Postemergence Control of Glyphosate/Paraquat-Resistant Hairy Fleabane (Conyza bonariensis) in Tree Nut Orchards in the Central Valley of California

2015 ◽  
Vol 29 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Marcelo L. Moretti ◽  
Anil Shrestha ◽  
Kurt J. Hembree ◽  
Bradley D. Hanson
Keyword(s):  
Field Experiments ◽  
Central Valley ◽  
Effective Management ◽  
Flowering Stage ◽  
Management Options ◽  
Leaf Stage ◽  
Tree Nut ◽  
Conyza Bonariensis ◽  
Almond Orchards ◽  
Hairy Fleabane

Hairy fleabane is an important weed in orchards and vineyards of California. Populations of glyphosate-resistant (GR) and glyphosate-paraquat-resistant (GPR) hairy fleabane have been documented in California but very little information is available on the efficacy of other POST herbicides on these populations. Greenhouse and field experiments were conducted to evaluate the efficacy of several POST herbicides registered in almond orchards on GPR, GR, and glyphosate/paraquat-susceptible (GPS) hairy fleabane plants. Plants were treated at the 8- to 12-leaf stage in greenhouse experiments, and at the bolting to flowering stage in field experiments. A sequential application of glyphosate (1,100 g ae ha−1) followed by paraquat (500 g ai ha−1) 14 d later did not control the GPR plants in any of the studies, but was effective in controlling the GR and GPS plants. Glufosinate at 1,050 g ai ha−1or saflufenacil at 48.8 g ai ha−1resulted in 90% or greater control of all populations in all studies, whereas glyphosate (1,100 g ae ha−1) + 2,4-D (1,090 g ae ha−1) resulted in inconsistent control (58 to 100%). The GPR population was not resistant to other common POST herbicide modes of action used in California tree nut orchards, and glufosinate and saflufenacil can provide growers effective management options for hairy fleabane in these crops.

scholarly journals Chemical control and herbicide resistance of hairy fleabane [Conyza bonariensis (L.) Cronquist] in Jordan

2022 ◽  
Author(s):  
Jamal R. Qasem
Keyword(s):  
Herbicide Resistance ◽  
Date Palm ◽  
Field Experiments ◽  
Weed Species ◽  
Jordan Valley ◽  
Application Rates ◽  
Conyza Bonariensis ◽  
Central Jordan ◽  
Nonchemical Weed Control ◽  
Hairy Fleabane

Two field experiments were conducted to evaluate the effectiveness of 12 herbicides in controlling hairy fleabane [ Conyza bonariensis (L.) Cronquist] in a date palm orchard located in the central Jordan valley during the spring of 2017. Results showed that C. bonariensis resists paraquat (2.5, 5 and 7.5kgha -1 ), oxadiazon (5kgha -1 ) and oxyflourfen (3.3kgha -1 ) herbicides applied at normal or higher than the recommended rates. None of the three herbicides was significantly effective against the weed and treated plants continued growing normally similar to those of untreated control. Higher rates (10-fold of the recommended rates) of the same herbicides failed to control the weed. The effect of other tested herbicides on the weed was varied with bromoxynil plus MCPA (buctril ® M), 2,4-D- iso-octyl ester, glyphosate, glyphosate trimesium and triclopyr were most effective and completely controlled the weed at recommended rates of application. Testing paraquat, oxadiazon and oxyflourfen using the normal recommended and 10-fold higher rates on two populations of C. bonariensis grown from seeds of the date palm and al-Twal (another site in the Jordan Valley) weed populations and grown in pots under glasshouse conditions showed that Date palm population was resistant to the three herbicides at both application rates while al-Twal site population was highly susceptible and completely controlled at normal and high rates of the three herbicides. It is concluded that certain populations of C . bonariensis developed resistance to paraquat, oxadiazon and oxyflourfen but control of this weed was possible using other herbicides of different mechanism of action. Herbicide rotation or other nonchemical weed control methods have been suggested to prevent or reduce the buildup and spread of resistant populations of this weed species. These results represent the first report on herbicide resistance of C. bonariensis in Jordan.

