scholarly journals Induction of Adult Female Sweetpotato Weevil (Cylas fromicarius elegantulus Summers) Volatile Attractant Triggered by Root Periderm Feeding

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 511D-511
Author(s):  
Yan Wang ◽  
Stanley J. Kays
Keyword(s):  
Capillary Column ◽  
Activity Index ◽  
Insect Pest ◽  
Active Components ◽  
Storage Roots ◽  
Sweetpotato Weevil ◽  
Volatile Attractant ◽  
Exit Port ◽  
Female Attractant ◽  
And Storage

The sweetpotato weevil is the single most critical insect pest of the sweetpotato worldwide. While male weevils can be lured to traps using a synthetic female pheromone, crop losses are not adequately reduced since damage is caused by the larvae arrising from eggs laid by female weevils in the storage roots. Identification of a female attractant could greatly enhance the control of the insect. The leaves and storage roots are known to emit volatiles that attract the female and in the following tests, we demonstrate that feeding by female weevils stimulates the synthesis of a volatile attractant which attracts additional females to the root. Undamaged, artificially damaged, and female weevil feeding damaged periderm were tested in dual-choice and no-choice olfactometers. Volatiles from feeding damaged roots were significantly more attractive than undamaged and artificially damaged roots. To test whether the volatile attractant was of weevil or root origin, volatiles were collected in MeCl2 after removal of the weevils and fractionated on a megabore DB-1 capillary column using a GC fitted with a TC detector. Fractions were collected from the exit port and their activity index (AI) determined using dual choice and no choice olfactometry. The active fraction was ascertained and active components identified via GC-MS.

scholarly journals Surface Chemical Differences Between Sweetpotato Lines with Varying Levels of Resistance to the Sweetpotato Weevil

1990 ◽  
Vol 115 (4) ◽  
pp. 696-699 ◽  
Author(s):  
Ki-Cheol Son ◽  
Ray F. Severson ◽  
Richard F. Arrendale ◽  
Stanley J. Kays
Keyword(s):  
Ipomoea Batatas ◽  
Methylene Chloride ◽  
Chemical Characterization ◽  
Fused Silica ◽  
Storage Roots ◽  
Sweetpotato Weevil ◽  
Or Groups ◽  
Fused Silica Capillary ◽  
Silica Capillary Column

Methodology was developed for the extraction of surface components of sweetpotato [Ipomoea batatas (L.) Lam.] storage roots. Surface components of storage roots were quantitatively extracted with methylene chloride using 8-minute ultrasonication. After removal of the solvent, the extract was treated with 3 Tri Sil-Z:1 trimethylsilylimidazol (v/v) to convert components with hydroxyl moieties to silyl ethers and then separated on a SE-54 fused silica capillary column. Distinctly different gas chromatography profiles were found between lines displaying moderate levels of resistance (`Resisto', `Regal', `Jewel') to the sweetpotato weevil [Cylas formicarius elgantulus (summers)] and weevil-susceptible lines (`Centennial', SC 1149-19, W-115), indicating a possible role of surface components in insect response. Chromatographic fractionation techniques were developed for separation of major components or groups of components. The results will allow subsequent bioassaying for the presence of an ovipositional stimulant(s) and other weevil behavior-modulating compounds and their chemical characterization.

scholarly journals Sensory Properties and Profiling of Tops and Storage Roots of Sweetpotato Genotypes

2019 ◽  
Vol 12 (4) ◽  
pp. 158-165
Author(s):  
Md. Abu Shahadat Hossain ◽  
A.F.M. Saiful Islam ◽  
Mohammad Noor Hossai Miah ◽  
Mohammad Mehedi Hasa Khan
Keyword(s):  
Sensory Properties ◽  
Storage Roots ◽  
And Storage

scholarly journals Organic mulches reduce crop attack by sweetpotato weevil (Cylas formicarius)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mudassir Rehman ◽  
Jian Liu ◽  
Anne C. Johnson ◽  
Taiwo Esther Dada ◽  
Geoff M. Gurr
Keyword(s):  
Water Conservation ◽  
Organic Materials ◽  
Management Practice ◽  
Integrated Management ◽  
Weed Suppression ◽  
Crop Damage ◽  
Storage Roots ◽  
Plant Materials ◽  
Sweetpotato Weevil ◽  
Cylas Formicarius

