Are sweetpotato weevils (Coleoptera: Brentidae) differentially attracted to certain colors?

The sweetpotato weevil Cylas formicarius (F.) (Coleoptera: Brentidae) is one of the most serious insects causing damage to sweetpotatoes in the world. Small populations of these insects can cause severe damage to tubers of the crop. Without proper and effective control, weevil populations are likely to cause a huge or complete loss of sweetpotato production in sweetpotato growing areas. Consequently, there is an urgent need for development of an eco-friendly control method for this weevil. Although some control methods are effective, toxic pesticides applications are detrimental and damaging to our environment. Although pheromone traps are currently being used, no effective control of this weevil was achieved. Therefore, studies were carried out as part of the development of a trapping system for C. formicarius. Previous color-choice field tests have confirmed that C. formicarius preferred red traps over gray, green, brown, blue, white, yellow, or black; light red was more attractive than other shades of red. The current study aimed to know whether C. formicarius behavior changes in indoor conditions. Among the eight colored traps tested in the laboratory, green-colored traps were more effective in attracting C. formicarius than all other colors. It attracted nearly double the number of weevils than standard traps presently being used by growers. Based on these results, it is recommended to use green-colored traps to mass trap weevils (by attracting and killing) from sweetpotatoes grown under indoor (storage) conditions. © 2014 Entomological Society of America

Field efficacy of insect pathogen, botanical, and jasmonic acid for the management of wheat midge Sitodiplosis mosellana and the impact on adult parasitoid Macroglenes penetrans populations in spring wheat

The wheat midge, Sitodiplosis mosellana, is a serious pest of wheat worldwide. In North America, management of S. mosellana in spring wheat relies on the timely application of pesticides, based on midge adults levels caught in pheromone traps or seen via field scouting during wheat heading. In this context, biopesticides can be an effective alternative to pesticides for controlling S. mosellana within an Integrated Pest Management program. A field study using insect pathogenic fungus Beauveria bassiana GHA, nematode Steinernema feltiae with Barricade polymer gel 1%, pyrethrin, combined formulations of B. bassiana GHA and pyrethrin, Jasmonic acid (JA) and chlorpyrifos (chemical check) was performed to determine to which extent they affect midge larval populations, kernel damage levels, grain yield, and quality, and the impacts on adult parasitoid Macroglenes penetrans populations. The results indicated that biopesticides JA and S. feltiae were the most effective in reducing larval populations and kernel damage levels, and produced a higher spring wheat yield when compared to the water control at both study locations (East Valier and North Valier, Montana, USA). Increased test weight in wheat had been recorded with two previous biopesticides at East Valier but not for North Valier, when compared over water control. These results were comparable in efficacy to the chlorpyrifos. This study also suggested that B. bassiana and pyrethrin may work synergistically, as exemplified by lower total larval populations and kernel damage levels when applied together. This study did not demonstrate the effect of any treatments on M. penetrans populations

Visual cues are relevant in behavioral control measures for cosmopolites sordidus (Coleoptera: Curculionidae)

Trap designs for banana root borer, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae), have been done essentially on the understanding that C. sordidus rely primarily on chemical cues. Our present results indicate that these borers also rely on visual cues. Previous studies have demonstrated that among the eight differently colored traps tested in the field, brown traps were the most effective compared with the performances of yellow, red, gray, blue, black, white, and green traps; mahogany-brown was more effective than other shades of brown. In the current study, efficiency of ground traps with different colors was evaluated in the laboratory for the capture of C. sordidius. Response of C. sordidus to pheromone-baited ground traps of several different colors (used either individually or as 1:1 mixtures of two different colors) were compared with the standardized mahogany-brown traps. Traps with mahogany-brown mixed with different colors had no significant effect. In contrast, a laboratory color-choice tests indicated C. sordidus preferred black traps over other color traps, with no specific preferences for different shades of black. Here again, traps with black mixed with other colors (1:1) had no influence on the catches. Therefore, any other color that mixes with mahogany-brown or black does not cause color-specific dilution of attractiveness. By exploiting these results, it may be possible to produce efficacious trapping systems that could be used in a behavioral approach to banana root borer control. © 2011 Entomological Society of America

Laboratory host range assessment of a predatory pentatomid, podisus maculiventris (Hemiptera: Pentatomidae) for field release on Guam

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 24120 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

Toxicological effects of pyrethroids on non-target aquatic insects

The toxicological effects of pyrethroids on non-target aquatic insects are mediated by several modes of entry of pyrethroids into aquatic ecosystems, as well as the toxicological characteristics of particular pyrethroids under field conditions. Toxicokinetics, movement across the integument of aquatic insects, and the toxicodynamics of pyrethroids are discussed, and their physiological, symptomatic and ecological effects evaluated. The relationship between pyrethroid toxicity and insecticide uptake is not fully defined. Based on laboratory and field data, it is likely that the susceptibility of aquatic insects (vector and non-vector) is related to biochemical and physiological constraints associated with life in aquatic ecosystems. Understanding factors that influence aquatic insects susceptibility to pyrethroids is critical for the effective and safe use of these compounds in areas adjacent to aquatic environments

Biorational versus conventional insecticides - Comparative field study for managing red spider mite and fruit borer on tomato

