Linda C. Whitehand

Methyl eugenol and cue-lure traps for suppression of male oriental fruit flies and melon flies (Diptera: Tephritidae) in Hawaii: effects of lure mixtures and weathering.

Abstract Methyl eugenol (4-allyl-1,2-dimethoxybenzene-carboxylate) and cue-lure [4-(p-acetoxyphenyl)-2-butanone] are highly attractive kairomone lures to oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, B. cucurbitae (Coquillett), respectively. Plastic bucket traps were evaluated as dispensers for methyl eugenol and cue-lure for suppression of the 2 fruit flies in Hawaii. Methyl eugenol and cue-lure mixtures were compared with pure methyl eugenol or cue-lure over 4 seasons. B. dorsalis captures differed significantly with treatment and season. B. dorsalis captures with 100% methyl-eugenol were significantly greater than all other treatments (25, 50, and 75%). B. cucurbitae captures also differed significantly with treatment but not with season. Captures with 100, 75, and 50% cue-lure were not significantly different. Bucket traps baited with cue-lure (+ malathion) and weathered under Hawaiian climatic conditions were attractive to B. cucurbitae up to 8 wk. Two methyl eugenol dispensers (canec disks and Min-U-Gel) were compared with bucket traps. Dispensers (methyl eugenol + malathion) were weathered for 2–16 wk under Hawaiian climatic conditions and bioassayed during summer and winter. Initially, captures of B. dorsalis were not significantly different for the 3 dispensers. Bucket traps and canec disks were most resistant to weather, remaining attractive to B. dorsalis flies up to 16 wk. Min-U-Gel was least resistant, losing attractiveness to B. dorsalis flies within 2 wk. On the basis of performance, bucket traps and canec disks were equally long-lived up to 14 wk; thereafter, bucket traps were slightly more attractive during winter. Canec disks were cheapest, but on the basis of possible environmental concerns, bucket traps may be the best all-around choice for areawide suppression of fruit flies.

Latex quantification in guayule shrub and homogenate

Commercial development of hypoallergenic latex from Parthenium argentatum (Gray), especially for the manufacture of latex medical and household goods, requires specific knowledge on the best lines, agronomic practices and storage conditions for the generation of maximal latex yield. Development can proceed only by using standard, accurate analytical techniques for latex extraction and quantification. In this paper, we describe a latex extraction method that parallels the proposed commercial extraction process and we demonstrate that different extraction equipment can introduce large variations in the apparent amount of extractable latex. An evaluation protocol for testing and optimizing the efficiency of alternative extraction equipment is presented. Also, we describe a rapid latex quantification method for use with shrub and shrub homogenates, confirm its accuracy with tissue balance analysis and show how it can be used to quantify latex in materials with unusually low latex content. The reproducibility of the basic method and of a variation of the method, were determined by analysis of identical homogenates by researchers at different locations.

Evaluation of Glyphosate for Managing Giant Reed (Arundo donax)

Abstract Giant reed is an invasive plant of riparian habitats throughout California and the United States. Glyphosate is approved for controlling giant reed in California. Sources indicate that 1.5% to 5% glyphosate solutions are effective at controlling giant reed. There is little published data on the relative efficacy of different concentrations of glyphosate which can be used to select an appropriate application regime for California habitats. We conducted two field experiments to test the hypothesis that glyphosate concentrations of 1.5%, 3%, and 5% applied as foliar sprays were equally effective at killing giant reed plants. Leaf chlorophyll content and the proportion of living stems declined significantly following treatment with 1.5% or greater solutions of glyphosate. New stems were observed the spring following treatment for plants treated with 1.5% glyphosate. No new stems were observed for plants treated with either 3% or 5% glyphosate. A treatment that included “bending and breaking” stems prior to treatment with 5% glyphosate provided control similar to 5% glyphosate alone. There was no there evidence that plants sprayed with only a mixture of the surfactant (Agridex), water, and a marking dye were affected beyond the short-term. These results indicate that 3% or 5% foliar applications with glyphosate were the most effective and consistent treatments for killing giant reed with a single late-season application. This result is especially important if the goal of the treatment program is to minimize the number of treatments, thus reducing labor costs and minimizing impacts on sensitive habitats by reducing the number of site visits. Nomenclature: Giant reed, Arundo donax L. ABKDO.

