scholarly journals A dual infection of two microscopic fungi on common milkweed (Asclepias syriaca) in Hajdúság region (East-Hungary)

2017 ◽  
pp. 189-195
Author(s):  
Tamás Tóth

Common milkweed (Asclepias syriaca L.) is one of the most noxious and invasive weed species in Hungary. A. syriaca invades arable lands, horticultural and forestry plantations, natural and semi-natural habitats too. In cases of field crops it can cause considerable yield losses mostly in maize (2–10%), soybean (12–32%) and sorghum (4–29%), but only with high rate of coverage. It can also increase these problems that the common milkweed can be serve as reservoir and host for viruses, other pathogens and pests.Because of the importance of common milkweed and in spite of demand to develop effective biological control, until now has not been developed a proper control program against A. syriaca. The aim of our research was to identify the necrotrophic fungal pathogens, which were involved in notable disease occurrence on this weed in different parts of Hajdúság region of Eastern-Hungary in 2016.To the isolation of fungi from leaves and their identification were based on morphological colony characters on potato dextrose agar (PDA) and Sabouraud dextrose agar (SDA). To the description of conidia features were used PDA for Alternaria and synthetic low-nutrient agar (SNA) for Fusarium species, respectively. The examination of axenic cultures revealed that the fungi isolated from the leaves of common milkweed were Fusarium sporotrichioides and Alternaria alternata.

2020 ◽  
Vol 34 (6) ◽  
pp. 834-842
Author(s):  
Caio A. C. G. Brunharo ◽  
Seth Watkins ◽  
Bradley D. Hanson

AbstractWeed control in tree nut orchards is a year-round challenge for growers that is particularly intense during winter through summer as a result of competition and interference with management and harvest operations. A common weed control program consists of an application of a winter PRE and POST herbicide mixture, followed by a desiccation treatment in early spring and before harvest. Because most spring and summer treatments depend on a limited number of foliar-applied herbicides, summer-germinating species and/or herbicide-resistant biotypes become troublesome. Previous research has established effective PRE herbicide programs targeting winter glyphosate-resistant weeds. However, more recently, growers have reported difficulties in controlling several summer-germinating grass weeds with documented or suspected resistance to the spring and summer POST herbicide programs. In this context, research was conducted to evaluate a sequential PRE approach to control winter- and summer-germinating orchard weeds. Eight field experiments were conducted in tree nut orchards to evaluate the efficacy of common winter herbicide programs and a sequential herbicide program for control of a key summer grass weed species. In the sequential-application strategy, three foundational herbicide programs applied in the winter were either mixed with pendimethalin, followed with pendimethalin in March, or applied as a split application of pendimethalin in both winter and spring. Results indicate that the addition of pendimethalin enhanced summer grass weed control throughout the crop growing season by up to 31%. Applying all or part of the pendimethalin in the spring improved control of the summer grass weed junglerice by up to 49%. The lower rate of pendimethalin applied in the spring performed as well as the high rate in the winter, suggesting opportunities for reducing herbicide inputs. Tailoring sequential herbicide programs to address specific weed challenges can be a viable strategy for improving orchard weed control without increasing herbicide use in some situations.


2018 ◽  
pp. 201-204
Author(s):  
Tamás Tóth ◽  
Arnold Szilágyi ◽  
György Kövics

A study of fungi responsible for severe leaf spots of common milkweed (Asclepias syriaca L.) in the Hajdúság region (East Hungary), Fusarium sporotrichioides and Alternaria alternata were isolated from infested leaf tissues. F. sporotrichioides was the most virulent fungus in pathogenicity tests conducted on healthy leaves of common milkweed plants. Inoculation of common milkweed (A. syriaca) in different growth stages with F. sporotrichioides yielded similar symptoms as the original ones. Spray mixtures containing 1.0×106 conidia/ml gave effective control when common milkweed plants were sprayed until runoff occurred. Laboratory (wet chamber) and field experiments showed that asexual spores of the fungal pathogen, F. sporotrichioides, exhibited bioherbicidal activity against common milkweed (A. syriaca). More efficient control efficacy was observable on elder plants (at flowering stage) than younger ones. These results initiate that this fungus may be a biocontrol agent for controlling this invasive weed but should clarify its hosts because it could infect cultivated plants as well.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Jackline Abu-Nassar ◽  
Maor Matzrafi

Solanum rostratum Dunal is an invasive weed species that invaded Israel in the 1950s. The weed appears in several germination flashes, from early spring until late summer. Recently, an increase in its distribution range was observed, alongside the identification of new populations in the northern part of Israel. This study aimed to investigate the efficacy of herbicide application for the control of S. rostratum using two field populations originated from the Golan Heights and the Jezreel Valley. While minor differences in herbicide efficacy were recorded between populations, plant growth stage had a significant effect on herbicide response. Carfentrazone-ethyl was found to be highly effective in controlling plants at both early and late growth stages. Metribuzin, oxadiazon, oxyfluorfen and tembutrione showed reduced efficacy when applied at later growth stage (8–9 cm height), as compared to the application at an early growth stage (4–5 cm height). Tank mixes of oxadiazon and oxyfluorfen with different concentrations of surfactant improved later growth stage plant control. Taken together, our study highlights several herbicides that can improve weed control and may be used as chemical solutions alongside diversified crop rotation options. Thus, they may aid in preventing the spread and further buildup of S. rostratum field populations.


