scholarly journals Yield Reductions of Wheat Cultivar Obora (UTIQUE96/FLAG-1) due to Russian Wheat Aphid (Diuraphis noxia) Infestation under Field Conditions at Selected Districts of West Showa Zone, Ethiopia

Author(s):  
Nahil Abebe ◽  
Mulugeta Negeri ◽  
Emana Getu ◽  
Thangavel Selvara

Background: Wheat (Triticum aestivum L.) is an important cereal crop as being consumed as staple food in the world as well as in Ethiopia. The production of wheat in Ethiopia decreased due to the incidence of insect pests. Out of insects’ pests the Russian wheat aphid (Diuraphis noxia) is the recent one that causes yield loss either directly or indirectly. Methods: The experiment was carried out at selected districts of West Showa zone, Ethiopia during off cropping season 2019 to evaluate the yield reduction in wheat crop due to the invasion of Russian wheat aphids. Malamar, Dimethoate, neem seeds, leaves, Beaveria bassiana and Metarhizium anisopliae were used in form of spray. Result: However, Malamar and Dimethoate highly significantly lowered the population of Diuraphis noxia. The combination of Beaveria bassiana and Metarhizium anisopleae significantly lowered the population of Russian wheat aphid. The combination of Neem leaf and Neem seeds, as well as Beaveria bassiana, proved to be effective against Russian wheat aphid yet they were protected and sound against the environments. Malamar showed the maximum decrease in Diuraphis noxia populations followed by Dimethoate, the combination of Beaveria bassiana and Metarhizium anisopleae.

Author(s):  
Kairovin Lakra

Phalaris minor and Cynodon dactylon is the very problematic grassy weeds of wheat crop are responsible for significant yield reduction. Therefore, the present experiment was conducted at CSAUAT, Kanpur during Rabi season 2017-18 and 2018-19 in split-plot design with four replication having four irrigation regimes in main plot viz. irrigation at CRI and active tillering stage (I1), irrigation at CRI + jointing + booting (I2), CRI + active tillering + booting + flowering stage (I3) and  irrigation at CRI + jointing + booting + flowering + milking stage (I4), and eight factors of weed management (W1-weedy check, W2-two hand weeding at 20 and 40 days after sowing (DAS), W3-sulfosulfuron 25 gha-1at 35 DAS, W4- pendimethalin (pre-em) fb WCPL-15, 400 gha-1at 35 DAS, W5- broadway (carfentrazone ethyl 20% + sulfosulfuron 25%WG) 100 gha-1at 35 DAS, W6- halauxafen + penxasulam 23.5%, 75 gha-1at 35 DAS, W7- halauxafen - methyl 1.21% w/w + fluroxypyr at 35 DAS and W8- clodinafop- propargyl 15% + metsulfuron 1%, 400 gha-135 DAS) were allocated to sub plots for assessing the effect of these treatments on grassy weeds. Irrigations at crown root initiation (CRI) and active tillering stage (I1) significantly reduce the density and weight of grassy weeds with highest WCE and crop resistance index (CRI) over other irrigation regimes. However, I4 irrigation recorded highest weed effectiveness (WE) and crop dry matter yield (CDMY) followed by I3. All the weed management options are significantly superior over weedy check. Among herbicidal treatments, lowest weed density and their weight, WE and the highest WCE, CRI, WPI and CDMY was recorded with the application of broadway (W5) followed by W8. Reducing irrigation frequency and the post emergence application of broadway are the best option for managing grassy weeds in wheat, but for higher CDMY more number of irrigations required.


Author(s):  
Dilbar Hussain ◽  
Muhammad Asrar ◽  
Bushra Khalid ◽  
Faisal Hafeez ◽  
Muhammad Saleem ◽  
...  

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 592
Author(s):  
Katja Kauppi ◽  
Ari Rajala ◽  
Erja Huusela ◽  
Janne Kaseva ◽  
Pentti Ruuttunen ◽  
...  

