scholarly journals Control of Aphids on Lettuce, 1996

1997 ◽  
Vol 22 (1) ◽  
pp. 134-134
Author(s):  
Casey W. Hoy ◽  
Michael J. Dunlap

Abstract ‘Red Fire’ leaf lettuce was planted at the Muck Crops Branch, Celeryville, OH, on 6 Aug. The field was fertilized with 800 lbs of 17-17-17 per acre. The experimental plots were three rows 20 inches apart, 30 ft long, with plant spacing at 12 inches within rows. Each treatment was replicated four times in a randomized complete block design. Pretreatment aphid counts were made 11 Sep by randomly selecting plants from the outside rows of each plot in replicates one and two and counting the number of aphids per plant. Pretreatment aphid counts averaged 32.2 aphids per plant. Treatment applications were made 11 and 19 Sep using a backpack sprayer delivering 50 gal/acre at 50 psi with a flat fan nozzle. Aphid populations were evaluated 17 and 26 Sep by randomly selecting five lettuce plants from the middle row of each plot and counting the density of aphids on each plant.

2003 ◽  
Vol 21 (3) ◽  
pp. 443-447 ◽  
Author(s):  
Márcio S. de Lima ◽  
Antonio I. I. Cardoso ◽  
Marcelo F. Verdial

Squash seeds yield and quality can be improved by proper population plant spacing and the pollen quantity, which influences the pollination quality and fertilization. Nine experiments were conducted as a factorial combination of three spacing between plants (0.8 x 0.3, 0.8 x 0.6 and 0.8 x 0.9 m), two quantities of pollen (50% of an anther and another entire one) and natural insect pollination. Seed and fruit production parameters, and seed quality were evaluated. A randomized complete block design, five replications, with ten plants per plot was adopted. Larger plant spacing increased the average number of mature fruits and seed yield per plant. Seed yield was directly proportional to the amount of pollen used during pollination. Higher amounts of pollen resulted in higher seed yield per area, but the plant spacing did not affect this characteristic. Manual pollination, using a whole anther, did not differ from natural pollination in relation to seed yield and quality.


2016 ◽  
Vol 41 (4) ◽  
pp. 713-723
Author(s):  
S Akther ◽  
F Ahmed ◽  
MR Islam ◽  
MA Hossen ◽  
AHMM Rahman Talukder

Field experiments were carried out in the Agronomy field of BARI, Joydebpur, RARS, Jamalpur and RARS, Ishurdi during two consecutive kharif seasons of 2012 and 2013 to determine the suitable plant spacing and optimum fertilizer dose for higher yield of mukhikachu. Three levels of spacing viz., 60 cm x 60 cm, 60 cm x 45 cm and 60 cm x 30 cm and three levels of fertilizer dose viz., recommended dose (3000-96-27-81-18 kg ha-1 of CD-N-P-K-S), 25% less than the recommended dose and 25% higher than the recommended dose were used as treatment variables. The experiments were laid out in factorial randomized complete block design with three replications. Results revealed that the closer spacing (60 cm x 30 cm) in combination with 25% higher than the recommended fertilizer dose gave the maximum edible yield of mukhikachu (two years average) at all locations (20.04 t ha-1, 20.75 t ha-1 and 16.63 t ha-1 at Joydebpur, Jamalpur and Ishurdi, respectively). The wider spacing (60 cm x 60 cm) coupled with 25% less than the recommended fertilizer dose produced the lowest yield (two years average). The maximum benefit- cost ratio (two years average) was obtained from the combination of the recommended fertilizer dose and 60 cm x 30 cm spacing, that were 2.93 at Joydebpur and 3.42 at Ishurdi, while at Jamalpur the maximum benefit-cost ratio (two years average) was found maximum from 60 cm x 30 cm spacing with 25% higher than the recommended fertilizer dose (3.12).Bangladesh J. Agril. Res. 41(4): 713-723, December 2016


2015 ◽  
Vol 52 (2) ◽  
pp. 105-114
Author(s):  
Anastasios Katsileros ◽  
Christos Koukouvinos

Abstract Variability among experimental plots may be a relevant problem in field genotype experiments, especially when a large number of entries are involved. Four field trials on 24 durum wheat genotypes were conducted in 2013/14 in order to evaluate the efficiency of Incomplete Block, Alpha and Augmented designs in comparison with the traditional Randomized Complete Block Design (RCBD). The results showed that the RCBD can be replaced by an Alpha design, which provides better control of variability among the experimental units when the number of treatments to be tested in an experiment exceeds twenty. The ranking of the genotypes across the four designs was not constant.


2016 ◽  
Vol 47 (6) ◽  
Author(s):  
Alubaidi & et al.

