scholarly journals Insecticidal Control of Brown Citrus Aphid on Sweet Orange, 1997

1998 ◽  
Vol 23 (1) ◽  
pp. 68-69
Author(s):  
P. A. Stansly ◽  
J. M. Conner ◽  
P. W. Carlin

Abstract The trial was conducted in a commercial block of four-year-old ‘Valencia’ orange rooted to Carrizo citrange planted on a 12 X 24 ft. spacing. A RCB block design was used with 4 replications in separate rows and 5 treatments distributed in single-row plots separated by at least one guard tree. At least 10 new shoots not yet fully expanded and heavily infested with BCA were tagged at the onset of the trial. Foliar treatments were sprayed by hand on 24 Jun using a trailer-mounted sprayer equipped with a 13” brass GunJet Spray Gun fitted with a hardened stainless steel #3 orifice disc-type nozzle. The sprayer was supplied by a gasoline-powered diaphragm pump operating at 200 psi and calibrated to deliver 101 gpa. Tagged colonies were evaluated one day prior to treatment and 2, 7, and 14 DAT using a rating scale of 0 to 6:0 = no aphids, 1 = 1-12 aphids, 2 = 12-50 aphids, 3 = 50-150 aphids, 4 = 150-500 aphids, 5 = 500-1,000 aphids, and 6 = > 1,000 aphids. Average colony size was estimated at 4.6 prior to treatments. In addition, aphids were counted on 5 new pieces of the youngest flush that could be found on each tree on 7, 14, 21 and 28 DAT.

1995 ◽  
Vol 20 (1) ◽  
pp. 80-80
Author(s):  
P. A. Stansly ◽  
J. M. Conner

Abstract Greenhouse-grown seedlings were transplanted in single rows on 30 Mar on 32 inch beds, 240 feet long on 6 foot centers covered whiteface polyethylene film. Six treatments and a control were assigned to 6 plots 19 ft long per bed in a randomized complete block design with 4 replications. Plots were separated by 3 ft of fall-planted collards to provide inocula of target pests. Spray treatments were applied for 8 consecutive weeks starting 13 Apr using a 12 tank sprayer equipped with a diaphragm pump powered by a gasoline engine mounted on a small trailer drawn by a 4-wheel drive Suzuki ATV. A single row boom consisting of 2 side drops with 2 nozzles each plus one nozzle over the row gave a total of 5 nozzles. Yellow Albuz® ceramic tipped nozzles were used at 80 PSI of pump pressure for a delivery rate of 35 gpa. Weekly evaluations were carried out on 8 randomly selected plants per plot by evaluating the inner 5 wrapper leaves and the head of each plant. Number and size of live DBM and CSCW larvae plus pupae were recorded. Damage was assessed using a Horsfall type rating scale from 1 (no apparent damage) to 6 (>30% leaf area eaten, head heavily damaged). At maturity the 8 best heads per plot were selected and graded for marketability based on insect damage to the head and the inner two wrapper leaves. Heads were considered marketable if they had less than 5% damage and the wrapper leaves had less than 10% damage.


2015 ◽  
Vol 17 (2) ◽  
pp. 67-76
Author(s):  
AM Mahmud ◽  
MY Ali ◽  
KG Quddus ◽  
S Parvin

A field experiment was conducted at the Agrotechnology Field Laboratory of Khulna University during the boro season to evaluate the effect of planting density on the performance of rice variety BRRI dhan28. The experiment received twelve treatments, which were divided into two distinct patterns - single row and paired row. The single row had four treatments and paired row had eight treatments. Planting densities were 40, 27, 20 and 16 hills m-2. The experiment was arranged in a randomized complete block design (RCBD) with three replications. Standard management practices were followed in raising crops. Results revealed that closer spacing produced higher yields where 40 hills m-2 produced the most (4.81 t ha-1), which was statistically similar with that of 27 hills   m-2. Paired row planting showed better performance than single row planting. Plant height, grains panicle-1, sterile spikelets panicle-1, 1000-grain weight, grain yield were found better in paired row planting. Paired row planting at a spacing of (35 cm + 15 cm) × 10 cm  i.e row to row distance is 35 cm & 15 cm and hill to hill distance is 10 cm; found the highest grain yield (4.81 t ha-1) and the lowest yield (2.97 t ha-1) was found in single row using a spacing of 25 cm × 25 cm.Bangladesh Agron. J. 2014, 17(2): 67-76


