scholarly journals Thrips (Thysanoptera) associated with onion (Allium cepa L.) and Welsh onion (Allium fistulosum L.)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Marta Olczyk ◽  
Maria Pobożniak

AbstractWe determined the abundance, species composition, sex ratio and seasonal dynamics of thrips on one cultivar of Welsh onion (Allium fistulosum) and eight cultivars of onion (Allium cepa) in South Poland within three vegetation seasons (2014–2016). Nine species of Thysanoptera were identified on A. cepa and A. fistulosum. Irrespective of the onion cultivar, Thrips tabaci was the dominant species (64.4% of all collected thrips specimens), while Frankliniella intonsa also occurred in high numbers (28.3%). Conversely, Welsh onion was most often inhabited by F. intonsa (62.7%), although T. tabaci was also numerous (28.3%). The predatory Aeolothrips intermedius accounted for 4.5% on A. cepa and 2.9% on A. fistulosum. In the most numerous species, T. tabaci, F. intonsa and A. intermedius populations were formed mainly by females. The cultivar most colonised by thrips was Kroll of A. fistulosum. The tested cultivars of A. cepa demonstrated varying degrees of attractiveness to thrips in the subsequent years. The relationship between populations of T. tabaci, F. intonsa and A. intermedius changed in the subsequent months of the growing season. In June, mainly T. tabaci and F. intonsa occurred on onion plants, while from July, the percentage shares of F. intonsa and the predatory A. intermedius in the thrips population on many onion cultivars increased. The level of attractiveness of A. cepa related to onion thrips, which is reported as a main pest of onion, varies depending on the year and cultivar.

2018 ◽  
Vol 87 (2) ◽  
pp. 165-176
Author(s):  
Muhammad Asghar ◽  
Mirza Muhammad Qadeer Baig ◽  
Muhammad Afzal ◽  
Naeem Faisal

Abstract The efficacy of five insecticides containing a.i. bifenthrin, dimethoate, spinosad, spinetoram and chlorfenapyr was evaluated following RCBD against Thrips tabaci in farmer’s field for two consecutive years. The data were recorded before and after 24 h, 48 h, 72 h and 7 days of spraying. The results showed that all the insecticides reduced thrips populations compared to controls. However, the maximum reduction in thrips population and highest onion bulb yield (34.07 t/ha) was obtained with dimethoate 40EC followed by bifenthrin 10EC (33.14 t/ha). The minimum onion bulb yield (25.71 t/ha) was obtained in the control, where no insecticide was applied against thrips. If onion thrips are not controlled, the damage they cause can reduce bulb yields by 9-25%. The highest incremental return over the control (Rs.83, 600/ha), net income (Rs.82, 913/ha) and maximum cost benefit ratio were also obtained in the treatment with dimethoate 40EC.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 769A-769
Author(s):  
M. Kopelberg ◽  
I.L. Goldman ◽  
J.E.P. Debaene ◽  
B.S. Schwartz

Onion (Allium cepa L.) and other vegetable Alliums have long been recognized for the antiplatelet properties. Consumers may benefit from the medicinal value of onions because they are commonly eaten raw in salads and the antiplatelet factor is destroyed by heat. Recent work indicates antiplatelet activity in Allium sp. may be due to the presence of native organosulfur compounds. The concentration of organosulfur compounds correlates positively with pungency, varies with onion cultivar, and is influenced by environmental factors. Bulb dry matter content, or solids, is positively correlated with pungency. Because antiplatelet activity may also be based on the activity of organosulfur compounds, it is possible these three factors are significantly correlated. The objective of this investigation was to examine the relationship among pungency, solids, and antiplatelet activity in four diverse onion genotypes. Replicated trials consisting of two mild and two pungent genotypes were conducted at four locations in 1994. Onion bulbs were harvested and analyzed for all three traits. Results from this investigation indicate significant positive correlations between antiplatelet activity, pungency, and solids in onion.


