Plant Pathology Commons^™

Effect Of Cutting Height On Tiller Population Density And Herbage Biomass Of Buffel Grass, L. S. Beltrán, P. J. Pérez, G. A. Hernández, M. E. García, S. J. Kohashi, H. J. G. Herrera

IGC Proceedings (1977-2023)

The aim of this trial was to investigate the effect of different cutting heights on tiller population density and herbage biomass of Buffel grass (Cenchrus ciliaris L) grown in miniature swards in a greenhouse. Four treatments with five replicates: five cm, ten cm, and 20 cm cutting height, and control (without cut) were randomly allocated. Intensity of defoliation affected the cumulative herbage harvested; the ten cm cutting height was greater (404.1 g DM m^-2) than 5 cm (317.6 g DM m^-2) and 20 cm (263.9 g DM m^-2), respectively. Cumulative herbage harvested in …

Leaf Appearance Rate In Brachiaria Decumbens Grown In Nitrogen And Potassium Rates, M. D. C. Ferragine, F. A. Monteiro, S. C. Da Silva

IGC Proceedings (1977-2023)

A greenhouse experiment was carried out with Brachiaria decumbens Stapf. cv. Basilisk grown in nutrient solution. Five nitrogen rates (42; 140; 238; 336 and 434 mg/L) and three potassium rates (78; 234 and 390 mg/L) were studied in a factorial experiment, in a randomized complete block design, with four replications. Green leaf number was evaluated in six times in the first period of growth (27, 30, 33, 36, 39 and 42 days after transplanting) and nine times in the second period (45, 48, 51, 54, 57, 60, 63, 66 and 69 days after transplanting). Data was registered in three plants …

Morphogenesis And Defoliation Frequency Of Italian Ryegrass (Lolium Multiflorum) And Paspalum Urvillei In Lowland Under Three Levels Of P And K, Fernando L. F. De Quadros, A. G. S. Pigatto, D. G. Bandinelli, E. Marchezan, Marta G. Da Rocha

IGC Proceedings (1977-2023)

This trial was conducted to evaluate growth dynamics and defoliation frequency of Italian ryegrass (Lolium multiflorum) and Paspalum urvillei in a lowland area under three levels of P and K. Using randomization tests we observed that, in a general way, fertilizer treatments were not the determinant factors of leaf appearance and elongation rates for both species. Only the leaf appearance rate of Paspalum urvillei at 100 % of recommendation level and the elongation rate for Italian ryegrass, in the same treatment, was different. Probably other factors, like drainage, are contributing to these results. I. ryegrass phyllochron ranged from …

Variability In Herbage Mass And Chemical Composition Within A Timothy Sward, O. Niemeläinen, E. Miettinen, P. Virkajärvi, L. Alakukku, K. Hakala

IGC Proceedings (1977-2023)

Variability in herbage mass (HM) and chemical composition of timothy (Phleum pratense L.) sward was studied in a three-hectare field. The field, which was flat, was divided into twelve sections and a sampling site was randomly selected in each. The study was carried out in Sotkamo (64^o 01’N, 28^o22’E) research station in Finland. Snow depth and frost conditions were measured in winter and soil water content was monitored in the growing season at each sampling site. Observations on the crop included assessment of herbage ground cover and winter damage percentage, stand height and HM and analysis …

Effects Of Temperature, Nitrogen Fertilisation And Leaf And Tiller Age On Specific Leaf Area Of Brachiaria Decumbens, J. Busqué, M. Herrero

IGC Proceedings (1977-2023)

Signal grass (Brachiaria decumbens Stapf) micro-swards were grown under controlled environmental conditions at different temperatures and nitrogen fertilisation rates. Specific leaf area was responsive both to temperature and nitrogen, but did not change with the level of insertion of the leaf in the tiller. Senescing leaves had higher specific leaf area than old extended green leaves and these had higher values than new extended green leaves. Changes in specific leaf area were more related to changes in leaf area and more exactly to changes in leaf width.

