Foraging by a Predaceous Beetle, Coleomegilla maculata (Coleoptera: Coccinellidae), in a Polyculture: Effects of Plant Density and Diversity

1982 ◽  
Vol 11 (4) ◽  
pp. 949-950 ◽  
Author(s):  
Stephen J. Risch ◽  
Roger Wrubel ◽  
David Andow
1971 ◽  
Vol 103 (8) ◽  
pp. 1115-1120 ◽  
Author(s):  
B. C. Smith

AbstractThe adult densities of Hippodamia tredecimpunctata tibialis (Say), Coccinella novemnotata Hbst., and Coccinella transversoguttata richardsoni Brown, on corn fluctuated in July and August and reached their maxima at pollination, whereas the density of Coleomegilla maculata lengi Timberlake fluctuated much less. C. maculata, H. tredecimpunctata, and C. transversoguttata were more numerous on plants with a liver diet applied to their foliage than on untreated plants. H. tredecimpunctata, C. novemnotata, and C. transversoguttata were less numerous on plants that had their tassels removed and produced no pollen than on intact plants. C. maculata, H. tredecimpunctata, and C. transversoguttata were more numerous on plants exposed to the maximum amount of sunshine than on plants that were shaded for part of each day. H. tredecimpunctata was more numerous on plants situated at low elevation than at high elevation, whereas C. transversoguttata was more numerous at high than at low elevation. C. maculata and H. tredecimpunctata were more numerous on plants near the middle of a corn field than on plants at the perimeter of a field adjacent to buckwheat, whereas C. novemnotata and C. transversoguttata were most numerous on plants near the perimeter. Two-species associations of C. maculata and H. tredecimpunctata, C. novemnotata and H. tredecimpunctata, C. novemnotata and C. transversoguttata, and C. novemnotata and H. tredecimpunctata occurred on individual plants. Plant density and time of planting affected coccinellid density. Adult density was greatest at a plant density of 3.2 plants per square metre and adults were more numerous on early than on late planted corn.


Author(s):  
Kenneth T. Pecinovsky ◽  
Garren O. Benson ◽  
Dale E. Farnham
Keyword(s):  

Author(s):  
V. Polyakov ◽  

The article presents the results of research on the formation of corn yield for grain depending on the elements of cultivation technology in the Forest-Steppe of Ukraine. The goal of the research was to identify the influence of plant density and fertilizer system on the yield of corn hybrids for grain. The research was conducted during 2017-2019 in the research field of Bila Tserkva National Agrarian University (Bila Tserkva NAU). Research methods: field, calculation and statistical. Results. Regularities of growth, development and formation of yield by plants are revealed, both in concrete conditions of years of researches, and taking into account average long-term values taking into account features of hybrid-oriented technology. According to the results of the experiment it was recorded that the maximum yields for growing early-maturing maize hybrid DN PIVYHA with FAO 180 in general were obtained at a pre-harvest density of 75 thousand units/ha and the use of combined organo-mineral fertilizer system - 11.09 t/ha; medium-early maize hybrid DN ORLYK, FAO 280 in general in the experiment provided a grain yield of 9.60 t/ha, and in terms of 2017 - 7.86 t/ha, in 2018 - 11.22 t/ha and in 2019 - 9, 72 t/ha, but the medium-ripe hybrid of corn DN SARMAT, FAO 380 provided a grain yield of 10.81 t/ha, and in the context of 2017 - 9.31 t/ha, in 2018 - 11.68 t/ha and in 2019 - 11.44 t/ha. Significant influence on the formation of the yield of corn has a hybrid factor (27 %), fertilizer system determines the level of productivity by 21 % and interacts closely with the conditions of the growing season (factor BV 9 %), growing season conditions also determine the level of productivity of corn plants (19 %), and the pre-harvest density determines this feature by 18 %. Conclusions: In the conditions of the Right Bank part of the Forest-Steppe of Ukraine there is an increase in the level of productivity of maize hybrids from early to medium-ripe hybrids, regardless of the influence of other experimental factors.


2013 ◽  
Vol 38 (2) ◽  
pp. 322-332 ◽  
Author(s):  
Ru-Fang WANG ◽  
Ji-Wang ZHANG ◽  
Peng LÜ ◽  
Shu-Ting DONG ◽  
Peng LIU ◽  
...  
Keyword(s):  

2010 ◽  
Vol 18 (4) ◽  
pp. 792-798 ◽  
Author(s):  
He-Zhong DONG ◽  
Zhen-Huai LI ◽  
Zhen LUO ◽  
He-Quan LU ◽  
Wei TANG ◽  
...  

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 523c-523
Author(s):  
Siegfried Zerche

Refined nutrient delivery systems are important for environmentally friendly production of cut flowers in both soil and hydroponic culture. They have to be closely orientated at the actual nutrient demand. To solve current problems, express analysis and nutrient uptake models have been developed in horticulture. However, the necessity of relatively laborious analysis or estimation of model input parameters have prevented their commercial use up to now. For this reason, we studied relationships between easily determinable parameters of plant biomass structure as shoot height, plant density and dry matter production as well as amount of nitrogen removal of hydroponically grown year-round cut chrysanthemums. In four experiments (planting dates 5.11.91; 25.3.92; 4.1.93; 1.7.93) with cultivar `Puma white' and a fixed plant density of 64 m2, shoots were harvested every 14 days from planting until flowering, with dry matter, internal N concentration and shoot height being measured. For each planting date, N uptake (y) was closely (r2 = 0.94; 0.93; 0.84; 0.93, respectively) related to shoot height (x) at the time of cutting and could be characterized by the equation y = a * × b. In the soilless cultivation system, dry matter concentrations of N remained constant over the whole growing period, indicating non-limiting nitrogen supply. In agreement with constant internal N concentrations, N uptake was linearly related (r2 = 0.94 to 0.99) to dry matter accumulation. It is concluded that shoot height is a useful parameter to include in a simple model of N uptake. However, in consideration of fluctuating greenhouse climate conditions needs more sophisticated approaches including processes such as water uptake and photosynthetically active radiation.


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