Pre-Release Assessment of Impact on Arundo donax by the Candidate Biological Control Agents Tetramesa romana (Hymenoptera: Eurytomidae) and Rhizaspidiotus donacis (Hemiptera: Diaspididae) Under Quarantine Conditions

Abstract. Impact by two potential biological control agents, Tetramesa romana Walker and Rhizaspidiotus donacis (Leonardi), on the invasive weed, giant reed, Arundo donax L., was assessed in a quarantine greenhouse before release. Tetramesa romana alone and T. romana plus R. donacis significantly damaged A. donax by suppressing leaf and stem lengths and stimulated production of side branches during a 12-week period. R. donacis plus T. romana only slightly more impacted the plant than did T. romana alone, most likely because of the longer life cycle of R. donacis that may require a longer period of time to cause measurable damage. No negative interactions were observed between the two candidate biological control agents. Therefore, based on their potential to significantly damage A. donax under greenhouse conditions and their narrow host ranges, T. romana and R. donacis are suitable candidates for biological control of this invasive reed grass in North America.

Compression Deformation and Structural Relationships of Medium Grain Cooked Rice

ABSTRACT Cooked rice quality is based on a number of factors including texture. Texture and structure of foods are closely related and aspects of the relationship can be explored by correlating compression measurements to structural observations of the compressed material. To obtain compression measurements, single cooked, milled rice grains were compressed in a texture analyzer to a specific percentage (% compression) of the original grain; the uncompressed grain is 0%. The experiment, using single grains in each case, was repeated multiple times. Compression percentages of 20, 30, 40, 50, 60, and 70% were measured against a constant resistance force in the texture analyzer. Structures of cooked rice grains at the various compression levels were compared by brightfield and fluorescence microscopy. The outside of an uncompressed, intact, cooked rice grain is swollen and distorted while the interior has three or more odd-shaped holes (voids). Each void is largest in the center of the grain and decreases in...

Effects of Methyl Bromide Concentration, Fumigation Time, and Fumigation Temperature on Mediterranean and Oriental Fruit Fly (Diptera: Tephritidae) Egg and Larval Survival

Abstract The effects of methyl bromide (MB) concentration (16, 32, 48, or 64 g/m3), fumigation temperature (15, 20, 25, or 30°C), and fumigation time interactions on the survival of Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), eggs and first and third instars were recorded. Increasing the fumigation temperature from 15 to 20°C or from 20 to 25°C resulted in a significant reduction in fumigation time required for equivalent egg and larval mortalities at all studied MB concentrations; no further reductions in fumigation time resulted from increasing the temperature from 25 to 30°C. Conversely, increasing temperature and time allowed for a reduction in MB concentration to obtain equivalent mortality. Thus, the optimum fumigation temperature for Mediterranean and oriental fruit fly eggs and larvae was 25°C. Reducing MB concentrations required for phytosanitary fumigations would save time and expense, and reduce the amount of MB released into the atmosphere during aeration. Mediterranean fruit fly was as or more tolerant to MB than oriental fruit fly in MB tolerance for eggs and first instars. The egg stage was generally more tolerant to MB regardless of concentration. However, Mediterranean fruit fly eggs showed similar tolerance to first instars at 25°C for the three highest concentrations and to third instars at 25 and 30°C for the highest concentration, with no significant difference between them. Therefore, eggs alone can be used to obtain MB fumigation efficacy and quarantine security data at fumigation temperatures between 15 and 30°C for Mediterranean and oriental fruit fly.

Experimental Design and Analysis in Field Studies of Aquatic Vegetation

ABSTRACT Field experiments may be useful for researchers and managers concerned with aquatic plants. Since experimental design and statistical analysis are closely related, this paper discusses statistical and practical considerations for conducting and evaluating field experiments with aquatic plants. Special emphasis is given to the analysis of variance, assumptions required for its use, and concepts related to it (e.g., statistical power, means comparison procedures, treatment structure, pseudoreplication, etc.). The paper concludes with a brief introduction to papers in the literature which illustrate the use of field experiments for studying aquatic plants.