The Use Of Cover Crops After A Maize Crop In The North Of Spain, D. Báez, M. Pinto, M. Rodríguez, G. Besga, J. M. Estavillo

IGC Proceedings (1977-2023)

This work intends to study N leaching losses in a field assay when crimson clover (Trifolium incarnatum) and italian ryegrass (Lolium multiflorum) was incorporated into the soil and quantify the their effect on N₂O, N total gaseous losses under controlled soil moisture and temperature conditions. Field assay: A split-plot design where main plot was the cover crop and the subplot was the rate of fertilizer (0 and 150 kg N ha^-1) applied to the subsequent maize crop. Laboratory assay: Residues of italian ryegrass and crimson clover were mixed with soil in containers, …

Multi-Year Application Of Dairy Slurry On Grassland: Effects On Crop, Soil Biota, Soil Nutrients, And N2O Emission, Shabtai Bittman, C. G. Kowalenko, D. E. Hunt, N. Patni, J. Paul, D. Raworth, J. Hountin, T. A. Forge, C. M. Monreal, O. Schmidt

IGC Proceedings (1977-2023)

The long-term effects of using manure as the principal nutrient source in intensive crop production systems are not well known. This paper reports on the effects of multi-year application of fertilizer or dairy slurry on a tall fescue (Festuca arundinacea Schreb.) sward. Slurry sustained greater grass yield than chemical fertilizer. Unlike fertilizer, slurry supplied 70 to 120 kg N/ha one year after application but little after one year; 4-years of manure applications built up the stable organic matter pool in the soil. Manure-N was less prone to leaching but more prone to N₂O emissions than fertilizer-N. Manured …

Sewage Sludge As An Alternative Fertilizer For Tropical Pasture Grasses, M. B. Adjei, J. E. Rechcigl

IGC Proceedings (1977-2023)

This study was conducted to determine the effects of source (Liquid sludge at pH 7 (LS7) or pH 11 (LS11), cake biosolid (CB) or ammonium nitrate (AM)) by rate (0, 80 or 160 kg ha^-1) of N application on bahiagrass forage yield, quality and tissue composition. Same plots were fertilized in March 1998 and 1999. Forage yield was measured at 30 d intervals from May through November and subsamples were dried and ground for quality analyses. The 2-year mean forage yield was similar for AM, LS7 and LS 11 fertilizer applications. Forage yield from CB application was 30% …

Phosphorus Fertilizer And Stocking Rate Effects On Soil Microbial Biomass Of A Long-Term Dairy Farmlet Experiment, S. R. Aarons, C. R. O’Connor, C. J. P. Gourley

IGC Proceedings (1977-2023)

The effects of a range of P fertilizer rates and dairy cow stocking rates on microbial biomass carbon and phosphorus were compared in a long-term farmlet trial in southeastern Australia. Pastures were stocked at 2, 3, or 4 cows/ha and received fertilizer at rates of 0, 35, 70 or 140 kgP/ha. There was no effect of either P fertilizer rate or stocking rate on microbial biomass C from 1995 to 1998. Increasing P application rate significantly increased the chloroform-released microbial P flush measured, but stocking rate had no effect on microbial P. There were significant temporal changes, with the seasonal …

Dry Matter Accumulation And Partitioning Between Vegetative And Reproductive Organs In Alfalfa (Medicago Sativa L.), E. D. Bolaños-Aguilar, Christian Huyghe, B. Julier, C. Ecalle

IGC Proceedings (1977-2023)

This work investigated the partitioning of dry matter between vegetative and reproductive plant organs in alfalfa during the reproductive period under field conditions. Two French varieties (Europe and Magali) were studied. Both varieties showed similar growth pattern of the different plant organs in 1998 and 1999. The mean dry matter of vegetative organs (shoots and leaves) over the two years was higher in Europe (567g/m²) than Magali (470g/m²). No vegetative growth was observed during the reproductive period. The root organs (measured to a depth of 0.20 m) and the reproductive organs showed an increase in dry …

Herbage Seed Production Possibilities In Finland, O. Niemeläinen, M. Kinnari

IGC Proceedings (1977-2023)

