LITTLE FIRE ANT ACTION PLAN
Plant Industry Division
December 8, 1999
Purpose:
To eradicate the little fire ant from Kauai, and to contain this
ant on the Island of Hawaii by a) controlling known infestations,
b) restricting the movement of the ant off the Big Island and
other islands by stepping up the inspection of plants moving between
islands, and c) surveying for additional infested sites on all
islands.
The Pest:
The little fire ant, Wasmannia auropunctata, is a tiny (<1
mm), slow moving, brownish-orange ant that lives primarily in
small clusters numbering a few dozen to a few hundred crawling
on the ground, under rocks and potted plants, in cracks and crevices,
under leaf litter or stones, or on ornamental trees and foliage.
It is also a nuisance pest indoors.
The ant feeds on other insects and arthropods, and honeydew from sucking insects. It has painful stings that produces silver-dollar size welts, has been reported to drive workers out of coffee fields because of the stinging, is attracted to fatty foods in households, and has been known to gradually eliminate other terrestrial species, such as beetles, spiders and centipedes, from newly colonized areas.
It prefers warm areas and will probably restrict its distribution to localities below 4,000 feet elevation. It is active in the shade and seeks refuge from the bright sun.
It is Neotropical in origin, known throughout central and northern South America, the West Indies, warmer portions of Mexico, southern Florida, West Africa, Galapagos Islands, New Caledonia, and Solomon Islands.
Infestations:
The ant occurs in four properties (3 properties belong to one
owner) in Hawaiian Paradise Park in Puna, in one parcel in Kapoho,
in a much larger fruit orchard and an unspecified area in adjoining
macnut fields and pastures in Papaikou, and in an unspecified
portion of a potted plant nursery in Panaewa in East Hawaii.
The ant also occurred in spots in a 3-week-old planting on
an estate at Kalihiwai, Kauai.
Infestations are believed to have started on the Big Isle at least
6 years ago. The point of origin of this pest is still unknown.
The ant does not spread readily on its own. The primary means of spread appears to be from plants dug up from the ground and moved elsewhere. Plants or other materials lying on the ground and potted plants grown on benches are also suspect.
PLAN
Statewide
Quarantine:
* Implement a 100% inspection policy of all plant material exported
from all islands. The type of inspection will vary depending
on the source of the plants and plant parts. Only plant material
which is free of the little fire ant (LFA) will be allowed to
leave the island.
Non-commercial Sources:
1. Plants moving as passenger baggage may be inspected at the
airport.
Commercial Sources:
Non-certified nurseries:
1. Shipments of all plants from all islands, except the Big Island,
will receive 100% visual inspection.
2. Shipments of 10 or fewer plants from the Big Island can be visually inspected. Potted plants will need to be depotted to determine that LFA is not present.
3. Shipments with more than 10 plants from the Big Island will be held for at least one hour. Peanut butter monitoring sticks will be placed in random pots and checked for the presence of ants after one hour. Each different type of plant must be tested.
4. Maintain a log (name, address, mailing address, and phone number) of all non-certified growers who ship plants from the island of Hawaii.
Certified nurseries:
1. As has been PQ's policy, burrowing nematode (BN)-certified nurseries will continue to be allowed to ship plants from their certified benches without inspection at the time of shipment. However, an added condition for BN-certification will be that the nursery is free of LFA.
2. Protocol for certifying that a nursery is free of LFA: Inspectors will monitor for the presence of LFA at the time of normal BN certification. Monitoring will be carried out by placing chopsticks, dipped in creamy peanut butter, at 10-15 foot intervals under the benches. The chopsticks will be placed out at the beginning of the BN certification process and any chopsticks infested with ants will be brought back to the office in labeled plastic zip-lock baggies to have the ants identified.
3. Plants from areas of the nursery other than the certified benches will be required to undergo 100% inspection as described under "non-certified nurseries".
* Develop treatment options for infested plants and for infested nurseries. Only Amdro has been tested and is effective for broadcast treatment. No drenches or sprays have been tested.