2020 ◽  
Vol 12 (18) ◽  
pp. 7816
Author(s):  
Vivek Kumar ◽  
Lucky Mehra ◽  
Cindy L. McKenzie ◽  
Lance S. Osborne

The early establishment of a biocontrol agent in the production system, whether in the greenhouse, nursery, or field, is essential for the success of the biological control program, ensuring growers’ profitability. In an effort to develop a sustainable pest management solution for vegetable growers in Florida, we explored the application of a preemptive biological control strategy, “Predator-In-First” (PIF), in regulating multiple pepper pests, Bemisia tabaci Gennadius, Frankliniella occidentalis Pergande, and Polyphagotarsonemus latus Banks under greenhouse and field conditions during different growing seasons. In these studies, two bell pepper cultivars (7039 and 7141) and the phytoseiid mite Amblyseius swirskii Athias–Henriot were used as a model system. Pepper seedlings (~8 week) of each cultivar were infested with varying rates of A. swirskii (20 or 40 mites/plant or one sachet/10 plant) and allowed to settle on plant hosts for a week before planting in pots or field beds. Results showed a comparative consistent performance of the treatment with the high rate of phytoseiids (40 mites/plant) in regulating B. tabaci and F. occidentalis populations in greenhouse studies, and B. tabaci and P. latus pests under field conditions. During two fall field seasons, higher marketable yields of 12.8% and 20.1% in cultivar 7039, and 24.3% and 39.5% in cultivar 7141 were observed in the treatment with the high rate of phytoseiids compared to the untreated control, indicating yield benefits of the approach. The outcome of the study is encouraging and demonstrates that PIF can be an important tool for organic vegetable growers and a potential alternative to chemical-based conventional pest management strategies. The advantages and limitations of the PIF approach in Florida pepper production are discussed.


2015 ◽  
Vol 22 (1) ◽  
Author(s):  
Annabella T. Carcusia ◽  
Pet Roey L. Pascual ◽  
James Francienne J. Rosit

Synthetic herbicide, the most popular weed control, causes environmental hazards. The use of allelopathy in controlling weeds is a possible alternative for sustainable weed management. The study was conducted to determine the allelopathic potentials of identified invasive weed species in terms of percent and rate of germination, plant height, length of leaves and roots and percent mortality of grasses, sedges, and broadleaves. The treatments were: T0-Pre/Post-emergence Herbicide, T1Tap Water, T2-Mimosa pudica extract,T3-Lantana camara extract,T4-Chromolaena odorata extract. These were compared according to their effects on Cenchrus spinifex, Conyza canadensis, Impatiens wallerana and Cyperus rotundus. Data were analyzed using Analysis of Variance (ANOVA) for Completely Randomized Design. A further test was done using Duncans Multiple Range Test (DMRT). For germination, Lantana camara is effective in reducing the percent germination and prolonging germination rate of most common weed species. On the other hand, Chromolaena odorata is effective in reducing the percent germination and prolonging the germination rate of Impatiens wallerana, while Mimosa pudica was effective against Cenchrus spinifex and Cyperus rotundus. For growth and development, Mimosa pudica was found to be the most effective in all common weed species, except for Cyperus rotundus where Chromolaena odorata was most effective on reducing the length of leaves and roots, and above ground fresh weight. Furthermore, Chromolaena odorata was found effective against both Cyperus rotundus and Conyza canadensis while Mimosa pudica was effective against Cenchrus spinifex in terms of percent mortality. Thus, such potential of invasive weed species for weed management should be utilized. 


2020 ◽  
Author(s):  
Marianne Jennifer Datiles ◽  
Ian Popay

Abstract Foeniculum vulgare, also known as sweet fennel, is a common kitchen herb used around the world - but it is also a highly invasive weed that can severely damage ecosystems. A risk assessment prepared for Hawaii gave the species a high risk score of 19 (PIER, 2015). F. vulgare is known to alter fire regimes and create dense stands, outcompeting native flora for nutrients and space (DiTomaso et al., 2013; Cal-IPC, 2015). It was listed in the Global Compendium of Weeds as an "agricultural weed, casual alien, cultivation escape, environmental weed, garden thug, naturalised, noxious weed, weed" (Randall, 2012), and is known to be invasive (mostly in natural habitats rather than agricultural land) in California, New Zealand, significant parts of Australia and a number of locations in the Pacific. (PIER, 2015). The species is a principal weed in Mexico and New Zealand, a common weed in Argentina, Australia, Hawaii, and Spain, weedy in Chile, Morocco, Uruguay, the USA, and Venezuela, and it is known to be adventive in China, Colombia (Holm et al., 1979; Flora of China Editorial Committee, 2015; PIER, 2015; Vascular Plants of Antioquia, 2015). It is also reported as invasive in Ethiopia and Kenya. It can regenerate by both seeds and roots, which often makes physical control methods ineffective and chemical control necessary once a population is established.


2007 ◽  
Vol 87 (4) ◽  
pp. 275-284 ◽  
Author(s):  
David Thornby ◽  
David Spencer ◽  
Jim Hanan ◽  
Anna Sher

2021 ◽  
Author(s):  
Julissa Rojas-Sandoval

Abstract M. nudiflora is classified as one of the world's worst weeds by Holm et al. (1977), infesting no less than 16 crops in 23 countries. It is a major weed species in rice and other crops (Moody, 1989), and is a moderately invasive weed species both in agricultural crops and non-agricultural areas in South and South-east Asia (Waterhouse, 1993). Its special ability to root easily at the nodes, propagating clonally through cut stems and dispersal during tillage and land preparation make this weed difficult to control. This trait coupled with its ability to adapt and survive a wide ecological window of soil types, pH, moisture availability and soil drainage makes M. nudiflora a weed to watch for potential spread into new areas in near future, and a species under the 'alert list' by the Invasive Species Specialist Group. Oliveira Pellegrini et al. (2016) recognize M. nudiflora as one of two Murdannia species invasive in the Neotropics.


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