|
Kokua Line June Watanabe |
‘Carpet method’ cited
to kill monkeypod pestsIt turns out there are other monkeypod trees being attacked by caterpillars in addition to the ones cited in the Keolu area (Kokua Line, July 7).
Two readers -- Toby Rushforth and Roy E. Pyles -- pointed to research by University of Hawaii entomology professors several years ago as providing an effective solution to getting rid of the caterpillars and saving the trees: taking carpet sprayed with an insecticide and wrapping it around the trunk of a tree.
"We had this problem on an entire street in Kaneohe several years ago," Rushforth said in an e-mail. "Several neighbors and I have done the carpet trick and pretty much avoided the caterpillar damage to our trees ever since. Since the poison is very localized and not in the grass, threat to birds, etc., is minimal -- maybe I'm even nailing a termite or two?"
Pyles, who formerly worked for a Big Island sugar plantation, also has found the carpet method "very effective," saying it does not endanger other insects, trees, plants or birds.
He's been on a personal campaign for the past five years to bring attention to the carpet method because he's concerned city and state agencies aren't doing enough to save the many monkeypods he sees being attacked by caterpillars.
Pyles is critical of the general approach to dealing with the caterpillars, which he says involves trimming a tree back "until it's a stump." So far, he says, he's found no one who has paid attention to his concerns.
"It just breaks my heart to lose these big, wonderful trees," Pyles said, especially when he feels there is an easy solution.
With those testimonials, we decided to track down the researchers and found Minoru Tamashiro at UH, where he's now a professor emeritus of entomology.
He said he saw the Kokua Line item and thought, "Gee whiz, they should've used my technique," believing it to be relatively easy and safe. "But I didn't call anybody."
Neither has anyone contacted him about the carpet method, which he and Wallace Mitchell described in a paper on "Control of Three Species of Caterpillars that Attack Monkeypod Trees" more than 25 years ago.
Tamashiro explained that although one or two of the species might attack other trees, such as the halekoa, the caterpillars cause the severest damage to monkeypods.
"The biology of these three species are real similar -- they go up the tree at night, they feed on the canopy at night, and early morning, they start coming down the trunk of the tree, hiding in cracks or going into the ground," he explained. "They make this trek -- going up and down -- every night."
Coming down, they're looking for a place to hide. So, Tamashiro said, "I figured I'll give them a place to hide" -- hence the carpeting around the tree trunks.
"It worked real well. They all went under the carpet (because) it was a real nice place to hide for them." At that time, Tamashiro used insecticides to dispose of the caterpillars, but "reduced the amount (of insecticides used) way, way down, just treating that (carpet) area. ... We cleaned out the infestation that way. We never had to treat the canopy. We didn't treat the ground."
Tamashiro did warn consumers, however, that "it's a situation that you don't want to fool around with insecticide," saying people should make sure to use a product that's safe for animals and humans, with a very short or nonexistent residual effect.
But you don't even have to use any insecticide. A good alternative is "manual control," Tamashiro said, where you just "manually knock (the caterpillars) out" after releasing the carpet. "We used to catch up to a thousand (caterpillars) under the carpet overnight," he said.
Rather than using any insecticide on the carpet, Desmond Ogata, a plant disease specialist with UH's College of Tropical Agriculture and Human Resources, suggests using a strong, soapy water solution.
Spray or douse the carpet or burlap bag with the soapy water and it will work just as well, he said. The other alternative is to douse the trunk of the tree with the soapy solution, which disrupts the caterpillar's hiding places, then, as Tamashiro suggested, knocking out caterpillars.
Ogata said that unless a pesticide is labeled for use in a specific way, he can't recommend that it be used in the carpet method.
Meanwhile, Tamashiro said the caterpillar problem crops up periodically. Decades ago when he worked on the problem, "the infestations were bad for about three years running," he said. "When they do that, they kill the trees because the trees never have a chance to come back. As new buds come up, the caterpillars just eat them up and the tree will eventually die from lack of nutrients."
Tamashiro noted that "we lost a lot of the big old monkeypods like that." There used to be "a whole line of monkeypod trees" lining the road from Wailuku to Lahaina, he recalled. "They got heavily infested and by the time I got involved, they had lost some trees. We stopped them by using the carpet technique."
For a problem like this, it helps to know what insect is involved "so you can tailor your control to the insect," Tamashiro said.
Q: My husband and I walk along the Ala Wai Canal for exercise. Every once in a while we see a motorized boat going up the canal. Is it against the law to do that? If so, who can we contact when we see people doing that?
A: Motorized vessels are not prohibited from the canal, as long as they are not used for commercial purposes, according to an official with the state Department of Land and Natural Resources' Division of Boating & Ocean Recreation.
Under the department's administrative rules, the general directive is that "the operation of vessels shall be accomplished in a manner that will not create a nuisance to area residents."
For example, water-skiing would not be allowed.
If you have a question or complaint about the water use of the Ala Wai Canal, call the Boating Division at 587-1973.
|
See the Columnists section for some past articles.
Got a question or complaint?
Call 529-4773, fax 529-4750, or write to Kokua Line,
Honolulu Star-Bulletin, 500 Ala Moana Blvd., No. 7-210,
Honolulu 96813. As many as possible will be answered.
E-mail to kokualine@starbulletin.com
