Granite Sand Research Articles

Adsorptive removal of non-ionic surfactants from water using granite sand

The adsorption of Triton X-100 in aqueous solution on the granite sand has been investigated to evaluate its ability as an adsorbent. Various parameters such as agitation time, adsorbent dose, adsorbent size, initial concentration of adsorbate, pH, temperature, and effect of interference ions were studied on the laboratory scale to establish optimum conditions for the removal of TX-100 from the effluents of different industries. Isotherm data were analyzed for possible agreement with the Langmuir and Frendlich adsorption isotherm equations. The first order rate equation by Lagergren was tested on the kinetic data. The rate of adsorption was conformed a pseudo first order kinetics with good correlation coefficient. The value of activation energy of sorption (Ea) was obtained as 44.6 kJ mol -1 . Results showed that granite sand exhibit reasonably good surfactant removals for nonionic types. The possible role of the adsorbent in a chromatographic column was also worked out.

Excess pore pressure and grain crushing of sands by means of undrained and naturally drained ring-shear tests

An investigation of excess pore-pressure generation of a weathered granitic sand, taken from the source area of a typical landslide caused as a result of liquefaction, and a fine silica sand was conducted, in which grain crushing within the shear zone of ring-shear test specimens was examined as the key phenomenon of rapid long-runout motion of landslides. In order to investigate and explain the low average apparent-friction angle, mobilized in a liquidized landslide, speed-controlled ring-shear tests were conducted under undrained conditions on weathered granitic-sand specimens, formed under a wide range of initial void ratios. It was revealed that very small steady-state shear resistances were obtained irrespective of the initial void ratios, which can explain the low average apparent-friction angle. In addition, two series of ring-shear tests on weathered-granitic and fine-silica sands were conducted under naturally drained conditions by keeping the upper drain valve of the shear box open during the tests. The first series of tests was performed under differing total normal stresses, but at the same shear speed, and the second series was conducted at differing shear speeds, but under the same total normal stress. In order to investigate and analyze excess pore-pressure generation and dissipation within the shear zone that is associated with grain crushing, permeability analyses were conducted by passing water through the sample box of the ring-shear test apparatus before and after shearing. In addition, grain-size distribution analyses of samples taken from the shear zone after shearing were carried out. For the weathered granitic-sand samples, a significant change in bulk permeability and large amount of grain crushing were observed. In these tests on the above soil, a considerable reduction of shear resistance, which increased proportionally to the total normal stress and shear speed, were obtained. It was observed that due to grain crushing, finer grains that lowered the permeability of the soil in the shear zone, were formed. It is likely that the decrease in permeability facilitated the generation of high excess pore pressures by reducing the pore-pressure dissipation rate from the shear zone; thus, flow behaviour was exhibited even under naturally drained conditions.

산불 관련 해양환경오염원들에 대한 해조류의 활력 측정

Plant ash and soil drainage, derived by frequent mountain fires during winter, might cause biological contamination to seaweeds at seashore and river mouse area. To thalli of Ulva pertusa, maximum non-lethal concentration(MNLC), lethal concentration 50 <TEX>$(LC_{50})$</TEX> and minimum lethal concentration (MLC) of pine needle ash were shown as 60, 350 and 550 mg/mL, respectively. The yellow loess and granite sand did not damage at concentrations of 20 and 200 mg/mL, respectively To thalli of Porphyra yezoensis, the MNLC, LC5O, MLC of pine needle ash were shown as 0.08, 0.4 and 1.0 mg/mL, respectively. Effects of yellow loess and granite sand were approximately 1/2 and 1/10 of the ash. To thalli of Undaria pinnatifida, the pine needle ash, yellow loess and granite sand did not damage at the concentration range of 20 to 40 mg/mL. Change of pigments <TEX>$(chlorophyll\;\alpha,\;lutein,\;\beta-carotene,\;phycoerthrin)$</TEX> was also determined at the MNLC, <TEX>$LC-{50}$</TEX> and MLC of pine needle ash. Among three seaweeds tested, P. yezoensis produced the most 2.7-fold of lutein and 2.3-fold of <TEX>$\beta-carotene$</TEX> at <TEX>$LC-{50}$</TEX> of the ash. Thus the P. yezoensis, appeared as a sensitive indicator, could be used as one of test organisms for determination of the biological effect of pollutants contaminated in marine environment.

