Application of alternative fumigants through drip irrigation systems     

Ajwa HA  Trout T  Mueller J  Wilhelm S  Nelson SD  Soppe R  Shatley D 《Phytopathology》2002,92(12):1349-1355

ABSTRACT Strawberry fields in California (9,500 ha annually) are pre-plant fumigated with methyl bromide and chloropicrin to prevent serious soil pest and disease problems. Although soil fumigation with methyl bromide has ensured stability of strawberry production, its use is being discontinued because of its effect on stratospheric ozone. The likely short-term alternatives such as 1,3-dichloropropene, chloropicrin, and metham sodium, although not ozone depleters, are potentially hazardous to the environment and humans if applied improperly. Water-soluble formulations of alternative fumigants can be applied through drip irrigation systems established to irrigate crops. In comparison to conventional shank methods of injection, application of soluble formulations through drip irrigation systems would be economical and environmentally friendly, reduce worker exposure, and allow for simultaneous or sequential application of a combination of fumigants. This paper discusses techniques developed to apply alternative fumigants through drip irrigation systems, and reviews ongoing studies to determine optimum application rates, soil conditions, plastic mulches, and amount of irrigation water used to apply these alternative fumigants.  相似文献   

Die Gliederung der forstwirtschaftlichen Produktionslehre     

Heinrich Wilhelm Weber 《Forstwissenschaftliches Centralblatt》1922,44(6):214-224

Ohne Zusammenfassung  相似文献   

Die Gliederung unserer Wissenschaft in eine Produktionslehre und eine Betriebslehre,ihre Geschichte und ihre Kritische Würdigung     

Dr. Henrich Wilhelm Weber 《European Journal of Forest Research》1921,43(11):421-435

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Kiefernstarkholzzucht     

Wilhelm Kuhn 《Forstwissenschaftliches Centralblatt》1918,40(8-9):307-321

Ohne Zusammenfassung  相似文献   

Zerkleinerung von Baumstoöcken durch die „Stubbenfräse” an Ort und Stelle     

Dr. Wilhelm Berwig 《Journal of pest science》1964,37(2):25-26

Ohne Zusammenfassung  相似文献   

Changes in water status and proline and abscisic acid concentrations in developing somatic embryos of pedunculate oak (Quercus robur) during maturation and germination     

Prewein C  Vagner M  Wilhelm E 《Tree physiology》2004,24(11):1251-1257

Somatic embryos of oak (Quercus robur L.) were matured on P24 media differing in gel strength (0.8, 0.9 and 1.0% (w/v) agar). Viscosity and osmotic potential (Psipi,medium) of the media were determined. Developing cotyledonary embryos were analyzed at maturity Stages I-III for water content, osmotic potential (Psipi,embryo) and concentrations of abscisic acid (ABA) and proline. Proliferation of embryogenic tissue, germination rates and the number of embryos formed were also determined in order to relate embryo quality to physiological parameters. Viscosity increased with agar concentration, a phenomenon apparently related to water availability. Many Stage III embryos with high germination potentials were obtained on P24 medium containing 1.0% agar. Embryo water content decreased progressively from 94 to 80% during embryo maturation. Stage I and II embryos that matured on media containing 0.8 or 0.9% agar had similar values of Psipi,embryo, whereas Psipi,embryo of Stage III embryos that matured on medium containing 1.0% agar was significantly lower, although Psipi,medium was unaffected by gel strength. Stage III embryos showed a nearly 16-fold increase in proline concentration and a 50% decrease in ABA concentration compared with Stage I embryos. We conclude that tissue water status and a complex relationship between ABA and proline concentrations, modulated by medium gel strength, are important factors in the maturation process and the quality of oak somatic embryos.  相似文献   

Ultrastructural aspects of beech bark degradation by fungi     

N. Parameswaran  G. E. Wilhelm  W. Liese 《Forest Pathology》1976,6(5):274-286

The degradation of beech bark by three wood-decaying fungi has been analyzed at the ultra-structural level and the micromorphological changes occurring in the walls of the diverse cell types compared with the decay pattern in wood cells.  相似文献   