In the seed production variety experiments in Finland from 1977 to 1992 the mean seed yield of timothy (Phleum pratense) cultivar Alma was 717 kg ha^-1, of meadow fescue (Festuca pratensis) cv. Boris 622 kg ha^-1, of tall fescue (Festuca arundinacea) cv. Retu 350 kg ha^-1, of perennial ryegrass (Lolium perenne) cv. Riikka, of cocksfoot (Dactylis glomerata) cv. Haka 295 kg ha^-1, and red clover (Trifolium pratense) cv. Hankkijan Venla 403 kg ha^-1. From 1988 to 1998 annual …

Identity And Population Density Of Thrips Hawaiiensis (Insecta: Thysanoptera) In Conventional “Magallanes” Pummelo Orchard In Carmen, Davao Del Norte, Philippines, Roderick Granada, Flor Ceballo, Pio Javier

The Philippine Agricultural Scientist

A conventional “Magallanes” Pummelo orchard in Brgy. Minda, Carmen, Davao del Norte, Philippines was selected to assess thrips species composition, population density, and associated natural enemies. The insecticide treated pummelo orchard was situated adjacent to vast Cavendish banana plantations. Thrips were collected weekly from September 2017 to July 2018 from five different randomly selected flowering pummelo trees by destructive sampling and yellow sticky trap methods. Thrips were sorted and examined under the microscope. Findings of the study showed that Thrips hawaiiensis (Morgan), (Thripidae: Thripinae) was the only species of thrips infesting “Magallanes” pummelo. This constitutes the first report in this …

Efficacy Study Of Selected Maize (Zea Mays L.) Genotypes Against The Asian Corn Borer, Ostrinia Furnacalis (Guenée), Yoryncita Marfori, Merdelyn Caasi-Lit, Tonette Laude

The Philippine Agricultural Scientist

Laboratory and screen house studies were conducted to assess the efficacy of selected twenty-six maize varieties against Asian corn borer (ACB), Ostrinia furnacalis (Guenée). Hierarchical tree based on resistance parameters clearly revealed that the twenty-six maize varieties are best classified into three groups, viz. resistant, intermediate, and susceptible. In laboratory test, the varieties RCS2, RCS4, RCS5, 'IPB Var13', Bt2, Bt3, and Bt4 were consistently identified as highly resistant. Further examinations in stalk feeding assay showed that the resistant varieties had sharp decline in larval survival (LS) on the 2^nd to the 5^th day of larval feeding in …

Paenibacillus Polymyxa Causes Yellow Withered Spot Disease In Dracaena Trifasciata In The South Of China, Baochun Lai, Yongwen Lin, Komivi Senyo Akutse, Ruiqing Dai

All Peer-Reviewed Publications

Mother-in-law’s tongue, Dracaena (Sansevieria) trifasciata S. is an ornamental houseplant of Asparagaceae family and native to tropical western Africa and southern Asia. Following a yellow withered spot symptom observed on up to one third of D. trifasciata plants at the field, a new bacterium pathogen was discovered for the first time in South of China. This pathogen was isolated from the early irregular yellow spot and its pathogenicity to the host plant was confirmed through artificial infection. Through both morphological characteristics and molecular DNA sequences using 16S rDNA and three housekeeping genes, the pathogen was identified and characterized as Paenibacillus …

Effect Of Fungicide Application On Seed Yield Of Perennial Ryegrass, Piotr Goliński

IGC Proceedings (1977-2023)

In four plot experiments established according to random blocks, application effectiveness of propiconazol + carbendazim (Tilt), propiconazol + fenpropimorph (Archer), flusilazol + carbendazim (Alert) and epoxiconazol + crezoxim-metil (Juwel) pesticides regarding the infection by fungal diseases of plant inflorescence structure, biological floret site utilisation, thousand seed weight and harvested seed yield of perennial ryegrass cv. Anna (2n) and cv. Maja (4n) was analysed. The Archer preparation was found to be the most effective, both in the case of Anna and Maja cultivars. Its application was found to increase seed yield in Anna and Maja cultivars by, respectively, 21,5% and 14,5%. …

