Browsing by Author "Kikuchi, R."

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Influence of Trap Type, Size, Color, and Trapping Location on Capture of Rhabdoscelusobscurus (Coleoptera: Curculionidae)
(2011-05) Reddy, Gadi V. P.; Balakrishnan, S.; Remolona, J. E.; Kikuchi, R.; Bamba, J. P.
The New Guinea sugarcane weevil, Rhabdoscelus obscurus (Boisduval) (Coleoptera: Curculionidae), is a pest of palm plantations, ornamental nurseries, and sugarcane (Saccharum L.). Field and laboratory studies have explored the effects of trap characteristics such as design, size, color, visual and olfactory cues, and location on capture of R. obscurus in date palm plantations and ornamental nurseries at five locations (Dededo, Mangilao, Malojloj, Inarajan, and Yigo) on Guam, USA. Ramp and ground traps captured similarly, and both captured significantly more adults than bucket and pitfall traps. For economy and ease of handling, the ground trap was used for all further experiments. Larger ground traps (≥40 by 25 cm) were more efficient than smaller traps (30 by 15 cm) in capturing adults in the field. Of the eight trap colors tested in the field, brown proved most effective, followed by, in order, yellow, red, gray, blue, black, white, and green; russet was more effective than other shades of brown. Mixing paint of the other colors with brown paint did not significantly improve its performance. In contrast, laboratory color-choice tests indicated R. obscurus preferred black traps over those of other colors and showed no preferences among different shades of black. Again, mixing paint of the other colors with black paint did not significantly improve their performance. Russet brown ground traps baited with pheromone lures caught significantly more adults than did identical traps without lures. Traps strapped to trees caught significantly more individuals than traps placed between trees or away from trees. Russet-brown ground traps 40 by 25 cm seemed to be the most effective at catching R. obscurus in the field, whereas otherwise identical black-colored traps were more efficient indoors.
Laboratory Host Range Assessment of a Predatory Pentatomid, Podisus maculiventris(Hemiptera: Pentatomidae) for Field Release on Guam
(2011-12) Reddy, Gadi V. P.; Kikuchi, R.
Predation by Podisus maculiventris (Say) (Hemiptera: Pentatomidae) was evaluated with Erionota thrax (L.) (Lepidoptera: Hesperidae), Pericyma cruegeri (Butler) (Lepidoptera: Noctuidae), Pareuchaetes pseudoinsulata Rego Barros (Lepidoptera: Arctiidae), Papilio polytes (L.) (Lepidoptera: Papilionidae) and Eudocima phalonia (L.) comb. nov. (Lepidoptera: Noctuidae). Both free-choice and no-choice experiments indicated that the P. maculiventris attacked and consumed all the larvae of the 5 species included in the tests. Although the larvae died at different intervals, most of them were dead within 24–120 h of the introduction of the predatory species. Since the P. maculiventris is polyphagous in nature and the present findings indicate that these predators will feed on the introduced biocontrol moth, P. pseudoinsulata, it is recommended not to take the predators out of the quarantine laboratory for the field release on Guam. Additionally, P. maculiventris will feed on some native species as they become available.
New mite species associated with certain plant species from Guam
(2011-04) Reddy, Gadi V. P.; Kikuchi, R.; Remolona, J. E.
Several new mite species have been reported from certain plants from Guam. Most remarkably, the spider mite, Tetranychus marianae (Prostigmata: Tetranychidae) and the predatory mite Phytoseius horridus (Mesostigmata: Phytoseiidae) (Solanum melongena) have been found on eggplant. The noneconomically important species of Brevipalpus californicus(Banks) Prostigmata: Tenuipalpidae),Eupodes sp. (Acarina: Eupodidae) and predator Cunaxa sp. (Prostigmata: Cunaxidae) have been reported on guava (Psidium guajava L.). Also, the non-economically important species Brevipalpus californicus Prostigmata: Tenuipalpidae), Lepidoglyphus destructor (Astigmata: Glycyphagidae) and a predator Amblyseius obtusus, species group Amblyseius near lentiginosus (Mesostigmata: Phytoseiidae), have been recorded on cycad (Cycas micronesica).
Threshold-based spraying decision programmes for the red spider mite Tetranychusmarianae on eggplant
(2012-09) Reddy, Gadi V. P.; Kikuchi, R.; Bautista, J. R.
The red spider mite, Tetranychus marianae McGregor (Acari: Tetranychidae), has been an important pest of eggplant Solanum melongena L. (Solanaceae) and other vegetables in the Mariana Islands. The damage due to T. marianae has been severe and caused huge economic losses. Because no threshold levels are available for T. marianae, many growers are applying up to 12 chemical applications per eggplant cropping period. This is not only expensive, but also results in lower yields because of extensive foliar damage and development of resistance in mites to chemicals. To diminish the calendar-based chemical applications and to preclude damage to foliage and fruit quality, this study was undertaken for the development of a threshold level for optimum timing of chemical applications for T. marianae. In the direction of this aim, an attempt was made to generate different threshold levels by applying chemical spray (Sun-spray 6E, 5 ml/l) within 12 h after reaching the threshold levels at 2, 4, 6, 8 and 10 mites/leaf, as well as current recommended calendar-based sprays and non-sprayed control in a replicated block design for the dry and wet seasons of 2010 at two locations (Yigo and Inaranjan) in Guam (USA). Based on T. marianae-infested leaves, incidence of T. marianae and yield levels, the plots sprayed at 2 or 4 mites/leaf in the dry season and 2–8 mites/leaf during the wet season had significantly lower leaf damage and incidence of T. marianae compared with a greater number of mites/leaf in calendar-based sprays and control plots. At the greater threshold levels, the mean yield was significantly reduced in comparison with the mean yield obtained when plots were sprayed at a threshold of 2–8 mites/leaf. Therefore, it is concluded that the optimum threshold chemical spray for T. marianae on eggplant is 4 mites/leaf during the dry season and 8 mites/leaf in the wet season.