Spray deposit patterns and persistence of diflubenzuron in some terrestrial components of a forest ecosystem after application at three volume rates under field and laboratory conditions     

Kanth M. S. Sundaram 《Pest management science》1991,32(3):275-293

Spray deposit patterns and persistence of diflubenzuron [1-(4-chlorophenyl)- 3-(2,6-difluorobenzoyl)urea] in white pine (Pinus strobus L.) and sugar maple (Acer saccharum Marsh.) canopies, forest litter and soil were studied after aerial application of a 250 g kg^?1 wettable powder formulation, ‘Dimilin® WP-25’, at 70 g active ingredient (a.i.) ha^?1, using three volume rates (10, 5 and 2.5 liters ha^?1) over three blocks in a mixed forest near Kaladar, Ontario, Canada, during 1986. Spray droplets were sampled at ground level using ‘Kromekote®’ cards, and diflubenzuron deposits were collected on glass plates. Droplets were the largest (with a volume median diameter of 250 μm) at the 10 liters ha^?1 rate, resulting in the highest number of droplets per cm² on the Kromekote cards and deposits of diflubenzuron on glass plates. Deposits on foliage, litter and soil were also correspondingly the highest. At the 5.0 and 2.5 liters ha^?1 rates, volume median diameter values were smaller (195 and 150 μm, respectively) and deposits on the substrates were markedly lower. In the spray block that received 10 liters ha^?1, diflubenzuron persisted in foliage as long as 120 days after treatment, but it lasted for only about a week in forest litter and soil samples. At 5 and 2.5 liters ha^?1, diflubenzuron failed to persist in foliage as long, and residues in litter and soil, which were barely above the quantification limit, persisted only for a few days. Laboratory studies, conducted under constant meteorological conditions using different droplet-size spectra, showed that deposit levels were not affected when the volume median diameter of the spray cloud decreased from 253 μm to 145 μm, but were markedly reduced as this progressively decreased from 92 to 37μm. The dissimilarities between the field and laboratory findings were attributed to meteorological and other factors influencing droplet deposition on tree canopy in aerial applications of pesticides over forests.  相似文献   

Effect of different types of litter material for rearing broilers     

Swain BK  Sundaram RN 《British poultry science》2000,41(3):261-262

1. Coir dust was evaluated as broiler litter in comparison with sawdust and rice husk using 135 commercial broilers. Forty-five broiler chicks were reared to 42 d on a 50 mm layer of each of these litters. 2. Birds reared on coir dust showed no difference in food consumption, body weight gain, food conversion efficiency production number and survivability in comparison to those reared on saw dust and rice husk. 3. It was concluded that coir dust is suitable as broiler litter when cheaply available.  相似文献   

Income Inequalities in Post­Colonial Peninsular Malaysia     

Jomo Kwame Sundaram  Ishak Shari 《Asia Pacific viewpoint》1982,23(1):67-76

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Malaysia’s New Economic Policy: A Class Perspective     

Jomo Kwame Sundaram 《Asia Pacific viewpoint》1984,25(2):153-172

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A reversibly switching surface     

Lahann J  Mitragotri S  Tran TN  Kaido H  Sundaram J  Choi IS  Hoffer S  Somorjai GA  Langer R 《Science (New York, N.Y.)》2003,299(5605):371-374

We report the design of surfaces that exhibit dynamic changes in interfacial properties, such as wettability, in response to an electrical potential. The change in wetting behavior was caused by surface-confined, single-layered molecules undergoing conformational transitions between a hydrophilic and a moderately hydrophobic state. Reversible conformational transitions were confirmed at a molecular level with the use of sum-frequency generation spectroscopy and at a macroscopic level with the use of contact angle measurements. This type of surface design enables amplification of molecular-level conformational transitions to macroscopic changes in surface properties without altering the chemical identity of the surface. Such reversibly switching surfaces may open previously unknown opportunities in interfacial engineering.  相似文献   

Antifeedant activity of a novel 6-(4,7-hydroxy-heptyl) quinone^? from the leaves of the milkweed Pergularia daemia on the cotton bollworm Helicoverpa armigera (Hub.) and the tobacco armyworm Spodoptera litura (Fab.)     

Manickam Pavunraj  Chellaiah Muthu  Savarimuthu Ignacimuthu  Sundaram Janarthanan  Veeramuthu Duraipandiyan  Nagappan Raja  Selvaraj Vimalraj 《Phytoparasitica》2011,39(2):145-150

The effects of crude extracts and an isolated compound from the leaves of milkweed, Pergularia daemia (Forssk) Choiv., on the antifeedant activity against two important lepidopteran pests, Helicoverpa armigera (Hub.) and Spodoptera litura (F.), were studied. Maximum antifeedant activity was recorded in ethyl acetate crude extract against H. armigera (70.3%) and S. litura (71.82%) at 1% concentration. Ethyl acetate crude extract was further subjected to column chromatography, which was performed using hexane as initial solvent and then by increasing the polar strength using ethyl acetate. Fractions collected at hexane and ethyl acetate (80:20) yielded 6-(4,7-hydroxy-heptyl) quinone, a novel compound which showed significant antifeedant activity against H. armigera (80.22% at 2000 ppm) and S. litura (68.31% at 2000 ppm).  相似文献   

