Re: Grubs
Here is a slightly old quote from Univ of Hawaii (search CTHAR), but it doesn't get into one of their recs, to lay pieces of corm face down on the dirt to get an idea of how thick they are. Somewhere they mention a threshold, when to spray, etc. But anyway, here is the quick quote:
"Banana Root Borer
The banana root borer is a relatively new insect pest. Limited field trials indicate that carbofuran (Furadan) reduces adult numbers. Literature indicated that Mocap and Lorsban (chlorpyrifos) are similarly effective. Mocap is registered, and Lorsban is not. Another chemical, Pirimicid (pirimiphos-ethyl), has been reported to be quite effective in several areas of the world. Unfortunately, the chemical company does not seem interested in obtaining further registrations in the U.S. Carbofuran and Mocap are being recommended in Hawaii because they also have nematicidal ability.
The root borer is found in windward Oahu and Honolulu, Molokai, and the Waihee area of Maui. DOA regulations require that corms be trimmed, visually inspected for infestation, and treated with hot water prior to export from infested islands. Trialtreatments with methyl bromide have not been effective (borers survived while corms did not).
Preliminary studies (Gettman. 1984. Control of the Banana Root Borer in Banana Planting Stock. PROC. 16TH. ANN H.B.I.A. CONF.) showed that a treatment of 43.3 oC for 3 hours is sufficient to kill all stages found in the center of corms 4 1/2 inches in diameter. Further studies could be done on increase of exposure period, corm size, and plant mortality."
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