Nonthymoma‐associated exfoliative dermatitis in 18 cats          下载免费PDF全文

Monika Linek  Silvia Rüfenacht  Chiara Brachelente  Claudia von Tscharner  Claude Favrot  Sylvia Wilhelm  Claudia Nett  Ralf S. Mueller  Ursula Mayer  Monika Welle 《Veterinary dermatology》2015,26(1):40-e13

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Induction of resistance against downy mildew pathogen in pearl millet by a synthetic jasmonate analogon     

Shantharaj Deepak  Sathyanarayana Niranjan-Raj  Shekar Shailasree  Ramachandra K. Kini  Wilhelm Boland  Hunthrike S. Shetty  Axel Mithfer 《Physiological and Molecular Plant Pathology》2007,71(1-3):96-105

The synthetic 1-oxo-indanoyl-l-isoleucine methyl ester (Ind-Ile-Me) represents a highly active mimic of octadecanoic phytohormones, which are involved in plant defenses against pathogens and pests. Seed treatments and foliar spray with Ind-Ile-Me were tested for induced resistance against downy mildew disease caused by the phytopathogenic oomycete Sclerospora graminicola in pearl millet (Pennisetum glaucum) under greenhouse and field conditions. Under greenhouse conditions, a 50% protection level was achieved after seed treatment. Seed treatment in combination with foliar spray resulted in 60% protection. The induction of resistance was correlated with the enhanced activities of defense-related proteins such as phenylalanine-ammonia-lyase, peroxidase, and enhanced level of hydroxyproline-rich glycoproteins. Under field conditions, a maximum protection of 62% was recorded upon seed treatment along with foliar spray. Hence, it infers that Ind-Ile-Me can be used as a valuable protection compound at least in downy mildew disease management.  相似文献   

Growth, survival and fillet composition of paddlefish, Polyodon spathula (Walbaum) fed commercial trout or catfish feeds     

Richard J Onders  Steven D Mims  Barbara A Wilhelm  & Jesse D Robinson 《Aquaculture Research》2005,36(16):1602-1610

Paddlefish are gaining increasing acceptance as an aquaculture species worldwide. Commercial trout feeds, containing high protein and lipid levels, are currently used in intensive culture; however, nutritional requirements of paddlefish are not currently known. A study was conducted examining the effects on growth, survival and fillet composition of juvenile paddlefish when fed commercial feeds differing in protein and lipid levels. Paddlefish larvae were first stocked in 14.0 m³ round tanks and fed trout starter feeds for 43 days until trained to accept a 1.6 mm pellet. Paddlefish juveniles of mean weight (±SE) 20±0.27 g were randomly stocked into six0.02 ha ponds at 12 500 ha^?1 and fed floating commercial trout or catfish (lower protein and lipid) feeds, twice daily (08:00 and 15:30 hours) for 92–97 days. At harvest, there were no significant differences in final weight, percent survival, specific growth rate , relative growth and feed conversion ratio between treatments, which averaged 223.6 g, 96.2%, 2.5% day^?1, 10.2 and 1.98 respectively. Surface feeding activity index was significantly higher in ponds supplied with catfish feed than in ponds supplied with trout feeds. Relative pellet buoyancy was not a factor in feeding activity. Fulton's condition factor averaged0.238, was not significantly different, and was similar to a reported value for extensively cultured paddlefish (zooplanktivore). There was no significant difference in liver somatic index between treatments, which averaged 1.91%. Percent protein and moisture of fillets averaged 14.9% and 80.9%, respectively, and were not significantly different between treatments. However, lipid content of fillets was significantly higher in paddlefish fed the trout feed (4.45%), compared with paddlefish fed the catfish feed (2.42%). Fillet lipid content for both treatments was higher than reported values for extensively cultured paddlefish. Percent abdominal fat was significantly higher (0.82%) in paddlefish fed the trout feed compared with paddlefish fed the catfish feed (0.52%). Results from this study indicate that paddlefish can be fed a commercial catfish feed labeled to contain 32% protein and 4.5% lipid without adverse effects on growth, survival and fillet composition, lowering production costs.  相似文献