1983 ◽  
Vol 10 (3) ◽  
pp. 265 ◽  
Author(s):  
RR Walker ◽  
E Torokfalvy ◽  
AM Grieve ◽  
LD Prior

Grafted plants of Valencia orange scion [Citrus sinensis (L.) Osbeck] on six different rootstocks were grown under glasshouse conditions and supplied with dilute nutrient solution containing either 0 or 75 mM NaCl. Salt treatment was increased to 150 mM NaCl after 49 days. Leaf water relations and leaf chloride, sodium and potassium concentrations were followed throughout the period of salt treatment until day 105, when salt treatment ceased, and thereafter until day 140. Seedlings of Rangpur lime (C. reticulata var. austera hybrid?), Cleopatra mandarin (C. reticulata) and sweet orange (C.sinensis) were treated similarly and leaf water relations and chloride concentrations were followed until salt treatment ceased on day 77. All Valencia-rootstock combinations adjusted osmotically to the salt stress imposed and maintained turgor pressures at or above control values. Mature leaves on seedlings of sweet orange behaved similarly to Valencia orange leaves on sweet orange rootstocks by maintaining turgor pressures higher than control values. In contrast, mature leaves on seedlings of the genotypes Rangpur lime and Cleopatra mandarin tended to lose turgor during the period of treatment with 150 mM NaCl. Leaf chloride analyses indicated that Rangpur lime and Cleopatra mandarin rootstocks restricted the uptake and/or transport of chloride to shoots. However, comparatively high concentrations of sodium (>approx. 200 mM, tissue water basis) were accumulated in mature leaves on all rootstocks during salt treatment. Leaf potassium concentrations remained similar to control values. The reduction in osmotic potential in mature Valencia leaves on rough lemon (C. jambhiri), Trifoliata (Poncirus trifoliata), Camzo citrange (C. sinensis × P. trifoliata) and sweet orange rootstocks on day 77 could be accounted for largely by the increase in sodium and chloride, whereas chloride (as NaCl) accounted for only approximately 50% of the reduction in osmotic potential in Valencia leaves on Rangpur lime and Cleopatra mandarin rootstocks. Stomatal resistances in mature Valencia leaves on all rootstocks were increased by salt treatment and showed only partial recovery after the cessation of salt treatment. The incomplete recovery may have been associated with the retention in leaves of high concentrations of sodium.


Plant Disease ◽  
1998 ◽  
Vol 82 (2) ◽  
pp. 263-263 ◽  
Author(s):  
A. J. Masuka

Rhizoctonia solani Kühn (teleomorph Thanatephorus cucumeris (A. B. Frank) Donk) anastomosis groups AG 4 and AG 3 cause, respectively, widespread stem rot and leaf spot diseases of tobacco in Zimbabwe (2). Stem rot leads to substantial field losses, necessitating routine chemical and biological control (1). A recent increase in reports on Rhizoctonia-induced damping-off in tobacco seedlings and lodging of mature field plants prompted detailed studies on the causal pathogen. Nuclear fluorescence microscopy studies of 83 isolates from diseased tobacco revealed the presence of binucleate isolates. The isolates were collected in 1981 (1 isolate), 1990 (1 isolate), 1996 (3 isolates), and 1997 (1 isolate) and caused damping-off in seedlings (2 isolates) and stem rot and lodging in field tobacco (4 isolates). We confirmed that all binucleate isolates contained only two nuclei per cell. There was variability in the number of nuclei among the multinucleate stem rot (mean 4.2, SE 0.265) and leaf spot (mean 7.5, SE 0.259) isolates. Two tested binucleate Rhizoctonia isolates were pathogenic to 7-week-old tobacco seedlings (cv. Kutsaga 35) in a greenhouse experiment, laid out as a randomized complete block design. Uninoculated healthy plants served as control. Based on a disease rating scale of 1 to 5 (1 = no disease and 5 = >50% stem damage), overall disease incidence was 88.9% 5 days after inoculation with macerated mycelium at the rate of 3.60 × 105 CFU per seedling, applied around the stem base. Over 50% of inoculated seedlings were rated in disease categories 4 and 5. Binucleate Rhizoctonia were consistently isolated from infected plants. A country-wide survey is being conducted to determine the incidence, distribution and severity of diseases caused by binucleate Rhizoctonia on tobacco in Zimbabwe. References: (1) J. S. Cole and Z. Zvenyika. Plant Pathol. 37:271, 1988. (2) S. I. Mpofu and A. M. Julian. J. Phytopathol. 140: 367, 1994.


