Pest Management Guidelines |
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A Systems Approach to Eliminating Quarantine Pests on Floral Ginger | ||
By: Arnold H. Hara, Trent Y. Hata, Victoria L. Tenbrink, and Ben K. S. Hu
Department of Entomology, University of Hawaii, College of Tropical Agriculture and Human Resources.
INTRODUCTION
In the field, floral ginger is often heavily infested with ants,
aphids, soft scales, and mealybugs. If unchecked, pest buildup
can make after harvest disinfestation time consuming and
difficult, if not impossible. Field use of insecticides alone,
however, cannot eliminate all quarantine pests. Therefore, a
combination of field pest management and treatment after harvest
is recommended for quarantine security on floral ginger exported
from Hawai'i. The advantage of control in the field followed by
treatment after harvest is that pest levels are reduced to the
point that the treatment is 100 percent effective. These
procedures plus a final inspection for live insects ensure
pest-free flowers that meet quarantine security requirements.
FIELD PEST MANAGEMENT
Monitor the field, identifying the pests and pest levels. Use
pest levels as the basis for making decisions on when to apply
insecticides. In order for the after harvest treatment to be 100
percent effective, less than 6 percent (6 out of 100 flowers)
should be infested with mealybugs in the field, and less than 33
percent (33 out of 100) should have aphids. A flower is
considered infested if a single live insect is found. Monitoring
should be incorporated into a year round field management program
because insects continuously reproduce in Hawai'i's mild climate.
Monitor pest levels by pulling down on tight, lower bracts and
green leaf sheaths to expose ants, aphids, and mealybugs. Scales
can be found anywhere on the flower, stem, or foliage. Spraying
based on pest identification and levels is more economical than
spraying on a calendar basis. Other advantages of this tactic
include conserving natural enemies and avoiding the development
of pesticide resistance.
Apply insecticides as foliar sprays at the label rate, providing
adequate coverage and targeting the flowers. Several applications
at 2week intervals may be necessary to achieve control. The
insecticides used must be labeled for outdoor use on general
ornamentals and should be effective against the target pests.
Ant control is a necessity. Ants feed on the honey dew secreted
by aphids, soft scales, and mealybugs and protect these insects
from attack by natural enemies (parasites and predators). This
leads to higher pest populations. An insecticide barrier
treatment is effective against ants foraging into the infested
ginger. The barrier treatment consists of spraying between bases
of ginger stalks and within a 2 foot radius around the ginger
clump. Dursban or Pageant (active ingredient chlorpyrifos, Dow
Elanco of Indianapolis, Indiana) is effective as an insecticide
barrier treatment.
Sanitation is another part of good pest management for floral
ginger. Remove all mature flowers from field, regardless of
marketability, so that flowers do not serve as hosts where pests
can multiply. Use wide spacing when planting and keep plants
trimmed back to avoid overgrown fields that are difficult to
spray. Wide spacing prevents easy spread of pests from plant to
plant
AFTER HARVEST TREATMENT
An insecticidal soap (active ingredient: potassium salts of fatty
acids) mixed with a pyrethroid, such Mavrik Aquaflow (active
ingredient: fluvalinate, Sandoz of Des Plaines, Illinois) is
recommended as a dip for flowers and foliage. This dip is the
second half of the systems approach for floral ginger. There are
several insecticidal soaps and pyrethroids on the market.
Follow the label rates for mixing, since concentrations vary.
Thoroughly mix the soap and pyrethroid in water. Protect the
solution from heat and sunlight, and replace it at least once a
week. To treat ginger, submerge the flowers, agitating them at
the beginning and end of a 5 minute dip period. Avoid
oversoaking. Do not rinse. Allow flowers to air dry before
packing. Inspect each flower at packing and discard or scrub
those with insects
SPECIAL NOTE: The 5 minute dip with agitation is only recommended
for ginger from fields where successful pest management is
practiced. For flowers that are not treated in the field and are
heavily infested with insects, a 2 step treatment is necessary.
The first step is a wash in a cleaning solution, e.g., LOC
(Liquid Organic Cleaner, Amway of Ada, Michigan), in which bracts
are opened to expose insects and the leaf petioles and stalks
scrubbed to remove scales. The tiny, green leaflets just below
the flower harbor green scales and should be clipped off. The
second step is the 5 minute dip in soap and pyrethroid.