Genetic Control Of Parthenogenesis In Kentucky Bluegrass: Results From A Sexual X Apomictic Cross, E. Albertini, G. Barcaccia, A. Porceddu, D. Rosellini, Mario Falcinelli

IGC Proceedings (1977-2023)

Apomixis, as it exists in Poa pratensis L., permits to combine genotype fixation with propagation by seed. The process of apomictic seed production involves the formation of embryo sacs without meiotic reduction (apospory) and embryos without egg cell fertilization (parthenogenesis). Further information on the genetic control of apomixis was obtained by analyzing aposporous parthenogenesis and the segregation of molecular markers in a progeny resulting from a “sexual” (S) x “apomictic”(A) cross. Data from the 35 F₁ plants examined so far have shown that parthenogenesis segregated 1:1, confirming control by a dominant gene, simplex in the parthenogenetic parent. Analysis of …

Effects Of Water Stress On Seed Production In Ruzi Grass (Brachiaria Ruziziensis Germain And Everard), N. Wongsuwan, A. C. P. Chu, B. R. Watkin

IGC Proceedings (1977-2023)

Water stress at different stages of reproductive development influenced seed yield in Ruzi grass differently. Under mild water stress, the earlier in the reproductive developmental stage the stress was applied (before ear emergence) the faster the plants recovered and the less the ultimate damage to inflorescence structure and seed set compared with the situation where water stress occurred during the later stages after inflorescences had emerged. Conversely, severe water stress before ear emergence had a severe effect in damaging both inflorescence numbers and seed quality. Permanent damage to the reproductive structures resulted in deformed inflorescences. Moreover, basal vegetative tillers were …

Effect Of Temperature On Phenology In Triple-Awned Grass (Stipagrostis Plumosa), Hossein Azarnivand, H. Dastmalchi

IGC Proceedings (1977-2023)

Phenology of triple-awned grass in different stages of vegetative growth, flowering and seed falling was investigated. Each phenological stage was related to minimum and maximum air and soil surface temperatures. Soil surface temperature was measured two times per day during different seasons. Climate data were obtained from the nearest weather station. The study was carried out in sand dunes of band-e-rig of Kashan in the central region of Iran. This species is important in terms of wind erosion control and livestock feeding in arid areas. The results showed that air temperatures ranged from –22 ^oC to 41.5 ^oC …

Morphogenesis And Growth Analysis Of Mombaçagrass (Panicum Maximum) During Establishment And Regrowth, Carlos A. M. Gomide, J. A. Gomide, C. A. M. Huaman

IGC Proceedings (1977-2023)

Mombaçagrass grown in pots was evaluated regarding leaf appearance, elongation and senescence rates; leaf area indices, photosynthetcly active radiation (PAR) interception and the growth indices: leaf area ratio (LAR), net assimilation rate (NAR) and relative growth rate (RGR). Three growths were considered: seminal growth and regrowth after harvest take on the 16^th and 37^th day of the seminal growth.

The seminal growth exhibited the highest values for leaf appearance, elongation and senescence rates as compared to aftermath growths. LAI rose linearly from the 20^th to the 77^th day of the seminal growth, as well as during …

Tillering Dynamics In Mombaça Grass (Panicum Maximum, Jacq.) Under Grazing, E. M. Coelho, V. R. Herling, M. A. Gomes, R. J. Schmidt, C. G. Lima

IGC Proceedings (1977-2023)

An experiment was conducted in Pirassununga, Southeastern Brazil, to observe tillering pattern of Mombaça grass (Panicum maximum Jacq.) after grazing. A complete randomized block design was used with treatments arranged in factorial (3 herbage allowances X 2 grazing periods). There was high and positive correlations between the total tiller population and the number of tillers until the third week after grazing, giving evidence of a higher tillering until the second week and a slight reduction on the third one. The Mombaça grass tillering dynamics alters along the weeks according the allowance level adopted.