Contrasting modes of survival by jack and pitch pine at a common range limit

Freezing tolerance, reproductive development, and seed germination of jack pine (Pinus banksiana Lamb.) and pitch pine (Pinus rigida Mill.) were compared in a small sympatric population in Acadia National Park in Maine, at the southern range limit of the former and the northern limit of the latter. Freezing tolerances of vegetative shoots and roots were similar for both species. Both species flower prolifically, and there was no evidence of differences in either pollen viability, cone survival, or proportion of viable seed (65–70% of the total). Regeneration success (established seedlings ranging from 1 to 13 years old) was similar overall for both species, but success by species varied greatly in some years. Jack pine regeneration was significantly associated with thinner soils, while pitch pine regeneration was associated with thicker soils in hollows. Jack pine seed germinated significantly faster than pitch pine seed, especially when day–night temperature was reduced. Pitch pine seedlings always exhibited a significantly higher shoot/root ratio than those of jack pine. The most northerly provenances of jack pine germinated significantly faster than those from the most southerly provenances. Jack pine also germinated at a significantly higher percentage than pitch pine in exposed granite sand. Thus relatively cool, dry conditions may favor establishment of jack pine seedlings, while pitch pine establishment may be favored in warmer, wetter conditions.

New porous ceramics for tangential filtration

Abstract The aim of the present work is to obtain ultrafiltration membranes of KTiOPO 4 (KTP). Clay A and granitic sand S ceramics were used as porous supports. The choice of these materials has been dictated by their natural abundance (low price) and their thermal stability. The performances of two ultrafiltration membranes, 1 (A/TiO 2 /KTP) and 2 (S/TiO 2 /KTP) were compared in terms of thickness, pore diameter and water flux. The water permeability measured for these two composite membranes is 40 and 50 l h −1 m −2 bar −1 , respectively. The thickness is less than 800 nm, and the pore diameters are centred near 4.5 and 4 nm, respectively, for a firing temperature equal to 400°C. These composite membranes can be used in tangential ultrafiltration.

Élaboration et caractérisation d'une céramique macroporeuse a base d'arène granitique

During this work, new porous ceramics based on granitic sand were prepared and their properties were characterized. The choice of this material is based on its natural abundance (low price). Powders mixed with certain organic additives can be extruded to fabricate a porous tubular configuration with a highly uniform porous structure. The sintering temperatures lay between 960 and 1070 °C. A ceramic membrane fired at 1040 °C had a mean pore diameter of 10 μm and the porosity was 45%. The obtained results allow to conclude that granitic sand membranes can be used both in tangential microfiltration and as supports of ultrafiltration.

The influence of tillage on semi-arid soil–water regimes in Zimbabwe

Little is known about the in situ hydrological properties of soils in the semi-arid regions of the world where subsistence agriculture is the common land use. The work reported here concentrates on three major soil types, considered representative of the agriculturally important Zimbabwean fersiallitic group of soils, and describes the water regimes that develop under conventional (flat) and improved (tied ridge) practices in response to natural and simulated rainfall. The first soil, typical of those used by small scale farmers, is a deep coarse-grained granitic sand with a low available water capacity. The second is a silty clay loam derived from mafic rocks and typical of the red clays associated with Zimbabwe's commercial farming areas. The third is a sandy loam that readily compacts and crusts under natural rainfall, prone to runoff and thus drought sensitive. The climate at each site has a five month rainy season, when most of the rain falls as heavy convectional storms and a dry spell from April to October. However, total seasonal rainfall at each site is unreliable (200 to 1100 mm) with unpredictable dry periods of 1–3 weeks, especially at the beginning and middle of the wet season when rain occurs as intense storms of short duration. Long term monitoring of the three soil types has shown that at the end of the dry season, the quantity of water stored in the top 0.3 m of the profile is negligible, typically below permanent wilting point. Water stored in the 0.9 m profile at the end of the dry season is more variable and depends on total seasonal rainfall, its distribution, the type of crop grown and the tillage management. At the beginning of the wet season, the recharge of the soil profile is of fundamental importance for subsequent crop establishment and can benefit from improved soil water storage in the previous season and tillage practices that help to catch the first rains of the wet season. In general terms the tillage treatment that impounds the most water (tied ridges) was the wettest, whatever the soil type. However, the incomplete wetting up of the tied ridges early in the wet season, frequently resulted in poor crop establishment or a delay in planting until the ridge structure was fully wetted. This was in contrast to the conventionally tilled soils, which were more uniformly wet in the top 200 mm of the soil profile and significantly wetter than the ridged soils early in the wet season. Irrespective of tillage technique, good weed management was critical to maximize the availability of water for crop growth.

