scholarly journals Evaluation of different insecticides for the management of onion thrips (Thrips tabaci Lindeman, 1889) (Thysanoptera, Thripidae) on onion (Allium cepa L.) crops

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.

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.


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.


Author(s):  
P. K. Ojha ◽  
R. Kumari ◽  
R. S. Chaudhary ◽  
N. K. Pandey

To determine Incremental Cost-Benefit Ratio (ICBR) of certain bio-pesticides and insecticide against 2nd larval instar of Helicoverpa armigera in chickpea, an experiment was conducted during winter 2011. Certain pesticides as sole treatments were tested with standard, low and high doses and in treatment combinations with one half of standard doses of two respective pesticides only once at 50% flowering and podding stage of the crop. Upon crop maturity; total grain yield, additional yield, increased income and net income were obtained for each respective treatment to determine its ICBR. Overall, the treatment combination of ½ Btk + ½ Azadirachtin had the highest ICBR of 1:27.57. The lowest ICBR of 1:5.25 was obtained with Azadirachtin-0.05 %, when other treatments had ICBR from 1:8.51 to 1:23.28.


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.


Plant Disease ◽  
2001 ◽  
Vol 85 (8) ◽  
pp. 838-842 ◽  
Author(s):  
A. Kritzman ◽  
M. Lampel ◽  
B. Raccah ◽  
A. Gera

Iris yellow spot virus (IYSV), a new tospovirus associated with a disease in onion (Allium cepa) that is known to growers in Israel as “straw bleaching,” was identified and further characterized by host range, serology, electron microscopy, and molecular analysis of the nucleocapsid gene. The transmissibility of IYSV by Thrips tabaci and Frankliniella occidentalis was studied. IYSV was efficiently transmitted by T. tabaci from infected to healthy onion seedlings and leaf pieces. Two biotypes of F. occidentalis, collected from two different locations in Israel, failed to transmit the virus. Surveys to relate the incidence of thrips populations to that of IYSV were conducted in onion fields. They revealed that the onion thrips T. tabaci was the predominant thrips species, and that its incidence was strongly related to that of IYSV. Forty-five percent of the thrips population collected from IYSV-infected onion and garlic fields in Israel transmitted the virus. IYSV was not transmitted to onion seedlings from infected mother plants through the seed, and was not located in bulbs of infected plants.


Author(s):  
Afifa Jahan ◽  
R. Arunjyothi ◽  
M. Jagan Mohan Reddy ◽  
T. Prabhakar Reddy ◽  
A. Shankar ◽  
...  

Pulses processing is a very huge business in India. In India, split of pulses are prepared called as “Dal” or “Dhal”. Regdram cultivating farmers are demotivated as there net returns are low due to continuous market fluctuation in prices of Redgram and this is becoming the reason for decrease in area of cultivation under Redgram. Milling pulses improves bio-availability of nutrients and Partial or complete removal of antinutritional and toxic compounds making it nutritive for human consumption. Mini dal mill is low investment enterprise to improve the net income of farmers. The present study concluded that the average gross income through sale of Redgram is Rs 41.3/KG without processing and Rs 63/KG with processing. The profitability is more with the processing of Redgram. The cost benefit ratio is 1:1.18 without processing and 1:1.80 with processing. Hence farmers must be educated to develop entrepreneurship and promote value added Redgram using mini dal mill.


2006 ◽  
Vol 59 ◽  
pp. 69-74
Author(s):  
N.A. Martin ◽  
P.J. Workman ◽  
D. Hedderley

Onion thrips Thrips tabaci (Thysanoptera Thripidae) is the main insect pest on New Zealand onions The onion industry recommends monitoring 50 or 100 plants in 10 or 20 groups of 5 plants and applying a cluster of insecticides when populations reach 01 thrips/plant The robustness of these guidelines was tested by monitoring six crops before and after the first cluster of insecticides Two people each recorded the numbers of adult and larval thrips in each crop on each occasion using the following strategies (1) 100 randomly stratified plants (2) 20 groups of five plants randomly selected from 1 m2 and (3) 20 groups of five adjacent plants giving a total of 300 plants sampled When sampling 100 plants estimates of thrips/plant were similar for each of the three sampling strategies However to obtain a particular level of precision fewer plants could be sampled using stratified randomly selected plants than groups of five plants


Author(s):  
Deepak Thakur ◽  
V. R. Upadhyay ◽  
Annu Ahirwar

A field experiment was conducted during kharif 2018-19 in Samajik Vigyan Kendra, Dr. B.R. Ambedkar University, Bordi, Sehore (M.P.) – INDIA. To assess the bio-efficacy of insecticides against mites and thrips insect pest of chilli pests. The bio-efficacy of three different insecticides, namely (i) Chlorfenapyr 240 SC - spray four time with different-different doses, (ii) Fipronil 5% SC and (iii) Imidacloprid 17.8 SL. One untreated plot was also used to   investigate against Mites and Thrips. Among these insecticides, Chlorfenapyr 240SC doses 288 g.a.i/hac gram active ingredient per hactare) has reduced maximum mites and thrips population and it is most effective  insecticides in chilli. The highest reduction of mites population recorded in treatment T4- (97.17%) followed by T3- chlorofenapyr (95.13%), T6- Imidacloprid (91.67%), T5- Fipronil 5% SC (85.35%), T2- chlorofenapyr (85.27%) and it was least in T1- chlorofenapyr (81.40%. Further, the thrips number  was maximum reduced in treatment T4- chlorofenapyr (90.69%) followed by T3- chlorofenapyr (89.80%), T5- Fipronil 5% SC (89.51%), T6- Imidacloprid (74.18%), T2- chlorofenapyr (69.74%) and T1- chlorofenapyr (68.44 %). Hence, present study was clearly indicated that the treatment T4- chlorofenapyr 240SC@288 proved, the most effective insecticides. The cost benefit ratio was noted higher in Fipronil 5% SC@ 10 g.a.i ha-1 (3.20) followed by imidacloprid 17.8 SL @ 50 g.a.i ha-1 (2.99).


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