Common Waterplantain,Alisma plantago-aquatica, Control in Wild Rice,Zizania palustris, with MCPA and 2,4-D

1988 ◽  
Vol 2 (3) ◽  
pp. 310-316 ◽  
Author(s):  
Joel K. Ransom ◽  
Ervin A. Oelke
Keyword(s):  
Wild Rice ◽  
Growth Stage ◽  
Field Experiments ◽  
Rice Yield ◽  
Leaf Growth ◽  
Application Time ◽  
Flowering Stage ◽  
Leaf Stage ◽  
Late Season ◽  
Treatment Stage

Field experiments were conducted to evaluate the effect of application time on common waterplantain control in wild rice with MCPA and 2,4-D. Common waterplantain control was greatest when MCPA or 2,4-D were applied at 1.1 or 1.7 kg ai/ha at the two-aerial leaf stage. The best late-season control was MCPA applied at the scape elongation growth stage. Common waterplantain was controlled adequately when 0.6 to 0.8 kg/ha of MCPA were applied at the scape elongation or early flowering stage. However, because of common water plantain interference and sensitivity of wild rice to late herbicide applications, the best treatment stage for wild rice yield was when MCPA was applied at 0.6 kg/ha to common waterplantain at the two-aerial leaf stage. Wild rice at this time is at the more tolerant one-aerial leaf growth stage.

Mentha arvensis control with amino triazole and glyphosate

1991 ◽  
Vol 71 (2) ◽  
pp. 561-563 ◽  
Author(s):  
J. A. Ivany
Keyword(s):  
Key Words ◽  
Field Experiments ◽  
Visual Control ◽  
Mentha Arvensis ◽  
Flowering Stage ◽  
Leaf Stage ◽  
Comparable Control

Field experiments showed that field mint (Mentha arvensis L.) could be controlled by using amino triazole or glyphosate applied where a crop was not present. Both herbicides gave comparable control with application at the six-leaf stage but, at the flowering stage, glyphosate was more effective than amino triazole, based on visual control rating in the year of application. Counts of regrowth shoots per square meter the next summer showed both herbicides to be equally effective in controlling field mint. Application at the flowering stage was more effective than at the six-leaf stage in one of the 2 yr of the study. Key words: Mentha arvensis, amino triazole, glyphosate, application stage, field mint

scholarly journals Effects of Almond Leaf Scorch Disease on Almond Yield: Implications for Management

Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 409-414 ◽  
Author(s):  
Mark S. Sisterson ◽  
Jianchi Chen ◽  
Mario A. Viveros ◽  
Edwin L. Civerolo ◽  
Craig Ledbetter ◽  
...  
Keyword(s):  
Yield Loss ◽  
Disease Incidence ◽  
Central Valley ◽  
Effective Management ◽  
Leaf Scorch ◽  
Lost Productivity ◽  
Direct Contrast ◽  
Management Techniques ◽  
Simple Economic ◽  
Almond Leaf Scorch

Almond leaf scorch (ALS) disease has been present in California's almond-growing regions for over 60 years. This disease is caused by the bacterium Xylella fastidiosa and the pathogen is vectored by xylem-feeding sharpshooters and spittlebugs. Currently, there are no effective management techniques that prevent trees from becoming infected. Within affected orchards throughout California's Central Valley, disease incidence and the risk of tree-to-tree spread appears to be low. Consequently, the decision to remove or keep infected trees depends on lost productivity. We compared yield and vitality between infected and uninfected almond for cvs. Sonora and Nonpareil. Sonora was examined at three sites over 3 years and Nonpareil was examined at one site over 2 years. Yields of ALS-affected trees were significantly lower for both cultivars, although yield losses of Sonora were proportionally greater than those of Nonpareil. Yields of infected trees did not decline incrementally over years; rather, they fluctuated similarly to those of uninfected trees. In addition, no infected trees died during the course of the study. These results are in direct contrast to previous anecdotal reports which suggest that yields of infected trees incrementally decline and infected trees eventually die. A simple economic model was developed to determine conditions under which rouging infected trees would increase returns. Based on the model, orchard age, yield loss due to infection, and the value of a maximally producing almond tree should be considered when deciding to remove ALS-affected trees.