Tomato, Lycopersicum esculentum L. (Solanaceae), is an important crop worldwide that is grown both outdoors and under protected structures, for fresh market consumption and for processing. In the Mariana Islands, tomato is grown as an outdoor crop throughout the year. Tomatoes are attacked by a variety of pests, including the tomato fruitworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and, in Pacific islands, the red spider mite Tetranychus marianae McGregor. These pests cause scarring, tissue damage, and aberrations in fruit shape or color, making the tomatoes undesirable for fresh market. Also, insect bodies, excretia or parts in fruits reduce their market suitability. Field trials aimed at improving management of these pests were undertaken at two locations in Guam (Yigo and Inarajan), USA in 2012 and 2013, assessing the efficacy of different biorational and conventional insecticides against T. marianae and H.armigera on tomato. At both locations, the mean percentage of mite-infested leaves and the population density of T.marianae were higher in control than in treated plots. An integrated pest management (IPM) program comprising sprays of selective insecticides (Petroleum spray oil, Beauveria bassiana, azadirachtin, and Bacillus thuringiensis), evaluated at 15, 30, 45 and 60 days after transplantation of tomato seedlings, significantly reduced the number of T.marianae-infested leaves and the density of T.marianae over plots treated with carbaryl, malathion, six applications of B.bassiana or B.thuringiensis and over both controls at both locations. Similarly, significantly lower fruit damage by H.armigera was recorded in the plots treated with the IPM program than in plots treated with carbaryl, malathion, or the control treatments at both locations. Marketable tomato yields from the plots which received with the IPM program were significantly greater at both locations than were those in the other treatments. © 2014 The Authors

Management of Insect Pests in the Production and Storage of Minor Pulses

Minor pulses are cultivated on a small scale by economically poor farming communities for subsistence food. Currently, these crops are under-utilized or neglected, although they are reasonable sources of protein and can increase food security in rural areas. Research and development is underway to improve the grain quality and increase the productivity of these crops, both of which are negatively impacted by insect pest damage. Synthetic pesticides have proven to be the most effective control agents against all pests of minor pulses which include sap sucking insects. However, considering the drawbacks of pesticide residues in the grain, environmental pollution, and damage to natural enemies associated with synthetic pesticide use, integrated pest management schemes for pulses are being developed. For example, economic thresholds are being developed for pests of green gram (Vigna radiata [L.] R. Wilczek) and black gram (Vigna mungo [L.] Hepper) to avoid unnecessary pesticide applications. The adoption of these integrated practices by farmers in resource-poor communities should improve food security in rural areas. Here, we summarize existing information about the integrated control of pests of pulse crops

Field evaluation of petroleum spray oil and carbaryl against tetranychus marianae (Acari: Tetranichidae) on eggplant

Tetranychus marianae McGregor (Acari: Tetranychidae) is a pest of several perennial crops and is widespread in the Pacific Basin, including the Mariana Islands where it was first reported. The mite is also present in the West Indies, Bahamas, southern USA, Nicaragua, Argentina, Brazil and Southeast Asia. Eggplant growers apply carbaryl 10 to 15 times against this pest during each cropping period. Some growers no longer cultivate eggplant and tomato because of uncontrollable mite infestations. Previous indoor studies have shown petroleum spray oil (PSO) to be effective against T. marianae. We therefore examined the comparative effectiveness of PSO (Sun-spray 6E®) at the rate of 5mL/liter, and carbaryl at the rate of 1.5 mL/liter, against T. marianae on eggplant at 2 locations in Guam. The mean percentages of mite infested leaves and the population densities of T. marianae at both the locations were significantly higher in control plots than in treatment plots. PSO treatments with 6 and 15 sprays more effectively reduced the number of T. marianae-infested leaves and populations of T. marianae than carbaryl treatments. Marketable yields of eggplant from PSO treated plots were significantly higher than from the other plots. We recommend 6 applications of PSO at 15, 25, 35, 45, 55 and 65 days of after transplanting for managing T. marianae on eggplant

Multidimensional relationships of herbicides with insect-crop food webs

Controlling weeds is critical for improving the yield and quality of crops. Herbicides are the most commonly applied pesticides in agro-ecosystems. Herbicides affect insects directly as contact damage and indirectly by influencing food supplies. The innate susceptibility, life stages, and mode of feeding of insects can affect the herbicide–insect interaction. Interaction of herbicides with insect pest and beneficial insects is mainly indirect and absence of weeds either can reduce the insect population or causes switching of host plant and hence can also increase the population. The direct effect of herbicides depends on carrier or surfactant used. Presence of herbicides also provides surfactant to insecticides and increases impact of insecticides. At present, most reports on impact of herbicides indicate alterations in insect survival or egg production due to increase or decrease in host plant population as an indirect affect, only a handful studies reported a direct topical effect of these herbicides on egg, larvae/nymphs and adults of various insects. Further exploration of this interaction seems intriguing. Use of bio-herbicides, cultural control methods, and judicious use of herbicides could offer ecologically sustainable approaches to reduce impact of herbicides on insects

Establishment of Cecidochares connexa (Diptera: Tephritidae) in Guam and its effect on the growth of Chromolaena odorata (Asteraceae)

The gall fly Cecidochares connexa (Macquart) (Diptera: Tephritidae) was imported from Indone ia into Guam in 1998. It was field-established at one location in north central Guam, and its spatial and temporal spread in Guam was monitored. The biology of the gall fly is presented. No relationship between the number of larvae in a gall and the dimensions of the gall (length and width) existed. Three pupae per gall was the most frequent density with a range of 1-7. The sex ratio of flies emerging from galls was 1:1 irrespective of number of larvae per gall. C. connexa-induced galls established a nutrient sink as a result of the formation of a nutritive tissue along the walls of the larval chamber. Younger galls contained more mineral nutrients, namely, calcium, iron, potassium, manganese, and zinc, which were depleted as the galls matured, but the reverse trend was noted for sodium. Galls developing on terminal meristems significantly reduced the length of the shoots of Chromolaena odorata (Asteraceac). © 2006 Entomological Society of America