Increased Mortality of the Swaine Jack-pine Sawfly, and Foliar Nitrogen Concentrations After Urea Fertilization

1973 ◽  
Vol 3 (1) ◽  
pp. 112-121 ◽  
Author(s):  
W. A. Smirnoff ◽  
B. Bernier

Mortality of the Swaine jack-pine sawfly larvae (Neodiprionswainei Midd.) introduced as colonies on jack-pine (Pinusbanksiana Lamb.) foliage was measured in untreated and urea-treated plots of natural forest. Following applications of urea (400 kg N/ha) repeated in two successive years, natural mortality increased from 40 to 70% after 4 weeks, from 33 to 51% after 6 weeks, and from 18 to 36% after 4 weeks for larvae introduced as 1st instar, 2nd instar, and 3rd instar, respectively. This was accompanied by a marked reduction in foliage consumption as revealed by direct measurements or by the weight of frass collected. With 3rd-instar larvae sprayed with a suspension of the virus Borrelinavirusswainei (Smirnoff), viral infection developed much more rapidly in larvae placed on fertilized trees, mortality reaching 100%, double that measured on unfertilized trees. Single applications of urea at lower rates (100 and 200 kg N/ha) revealed a trend of increasing mortality for both unsprayed and virus-sprayed larvae with increasing urea application rate and increasing nitrogen concentration in the needles. Changes in the nitrogenous composition of needle tissue are considered an important factor in the increased larval mortality.

2020 ◽  
Vol 41 (2) ◽  
pp. 115
Author(s):  
NFN Sukristiyonubowo ◽  
Sugeng Widodo ◽  
Kusumo Nugroho

<p align="center"> </p><p><strong>Abstract. </strong></p><p>Study on plot scale nitrogen balance of newly developed lowland rice was conducted in Kleseleon village, Malaka District, Nusa Tenggara Timur in 2014. The soil was classified as ustifluvent with ustic moisture regime. Five treatments were tested including T0: farmers practices, T1: NPKat recommendation rate + Rice straw compost, T2: NPKat recommendation rate + Smart + Rice straw compost, T3: ¾ NPKat recommendation rate + Smart + Rice straw compost and T4: NPKat recommendation rate + Smart + Rice straw compost, in which N, P  and K were split two times. Nitrogen balance was computed according to the differences between nitrogen gains and losses. To quantify total nitrogen input, nitrogen<strong> </strong>content in urea, dosage of urea, rate of compost, nitrogen concentration in compost, irrigation water supply, and nitrogen concentrations in rain water were collected. Output parameters included<strong> </strong>rice grains yield, rice straw production, nitrogen concentrations in rice grains and rice straw. The results indicated that surplus nitrogen balances were taken place in all treatments including the farmer practices. Concerning the environmental, agronomical and economic point of views, the recommendation of urea fertilizer rate at least was about 100 kg ha<sup>-1</sup> season<sup>-1</sup> like done in the farmer practices plus the compost rate about 3000 kg ha<sup>-1</sup> season<sup>-1</sup>. Urea should be available in the district level every planting season was the urea application rate multiplied by total low land area in Malaka district equal to 1.207 tons district <sup>-1</sup> season <sup>-1</sup>.</p><p><strong>Abstrak.</strong> Percobaan neraca hara nitrogen pada skala petak pada sawah bukaan baru dilaksanakan di Dusun Kleseleon, Kabupaten Malaka, Propinsi Nusa Tenggara Timur pada Tahun Anggaran 2014. Tanah yang digunakan termasuk golongan ustifluvent denga kelembaban tanah ustik. Lima teknologi yang menjanjikan diuji pada percobaan ini meliputi T0: Praktek Petani sebagai kontrol, T1: NPKpada dosis  rekomendasi + Kompos jerami, T2: NPKpada dosis  rekomendasi + Smart + Kompos jerami , T3: ¾ NPKpada dosis  rekomendasi rate + Smart + Kompost jerami dan T4: NPKpada dosis rekomendasi + Smart + Kompos jerami, dimana  N, P  dan K diberikan dua kali. Keseimbangan N dihitung berdasarkan berdasarkan selisih antara nitrogen yang masuk ke lahan sawah dengan nitrogen yang hilangdari lahan sawah . Untuk menghitung nitrogen yang masuk ke lahan sawah diperlukan kandungan N pada urea, dosis pupuk urea, kadar nitrogen dalam kompos,  takaran kompos, air irigasi dan kandungan nitrogen pada air irigasi dan air hujan. Sedangkan nitrogen yang hilang dari lahan sawah meliputi hasil gabah dan produksi jerami serta kadar nitrogen pada gabah dan jerami. Hasil penelitian menjukkan bahwa positif nitrogen balance pada semua perlakuan. Mengingat bahaya pencemaran lingkungan, keuntungan agronomik dan ekonomis yang didapat, pemberian Urea sebaiknya dikurangi dari  250 kg ha<sup>-1</sup>musim<sup>-1</sup> menjadi 100 kg Urea kg ha<sup>-1</sup>musim<sup>-1</sup> seperti pada praktek petani dengan memberi kompos jerami sebanyak 3000 kg ha<sup>-1</sup>musim<sup>-1</sup>. Dengan demikian urea yanbg harus tersedia di Kabupaten Malaka setiap musim tanam sebanyak dosis urea rekomendasi dikalikan dengan luas sawah di kabupaten Malaka sama dengan  1.207 ton kabupaten <sup>-1</sup> musim<sup>-1</sup>.</p>