Liquefaction and the Steady State of Weathered Granitic Sands Obtained by Undrained Ring Shear Tests: A Fundamental Study of the Mechanism of Liquidized Landslides.

Liquidized landslides have caused many disasters because of their high mobilities and long travel distances. The 1995 Takarazuka Golf Course landslide is a typical liquidized landslide with a runout of 180 meters. A series of undrained speed-controlled ring shear tests and another series of undrained strain-controlled triaxial compression tests were conducted on weathered granitic sands to determine the conditions under which liquidized landslides are generated in order to investigate the process of liquefaction and shear behavior in the steady state as key phenomena in such landslides. Test results showed that liquefaction was generated in loose to dense specimens in the ring shear tests, whereas in triaxial compression tests liquefaction occurred only in loose specimens. The apparent friction angles in the steady state obtained by the ring shear tests after grain crushing terminated were smaller than the values for the Takarazuka Golf Course landslide. Because that landslide showed a clear shear surface, grain crushing in that surface must have been complete or almost complete. The direct shear state with large shear displacement reporduced in the ring shear tests corresponds to the state of shearing in the sliding surface of the landslide. The small apparent friction angles obtained in the ring shear tests therefore provide a good understanding of the high mobility of liquidized landslides.

The fracture characteristics of crushed limestone sand concrete

The use of crushed sand as a fine aggregate has rapidly increased due to a shortage of river sand. Accordingly, research on crushed sand concrete is required. In this research, the fracture characteristics of crushed limestone sand concrete were experimentally investigated through a wedge splitting test, and the results were compared with those of crushed granite sand concrete and river sand concrete. The strength of crushed limestone sand concrete was also investigated. It was shown that the fracture energy of concrete was little influenced by the type of fine aggregate. In addition, the fracture energy of crushed sand concrete was slightly higher than that of river sand concrete. This seems to be due to very fine sand (VFS) included in crushed sand, which tends to improve the cohesion between cement paste and aggregate. Also, the fracture energy was not proportionally increased with an increase of concrete strength. The characteristic length of crushed limestone sand concrete was almost the same as that of river sand concrete or crushed granite sand concrete. The characteristic length greatly decreased as the strength of concrete increased.

Chemical weathering rates of a soil chronosequence on granitic alluvium: I. Quantification of mineralogical and surface area changes and calculation of primary silicate reaction rates

Mineral weathering rates are determined for a series of soils ranging in age from 0.2–3000 Ky developed on alluvial terraces near Merced in the Central Valley of California. Mineralogical and elemental abundances exhibit time-dependent trends documenting the chemical evolution of granitic sand to residual kaolinite and quartz. Mineral losses with time occur in the order: hornblende > plagioclase > K-feldspar. Maximum volume decreases of >50% occur in the older soils. BET surface areas of the bulk soils increase with age, as do specific surface areas of aluminosilicate mineral fractions such as plagioclase, which increases from 0.4–1.5 m 2 g −1 over 600 Ky. Quartz surface areas are lower and change less with time (0.11–0.23 m 2 g −1). BET surface areas correspond to increasing external surface roughness (λ = 10–600) and relatively constant internal surface area (≈ 1.3 m 2 g −1). SEM observations confirm both surface pitting and development of internal porosity. A numerical model describes aluminosilicate dissolution rates as a function of changes in residual mineral abundance, grain size distributions, and mineral surface areas with time. A simple geometric treatment, assuming spherical grains and no surface roughness, predicts average dissolution rates (plagioclase, 10 −17.4; K-feldspar, 10 −17.8; and hornblende, 10 −17.5 mol cm −1 s −1) that are constant with time and comparable to previous estimates of soil weathering. Average rates, based on BET surface area measurements and variable surface roughnesses, are much slower (plagioclase, 10 −19.9; K-feldspar, 10 −20.5; and hornblende 10 −20.1 mol cm −2 s −1). Rates for individual soil horizons decrease by a factor of 10 1.5 over 3000 Ky indicating that the surface reactivities of minerals decrease as the physical surface areas increase. Rate constants based on BET estimates for the Merced soils are factors of 10 3–104 slower than reported experimental dissolution rates determined from freshly prepared silicates with low surface roughness (λ < 10). This study demonstrates that the utility of experimental rate constants to predict weathering in soils is limited without consideration of variable surface areas and processes that control the evolution of surface reactivity with time.