The effect of weeds, plant diseases and insect pests on spring barley (Hordeum vulgare) and spring wheat (Triticum aestivum) grain and nutrient yield was examined. Long-term field trial data was used to assess the impact of different pests on grain yield. In the absence of pesticides, fungal diseases caused the largest annual yield-reduction in spring wheat and spring barley, 500 kg ha−1 on average. Converting yield loss to nutrient yield loss this represented reductions of 8.1 and 9.2 kg ha−1 in nitrogen and 1.5 and 1.6 kg ha−1 in phosphorus, respectively. Likewise, it was estimated that weeds decrease the yield of spring barley and spring wheat for 200 kg ha−1, which means reductions of 3.7 and 3.2 kg ha−1 in nitrogen and 0.6 kg ha−1 in phosphorus, respectively. For insect pests yield-reduction in spring barley and spring wheat varied between 418 and 745 kg ha−1 respectively. However, because bird cherry-oat aphid (Rhopalosiphum padi L.) incidence data was limited, and aphids are highly variable annually, nutrient yield losses caused by insect pests were not included. Based on the current study, the management of weeds, plant diseases and insects maintain cereal crop yield and may thus decrease the environmental risks caused by unutilized nutrients.


1997 ◽  
Vol 6 (4) ◽  
pp. 337-339
Author(s):  
Jonathan Robinson

Colonies of Diuraphis (Holcaphis) frequens (Walker) were found on wheat, Triticum aestivum L. in the vicinity of Jokioinen in south-west Finland in summer 1997. The aphid was present in all wheat fields inspected, and was particularly abundant on spring wheat plants of field and plot margins. The aphid was also common on its recognised, host Elymus repens (L.) Gould (couch grass). Damage symptoms, longitudinal chlorotic streaking of tightly rolled leaves, resembled those caused by Diuraphis noxia (Mordvilko), the Russian wheat aphid. Diuraphis frequens appears unlikely to become a serious pest of wheat, and its relative abundance during 1997 may have resulted from particularly hot, dry weather.


Weed Science ◽  
2019 ◽  
Vol 67 (6) ◽  
pp. 666-672 ◽  
Author(s):  
Sudheesh Manalil ◽  
Bhagirath Singh Chauhan

AbstractTurnipweed [Rapistrum rugosum (L.) All.] and Mexican pricklepoppy (Argemone mexicana L.) are increasingly prevalent in the northern cropping regions of Australia. The effect of different densities of these two weeds was examined for their potential to cause yield loss in wheat (Triticum aestivum L.) through field studies in 2016 and 2017. There was 72% to 78% yield reduction in wheat due to competition from R. rugosum. Based on the exponential decay model, 18.2 and 24.3 plants m−2 caused a yield reduction of 50% in 2016 and 2017, respectively. Rapistrum rugosum produced a maximum of 32,042 and 29,761 seeds m−2 in 2016 and 2017, respectively. There was 100% weed seed retention at crop harvest. Competition from A. mexicana resulted in a yield loss of 17% and 22% in 2016 and 2017, respectively; however, plants failed to set seeds due to intense competition from wheat. Among the yield components, panicles per square meter and grains per panicle were affected by weed competition. The studies indicate a superior competitiveness of R. rugosum in wheat and a suppressive effect of wheat on A. mexicana. The results indicate that a wheat crop can be included in crop rotation programs where crop fields are infested with A. mexicana. High seed retention in R. rugosum indicates the possibility to manage this weed through seed catching and harvest weed seed destruction.


2018 ◽  
Vol 38 (01) ◽  
Author(s):  
O. P. Gangwar ◽  
Akanksha P.K. Singh

Several environmental stresses are the major hindrances in achieving the attainable yield in wheat crop. The actual losses due to biotic stresses is estimated in the range of 26-29%, however, abiotic stresses have more adverse effects on crop yield and are responsible for about 70% of yield reduction worldwide. Agrochemicals are widely considered as an effective management strategy for wheat crop diseases and insect pests but they adversely affect the human and animal health due to accumulation of chemical residues in the soil, plant tissues and grains. Hence, there is a need for alternate management strategies to protect crop plants against various stresses. Species of the genus Trichoderma are economically important as biocontrol agents, serving as a potential alternative to agrochemicals for overcoming the biotic and abiotic stresses. The importance of Trichoderma in alleviating the myriad of biotic and abiotic stresses of wheat is discussed in this review article.


