Organic Pineapple Working Group

[Organic Pineapple Working Group <opwg AT lists.ibiblio.org>]

Dear Rob:

References on the only work I could find that has been done on heat treatment of pineapple planting material is pasted below.

With best wishes,
Duane

Hu J.S., Sether D.M., Harrington H.M., Ullman D.E. (1995) Two-step heat treatment of pineapple crowns increases thermotolerance. HortTechnology 5:63-66.
The thermotolerance of pineapple crowns (cv. Champaka 153) to heat treatments of 50°C and above (used to produce virus-free stock) was increased with a 30-min pretreatment at 30, 35 or 40°. Crowns receiving a 30-min heat pretreatment, before a second treatment at 50 or 55°, exhibited significantly less leaf damage than controls receiving no pretreatment. The degree of thermotolerance was dependent upon the season in which crowns were harvested; greater thermotolerance occurred in crowns harvested in Apr. than in those harvested in Oct. Maximum thermotolerance occurred after an interval of at least 8 h between the first treatment and the higher temperature heat treatment. Thermotolerance was stable for at least 24 h after the pretreatment.

Hu J.S., Sether D.M., Ullman D.E., Lockhart B.E. (1997) Mealybug wilt of pineapple: pineapple viruses and two-step heat treatment of pineapple crowns. Acta Horticulturae 425:485-492.
An electron microscope (EM) assay able to detect pineapple wilt-associated closterovirus (PCV) from samples equivalent to less than 1 mg leaf tissue was developed and used to identify pineapple leaf materials having high PCV level. The latter was then purified at concentrations never achieved before. Monoclonal antibodies to PCV were produced using partially purified virus. From about 300 cell lines, 38 were found to be promising. Six of them were selected for cloning. Four clones were selected for production of ascites. One of the monoclonal antibodies was found to decorate PCV. Recently, using partially purified virus samples in EM studies, a badnavirus from pineapple samples was found. This virus (PBV) has been amplified in PCR tests. The PBV may be important to mealybug-wilt etiology and will be part of continuing investigation. Results showed that pretreatment of crowns at 30°C followed by later treatments at 50°C gave increased vigour and yield and reduced damage. Thermotolerance stimulated by pretreatment at 30 to 40°C peaks approximately 7 hours after pretreatment and remains active for at least 24 hours.

Ullman D.E., German T.L., Mcintosh C.E., Williams D.D.F. (1991) Effect of heat treatment on a closteroviruslike particle associated with mealybug wilt of pineapple. Plant Disease 75:859-861.
Department of Entomology, University of Hawaii, 3050 Maile Way, Room 310, Honolulu, HI 96822, USA Pineapple crowns (cv. Smooth Cayenne) known to be infected with a closterovirus-like particle associated with mealybug wilt of pineapple were heat-treated in water at 40, 50 and 60degC for 30, 60 and 120 min at each temp. Plant survival was 80-100% at 40 and 50deg, and ELISA demonstrated that 60-100% of these surviving plants were free of closterovirus-like particles. Heat treatment at 60deg increased plant mortality and did not improve the percentage of plants free of virus. Plant survival decreased to 70, 20 and 0% with treatments of 60deg for 30, 60 and 120 min, respectively. Plants placed in the field and greenhouse and maintained free of mealybugs were shown, with ELISA and subsampling for virus purification, to remain free of closterovirus-like particles through forcing for fruit production and harvest. In addition, these plants produced fruit, crowns, and ratoon growth free of closterovirus-like particles

Ullman D.E., Hu J.S., Sether D., Gonsalves A., Williams D.D.F., Fleisch H. (1993) Heat treatment of pineapple: subsequent growth and occurrence of mealybug wilt of pineapple. Acta Horticulturae 334:407-410.
    Mealybug wilt of pineapple (MWP), a plant disorder associated with populations of mealybugs feeding on pineapple plants, presents a serious threat to commercial pineapple production wherever mealybugs occur as pests.  Recently, a pineapple closterovirus (PC) was found widely distributed in commercial pineapple in the Hawaiian islands and proposed as a potential cause of MWP.  Following heat treatment of pineapple crowns, PC could no longer be detected and growth was more rapid than that observed in non-heat treated plants.  Planting of heat treated, putatively PC-free pineapple in a commercial plant crop with severe MWP showed that heat treated plants were not readily colonized with mealybugs, nor did they show symptoms of MWP, even after more than 2 years adjacent to commercial plants with high mealybug populations and severe MWP symptoms.  Following the harvest of the second ratoon crop, these plants were dissected and found to have varying numbers of the mealybug, Dysmiococcus brevipes, on the roots and at the base of leaves.  The ant, Pheidole megacephala was present throughout the area and observed on leaves with mealybugs.  Other pest species found among the heat treated plants were nematodes of various types (spiral, root knot and pin) and the fungus, Phytophthora sp.  Plants have not yet been tested for presence of PC.  While we are unable to draw any conclusions from this work on the etiology of MWP, our findings in this and previous experiments suggest that heat treatment of pineapple warrants further investigation as a means for improving pineapple growth and possibly protecting pineapple from MWP.


Organic Pineapple Working Group wrote:

 

 

Dear OPWG,

I am interested to know if anyone has any reports or research bulletins describing the methods and efficiency of hot water treatment to control diseases (of all types) in pineapple suckers.

Yours sincerely,

Rob Moss

WAFF.

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-- 
Duane P. Bartholomew, Ph.D.
Agronomist emeritus
Dept. of Tropical Plant & Soil Science
University of Hawaii at Manoa
Honolulu, HI 96822
Pineapple News at http://www.ishs-horticulture.org/workinggroups/pineapple/