Effect of Backfill Amendment on Growth of Red Maple

Balled-and-burlapped red maple (Acer rubrum) trees were planted in holes backfilled with 1) native soil, 2) 50:50 (v/v) aged pine bark: soil, 3) 50:50 (v/v) Mr. Natural Concentrated Landscape Media (CLM): soil, and 4) 100% CLM. The CLM is an improved, proprietary soil amendment composed of top soil, pine humus, granite sand, crushed granite, expanded shale, and composted poultry litter. The CLM: soil treatment increased fibrous root growth within the planting hole after five months but did not increase shoot growth. Aged pine bark induced nitrogen deficiency symptoms and reduced shoot growth during the first year. Shoot growth of the treatments did not differ after two years. The data support use of native soil in backfilling planting holes.

Field moisture characteristics of two fersiallitic soils in Zimbabwe

Abstract. Little is known about the in situ hydrological properties of Zimbabwean soils. This paper describes the water retention and transmission properties of two agriculturally important Zimbabwean fersiallitic soils measured in situ by the instantaneous profile method. The first soil, typical of those used by small scale farmers, is a deep coarse grained granitic sand. The second is a silty clay loam derived from mafic rocks, typical of the red clays associated with Zimbabwe's commercial farming areas. The K‐θ functions for each layer of the sand were very similar and the profile could be described by a single function, with permeability increasing with depth. In contrast, the silty clay loam could not be described by a single function, as permeability decreased with depth. However, in both soils water movement became negligible below a matric potential of—0.01 MPa; this is thought to be a more appropriate field approximation of the upper limit of plant available water than—0.033 MPa which is often used for tropical soils.

102 EFFECT OF BACKFILL AND PLANTING BED AMENDMENTS ON GROWTH AND DROUGHT TOLERANCE OF ACER RUBRUM

Commonly used planting techniques and soil amendments were compared to determine their effect on root growth, shoot growth, and drought tolerance of 2.5 cm caliper Acer rubrum. Study I: Trees were planted on 6 April 1992 into holes backfilled with 1) native soil, 2) 50% aged pine bark: 50% native soil, 3) 50% Mr. Natural™:50% native soil, or 4) 100% Mr. Natural™. Mr. Natural™ consists of granite sand, expanded shale, and composted poultry litter. After two years, no differences in growth or survival existed. Study II: On 8 April 1992, trees were planted in 1) unamended planting holes, 2) tilled planting beds, or 3) tilled and pine bark-amended planting beds. Five months after planting, the root growth in the tilled and tilled-amended beds did not differ, but both had more root growth than planting holes. Amendment-induced nitrogen deficiency reduced shoot growth of the tilled-amended treatment during the first year. After two years, the planting hole treatment exhibited the least shoot growth, while shoot growth of tilled and tilled-amended treatments did not differ. StudyIII: Selected trees in study II were drought stressed for 8 weeks beginning 4 August 1993. No differences in relative leaf water content among treatments were observed Results suggest that native soil should be used as backfill in planting holes; however, tilling a planting bed increases root and shoot growth compared to planting in a hole. Amending beds with pine bark did not increase growth or drought tolerance.

SEM investigations of fracture surfaces using stereo pairs: III fracture surfaces of mortars

Fracture surfaces of mortars prepared using previously described materials and fractured in bending using the ISRM Method I protocol have been examined using stereo pairs produced at various magnifications in a scanning electron microscope. “High performance” mortars containing silica fume and high superplasticizer dosages are seen to generate mostly nearly planar surfaces that expose little crushed sand surface. Plain cement paste mortars prepared at the same low water:cement ratio (0.3) show much rougher surfaces at various magnifications, and the details of fracturing are somewhat dependent on the characteristics of the specific sand. Cleavage surfaces may be fairly commonly exposed, especially with crushed granite sand. The presence of air voids locally does not appear to influence significantly the fracture path, and no obvious differences were detected between the slow crack growth zone expected at the beginning of the fracture and the fast fracture zone expected near the end.