An alternative to chemical insecticidal dip after harvest is hot
water immersion of ginger. Research has demonstrated that a
systems approach consisting of insecticide application before
harvest and hot water immersion after harvest at 49°C (120°F)
for 12 minutes provided quarantine security, eliminating all
insect pests of floral ginger including aphids, mealybugs,
cardamom thrips, green scales, and ants. Vase life of hot water
treated flowers was not affected in small, experimental tanks.
Testing is continuing to confirm the safety and efficacy of the
treatment in large, commercial capacity tanks.
SAFETY FOR AFTER HARVEST DIP TREATMENT
Insecticidal soaps and Mavrik Aquaflow have the signal word
"CAUTION" which indicates the lowest level of the three
categories of risk to workers. Some pyrethroids are in higher
risk categories. Read labels carefully. Avoid breathing spray
mist and contacting eyes, skin, or clothing. All safety
precautions on the label regarding protective clothing and
equipment must be followed. Eye protection, elbow-length rubber
gloves, rubber or plastic apron, and waterproof boots are
necessary because of possible exposure by splashing. The label
may have additional requirements. When the dip is not in use, a
locked cover over the dip container will prevent animals and
children from contacting the pesticide.
DISPOSAL OF USED DIP SOLUTIONS
Proper disposal of the chemicals must be considered in setting up
a dip operation. Used dip solutions should be disposed of by
applying to approved crops in accordance with all label
directions, including dilution rate and approved site. Contact
the Hawai'i Department of Agriculture, Pesticide Branch, if in
doubt about proper disposal.
PRECAUTIONARY STATEMENT
Use pesticides safely. Follow the pesticide label. Consult with
the Cooperative Extension Service or the Hawai'i State Department
of Agriculture for authorized special local need registrations or
additional information. The user is responsible for the proper
use, application, storage, and disposal of pesticides.
DISCLAIMER
Reference to a company or product name does not imply approval or
recommendation of the product by the College of Tropical
Agriculture and Human Resources, Cooperative Extension Service,
University of Hawai'i' i, or the United States Department of
Agriculture and does not imply its approval to the exclusion of
other products that may be suitable. All materials should be used
in accordance with label instructions or manufacturers'
directions.
REFERENCES
Hansen, J. D., A. H. Hara, and V. L. Tenbrink. 199: Insecticidal
dips for disinfesting commercial for tropical cut flowers and
foliage. Tropical Pest Management 38:245249.
Hata, T. H., and A. H. Hara. 1988a. Phytotoxicity on red ginger,
Hawaii, 1986. Insecticide and Acaricide Tests 13:362.
--.1988b. Control of soft scale and aphids in red ginger Hawaii,
1986.1nsecticide and Acaricide Tests 13:362
--. 1992. Evaluation of insecticides against pests o: floral red
ginger in Hawaii. Tropical Pest Management 38:234236.
Hata, T. H., A. H. Hara, E. B. Jang, L. S. Imaino, B. S. Hu, and
V. L. Tenbrink. 1992. Pest management before harvest and
insecticidal dip after harvest as systems approach to quarantine
security for red ginger Journal of Economic Entomology 85:2310231
Tenbrink, V. L., J. D. Hansen, and A. H. Hara. 1991 Postharvest
control of banana aphid using dips, 1989. Insecticide and
Acaricide Tests 16:258.
1991 a. Postharvest control of mealybugs using dip, 1990.
Insecticide and Acaricide Tests 16:258.
l991b. Phytotoxicity of Safer's Insecticidal Soap and Mavrik
Aquaflow as a postharvest dip, 1990. Insecticide and Acaricide
Tests 16:261262.
Tsuda, D. M., and A. H. Hara. 1990 Cardamom thrips flowering red
ginger. Hawai'i Institute of Tropical Agriculture and Human
Resources, University Hawaii at Manoa. HITAHR Brief No. 083.
Issued in furtherance of Cooperative Extension work, Acts of May
8 and June 30, 1914, in cooperation with the U.S. Department of
Agriculture Noel P Kefford, Director of the Institute and Dean of
the College, Cooperative Extension Service, College of Tropical
Agriculture and Human Resources, University of Hawaii at Manoa,
Honolulu, Hawaii 96822. An Equal Opportunity Employer providing
programs and services to citizens of Hawaii without regard to
race, color, national origin, or sex. 12/93.