Abstract Mulching with organic materials is a management practice with long history for weed suppression, soil water conservation and erosion control. Its potential impact on crop pests is less well explored. Here we report its utility for reducing crop damage by the serious pest, sweetpotato weevil (Cylas formicarius). Laboratory bioassays measured the response of adult female weevils to sweetpotato storage roots beneath mulches of fresh or dried plant materials. Weevils were significant repelled by fresh basil, catnip, basil lime and dry eucalyptus, cypress, lucerne and sugarcane. A subsequent field study found that mulches of dry cypress, eucalyptus and lucerne reduced movement of weevils from a release point to reach sweetpotato plants and lowered level of damage to storage roots. Results demonstrate that mulching with organic materials merits further testing as part of the integrated management of sweetpotato weevil, particularly to protect developing storage roots during dry periods when soil cracking can facilitate access by pests.

Concentrations of essential and nonessential elements in shoots and storage roots of carrot grown in NaCl and Na2SO4salinity

2009 ◽  
Vol 38 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Ali Inal ◽  
Aydin Gunes ◽  
David J. Pilbeam ◽  
Yusuf K. Kadioglu ◽  
Figen Eraslan
Keyword(s):  
Storage Roots ◽  
And Storage

scholarly journals Sweetpotato Transplant Holding Duration Effects on Plant Survival and Yield

2017 ◽  
Vol 27 (6) ◽  
pp. 818-823 ◽  
Author(s):  
William B. Thompson ◽  
Jonathan R. Schultheis ◽  
Sushila Chaudhari ◽  
David W. Monks ◽  
Katherine M. Jennings ◽  
...  
Keyword(s):  
North Carolina ◽  
Ipomoea Batatas ◽  
Storage Root ◽  
Storage Roots ◽  
Higher Plant ◽  
Root Numbers ◽  
Dry Conditions ◽  
Plant Stand ◽  
And Storage ◽  
Lower Plant

Studies were conducted in North Carolina to determine the effect of holding durations (HDs) [0, 1, 3, 5, and 7 days before planting (DBP)] of ‘Covington’ sweetpotato (Ipomoea batatas) transplants on plant stand and storage root numbers and yield in production fields. In a second field study, the effect of preplant irrigation (PI) treatments (PI and nonirrigation) were evaluated along with the transplant HD on plant stand, storage root numbers, and yield. Transplants held for 7 DBP did not survive as well as the other treatments (lower plant stands) and had lower no. 1, marketable, and total storage root numbers and yields than other holding treatments. HD of 1 or 3 DBP resulted in higher plant stands, and no. 1, marketable, and total numbers of storage roots and yields than holding for 0, 5, or 7 DBP. This study affirms the importance of soil moisture at and shortly after planting for transplant survival and yield. Holding transplants for 1–3 DBP can improve stand establishment and yields when dry conditions occur either before or soon after planting. However, holding transplants for 7 DBP can result in reduced plant stands and yields when stress/dry conditions occur soon after planting.

scholarly journals Characterization of Isolates of Fusarium spp. Obtained from Asparagus in Spain

Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1441-1451 ◽  
Author(s):  
C. Corpas-Hervias ◽  
J. M. Melero-Vara ◽  
M. L. Molinero-Ruiz ◽  
C. Zurera-Muñoz ◽  
M. J. Basallote-Ureba
Keyword(s):  
Random Amplified Polymorphic Dna ◽  
Fusarium Species ◽  
Dry Weight ◽  
Asparagus Officinalis ◽  
Storage Roots ◽  
Fusarium Spp ◽  
Root Dry Weight ◽  
Microbial Analysis ◽  
And Storage