scholarly journals Control of Volunteer Glyphosate-Resistant Canola in Glyphosate-Resistant Sugar Beet

2015 ◽  
Vol 29 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha
Keyword(s):  
Sugar Beet ◽  
Field Experiments ◽  
Agricultural Research ◽  
Effective Control ◽  
Additional Advantage ◽  
Leaf Stage ◽  
Beet Root ◽  
Control Volunteer ◽  
Sugar Beet Root ◽  
Herbicide Programs

Occurrence of glyphosate-resistant (GR) canola volunteers in GR sugar beet is a management concern for growers in the Northern Great Plains. Field experiments were conducted at the Southern Agricultural Research Center near Huntley, MT, in 2011 and 2012 to evaluate effective herbicide programs to control volunteer GR canola in GR sugar beet. Single POST application of triflusulfuron methyl alone at the two-leaf stage of sugar beet was more effective at 35 compared with 17.5 g ai ha−1. However, rate differences were not evident when triflusulfuron methyl was applied as a sequential POST (two-leaf followed by [fb] six-leaf stage of sugar beet) program (17.5 fb 17.5 or 35 fb 35 g ha−1). Volunteer GR canola plants in the sequential POST triflusulfuron methyl–containing treatments produced little biomass (11 to 15% of nontreated plots) but a significant amount of seeds (160 to 661 seeds m−2). Ethofumesate (4,200 g ai ha−1) PRE followed by sequential POST triflusulfuron methyl (17.5 or 35 g ha−1) provided effective control (94 to 98% at 30 d after treatment [DAT]), biomass reduction (97%), and seed prevention of volunteer GR canola. There was no additional advantage of adding either desmedipham + phenmedipham + ethofumesate premix (44.7 g ha−1) or ethofumesate (140 g ha−1) to the sequential POST triflusulfuron methyl–only treatments. The sequential POST ethofumesate-only (140 fb 140 g ha−1) treatment provided poor volunteer GR canola control at 30 DAT, and the noncontrolled plants produced 6,361 seeds m−2, which was comparable to the nontreated control (7,593 seeds m−2). Sequential POST triflusulfuron methyl–containing treatments reduced GR sugar beet root and sucrose yields to 18 and 20%, respectively. Consistent with GR canola control, sugar beet root and sucrose yields were highest (95 and 91% of hand-weeded plots, respectively) when the sequential POST triflusulfuron methyl–containing treatments were preceded by ethofumesate (4,200 g ha−1) PRE. Growers should utilize these effective herbicide programs to control volunteer GR canola in GR sugar beet. Because of high canola seed production potential, as evident from this research, control efforts should be aimed at preventing seed bank replenishment of the GR canola volunteers.

scholarly journals Fall and spring seeding date effects on herbicide-tolerant canola (Brassica napus L.) cultivars

2004 ◽  
Vol 84 (2) ◽  
pp. 419-430 ◽  
Author(s):  
G. W. Clayton ◽  
K. N. Harker ◽  
J. T. O’Donovan ◽  
R. E. Blackshaw ◽  
L. M. Dosdall ◽  
...  
Keyword(s):  
Field Experiments ◽  
Plant Density ◽  
Early Spring ◽  
Yield Response ◽  
Management Options ◽  
Brassica Napus L ◽  
Seeding Date ◽  
Herbicide Tolerant ◽  
Root Maggot ◽  
Crops Yield