This experiment was conducted at the farm of field crop department, College of Agriculture, University of Baghdad during two summer seasons (2010 and 2011) in order to know the response of cotton var. Lashata to nitrogen levels and spacing between holes. A randomized complete block design under arrangement of split plot with four replications was used. The plant spacing; 10, 20 and 30 cm between holes and 75 cm between rows considered as main plots, while three nitrogen levels (150, 200 and 250 Kg N.ha-1) are considered as sub plots. The results showed that using 10 cm between hills were significantly superior in boll weight (3.69 and 4.26) gm.boll-1, seed cotton yield (3.03 and 3.6) t.ha-1 and lint yield (1.13 and 1.30) t.ha-1 in both seasons 2010 and 2011 respectively. While, 30 cm spacing significantly superior in number of open bolls (12.10 and 13.6) bolls.plant-1 and ginning percentage (39.05 and 37.44)% in both seasons respectively. The nitrogen fertilizer 250 kg N ha-1 was significantly superior in dehiscence bolls number, seed cotton yield, lint yield and ginning percentage in both seasons 2010 and 2011 respectively. It can be concluded that 'using 10 cm spacing between holes with 250 kg N ha-1 to achieve highest seed cotton yield.  


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Bee Khim Chim ◽  
Peter Omara ◽  
Natasha Macnack ◽  
Jeremiah Mullock ◽  
Sulochana Dhital ◽  
...  

Maize planting is normally accomplished by hand in the developing world where two or more seeds are placed per hill with a heterogeneous plant spacing and density. To understand the interaction between seed distribution and distance between hills, experiments were established in 2012 and 2013 at Lake Carl Blackwell (LCB) and Efaw Agronomy Research Stations, near Stillwater, OK. A randomized complete block design was used with three replications and 9 treatments and a factorial treatment structure of 1, 2, and 3 seeds per hill using interrow spacing of 0.16, 0.32, and 0.48 m. Data for normalized difference vegetation index (NDVI), intercepted photosynthetically active radiation (IPAR), grain yield, and grain N uptake were collected. Results showed that, on average, NDVI and IPAR increased with number of seeds per hill and decreased with increasing plant spacing. In three of four site-years, planting 1 or 2 seeds per hill, 0.16 m apart, increased grain yield and N uptake. Over sites, planting 1 seed, every 0.16 m, increased yields by an average of 1.15 Mg ha−1(range: 0.33 to 2.46 Mg ha−1) when compared to the farmer practice of placing 2 to 3 seeds per hill, every 0.48 m.


Author(s):  
Bhuneshwar Verma ◽  
L. K. Ramteke ◽  
M. Shahid

The experiment was conducted to find out the effect of plant spacing on the performance of rice variety IR-64 and IR64-Sub1 under conventional and Submerged condition at the National Rice Research Institute (NRRI), Cuttack, Odisha during the Rabi season of 2018. Different planting densities were maintained using different spacing's. These include (S1) 15 cm × 10 cm, (S2) 15 cm × 20 cm. The experiment was laid out in a randomized complete block design with 3 replications spacing of 15 cm × 10 cm with produced the highest grain yield of 350 gm-2 in submerged condition on IR64-Sub1 rice cultivar, which was significantly higher than the yield with recommended density (15 cm × 10 cm with IR64 Sub1). This yield was increased due to higher number of panicles m-2. This result suggests that higher planting density (15 cm×10 cm) rather than increased number of seedling hill-1 is necessary for getting higher yield of IR-64Sub1 rice cultivar in continuous submerged condition (where V1=IR 64, V2=IR-64 Sub1, S1=15 cm×10 cm, S2=20 cm×15 cm).


Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 999-1004 ◽  
Author(s):  
L. E. del Rio ◽  
C. A. Martinson ◽  
X. B. Yang

Field studies were conducted to evaluate the effectiveness of Sporidesmium sclerotivorum to control Sclerotinia stem rot of soybean (SSR) at Ames, Humboldt, and Kanawha, IA, between 1996 and 1998. Experimental plots (3 × 3 m) were infested with S. sclerotivorum macroconidia once at a rate of 0, 2, or 20 spores per cm2 in the fall of 1995 or the spring of 1996, under two crop rotation schemes. A randomized complete block design with four replications in each location was used. Plots infested with 20 spores per cm2 had 62% less SSR (P = 0.05) than control plots at Humboldt in 1996. No differences were detected between fall and spring applications. In 1998, plots treated with either 2 or 20 spores per cm2 had 51 to 63% less SSR (P = 0.05) than control plots at Ames and Kanawha. In 1998, SSR was completely suppressed in all plots at Humboldt, while the commercial field surrounding the experimental plots had 17% SSR. S. sclerotivorum was retrieved from all infested plots at all locations 2 years after infestation with sclerotia of Sclerotinia sclerotiorum as bait. At Humboldt, S. sclerotivorum was also retrieved from control plots. Two larger plots (10 × 10 m) were infested with 20 or 100 spores per cm2 in the fall of 1996 or spring of 1997 in six commercial fields. SSR incidence, which was measured in transects up to 20 m from the infested area at 5-m intervals, was reduced 56 to 100% (P = 0.05) in four fields compared with the surrounding uninfested areas in the commercial fields. Dispersal of the control agent was evident by the fact that SSR incidence gradually increased from the edge of the infested macroplots up to about 10 m into noninoculated areas of the commercial field. This paper constitutes the first report describing the biocontrol of a disease on field crops that may be employed economically.