624 (PS 3) SOIL AMENDMENT INCREASES GROWTH OF SALVIA SPLENDENS AND CATHARANTHUS ROSEUS

Commonly used soil amendments for ornamental annual plantings were compared to determine their effect on growth of Salvia splendens `Hotline Red' (Salvia) and Catharanthus roseus `Peppermint Cooler' (Vinca). Transplants of the annuals were planted in amended outdoor beds on June 12 1992. Treatments were 1) an unamended, rototilled control and 2) aged pine bark, 3) granite sand or 4) a regionally commercially available product Mr. Natural™. Mr. Natural™ consists of granite sand, expanded shale, and composted poultry litter. A 9-cm-deep surface layer of the amendments was rototilled into 20 cm of clay soil. One-half of the plants were fertilized with the recommended rate of 0.15 kg/m2 of 14-14-14 Osmocote, and one-half were not fertilized. On July 14 and August 10, shoot dry weight was determined, and a growth index was calculated from the width and height of growth. Fertilizing increased the growth index and dry weight in all treatments. Plants in the aged pine bark and no fertilizer treatment were consistently the smallest plants and exhibited nitrogen deficiency symptoms. For both dates, the Mr. Natural™ vinca plants had the greatest dry weight and growth index. On the first date, Mr. Natural™ salvia plants did not differ from the sand treatment but had 50% greater dry weight than the unamended control. Mr. Natural™ salvia plants were the largest plants on the second harvest date.

Seasonal nitrification measurements with different species of forest litter applied to granite-sand-filled lysimeters in the field

The biodegradation of litter from Festuca silvatica, Abies pectinata, Fagus silvatica, Calluna vulgaris, Picea abies associated with forest brown acid soils or with podzolic soils was studied in field lysimeters filled with granite sand. Analysis of the leachates collected during 2 years made it possible to determine NO inf3 sup- , NH inf4 sup+ , and soluble organic N production in order to investigate the specific influence of the different species of litter on the mineralization of organic N and the variations in nitrification. With Festuca silvatica (grass), active nitrification was observed after the addition of fresh litter in autumn (fall of leaves). Nitrification remained significant in winter, reached a maximum in spring until early summer, and then decreased after mineralization of the easily mineralizable organic N. Nitrification was the major N transformation process in this litter. The addition of fresh litter of Abies pectinata (fir), Fagus silvatica (beech), Calluna vulgaris (heather), and Picea abies (spruce) in autumn induced an inhibition of nitrification during winter and spring. With these litter species, nitrification started again by the end of spring and was at a maximum in summer and autumn until leaf fall. By comparison with Festuca, inhibition observed in winter and spring with the other litter species was definitely due to the chemical composition of the leaves. Simultaneously, a lower C mineralization of these plant material occured. These litter species, in particular Calluna and Picea released leachates containing significant amounts of soluble organic N that were only slightly decomposed. We conclude that NO inf3 sup- production outside of the plant growth period can definitely be involved in soil acidification and weathering processes.

Dissolution of Granitic Sand by pH-Buffered Carboxylic Acids: A Flow-Through Experimental Study at 100 degrees C and 345 Bars (1)

Experiments were performed to investigate the effects of monofunctional and difunctional carboxylic acids on feldspar dissolution and aluminum mobility under conditions which approximate diagenesis, including low temperature, high mineral surface area/fluid volume, and open-system conditions. Granitic sand (63% feldspar) was reacted at 100 degrees C and 345 bars with distilled water, pH-buffered oxalic acid, and pH-buffered acetic acid in a flow-through system at various flow rates. At essentially constant pH, the concentrations of Al, SiO[2], and other components are enhanced in acetate-bearing and oxalate-bearing pore fluids. For example, steady-state concentrations of Al reached 80 ppm in buffered oxalic acid (approximately 1000 ppm oxalate) and 14 ppm buffered acetic acid (approximately 4000 ppm acetate). These concentrations are higher by factors of 800 and 130, respectively, than previously calculated values for kaolinite solubility at the same pH in the absence of organics. In general, Al and SiO[2] in the pore fluid vary directly with oxalate and inversely with flow rate. Elevated metal concentrations are apparently due to formation of organic anion complexes and/or increased reaction kinetics. Al/Si, Al/K, and Al/Na molar values in solution exceed stoichiometric ratios for feldspar. Al-favored ratios seem to be due to incongruent dissolution of feldspars by preferential formation of Al-oxalate complexes. Geologically reasonable concentrations of both monofunctional and difunctional carboxylic acids can enhance substantially the solubility of Al under moderately acidic conditions, although oxalate has a much greater effect than acetate. The acetate system may buffer the pH in formation waters and allow rapid dissolution of aluminosilicates and creation of secondary porosity through reaction with carboxylic acid anions. The effectiveness of the buffering and dissolution processes depends on many factors, including type and availability of organic acids, pH, temperature, flow rate, mineralogic composition and associated reaction kinetics.