More flexible and effective weed control with herbicide-tolerant B. napus canola allows for additional seeding management options, such as fall (dormant) and early spring (ES) seeding. Field experiments were conducted at Lacombe and Beaverlodge (1999–2001), Didsbury (1999–2000), and Lethbridge (2000–2001), Alberta, Canada, primarily to evaluate the effect of fall (late October-November), ES (late April-early May), and normal spring (NS) (ca. mid-May) seeding dates on glufosinate-, glyphosate-, and imidazolinone-tolerant canola development and yield. Fall seeding resulted in 46% lower plant density and nearly double the dockage than spring seeding. ES-seeded canola had 19% higher seed yield and 2.1% higher oil content than fall-seeded canola. ES seeding significantly increased yield compared to fall-seeded canola for 8 of 10 site -years or compared to NS seeding for 4 of 10 site-years; ES-seeded canola equalled the yield of NS-seeded canola for 6 of 10 site-years. Yield response to seeding date did not differ among herbicide-tolerant cultivars. Seeding date did not influence root maggot damage. Seeding canola as soon as possible in spring increases the likelihood of optimizing canola yield and quality compared to fall seeding and traditional spring seeding dates. Key words: Dormant seeding, seeding management, root maggot, herbicide-resistant crops, yield components, operational diversity

scholarly journals Givira ethela (Neumoegen and Dyar, 1893) (Lepidoptera: Cossidae), A Previously Unidentified Pest on Vitis vinifera (L.)

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 239
Author(s):  
Davide Scaccini ◽  
Enrico Ruzzier ◽  
Kent M. Daane
Keyword(s):  
Vitis Vinifera ◽  
Natural Enemies ◽  
Management Practices ◽  
Agricultural Sector ◽  
Central Valley ◽  
Vitis Vinifera L ◽  
Correct Identification ◽  
Pest Species ◽  
Monitoring Methods ◽  
Management Options

Grape cultivation is a billion-dollar agricultural sector in California, where invasive or novel pest species can disrupt management practices. We report herein on a new pest associated with California vineyards, the carpentermoth Givira ethela (Neumoegen and Dyar, 1893). Rather than an invasive species, G. ethela appears to be a newly recognized wood-boring pest of Vitis vinifera (L.) in regions of California’s Central Valley, where its initial occurrence has been dated back to, at least, the beginning of the 2000s. The habitus of adult, genitalia and pupa is illustrated. Givira ethela distribution in California is updated including published records and new data. Carpentermoth galleries seem to facilitate the access of Planococcus ficus Signoret, 1875 to vine sap and protection from natural enemies, environmental stresses, and pesticide treatments. Notes on pest status, life history, monitoring practices, natural enemies, and management options on grapes are also discussed. Tools for the Integrated Pest Management of G. ethela should include the correct identification of the insect and its damage, a full understanding of its biology and ecology, the application of monitoring methods, and the identification of economic thresholds and injury levels.

Lack of Cross-Resistance of Paraquat-Resistant Hairy Fleabane (Conyza bonariensis) to Other Toxic Oxygen Generators Indicates Enzymatic Protection is Not the Resistance Mechanism

Weed Science ◽  
1989 ◽  
Vol 37 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Kevin C. Vaughn ◽  
Martin A. Vaughan ◽  
Patrick Camilleri
Keyword(s):  
Electron Microscopy ◽  
Chlorophyll Fluorescence ◽  
Resistance Mechanism ◽  
Cross Resistance ◽  
Oxygen Generator ◽  
Conyza Bonariensis ◽  
Singlet Oxygen Generator ◽  
Chlorophyll Bleaching ◽  
Direct Measures ◽  
Hairy Fleabane

Cross-resistance of the paraquat-resistant (R) hairy fleabane to other compounds that accept electrons from photosystem I (PSI) or produce toxic oxygen species was determined by chlorophyll loss, electron microscopy, and chlorophyll fluorescence suppression. Although the R bioype is approximately 100 x more resistant to paraquat than the susceptible (S) biotype based upon the assays for tissue damage, little or no cross-resistance was observed to a number of other PSI electron acceptors, including the bipyridilium herbicide morfamquat. A low level of resistance (approximately 10-fold) was noted to diquat and the singlet oxygen generator rose bengal. As measured by chlorophyll fluorescence suppression, the R biotype was about 100-fold resistant to paraquat, but only 10-fold resistant to diquat, and exhibited no resistance to morfamquat. Because differences observed with this protocol are direct measures of the ability of the herbicide to reach the active site and the results correlate with the level of resistance observed by chlorophyll bleaching or electron microscopy, these data suggest that compartmentalization is the major factor in paraquat resistance in hairy fleabane.

