Vapor heat treatments to disinfest tropical cut flowers and foliage were evaluated using a commercial facility. Efficacy was determined for specific durations against representative Hawaiian quarantine pests on their plant hosts. Nymphs and adults of aphids, soft and armored scales, mealybugs, and thrips were killed after 1 hour at 46.6C, and both life stages of aphids and armored scales along with mealybug nymphs after 2 hours at 45.2C. Injury to several varieties of Hawaiian floral commodities (Araceae, Musaceae, Zingiberaceae, Heliconiaceae, Orchidaceae, Marantaceae, Lycopodiaceae, Agavaceae, Proteaceae) during these treatments was determined. Large heliconias, most red ginger, bird-of-paradise flowers and leaves, and most foliage were not damaged; anthuriums, pincushion protea, and orchid flowers and foliage were very sensitive to vapor heat. Treatment modification was needed to reduce plant injury to these commodities without losing efficacy. The number of shelf-life days of the treated plant material was estimated from the visual ratings.
James D. Hansen, Arnold H. Hara, and Victoria L. Tenbrink
Trent Y. Hata, Arnold H. Hara, and James D. Hansen
Feeding preference of melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae) was evaluated on 21 Dendrobium cultivars and the bamboo orchid Arundina graminifolia (D. Don) Hochr. Pigmented flowers resembling the morphotype phalaenopsis from Phalaenanthe sections were preferred over nonpigmented phalaenopsis, Phalaenanthe × Ceratobium hybrids, and bamboo orchids. This study suggests the separation of susceptible cultivars from preferred cultivars as a pest management strategy for melon thrips control.
David H. Oil, Gary Ueunten, Alan Yamaguchi, Mike A. Nagao, Arnold H. Hara, and Wayne T. Nishijima
A new problem of macadamia trees (Macadamia integrifolia Maiden and Betche) in Hawaii is characterized by slight leaf chlorosis, followed by rapid leaf browning, and tree death. Ambrosia beetle [Xyleborus affinis Eichhoff and X. perforans Wollastan (Coleoptera: Scolytidae)] infestations and fungal fruiting bodies were present on trees that subsequently exhibited the decline pattern. `Ikaika' was the most susceptible cultivar, and tree death occurred 8.3 ± 2.6Sd months after beetle infestations were detected.
Arnold H. Hara, Trent Y. Hata, Victoria L. Tenbrink, Benjamin K.S. Hu, and Mike A. Nagao
Postharvest treatments significantly reduced or eradicated pests on various tropical cut flowers and foliage. Immersion in water at 49° C for 10 minutes killed armored scales on bird of paradise leaves, Strelitzia reginae Banks, as well as aphids and mealybugs on red ginger, Alpinia purpurata (Vieill.) K. Schum. Vapor heat treatment for 2 hours at 45.2° C provided quarantine security against armored scales on bird of paradise leaves. A 5 minute dip in fluvalinate combined with insecticidal soap eliminated aphids and significantly reduced mealybugs on red ginger. A 3 minute dip in fluvalinate, a 3 minute dip in chlorpyrifos, or a 3 hour fog with avermectin-B significantly reduced thrips on orchids, Dendrobium spp., without injury to the flowers. No postharvest treatment was both effective and nonphytotoxic on all commodities.
James D. Hansen, Harvey T. Chan Jr., Arnold H. Hara, and Victoria L. Tenbrink
Phytotoxicity from hydrogen cyanide (HCN) fumigation was measured in several varieties of Hawaiian cut flowers and foliage (Zingiberaceae, Heliconia, Orchidaceae, Marantaceae, Lycopodiaceae, Agavaceae, Proteaceae) as a potential disinfestation treatment. Concentrations tested were 2500, 3700, 4600, and 5500 ppm HCN for 30 min. All foliage and most heliconia were undamaged at fumigation levels of 5500 ppm HCN; most protea and `Midori' anthuriums were uninjured at 4600 pm HCN; red and pink ginger were uninjured at 3700 ppm HCN; and all pincushion protea showed phytotoxicity to HCN. Red ginger was quickly damaged when exposed to sunlight immediately after treatment at 2500 ppm HCN. No injury was observed in simulated shipment tests of red ginger and `Ozaki' anthuriums fumigated at 2500 ppm HCN. Wet, red ginger flowers longer than 6 cm were damaged at 2500 ppm HCN, whereas shorter flowers were uninjured. Wet `Ozaki' anthuriums showed phytotoxicity only at 4600 ppm HCN. Wet, treated lycopodium and bamboo orchid foliage was not injured. The number of marketable days and shelf life of the treated plant material were estimated from the visual ratings.
Trent Y. Hata, Arnold H. Hara, Mike A. Nagao, and Benjamin K.S. Hu
Frangipani (Plumeria hybrid `Donald Angus') cuttings immersed in hot water (49C for 10 min) followed by 0.8% indole-3-butyric acid (IBA) basal treatment (hot water + IBA) had greater root length and weight compared to the nontreated control, hot water, or IBA treatment alone. Greater percentage of rooting and number of roots per cutting were observed for hot-water-treated + IBA-treated cuttings compared to the non-treated control and hot-water treatment alone. In a second study, Dracaena fragrans (L.) Ker-Gawl. `Massangeana', D. deremensis Engl. `Warneckii', D. deremensis Engl. `Janet Craig', D. marginata Lam., and cape jasmine (Gardenia jasminoides Ellis) cuttings displayed results similar to those observed with Plumeria cuttings. In addition to enhancing rooting, hot water + IBA also stimulated the number of shoots per cutting on anthurium (Anthurium andraeanum Andre `Marian Seefurth'), croton [Codiaeum variegatum (L.) Blume var. pictum (Lodd.) Mull. Arg.], D. marginata, D. fragrans, Plumeria, and ti (Cordyline terminalis `Ti') cuttings.