contacted through project activities.

Activities: Oahu activities included two workshops, Palauan taro planting material distribution, two field demonstration trials for luau production, two on-farm trials to evaluate the varieties for poi processing, product evaluations with 5 commercial laulau processing operations, three taro taste test evaluations with growers and consumers, two annual taro days for the general public, and the maintenance of a taro collection at the Urban Garden Center including some disease resistant varieties for public viewing.

Adoption: There are at least 6 farms on Oahu which have adopted the disease resistant varieties. A representative for the Tongan Farmers Association reported that both the P1 and P20 varieties were much easier to grow than non-resistant taro and were of excellent quality for Tongan taro preferences. Another organization with a significant representation of Tongan and Samoan immigrants also indicated that the disease resistant taro varieties were excellent when used as Polynesian table taro. Both organizations plan to increase the production of these taro varieties.

Four commercial growers have been producing and marketing several of the Palauan taro varieties for luau. One of these growers produces the luau under upland condition and indicated that his buyers were happy with his product and he had developed a steady market.

A total of 25 home gardeners grow the disease resistant taro to augment their production of luau when the weather is very wet and there are high levels of disease.

Further project information can be accessed at: http://www.extento.hawaii.edu/IPM/taro/default.htm


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The project leaders wish to acknowledge the following for their assistance:

Ronald F. L. Mau and Jari Sugano who coordinated the Western Region Integrated Pest Management Program Funds (a Smith-Lever 3(d) Extension IPM grant) which made this project possible during the first year,

The CTAHR VIP Grant Program, which made this project possible during the second and third years,

Resource faculty: Agent Roy Yamakawa for the Kauai report and his astute observations, Dr. Eduardo Trujillo for providing the starter planting materials and technical support, Dr. Janice Uchida, and Dr. James Silva,

The cooperating growers and cooperating commercial taro processors for making the field and product evaluations possible,

And the CTAHR Agricultural Research Technicians and support staff.