HortScience ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 185-188 ◽  
Author(s):  
Desalegn D. Serba ◽  
Osman Gulsen ◽  
Bekele G. Abeyo ◽  
Keenan L. Amundsen ◽  
Donald J. Lee ◽  
...  

Hybridization and selection has been one of the methods used to generate turfgrass cultivars in buffalograss improvement. Three half-sib populations were developed by crossing three buffalograss female genotypes, NE 3296, NE 2768, and NE 2769, with NE 2871, a male genotype, to 1) investigate the pattern of genetic variability generated for turfgrass characteristics through hybridization; 2) assess the effect of parental change on the level of genetic variability generated in a buffalograss diploid population; and 3) predict the performance of a progeny generated from two heterozygous parents for turfgrass performance. The four parents and 20 random F1 progeny selected from each population were established in 2006 at the John Seaton Anderson Turfgrass Research Facility located near Mead, NE. A randomized complete block design (RCBD) was used with the progeny nested in the crosses. A visual rating scale of 1–9 was used to evaluate the population. Mean population lateral spread, genetic color, density, and turfgrass quality from early summer to fall ranged from 3.5 to 4.5, 7.1 to 7.9, 6.9 to 8.1, and 5.2 and 6.8, respectively. There were significant differences among the crosses and the parents for all the traits studied except quality in June and August. The progeny nested within crosses differed for turfgrass genetic color and quality. Best linear unbiased prediction (BLUP) indicated a high improvement potential for turfgrass lateral spread and spring density in NE 2768 × NE 2871 and for turfgrass genetic color in NE 3296 × NE 2871. From these findings, it can be concluded that hybridization breeding is a worthwhile approach for generating and identifying transgressive segregants for specific buffalograss traits.


HortScience ◽  
2010 ◽  
Vol 45 (6) ◽  
pp. 875-881 ◽  
Author(s):  
William S. Castle ◽  
James C. Baldwin ◽  
Ronald P. Muraro