2020 ◽  
pp. 159-169
Author(s):  
Narel Y. Paniagua-Zambrana ◽  
Rainer W. Bussmann ◽  
Carolina Romero

2013 ◽  
Vol 39 (2) ◽  
pp. 341-345
Author(s):  
Roch W. Doruchowski

The research was carried out in 1977 and 1978. The inheritance of undertones, dry skin color from light straw to brown was controlled by two additive genes. The segregation ratio obtained was 15:1 and 11:5. The dry skin of a dark color (dark yellow, bronze, brown ochre, orange-brown) was stronger than the skin with a straw yellow or yellow color. Skin adherence was strictly related to its color. This was proved by statistical analysis of the correlation.


Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 938-943 ◽  
Author(s):  
A. S. Grode ◽  
E. Brisco-McCann ◽  
P. Wiriyajitsonboom ◽  
M. K. Hausbeck ◽  
Z. Szendrei

Onion thrips (Thrips tabaci) is a major insect pest of onion and it has been identified as a likely vector of Pantoea agglomerans (bacterial stalk and leaf necrosis), a relatively new pathogen to Michigan’s onion industry. Our objective was to develop an integrated insect and disease management program by examining the efficacy of bactericides and insecticides alone and in combination to limit bacterial stalk and leaf necrosis caused by P. agglomerans. We also examined the association of onion thrips and disease incidence in the field, because thrips are known to transmit this pathogen. In the pesticide trial, insecticides reduced both thrips abundance and bacterial stalk and leaf necrosis incidence whereas bactericides alone did not reduce disease severity. Positive correlations among thrips population density, numbers of thrips positive for P. agglomerans, and bacterial stalk and leaf necrosis incidence in onion fields were determined. This study suggests that onion thrips feeding can facilitate the development of bacterial stalk and leaf necrosis in Michigan’s commercial onion fields, and results from the pesticide trials indicate that thrips feeding damage is positively correlated with disease incidence. Therefore, in order to reduce bacterial stalk and leaf necrosis incidence in onion, management efforts should include reducing onion thrips populations through the use of insecticides and other cultural practices.


Genome ◽  
2015 ◽  
Vol 58 (4) ◽  
pp. 135-142 ◽  
Author(s):  
Tadayuki Wako ◽  
Ken-ichiro Yamashita ◽  
Hikaru Tsukazaki ◽  
Takayoshi Ohara ◽  
Akio Kojima ◽  
...  

Bunching onion (Allium fistulosum L.; 2n = 16), bulb onion (Allium cepa L. Common onion group), and shallot (Allium cepa L. Aggregatum group) cultivars were inoculated with rust fungus, Puccinia allii, isolated from bunching onion. Bulb onions and shallots are highly resistant to rust, suggesting they would serve as useful resources for breeding rust resistant bunching onions. To identify the A. cepa chromosome(s) related to rust resistance, a complete set of eight A. fistulosum – shallot monosomic alien addition lines (MAALs) were inoculated with P. allii. At the seedling stage, FF+1A showed a high level of resistance in controlled-environment experiments, suggesting that the genes related to rust resistance could be located on shallot chromosome 1A. While MAAL, multi-chromosome addition line, and hypoallotriploid adult plants did not exhibit strong resistance to rust. In contrast to the high resistance of shallot, the addition line FF+1A+5A showed reproducibly high levels of rust resistance.


2013 ◽  
Vol 152 (6) ◽  
pp. 885-893 ◽  
Author(s):  
M. POBOŻNIAK ◽  
E. H. KOSCHIER

SUMMARYThe polyphagous onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae) is a serious pest in many protected and field crops and has recently been found to occur in high numbers in Pisum sativum L. crops. In the present study, the abundance of T. tabaci was compared on two pea cultivars in the field. Data on sweep net catches at different sampling times during the day suggest that peak activity of the thrips is at noon. Significantly more thrips larvae and adults were caught on the early pea cultivar Cud Kelwedonu compared with the very early cultivar Pionier, particularly during and after flowering of the peas. Analysis of primary plant compounds indicated that the higher leaf nitrogen and sucrose contents in the leaves of cvar Cud Kelwedonu promote thrips population growth in pea. The preference of T. tabaci for leaves of cvar Cud Kelwedonu was confirmed in experiments in the laboratory. Thrips tended to settle, caused significantly more feeding damage and laid significantly more eggs on the leaves of Cud Kelwedonu. Knowledge on abundance, activity patterns and host use of T. tabaci in pea may contribute to optimizing cultivar selection, monitoring and timing of possible control measures in the future.


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