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.

scholarly journals Sweetpotato Volatile Chemistry in Relation to Sweetpotato Weevil (Cylas formicarius) Behavior

2002 ◽  
Vol 127 (4) ◽  
pp. 656-662 ◽  
Author(s):  
Yan Wang ◽  
Stanley J. Kays
Keyword(s):  
Gas Chromatography ◽  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Biologically Active ◽  
Volatile Fraction ◽  
Storage Roots ◽  
Sweetpotato Weevil ◽  
Plant Parts ◽  
Cylas Formicarius

The sweetpotato weevil (SPW) [Cylas formicarius elegantulus (Summers) (Coleoptera: Curculionidae)] is the single most devastating pest of the sweetpotato [Ipomoea batatas (L.) Lam.] worldwide. Attempts to develop host-plant resistance have been only moderately successful due in part to deficiencies in parent and progeny selection methods. Host-plant phytochemicals play critical roles in insect behavior, modulating a cross-section of key behavioral decisions. Thus, identification of the phytochemicals the female weevil uses in decision making could greatly facilitate development of host-plant resistance. The volatile chemistry of the sweetpotato was studied in relation to the host-finding behavior of the female weevil. Critical biologically active volatiles were determined via isolation (Tenax trapping), fractionation (gas chromatography-thermal conductivity detector), identification (gas chromatography and gas chromatography-mass spectroscopy), and bioassay (olfactometry). Differences in volatile chemistry among sweetpotato clones that may relate to differences in resistance or susceptibility to the female SPW were assessed. Volatile extracts from storage roots (site of oviposition) and aerial plant parts were attractive to female SPW, the former being substantially greater. In total, 33 compounds were identified from storage roots and aerial plant parts, including 23 terpenes. Three oxygenated monoterpenes (nerol, Z-citral, and methyl geranate), found in storage roots but not aerial plant parts, were identified as attractants. The sesquiterpene volatile fraction was repellent to female SPW with α-gurjunene, α-humulene, and ylangene active in the concentration range emanating from storage roots. The aerial plant parts emanated a higher composite concentration of sesquiterpenes than storage roots. Differences in the relative attraction among four sweetpotato cultivars to female SPW was inversely correlated with the composite concentration of headspace sesquiterpenes. Selection of clones with decreased volatile attractants and/or increased deterrents using an analytical means of quantification may significantly facilitate developing resistance to the SPW.

scholarly journals Integrated Management of Weeds in Direct-Seeded Rice in Cambodia

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1557
Author(s):  
Robert Martin ◽  
Bunna Som ◽  
Joel Janiya ◽  
Ratha Rien ◽  
Sophea Yous ◽  
...  
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Rice Field ◽  
Field Experiments ◽  
Integrated Management ◽  
Weed Suppression ◽  
Crop Damage ◽  
Integrated Weed Management ◽  
Crop Tolerance ◽  
Direct Seeded

The objective of this work was to determine the value of improved establishment methods and herbicide applications as alternatives to high seeding rates to improve weed suppression in rice. Field experiments were carried out in 2010 and 2011 to determine optimal seeding rates and seeding methods with and without weed competition in wet-seeded rice. Under wet seeding conditions, drum seeding at 80 kg ha−1 was the most profitable treatment for both weed-free and unweeded rice. Although pre-emergence herbicides are beginning to be adopted in wet-seeded rice, they are seldom used in dry direct-seeded rice in Cambodia. Experiments were carried out in 2018 and 2019 to test crop tolerance and the efficacy of butachlor, oxadiazon, pendimethalin and pretilachlor applied post-sowing and pre-emergence to dry direct-seeded rice. Oxadiazon and butachlor, with the option for a post-emergence herbicide, provided effective weed control and a high grain yield in dry direct-seeded rice. Pretilachlor did not effectively control weeds under dry seeding conditions. Although pendimethalin exhibited good weed control, crop damage was a risk in poorly prepared seedbeds which typify Cambodian rice systems. With an effective integrated weed management strategy, it might be possible to safely reduce seeding rates below 80 kg ha−1 using drum or drill seeding machines.

scholarly journals Irrigation Affects Yield and Sweetpotato Weevil [Cylas formicarius elegantus (Summers)] Infestation of Sweetpotato

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 829A-829
Author(s):  
S.M.A. Crossman ◽  
M.C. Palada ◽  
J.A. Kowalski
Keyword(s):  
Soil Moisture ◽  
Root Biomass ◽  
Inverse Relationship ◽  
Damage Index ◽  
Storage Roots ◽  
Sweetpotato Weevil ◽  
Cylas Formicarius ◽  
Moisture Regimes ◽  
Irrigation Treatments