2020 ◽  
Vol 3 (2) ◽  
pp. 71
Author(s):  
Fatiani Manik ◽  
Rasiska Tarigan ◽  
Susilawati Barus

The quality of seed needs to be considered in carrot seed production to maintain its productivity. The research aims to find out the response of stecklings age and plant spacing on carrot seed quality and production. This research was held on July 2018 – April 2019 in Berastagi field trial (1340 m MSL). The experiment used Randomized Complete Block Design (RCBD) with two factors, i.e., stecklings age (2 and 3 months) and plant spacing (25, 50, 75, and 100 cm), replicated four times (32 experiment units), 10 plants from each experiment units were taken as samples. The result showed that stecklings age and plant spacing were affected to plant vegetative and generative stages. The combination of 2-month stecklings and 50 cm plant spacing increased the number of secondary umble, if compared to cultivation, which was generally used by the farmer (3-month stecklings and 25 cm plant spacing). The best quality of carrot seed was obtained from the combination of 3-month stecklings and 50 cm plant spacing.


AGRICA ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 1-9
Author(s):  
I Wayan Sunarta

Diversification of plant species is needed to anticipate price fluctuation of vegetables. Intercropping system compared to monoculture can give more benefits to farmers. The arrangement of plant spacings of sweet corn and cabbage variety is expected to result in higher yields and benefits in intercropping. The field experiment, which had the objective to study the effects of plant spacing of sweet corn and cabbage variety on yields of sweet corn and cabbage in the intercropping system, had been conducted from March to July 2008. The experiment was carried out at the dryland farming area at Candikuning Village, district of Baturiti, Tabanan regency, 1.200 m asl. In the experiment, a randomized complete block design with two factors namely plant spacing of sweet corn (120 cm x40 cm, 180 cm x 40 cm and 240 cm x 40 cm) and variety of cabbage (Green Nova and Summer-Autumn) were used. Plant spacing of cabbage was 60 cm x 40 cm. All treatments were replicated four times. The results of the experiment showed that the effect of interaction between plant spacing of sweet corn and cabbage variety in intercropping was not significant on yields of sweet corn and cabbage. Individually, sweet corn plant spacing of 120 cm x40 cm gave the highest fresh weight of cob without husk (10,91 t ha"'), which was 44.50% and 80.93% respectively higher than the spacing of ! 80 cm x 40 cm and 240 cm x 40 cm. The spacing of 180 cm x 40 cm resulted in not the significantly different fresh weight of cob with husk but gave the highest fresh weight of cabbage heads (56.101 ha'1), which was 27.36% higher than that at sweet corn spacing of 120 cm x 40 cm and was not significantly different from that at 240 cm x 40 cm. Cabbage variety Green Nova gave the highest head (56.101 ha1), which was 14.48% higher than variety Summer-Autumn. Intercropping between cabbage variety Green Nova and Sweet corn at 180 cm x 40 cm spacing resulted in the highest benefit (Rp. 20,488125 t ha'1), which was Rp. 3,335500 higher than the average benefit of cabbage monoculture. The efficiency of land use in intercropping was higher (LER: 1.69) than in monoculture (LER: 1). It is suggested to use cabbage variety Green Nova intercropped with sweet corn at I 80 cm x 40 cm spacing. An experiment studying the effect of cabbage intercropped with sweet corn and other short season vegetables planted after harvesting cabbages is also suggested.


2015 ◽  
Vol 26 (2) ◽  
pp. 129-135
Author(s):  
MS Sahariar ◽  
MR Karim ◽  
MA Nahar ◽  
M Rahman ◽  
MU Islam

A field experiment was conducted at the Horticulture Farm of the Department of Horticulture, Bangladesh Agricultural University, Mymensingh to investigatethe effect of mulching and plant spacing on the growth and yield of French bean during the period from November 2014 to January 2015. The experiment consisted of three types of mulchingnamely (i) control (without mulch), (ii) water hyacinth and (iii) black ploythene much and three levels of spacing viz., (i) 30 cm x 25 cm (ii) 30 cm x 20 cm and (iii) 30 cm x 15 cm. The experiment was laid out in randomized complete block design with three replications. Results showed that both mulching and plant spacing significantly influenced the growth and yield components of French bean. Black polythene mulch produced the highest yield (5.82 t/ha) and the lowest yield (4.92 t/ha) was recorded fromno mulch treatment. The maximum yield (6.22 t/ha) was obtained from 30 cm x 15 cm plant spacing and the lowest (4.58 t/ha) was obtained with 30 cm x 25 cm plant spacing. The combined effects of mulching and plant spacing were statistically significant. The combination of black polythene mulch with 30 cm x 15 cm spacing gave the highest yield (6.97 t/ha) and the lowest yield (3.94 t/ha) was received from without mulching at spacing of 30 cm x 25 cm treatment combination. Considering the above findings the black polythene mulch with 30 x 15 cm plant spacing  may be recommendfor French bean cultivation.Progressive Agriculture 26 (2): 129-135, 2015


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