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

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.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mudassir Rehman ◽  
Jian Liu ◽  
Anne C. Johnson ◽  
Taiwo Esther Dada ◽  
Geoff M. Gurr

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.


2002 ◽  
Vol 127 (4) ◽  
pp. 656-662 ◽  
Author(s):  
Yan Wang ◽  
Stanley J. Kays

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.


2009 ◽  
Vol 78 (5) ◽  
pp. 1145-1151 ◽  
Author(s):  
Takashi Kuriwada ◽  
Norikuni Kumano ◽  
Keiko Shiromoto ◽  
Dai Haraguchi

2017 ◽  
Vol 9 (12) ◽  
pp. 241 ◽  
Author(s):  
Casinga Mubasi Clérisse ◽  
Neema Ciza Angélique ◽  
Kajibwami Cikuru Marie-Angélique ◽  
Nabahungu Nshwarasi Leon ◽  
Mambani Banda Pierre

This study investigated the influence of three soil moisture irrigation regimes on concentration of seed iron and zinc content of four biofortified bean varieties promoted for eradication of malnutrition in Sud-Kivu highlands. A field experiment was conducted in the Hogola marsh highlands during two cultural seasons B2013 and B2014. The experiment design was a RCBD with a split plot arrangement where the main plots were 110 m2 and split plots 20 m2. A strategic application of homogenisation of the experimental site’s soil fertility by chemical fertilizers of the type: CaCO3, KCl and DAP was conducted out. Four biofortified varieties (CODMLB001, RWR2245, HM21-7 and RWK10) constituted main factor, while water regimes respectively [bottom of the slope: R1 = 48% soil moisture, at the middle of the slope R2 = 37% soil moisture and at the top of the slope: R3 = 29% soil moisture according to the gradient of humidity] represented secondary factor and seasonality, tertiary factor. The study showed that the concentrations of iron and zinc were highly correlated with soil moisture regimes. The variety HM21-7 demonstrated better adaptability because it showed a low rate of reduction of iron and zinc concentration under the three soil moisture regimes and was therefore best suited to fight malnutrition in the Sud-Kivu province.


1990 ◽  
Vol 115 (4) ◽  
pp. 696-699 ◽  
Author(s):  
Ki-Cheol Son ◽  
Ray F. Severson ◽  
Richard F. Arrendale ◽  
Stanley J. Kays

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.


2017 ◽  
Vol 9 (3) ◽  
pp. 1465-1468 ◽  
Author(s):  
Naveen Kumar ◽  
Suresh Kumar ◽  
Parveen Kumar ◽  
Meena Sewhag

A field experiment was conducted during rabi season 2011-2012 at Research Farm, CCS Haryana Agri-cultural University, Hisar, Haryana (India) to study the periodic soil moisture depletion and ground water use by bed planted barley as influenced by cultivars, crop geometry and moisture regimes under shallow water table conditions. The experiment was laid out in split plot design with three replications keeping combinations of three cultivars viz., BH 393, BH 902 and BH 885 and two crop geometries viz 2 rows per bed and 3 rows per bed (70 cm wide with 40 cm top and 30 cm furrow) in main plots and three moisture regimes (irrigation at IW/CPE 0.3, 0.4 & 0.5) in sub plots. The results revealed that maximum soil moisture depletion (105 mm) and ground water contribution (62 mm) were recorded in BH 902, followed by BH 393 and BH 885. Among crop geometries, soil moisture depletion (96.6 mm) and ground water contribution (61 mm) were recorded higher in 3 rows per bed than 2 rows per bed. Among three moisture regimes, the soil moisture depletion (108 mm) and ground water contribution (65 mm) decreased with increase in moisture regime from irrigation at IW/CPE 0.3 to irrigation at IW/CPE 0.4 or 0.5.


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