Microbial analysis of asparagus plants (Asparagus officinalis) obtained from four nurseries in Spain in 2002 to 2003 indicated high frequencies of Fusarium proliferatum, F. oxysporum, and F. moniliforme in the rhizomes and storage roots. Out of 201 isolates of Fusarium obtained from nursery crowns and from plants sampled in nine established asparagus fields, the highest frequency of highly pathogenic isolates was observed from samples collected from fields, and included some extremely virulent isolates of F. solani. For isolates of low to moderate virulence, the percentage of those significantly (P = 0.01) associated with root dry weight loss was larger for F. proliferatum (53.8%) than for the other Fusarium species (10.3 to 23.1%). Random amplified polymorphic DNA (RAPD) analysis of 19 isolates of Fusarium spp. grouped all F. proliferatum and F. moniliforme isolates together and, in a second cluster, five of the eight isolates of F. oxysporum. Asparagus cultivars Verde-Morado and Dariana were the least susceptible of 11 cultivars commonly grown in Spain; isolates of F. solani and F. moniliforme proved highly virulent; and a significant interaction was observed among pathogen isolates and asparagus cultivars when representative pathogenic isolates of F. proliferatum, F. oxysporum, F. moniliforme, and F. solani were tested on those cultivars. Larger reductions in root dry weight were associated with F. proliferatum and F. solani than with F. oxysporum and F. moniliforme, and differences in root and stem dry weights among cultivars were significant.

scholarly journals BORON APPLICATION TIMING AND RATE ON BLISTER-LIKE SYMPTOMS IN `HERNANDEZ'

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 760g-761
Author(s):  
Jonathan R. Schultheis ◽  
Dennis E. Adams
Keyword(s):  
Foliar Application ◽  
Block Design ◽  
Storage Roots ◽  
Fresh Market ◽  
Application Timing ◽  
Yield And Quality ◽  
Randomized Complete Block Design ◽  
Good Yielding ◽  
And Storage

Boron has been used to overcome the disorder blister in varieties such as `Jewel'. `Hernandez' is an attractive, good-yielding variety with uniform shape that will consistently pack out at 80% to 90%. Over time in storage, however, roots develop blister-like symptoms, rendering roots unmarketable for fresh market. Our objective was to evaluate the effect of different B rates and application times on the yield and quality of `Hernandez' roots. Rates were varied up to 2.24 kg actual B/ha 6 days after planting, while various soil and foliar application times (6, 34, and 69 days after planting) were evaluated at 1.12 kg·ha–1. In 1994, three row plots were arranged in a randomized complete block design and replicated four times. Planting was on a deep sand to maximize the effect of the B carrier Solubor. Roots were harvested, graded, and weighed 120 days after planting and storage roots evaluated for blister-like symptoms in Mar. 1995. No significant differences in yield were attributed to B rate or application method. Blister-like symptoms were more severe when no B was applied; however, application of B did not eliminate symptoms, as most roots had the blister-like appearance. Boron application did not solve the problem, but symptoms were less apparent when some B was applied.

scholarly journals Incidence of End Rots and Internal Necrosis in Sweetpotato Is Affected by Cultivar, Curing, and Ethephon Defoliation

2013 ◽  
Vol 23 (6) ◽  
pp. 886-897 ◽  
Author(s):  
Christopher A. Clark ◽  
Washington L. da Silva ◽  
Ramón A. Arancibia ◽  
Jeff L. Main ◽  
Jonathan R. Schultheis ◽  
...  
Keyword(s):  
Ipomoea Batatas ◽  
Breeding Line ◽  
Storage Roots ◽  
Postharvest Storage ◽  
Breeding Lines ◽  
Multiple Environments ◽  
Internal Necrosis ◽  
Production Areas ◽  
And Storage

Two distinct syndromes have emerged in some production areas that have caused losses of sweetpotato (Ipomoea batatas) storage roots during postharvest storage: a complex of fungal rots (end rots) progressing from either end of storage roots and a necrotic reaction (internal necrosis) progressing internally from the proximal end of storage roots. This study was conducted in multiple environments to evaluate whether the use of preharvest ethephon application and storage with or without curing after harvest could be used to screen sweetpotato breeding lines for susceptibility/resistance to these two disorders. Treating vines with ethephon 2 weeks before harvest and placing harvested roots directly into storage at 60 °F without curing resulted in the greatest incidence of end rots in each state and there were significant differences in incidence among the sweetpotato genotypes evaluated. However, when ethephon was not used and roots were cured immediately after harvest, the incidence of end rots was low in all the genotypes evaluated except for one breeding line. Incidence and severity of internal necrosis were greatest when ethephon was applied preharvest and roots were cured immediately after harvest, but two cultivars, Hatteras and Covington, had significantly more internal necrosis than all others.