Survey:
* Continue following leads of plant movements, etc. from infested
sites with priorities established as follows: soil or plants
dug from the ground (highest risk); plants, materials, equipment
lying on the ground (high risk); plants from benches (moderate
risk).
* Use peanut butter bait sticks to detect or delimit little fire ant infestations keeping in mind that bait sticks are most effective under shady or overcast conditions. If sticks are painted, make sure that paint has dried for at least one week before use.
* Bait sticks should be placed no more than 10-15 feet apart due to the short foraging distance of this ant.
* Statewide surveys are complemented by PQ surveys of nurseries to certify nurseries.
* News Release to inform public of this pest and, in that way, obtain new leads of infestations.
Kauai
Treatment:
* Initiate eradication procedures immediately by treating entire
20 acres with Amdro toxicant-bait. (TOTAL TREATMENT AREA = 20
Acres)
* Retreat immediately if it rains within 24 hours after first treatment. If not, retreat within one week after 1st treatment.
* Subsequent retreatments may be done around high risk plants.
Post-treatment
Monitoring:
* Monitor with bait sticks once per week for 2 months, once per month for next 4 months.
* Periodically monitor site for the ant after 6 months.
Big Island
Treatment:
* Initiate control procedures immediately by treating with Amdro
as follows (TOTAL TREATMENT AREA = 206 Acres):
1. Kapoho - Apply Amdro to infested site and adjoining properties (10+ acres) as well as an additional 20 acres of border around the infested area (30 acres total).
2. Puna - Apply Amdro to the 4 infested sites and adjoining properties (12 acres) as well as an additional 24 acres of border around the 4 infested areas (36 acres total).
3. Papaikou - Test Extinguish or other IGRs for efficacy in treating the 35 acres of infested fruit orchard, adjoining macnut farm, adjoining pasture, and adjoining houselot as well as an additional 100 acres of border around the infested sites and high risk sites where plant materials have been moved to (135 acres total).
4. Panaewa - Apply Amdro to the two infested sites (0.5 acre) on one property as well as an additional 5 acres of border around the infested area (5 acres total).
* Retreat immediately if it rains within 24 hours after 1st treatment. If not, retreat within one week after 1st treatment.
* Retreat as needed based on surveys.
Post-treatment
Monitoring:
* Monitor with peanut butter bait sticks once per week for 2
months, once per month for next 4 months.
* Periodically monitor the site for the ant after 6 months.
Test Plots:
* Use Extinguish and other available IGRs (that are cleared for
use on food crops) to determine effectiveness of these materials
against the little fire ant. Extinguish is being tested in macnut
fields.
* Test dip-treatments and sprays for efficacy against this ant.
Critical Needs
* Need to know where LFA occurs on all islands. LFA has been
in East Hawaii for at least 5-6 years (2 sources), sufficient
time for it to move to other islands on plant materials. Because
of its cryptic nature (tiny, slow-moving), it is easy to overlook
this pest. Even its ability to sting does not lend itself to
surveys since it does not sting readily. It's attraction to
peanut butter is a plus in surveys, but sticks must be placed
close together (10-15 feet) because of its limited foraging distance.
* Need to find an effective treatment for LFA in food crop and pasture settings. Amdro cannot be used on food crops (fruits, nuts, vegetables) and is cleared for use in pastures only in certain states, not including Hawaii.
* Need to test if available dip-treatments and sprays for potted plants are effective on all stages of LFA.
* Need additional manpower to conduct ground treatments and monitoring programs. Department of Health's Vector Control personnel has been assisting personnel on the Big Island.
* Need additional financial resources for chemicals and application of the ant baits. Depending on which ant bait is used, it may be more effective to broadcast the material via aerial applications from helicopter. The terrain may be unsuitable for ground treatments, and LFA is also known to nest in tree trunks.
* If cooperation for treatment is not received or may be a problem, need to list LFA in Chapter 4-69A: Pests for Control or Eradication, Hawaii Administrative Rules following full rulemaking procedures.