Productivity of Rainfed Sorghum — A Physiological Analysis     

D. Durga  Devi  K. M. Sundaram  N. Natarajaratnam 《Journal of Agronomy and Crop Science》1987,159(5):360-364

A field experiment was conducted to study the varietal variability of productivity in sorghum under rainfed conditions. Six varieties viz., TNS 24, TNS 27, CO 20, CO 19, CO 24 and K3 were utilized in this study. Among these varieties TNS 24, CO 19 and TNS 27 were found to be tolerant to drought situations while K 3, CO 20 and CO 24 were susceptible. The classification was mainly based on the yield data. Highest leaf area was observed in tolerant varieties, The reduction in leaf area at the harvest stage was also minimal (6.8%) in the tolerant varieties. LAD and CGR also showed higher values in the tolerant varieties. The dry matter accumulation was higher in the tolerant varieties. The yield improvement in the tolerant genotypes is mainly due to the increased dry matter accumulation while harvest index is not related to yield in the varieties studied.  相似文献   

Mapping and marker-assisted breeding of a gene allelic to the major Asian rice gall midge resistance gene <Emphasis Type="Italic">Gm8</Emphasis>     

V. S. A. K. Sama  K. Himabindu  S. Bhaskar Naik  R. M. Sundaram  B. C. Viraktamath  J. S. Bentur 《Euphytica》2012,187(3):393-400

Host plant resistance is the preferred management strategy for Asian rice gall midge (Orseolia oryzae), a serious pest in many rice-growing countries. Identification of simple sequence repeat (SSR) markers that are tightly linked to pest resistance genes can accelerate development of gene pyramids for durable/multiple resistance. Based on conventional and molecular allelism tests, we report herein that rice genotype Aganni possesses Gm8 gene, conferring hypersensitive independent (HR– type) resistance to gall midge biotypes GMB1, GMB2, GMB3, GMB4, and GMB4M. The gene Gm8 was mapped to chromosome 8 within a 400-kbp region, and the SSR markers RM22685 and RM22709 flank the gene closely. Using these closely linked flanking markers, nine other gall midge-resistant genotypes were identified as carrying the same gene Gm8. Through marker-assisted selection, Gm8 has been introgressed into an elite bacterial blight-resistant cultivar, Improved Samba-Mahsuri (IS).  相似文献   

Persistence of tebufenozide in aquatic ecosystems under laboratory and field conditions     

K. M. S. Sundaram 《Pest management science》1997,51(1):7-20

The persistence and dissipation behaviour of tebufenozide, an ecdysone agonist, were investigated: (1) under laboratory conditions in aquatic models set up in glass aquaria, and (2) under field conditions in in-situ aquatic enclosures deployed in a mixed-wood boreal forest lake. Two models were set up in the laboratory study (Study I), which was conducted at constant conditions of temperature, water pH and photoperiod. In Model I, partitioning of tebufenozide from sediment, treated at a concentration of 1400 μg kg^-1, into untreated water was examined. The results showed that the chemical moved very little from the treated sediment into water. The concentration in sediment and water decreased gradually during the 90-day incubation period. Tebufenozide disappeared faster from the top layer of sediment than from the middle and bottom layers. The half-lives of disappearance were 64 days for the top layer but >90 days for the middle and bottom layers respectively. In Model II, partitioning from water, treated at a concentration of 350 μg litre^-1, into untreated sediment was investigated. The results showed that the chemical moved from treated water into sediment due to adsorption. Little vertical downward movement of the adsorbed residues from the top layer of sediment occurred into layers beneath. The adsorbed residues were also not released readily back into water. The concentration in water and sediment decreased gradually during the 90-day incubation period. The half-life of dissipation from water was 67 days. The field microcosm study (Study II), conducted under fluctuating conditions of temperature, water pH and photoperiod, involved application of tebufenozide onto aquatic enclosures at four concentrations of 0·05, 0·10, 0·26 and 0·5 mg litre^-1. This study also showed that the chemical moved downwards from the applied location and was adsorbed onto sediment. The chemical persisted longer in Study II than in Study I. Tebufenozide, being photo-labile, probably degraded faster after constant exposure to light in Study I than after exposure to fluctuating light in Study II. At 90 days after treatment in Study I, only about 55% of the applied material persisted in the sediment, and there was little accumulation. In Study II, the material not only persisted but also was accumulated in the sediment, since at 92 days post-treatment the residues were about 25 times higher than the applied concentration level. Residues in water also decreased more rapidly in Study I than in Study II, because the concentration at 90 days post-treatment was about 41% of the applied value. In Study II, however, about 65% of the applied chemical persisted in water at 92 days post-treatment. While the long persistence of tebufenozide in both the laboratory and field studies was attributable to its low vapour pressure, low water solubility, high octanol/water partition coefficient etc., the differences in the persistence characteristics observed in the two studies were due to the fluctuating environmental conditions and water pH encountered in the field study, compared with the constant environmental conditions and water pH utilized in the laboratory study. © 1997 SCI.  相似文献   

Antifungal activity of 1,3-disubstituted symmetrical and unsymmetrical thioureas     

Krishnamurthy Ramadas  Govindaraghavan Suresh  Narayanasamy Janarthanan  Selladurai Masilamani 《Pest management science》1998,52(2):145-151

1,3-disubstituted aliphatic and aromatic symmetrical and unsymmetrical thioureas were synthesised by novel routes and the antifungal activities of these compounds against two plant pathogens, Pyricularia oryzae and Drechslera oryzae were studied in Czapek-Dox medium at four different concentrations using acetone as the control and the structure-activity relationship among the substituted thioureas is reported. © 1998 SCI.  相似文献