A study was conducted to evaluate the effect of irrigation on yield and sweetpotato weevil (SPW) infestation of sweetpotato storage roots. Sweetpotato was grown in plots under controlled soil moisture regimes. The treatments were rainfed (no applied irrigation) and irrigation applied to maintain soil moisture levels at 20, 40, and 60 kPa, based on tensiometer readings. The 40- and 60-kPa treatments produced the highest yield of root biomass. Irrigation applied at 40 kPa produced significantly more medium-sized storage roots (8.1 t·ha–1) than the rain-fed treatment, which produced 4.4 t·ha–1. All of the irrigation treatments produced significantly more marketable storage roots with a lower mean damage index (MDI) than the rain-fed treatment. There was an inverse relationship between MDI and soil moisture levels among the irrigation treatments. A significantly higher percentage of storage roots (51.5%) from the 20-kPa treatment were rated in the Damage Index (DI)-1 (uninfested roots) category than from the rain-fed treatment (27.7%). Additionally, the percentage (29.4%) of storage roots from the rain-fed treatment rated in the DI-6 (most severe) category was significantly higher than the applied irrigation treatments, with 13.9%, 13.9%, and 6.0% respectively, for the 60-, 40-, and 20-kPa treatments. Irrigation therefore has potential to increase sweetpotato yields while reducing SPW infestation levels.

Copulation reduces the duration of death-feigning behaviour in the sweetpotato weevil, Cylas formicarius

2009 ◽  
Vol 78 (5) ◽  
pp. 1145-1151 ◽  
Author(s):  
Takashi Kuriwada ◽  
Norikuni Kumano ◽  
Keiko Shiromoto ◽  
Dai Haraguchi
Keyword(s):  
Sweetpotato Weevil ◽  
Death Feigning ◽  
Cylas Formicarius

Enhancement of iron availability by some organic materials

1979 ◽  
Vol 93 (1) ◽  
pp. 115-120 ◽  
Author(s):  
A. A. Parsa ◽  
A. Wallace ◽  
J. P. Martin
Keyword(s):  
Calcareous Soil ◽  
Dry Matter ◽  
Organic Materials ◽  
Iron Availability ◽  
Lawsonia Inermis ◽  
Plant Materials ◽  
Phenolic Substances ◽  
And Control ◽  
Layer Chromatography ◽  
Positive Effect

SUMMARYIn a preliminary laboratory experiment in Iran, not reported here, 5 out of 30 plant materials incorporated into a highly calcareous soil had a positive effect on increasing the DTPA- (diethylenetriaminepentaacetic acid)-extractable Fe and all except one significantly increased the vegetative growth of sorghum. The plant materials included Lawsonia inermis L., Malva silvestris L., Zyzyphus nummularia Wak. and Lavandula carnopifolia L. A glasshouse study was repeated with two California soils pretreated with 0·5% Fe2O3 to determine if these organic materials have practical value in making Fe available to plants. A calcareous, Fe-deficient Hacienda (fine-loamy, mixed, thermic aquic natrargid) and a non-calcareous Yolo (fine-silty, mixed, non-acid, thermic typic xerothents). The previously mentioned organic materials and Laminaria saccharina L. (Lamour) were incorporated into the soils at two rates, 15000 and 20000μg/g, as air dry and in ash form. An adequate supply of major and micronutrients other than Fe was ensured. Other treatments included 5 μg Fe/g as FeSO4, Fe-138 chelate and control. All of the plant materials with the exception of L. carnopifolia significantly increased dry-matter yield and Fe, Zn, Cu and Mn uptake by sorghum in the Hacienda soil. In the Yolo soil the above were not significant. Thin-layer chromatography of the extracts of the plant materials revealed the presence of significant quantities of phenolic substances.

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 Valuation of Weather Manifested Rice Cultivation in Bangladesh: A Way Forward

2019 ◽  
Vol 2 (1) ◽  
pp. 62-64
Author(s):  
Afroza Chowdhury ◽  
Abdullah Al Mamun ◽  
Niaz Md. Farhat Rahman
Keyword(s):  
Weather Forecasting ◽  
Management Practice ◽  
Weather Prediction ◽  
Real Data ◽  
Crop Damage ◽  
Financial Benefit ◽  
Climatic Effects ◽  
Advisory Service ◽  
Good Management Practice ◽  
The Cost

Good crop yield entirely depends on good management practice and quality management of crops allied with authentic weather forecasting can reduce risk, crop damage, cost of production and increase the yield as well. Bangladesh Rice Research Institute (BRRI) had aimed this study for quantifying the financial benefit of forecasting and validating micro climatological factors and their impacts on paddy production through experimentation and arranging for weather based agro meteorological advisory service delivery to the farmers applying the tools of ICT. A next-generation meso-scale numerical weather prediction system, WRF (Weather Research and Forecasting) model was used for generating atmospheric simulations based on real data (observations, analyses or idealized conditions). Field experiment was conducted in the areas of five different agro microclimatological conditions for Boro rice production, namely; Gazipur, Habiganj, Rajshahi, Barishal and Satkhira. Then the experimental fields were managed according to the weekly management advisory based on weather forecasts. Results obtained suggest that the application of weather predictability accrued a comparative rice yield benefit of 9-12% and a 3–5% reduction in the cost of cultivation. Countrywide application of agro-meteorological advisory service may pave the way for averting adverse climatic effects on agriculture.

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