‘Hamlin’ is a principal sweet orange grown in Florida for processing. It is productive but produces juice with low soluble solids content and poor color. A long-term trial was conducted in central Florida to determine rootstock effects on yield and juice quality and the effect of economic analysis on the interpretation of the horticultural results. The trees were a commonly used commercial selection of ‘Hamlin’ sweet orange [Citrus sinensis (L.) Osb.] propagated on 19 rootstocks planted in a randomized complete block design of three-tree plots with six replicates in a Spodosol soil at a density of 350 trees/ha. Routine horticultural data were collected from the original trial (H1) for 10 years. Trees on some rootstocks that grew and yielded poorly were removed within a few years and replaced with a second trial (H2) with 13 rootstocks from which data were collected for 5 years. The H1 data were financially analyzed to compare the relative usefulness of horticultural and economic data in interpreting results and making rootstock decisions. In H1 after 10 years, tree height ranged from greater than 5 m [Volkamer lemon (C. volkameriana Ten. & Pasq.)] and Cleopatra mandarin (C. reshni Hort. ex Tan.) to 2.4 m {Flying Dragon trifoliate orange [Poncirus trifoliata (L.) Raf. ]}. In H2, the trees on somatic hybrid rootstocks were ≈2 m tall after 8 years and 4.4 m among those on mandarins and C-32 citrange (C. sinensis × P. trifoliata). Tree losses from citrus blight were generally low except for the trees on Carrizo and Troyer citranges (greater than 50%). Horticulturally, the highest performing trees in H1, measured by cumulative yield and soluble solids production over 10 years, were those on Carrizo, Troyer, and Benton citranges; poor performers were those on Smooth Flat Seville and Kinkoji (putative sour orange hybrids). Fruit yield and soluble solids production were directly related to tree height regardless of the difference among rootstocks in juice quality. The same relationship existed among the trees in H2 in which the best rootstocks were C-32 and Morton citranges. Trees on Swingle citrumelo (C. paradisi Macf. × P. trifoliata) ranked no. 12 of 19 rootstocks and 9 of 13 rootstocks in H1 and H2, respectively. Financial interpretation of the outcomes to include tree replacement resulting from blight losses did not substantially change the horticultural interpretations. Additional financial analyses demonstrated that the performance of trees on rootstocks with relatively low productivity/tree, like those on C-35 citrange and Kinkoji, would equal those on more vigorous rootstocks when tree vigor was properly matched with spacing. Yield determined the economic outcomes and financial analysis aided the interpretation of rootstock horticultural effects but did not greatly alter the relationship among rootstock results. Highly significant correlations between annual and cumulative data indicated that relative rootstock performance among ‘Hamlin’ orange trees in Florida could be reliably determined based on the first 4 cropping years.


2010 ◽  
Vol 6 (3) ◽  
pp. 138
Author(s):  
Mutiara Tirta Prabandari Lintang Kusuma ◽  
Ronny Tri Wirasto ◽  
Emy Huriyati

Background: Adolescent is a transition phase from childhood to adulthood that marked by the change on physical, mental and psychosocial aspect. Adaptation on the change that people met in their life is called psychosocial stress. Stress makes a change on food habit and a disturbance on nutrition’s absorbance. Those circumstances affect people’s nutritional status.Objectives: To identify the correlation between psychosocial stress and nutritional status among SMP Stella Duce 1 Yogyakarta’s students.Methods: This study was an observational study which used a cross sectional design. It held by quantitative approach to identify the relationship between psychosocial stress and nutritional status. Subject of the study were 85 students of SMP Stella Duce 1 Yogyakarta. Respondent’s identities were collected by using identity questionnaire. Psychosocial stress’s status was collected by using SRRS questionnaire (social readjustment rating scale) that was modified for adolescent. Respondent’s calories intakes were assessed by using the form food recall 3 x 24 h. Anthropometrics data collected were weight and height. The adjustment of psychosocial stress’s status used SRRS questionnaires. Calories intake were measured by using nutrition software (Fp2). Student’s nutritional status was measured by using Epi 2000 software. Relationship’s analysis among variables uses statistical test of SPSS 12.00, with the correlation or linear regression test.Result: From this study, 49.4% (42 people) have normal nutritional status, 4.7 % at under nutrition level, 25.9% at risk of obesity, and 20% obesity. From the measurement of psychosocial stress’s score, there were 61.2% (52 people) in a non-tress condition, while the other was on stress at different level. Statistical test showed that there was no relationship between psychosocial stress and nutritional status (p > 0.05).Conclusion: There was no significant relationship between psychosocial stress and nutritional status among SMP Stella Duce 1 Yogyakarta’s students.


Author(s):  
Dharma Oraon ◽  
A. K. Singh ◽  
Ajit Kumar Singh ◽  
S. Kumar ◽  
R. K. Singh ◽  
...  