scholarly journals Screening of sweetpotato germplasm collections for sweetpotato weevil (Cylas spp.) resistance in Tanzania

2020 ◽  
pp. 1707-1714
Author(s):  
Filson Kagimbo ◽  
Hussein Shimelis ◽  
Julia Sibiya
Keyword(s):  
Durable Resistance ◽  
Resistance Breeding ◽  
Root Weight ◽  
Root Number ◽  
Storage Roots ◽  
Damage Score ◽  
Sweetpotato Weevil ◽  
Lattice Design ◽  
Germplasm Collections ◽  
Western Tanzania

Weevil damage caused by sweetpotato weevil (Cylas spp.) is a major constraint to sweetpotato production in Tanzania due to a lack of improved varieties with durable resistance. The objective of this study was to screen sweetpotato germplasm collections for weevil resistance and to select the best parents to be used in resistance breeding. Field studies involving 96 sweetpotato genotypes were conducted at two weevil hotspot sites in Western Tanzania using a 12 x 8 lattice design with three replications at each site. Data collected included yield and yield related traits, weevil reaction and weevil damage score. The tested genotypes differed significantly (P < 0.01) for sweetpotato storage root number, root weight, root infestation and root damage score. Weevil infestation on storage roots significantly (P ≤0.05) correlated with total root number (r = 0.38) and weevil damage score (r = 0.79). Marketable root weight and total root weight were significantly correlated with infested root weight each with r = 0.45. The study identified nine sweetpotato genotypes expressing resistance and 10 genotypes with moderate resistance to weevil. Five genotypes including Magunhwa, Chuchu ya Nesi, Rugomoka, Tumauma and New Kawogo were selected with weevil resistance and desirable yield and yield-related traits. These genotypes can be used in future weevil resistance breeding programs of sweetpotato in Western Tanzania or related agro-ecologies.

scholarly journals Yield, Quality and Physiological Traits of Red Beet Under Different Magnesium Nutrition and Light Intensity Levels

Agronomy ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 379
Author(s):  
Sara D’Egidio ◽  
Angelica Galieni ◽  
Fabio Stagnari ◽  
Giancarlo Pagnani ◽  
Michele Pisante
Keyword(s):  
Light Intensity ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Dry Weight ◽  
Total Phenolic ◽  
Storage Roots ◽  
Light Reduction ◽  
Red Beet ◽  
Application Rates ◽  
And Storage

The effects of light intensity and Magnesium (Mg) supply on quality traits, yield and macronutrient assimilation of red beet plants were studied in two greenhouse experiments (in 2017 and 2018). According to a split-plot design, we compared two photosynthetically active radiation (PAR) levels (100% PAR, Full Light, FL and 50% PAR, Light Reduction, LR) as the main factor and three Mg application rates (0, 30, and 60 kg Mg ha−1: MG_0, MG_30 and MG_60, respectively) as the secondary factor. Yield and dry matter accumulations were principally affected by Mg. In both growing seasons, storage root dry weight (DW) increased about 5-fold in MG_60 with respect to MG_0; the highest leaves DW was achieved with the “LR × MG_60” treatment. Nitrogen and Mg contents in leaves and storage roots increased as Mg availability increased; also, the highest chlorophyll content was obtained combining LR and a high Mg rate. Moreover, the reflectance-derivative Normalized Difference Vegetation Index (NDVI670) and Chlorophyll Index (CI) allowed for discriminating the Mg sub-optimal supply in red beet plants. Sucrose was found to be the most abundant sugar in both the leaves and storage organs and was affected by Mg supply. Total phenolic content and betalains in storage roots at harvest were affected by both PAR and Mg application rates. Our results highlight the potential of Mg nutrition in ensuring good yield and quality of red beet crops.

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