Boron, copper, and zinc requirement of flue‐cured tobacco grown on a granitic sand

Abstract From 1982 to 1984, a tobacco farm survey of Mareeba‐Dimbulah area revealed cured leaf high in B and low in Cu and Zn content, with soils low in HWS B (<0.1 mg/kg) and DTPA extractable Cu <...

The Species Composition of Soil Seed Banks Beneath Lowland Tropical Rainforests in North Queensland, Australia

Twelve surface soil samples from each of four rainforest types on different soils of the huLmid, tropical lowlands of north Queensland were removed to germination-house conditions, Seed germination was monitored over a period of 14 weeks between AugLst and November. Seedling numbers at the four sites (mean densities ranged from 588 m-2 to 1068 m-2) were comparable to numbers recorded elsewhere by similar techniques in tropical rainforest soils. The numbers of germinated seeds were significantly higher at the site with coarse granitic sands than at the three sites with finer-textured soils. This was attribuLted to the ease with which seeds could be incorporated into the coarse-textured soil. Most of the seedlings produced at all sites were secondary species or weeds of the forest margins, many being common to all sites. The characteristic abundance of some secondary species at one or two sites could be explained usually in terms of the prevalence of those species in the standing rainforest on the sites. Only a few largeseeded primary forest species were germinated and most of these were fruiting at the time of sampling. The absence of many primary forest trees from the seed banks can be explained by the obligately quick-germinating, short-lived natuLre of their seeds. The large size of the potentially longer-lived seeds of some primary forest species was considered to be important in preventing their incorporation in the soil profile and, hence, affecting their susceptibility to predation and longevity on the forest floor. THE COMPOSITION OF VIABLE SEED in soils beneath a plant community is one indicator of the regrowth potential of that community. Most studies of soil seed storage have been conducted in temperate agricultural and pastoral situations where the information has been used to control weeds and predict compositional changes under various intensities of management (Milton 1943, 1948; Champness and Morris 1948; Douglas 1965; Suckling and Charlton 1978). The results of soil seed studies have been useful in predicting successional changes and interpreting past plant communities which occupied an area (Oosting and Humphreys 1940, Howard 1974), predicting and interpreting the results of various intensities of disturbance (Olmsted and Curtis 1947, Floyd 1966, Howard and Ashton 1967, Thompson 1978), and interpreting the pathways of natural regeneration and the strategies of establishment of individual species (Liew 1973, Baskin and Baskin 1978). However, few soil seed studies of tropical rainforests have been conducted (Symington 1933, Keay 1960, Guevara and Gomez-Pompa 1972, Liew 1973, Cheke et al. 1979) and more are urgently required (Whitmore 1978). This paper reports the results of a study designed to define the compositions of the soil seed banks of four Australian tropical rainforest sites containing different soils. It forms part of a larger study of secondary succession which is being carried out in the same area.

Sugarcane Rootstalk Borer Weevil Regulatory Treatment in Ornamental Plants, 1982

Abstract Tests were conducted to develop a potting soil amendment to prevent movement of Diaprepes abbreviatus larvae in ornamental plants. Heptachlor is presently used in the potting soil for ornamental plants produced in the weevil areas. Lindane was mixed with Terra-lite Metro Mix, a commercial potting soil containing Canadian sphagnum peat moss, domestic horticultural vermiculite, processed, bark, composted pine bark, and washed granite sand in March. The rates/acre were computed on a 6-in depth acre with 800 yd of treated soil/acre. Coral Ardisia, Ardisia crispa, an ornamental plant that supports development of D. abbreviatus was planted in 6-in pots, and 20 plants/treatment were used. Plants were infested with 100 first stage larvae 4 mo after treatment and the soil examined for larvae 2 mo later. Plants wepe maintained in a covered screen enclosure.