The FLD experiment was conducted in 20 replication (Farmers field) in National Innovation on Climate Resilient Agriculture (NICRA) village Mardanpur in Arra Panchat of Chatra block in Chatra district of Jharkhand on three consecutive year 2014-15, 2015-16 and 2016-17. The FLD experiment was conducted in randomized block design with 2000 m2 plot size for each technological option. The two technology options are as follows TO-I: (Farmers Practice) Burning of plant leaf in forest area and use as cooking material and transplanting ginger in the month of May without mulching with N100P60K60. TO-II: Mulching of ginger field by plant leaf (5 q/ha) with N75P40K45. The rationale behind selection of technology option (TO-II) was disseminate scientific recommendations i.e. mulching of ginger field to demonstrated famers convincing the benefit of mulching in the place of burning leaf in forest area. The data on soil chemical analysis before and after mulching, yield and economic was recorded for better interpretation matrix ranking was done for each of intervened treatments on the basis of farmers criteria matrix ranking was accomplished through participatory rural appraisal. Farmer’s reaction was measure in five point rating scale. The overall score reflecting the degree of favorable, unfavorable and neutral to the related technology intervention (Negative = 2.5, Natural = 2.3 – 3.5 and positive above = 3.5). Result indicated that on an average ginger yield was 144.83 q/ha in farmers practice where as in technology option (TO-II), it was 187.7 q/ha respectively. Return per rupee spent was also found more in TO-II i.e. 4.99 as compare to farmer practice i.e. 3.88.


1995 ◽  
Vol 20 (1) ◽  
pp. 115-115
Author(s):  
James J. Linduska ◽  
Marylee Ross ◽  
Karen Mulford ◽  
John Nottingham

Abstract ‘Kennebec’ potatoes were planted in 20 foot rows on 25 Apr, ‘94. Plots consisted of a single treatment row. The distance between rows was 64 inches and the distance between plants within the row was 10 inches. Plots were arranged in a randomized complete block design with 4 replications. The soil was a Norfolk "A" loamy sand. Initial furrow treatments were applied to the seed at the rate of 20 gal per acre with a small watering can. Admire foliar treatments were applied at a rate of 50 gal per acre on 8, 23 and 29 Jun with a custom built compressed air row crop sprayer with each row being covered by 6 drop nozzles delivering 50 gal/acre at 30 psi. In evaluating the treatments, direct counts of the number of Colorado potato beetle adults, larvae and egg masses/10 plants and the % defoliation were recorded. Defoliation categories were assigned using a pretransformed defoliation rating scale, based on dividing 90° into 13 steps corresponding to arcsin transformation values (Little & Hills 1978). Yields were taken on 20 Jul from 20-ft of row.


2019 ◽  
Vol 109 (12) ◽  
pp. 2064-2073 ◽  
Author(s):  
Juan Camilo Cifuentes-Arenas ◽  
George Andrew Charles Beattie ◽  
Leandro Peña ◽  
Silvio Aparecido Lopes

Murraya paniculata and Swinglea glutinosa are aurantioid hosts of the Asian citrus psyllid (ACP) Diaphorina citri, the principal vector of ‘Candidatus Liberibacter asiaticus’ (Las). Las is the pathogen associated with huanglongbing (HLB), the Asian form of which is the most devastating disease of Citrus species and cultivars (Rutaceae: Aurantioideae). M. paniculata is a common ornamental and S. glutinosa is grown as an ornamental, a citrus rootstock, and a hedgerow fence plant. Because of the uncertain status of these plants as reservoirs of Las, a series of cross-inoculation bioassays were carried out in different environments, using infected Valencia sweet orange (Citrus × aurantium) infected shoot tops as a source of inoculum and D. citri nymphs and adults reared on M. paniculata and S. glutinosa to inoculate pathogen-free Valencia orange plantlets. In contrast to sweet orange, Las was more unevenly distributed and reached much lower titers in M. paniculata and S. glutinosa. Infections in M. paniculata and S. glutinosa were also transient. Very few insects that successfully acquired Las from M. paniculata and S. glutinosa were able to transmit the pathogen to healthy citrus. Transmission rates were low from M. paniculata (1.0%) and S. glutinosa (2.0%) and occurred only in a controlled environment highly favorable to Las and ACP using 10-day-old adults that completed their life cycle on Las-positive plants. Our study showed that in HLB-endemic areas, M. paniculata and S. glutinosa can be deemed as epidemiologically dead-end hosts for Las and are not important alternative hosts of the pathogen for transmission to citrus. However, under a combination of conditions highly favorable to Las infection and transmission and in the absence of effective quarantine procedures, these plants could eventually serve as carriers of Las to regions currently free from HLB.


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