scholarly journals Coexisting ecosystem states in a tropical coastal lagoon under progressive eutrophication in the northern Cuban keys

2018 ◽  
Vol 82 (3) ◽  
pp. 139 ◽  
Author(s):  
Roberto González-De Zayas ◽  
Martin Merino-Ibarra ◽  
Patricia M. Valdespino-Castillo ◽  
Yunier Olivera ◽  
Sergio F. Castillo-Sandoval
Keyword(s):  
Residence Time ◽  
Coastal Lagoon ◽  
Spatial And Temporal Variability ◽  
Positive Trend ◽  
Water Residence Time ◽  
Effective Management ◽  
Management Options ◽  
Trophic Index ◽  
Tropical Coastal Lagoon ◽  
Mollusc Assemblages

Through a nested suite of methods here we contrast the coexistence of different ecosystem states in a tropical coastal lagoon, the Laguna Larga, with increasing eutrophication stress between 2007 and 2009. Water temperature averaged 27.4°C in the lagoon and showed a slight positive trend during the study period. Salinity averaged 35.0±6.2, exhibiting high spatial and temporal variability, and also a slight positive trend in time. In contrast, dissolved oxygen showed a substantial decreasing trend (–0.83 ml L–1 y–1; –13.3% y–1) over the period, while nutrients increased dramatically, particularly total phosphorus (2.6 µM y–1), in both cases sustaining the progression of eutrophication in the lagoon during the three years we sampled. The Karydis nutrient load-based trophic index showed that the lagoon has a spatial pattern of increasing eutrophication from the sea and the outer sector (oligotrophic-mesotrophic) to the central (mesotrophic) and the inner sector (mesotrophic-eutrophic). Two ecosystem states were found within the lagoon. In the outer oligotrophic sector, the dominant primary producers were macroalgae, seagrasses and benthic diatoms, while mollusc assemblages were highly diverse. In the inner and central sectors (where trophic status increased toward the inner lagoon) a phytoplankton-dominated ecosystem was found where mollusc assemblages are less diverse. In spite of the progression of eutrophication in the lagoon, these two different ecosystems coexisted and remained unchanged during the study period. Apparently, the effect of water residence time, which increases dramatically toward the inner lagoon, dominated over that of nutrient loadings, which is relatively more homogeneously distributed along the lagoon. Therefore, we consider that actions that reduce the water residence time are likely the most effective management options for this and other similarly choked lagoons.

SAWFLY RESISTANCE IN WHEAT: III. CHANGES IN RESISTANCE DURING THE DEVELOPMENT OF THE WHEAT PLANT

1960 ◽  
Vol 40 (1) ◽  
pp. 7-20 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
Quantitative Data ◽  
Field Experiments ◽  
Wheat Plant ◽  
Flowering Stage ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Stage Of Development ◽  
First Instar ◽  
Golden Ball

Quantitative data obtained in field experiments showed that the resistance of wheat to attack by the wheat stem sawfly (Cephus cinctus Nort.) depended on the stage of development of the plants at the time of oviposition. Wheat plants were usually most heavily infested for a part or all of the period from 1 week before shot blade to 1 week after the flowering stage. Rescue, H46146, H4191, Golden Ball, and Melanopus lost their resistance to the development of the eggs and first-instar larvae some time between shot blade and flowering. Thatcher and Red Bobs did not show this type of resistance. The mortality of the older larvae increased in plants infested toward maturity. The time at which this increase began depended on the variety involved and ranged from just before shot blade to just after flowering.

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