1972 ◽  
Vol 104 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Walter Tostowaryk

AbstractExperiments were carried out to determine the functional response of Podisus modestus (Dallas) to densities of two colonial species of jack pine sawfly, Neodiprion swainei (Middleton) and N. pratti banksianae (Rohwer). Two types of functional response curve were exhibited by the pentatomids, a domed response curve and a negatively accelerated curve.The domed response was caused by the more effective defense reactions of the sawfly larvae at higher densities.An equation is proposed for the domed response curve. The implications of the domed functional response are discussed in relation to the social behavior of these sawflies.


1991 ◽  
Vol 21 (10) ◽  
pp. 1447-1458 ◽  
Author(s):  
Deborah G. McCullough ◽  
Herbert M. Kulman

Effects of nitrogen fertilization on growth, foliar nitrogen concentration, and monoterpenes were determined on 7- to 11-year-old jack pine (Pinusbanksiana Lamb.) on two sites in northwestern Wisconsin. One site established after wildfire; the other after clear-cutting. Jack pine budworm (Choristoneurapinuspinus Free.) larvae were caged on fertilized and unfertilized trees on each site. Relations among foliar nitrogen, monoterpenes, larval survival, and adult budworm weight were examined. Foliar nitrogen concentration, needle weight, shoot and diameter growth, and monoterpene production were lower on wildfire site trees than on clear-cut site trees, and were significantly increased on both sites by fertilization. Fertilization increased production of staminate cones on the wildfire site. Height growth differed between sites but was unaffected by fertilization. Contrary to expectations based on the resource availability theory, foliar nitrogen and monoterpene levels were positively related. Survival of jack pine budworm larvae was greater on clear-cut than on wildfire site trees, but was not significantly affected by fertilization. Larvae on low-nitrogen trees on the wildfire site clipped more foliage than those on the clear-cut site, suggesting compensatory feeding. Adult female weight was higher for larvae on wildfire than clear-cut site trees. Two monoterpene compounds and site-related differences were the best predictors of adult female weight based on regression.


1958 ◽  
Vol 36 (2) ◽  
pp. 175-183 ◽  
Author(s):  
A. W. Ghent

The heads of feeding larvae of the jack pine sawfly are consistently oriented towards the needle tips. This orientation is not obtained from the apically-directed needle teeth, and is found to be independent of gravity and of the flexibility of the foliage. Though light can act to disrupt the orientation, larvae adopt the orientation in darkness so that light cannot be postulated as an essential directive stimulus. The behavior is identified as a "free-end" response, and possible underlying mechanisms are discussed.


1994 ◽  
Vol 10 (3) ◽  
pp. 399-416 ◽  
Author(s):  
Barrios E. ◽  
Herrera R.

ABSTRACTSeasonally flooded forests represent a transition between terrestrial and aquatic ecosystems. The Mapire river, a tributary of the Orinoco river, floods its surrounding forests during the wet season (May–December). The soils are very acid and the total nitrogen concentration (0.1%) is only half that found in nearby soils flooded by Orinoco waters. Ammonium-nitrogen predominates in the soil during the flooded period while nitrate-nitrogen concentrations are higher in the dry period. Wide fluctuations in the inorganic nitrogen fractions did not considerably affect the annual course of soil nitrogen.The predominance of mineralization versus nitrification (56 and 5 μgsoil month−1respectively) and possibly the synchronization of nitrogen availability with plant demand could be considered as nitrogen conserving mechanisms.In synchrony with the hydrologic cycle, the seasonally flooded forest studied shows a nitrogencycle where inputs and accumulation are maximized when the system is under minimum stress (dry season). During flooding, the system enters a period of dormancy making minimal use of nutrient and energy to avoid or tolerate anaerobiosis.