2002 ◽  
Vol 57 (9-10) ◽  
pp. 867-873 ◽  
Author(s):  
Mohase Lintle ◽  
Amie J. van der Westhuizen

Elicitors are molecules which can induce the activation of plant defence responses. Elicitor activity of intercellular wash fluid from Russian wheat aphid, Diuraphis noxia (Mordvilko) infested resistant (cv Tugela DN), and susceptible (cv Tugela), wheat (Triticum aestivum L.), was investigated. Known Russian wheat aphid resistance related responses such as peroxidase and β-1,3-glucanase activities were used as parameters of elicitor activity. The intercellular wash fluid from infested resistant plants contains high elicitor activity while that from infested susceptible plants contains no or very little elicitor activity. After applying C-18 reverse phase and concanavalin A Sepharose chromatography, elicitor active glycoproteins were isolated from the intercellular wash fluid of Russian wheat aphid infested resistant wheat. The elicitor-active glycoproteins separated into three polypeptides during sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isolated glycoproteins elicited peroxidase activity to higher levels in resistant than in susceptible cultivars. It was evident that the glycoproteins were probably a general elicitor of plant origin. Information gained from these studies is valuable for the development of plant activators to enhance the defence responses of plants.


1996 ◽  
Vol 23 (5) ◽  
pp. 645 ◽  
Author(s):  
AJVD Westhuizen ◽  
Z Pretorius

The protein composition of intercellular fluids from three different wheat cultivars (Triticum aestivum L. cvv. Tugela DN, Molopo DN and Betta DN) with resistance to the Russian wheat aphid, Diuraphis noxia (Mordvilko) and the corresponding near-isogenic susceptible cultivars (Tugela, Molopo and Betta) were studied under conditions of infestation and non-infestation. The aim was to gain information on the mechanism of resistance and the possible presence of molecular markers of resistance. Aphid infestation induced the accumulation of specific corresponding proteins in the intercellular fluids of resistant cultivars only. The infestation-related proteins were of different molecular mass ranges (28-33; 22-24; 18.5-19.5 and 15.5-17 kDa). Some were serologically related to PR proteins. We suspect that the infestation-related proteins are involved in resistance to the Russian wheat aphid. Although not particularly time saving, the intensified bands of infestation-related proteins on SDS-PAGE gels may be useful for determining resistance.


2010 ◽  
Vol 61 (12) ◽  
pp. 970 ◽  
Author(s):  
M. Ricciardi ◽  
E. Tocho ◽  
M. S. Tacaliti ◽  
A. Vasicek ◽  
D. O. Giménez ◽  
...  

Diuraphis noxia (Russian wheat aphid, RWA), one of the most aggressive pests of wheat, has evolved several biotypes with virulence matching known Dn resistance genes. This paper was aimed at determining the location of plant-defence genes triggered by RWA in a set of doubled haploid (DH) lines obtained from the cross of winter wheat varieties ‘Spark’ and ‘Rialto’. Both parental lines, 110 DH and CItr2401 (a RWA-resistant line) were screened for antixenosis, tolerance and antibiotic mechanisms of resistance with a population of RWA collected in Argentina. Antixenosis was not significantly linked to any marker locus. Tolerance traits showed significant associations with several chromosomes. Quantitative trait loci (QTL) for the foliar area developed during infestation was significantly associated with marker loci Xpsp3103 on 4DS, and Xgdm3 on 5DS. QTL for chlorophyll content in the infested plants were significantly associated with the marker loci Xgwm533 on 3BS and Xpsp3094 on 7AL, and a QTL for the number of expanded leaves was associated with the marker loci Xwmc264 on 3AS and XwPt8836 on 4DS. QTL for most of the tolerance traits were significantly associated with the same chromosome intervals on chromosomes 4DS and 5DS. The 4DS QTL were linked to or had a pleiotropic effect on Rht-D1. Most of the antibiosis traits were significantly associated with the same marker loci on chromosomes 4A (XwPt7405), 1B (XwPt9032) and 5B (Xbarc109 and Xbarc74). Several novel genes conferring tolerance and antibiosis to RWA were identified and these could be transferred into wheat cultivars to enlarge the genetic base of defence against this aphid pest. These new genes can be designated as QDn.unlp genes, following the rules for gene nomenclature in wheat.


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