2013 ◽  
Vol 80 (2) ◽  
pp. 704-713 ◽  
Author(s):  
Estéfani García-Ríos ◽  
Alicia Gutiérrez ◽  
Zoel Salvadó ◽  
Francisco Noé Arroyo-López ◽  
José Manuel Guillamon

ABSTRACTThe effect of the main environmental factors governing wine fermentation on the fitness of industrial yeast strains has barely received attention. In this study, we used the concept of fitness advantage to measure how increasing nitrogen concentrations (0 to 200 mg N/liter), ethanol (0 to 20%), and temperature (4 to 45°C) affects competition among four commercial wine yeast strains (PDM, ARM, RVA, and TTA). We used a mathematical approach to model the hypothetical time needed for the control strain (PDM) to out-compete the other three strains in a theoretical mixed population. The theoretical values obtained were subsequently verified by competitive mixed fermentations in both synthetic and natural musts, which showed a good fit between the theoretical and experimental data. Specifically, the data show that the increase in nitrogen concentration and temperature values improved the fitness advantage of the PDM strain, whereas the presence of ethanol significantly reduced its competitiveness. However, the RVA strain proved to be the most competitive yeast for the three enological parameters assayed. The study of the fitness of these industrial strains is of paramount interest for the wine industry, which uses them as starters of their fermentations. Here, we propose a very simple method to model the fitness advantage, which allows the prediction of the competitiveness of one strain with respect to different abiotic factors.


1992 ◽  
Vol 22 (8) ◽  
pp. 1089-1093 ◽  
Author(s):  
R. Trowbridge ◽  
F.B. Holl

An overdense lodgepole pine (Pinuscontorta Dougl. ex Loud.) stand was knocked down and the site was prepared by broadcast burn, windrow burn, or mechanical forest floor removal. Inoculated alsike clover (Trifoliumhybridum L.) was seeded at 0, 10, 20, and 30 kg/ha for the three different site preparation treatments to determine the effects of (i) site preparation on infection and effectiveness of the clover–Rhizobium symbiosis and clover percent cover and (ii) the clover–Rhizobium N2-fixing symbiosis on survival, early growth, and foliar nitrogen concentration of lodgepole pine seedlings. The N2-fixing symbiosis established well in all treatments. Clover percent cover increased with increasing rate of seeding, although by relatively few percent in the clover seeded plots. Broadcast burning, windrow burning, and mechanical forest floor removal did not affect the establishment of the N2-fixing symbiosis or clover percent cover. Lodgepole pine survival was not affected by the seeding treatments in any year, nor were height measurements during the first three growing seasons. Seedling height was slightly less in clover-seeded plots compared with controls in the fourth growing season. Lodgepole pine seedlings on clover-seeded plots had decreased diameter growth compared with controls during the first three growing seasons, but incremental diameter growth no longer showed this effect by the fourth growing season. Needle mass (g/100 needles) was less in clover-seeded plots at the end of the second growing season, but this effect was reversed by the fourth growing season, when both needle mass and foliar nitrogen concentration in lodgepole pine foliage were greater in clover-seeded plots.


Bragantia ◽  
2012 ◽  
Vol 71 (3) ◽  
pp. 394-399 ◽  
Author(s):  
Djeimi Isabel Janisch ◽  
Jerônimo Luiz Andriolo ◽  
Vinícius Toso ◽  
Kamila Gabriele Ferreira dos Santos ◽  
Jéssica Maronez de Souza

The objective of this research was to determine growth and dry matter partitioning among organs of strawberry stock plants under five Nitrogen concentrations in the nutrient solution and its effects on emission and growth of runner tips. The experiment was carried out under greenhouse conditions, from September 2010 to March 2011, in a soilless system with Oso Grande and Camino Real cultivars. Nitrogen concentrations of 5.12, 7.6, 10.12 (control), 12.62 and 15.12 mmol L-1 in the nutrient solution were studied in a 5x2 factorial randomised experimental design. All runner tips bearing at least one expanded leaf (patent requested) were collected weekly and counted during the growth period. The number of leaves, dry matter (DM) of leaves, crown and root, specific leaf area and leaf area index (LAI) was determined at the final harvest. Increasing N concentration in the nutrient solution from 5.12 to 15.12 mmol L-1 reduces growth of crown, roots and LAI of strawberry stock plants but did not affect emission and growth of runner tips. It was concluded that for the commercial production of plug plants the optimal nitrogen concentration in the nutrient solution should be 5.12 mmol L-1.


1953 ◽  
Vol 46 (4) ◽  
pp. 703-703 ◽  
Author(s):  
Daniel M. Benjamin ◽  
Norbert B. Underwood
Keyword(s):  

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