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Title: Sustainable Management of Megalurothrips distalis Karny (Thysanoptera: Thripidae) in Mungbean, Vigna radiata L.
Authors: Nadeem, Muhammad
Keywords: Agriculture and Veterinary Sciences
Issue Date: 2021
Publisher: Gomal University, D.I.Khan.
Abstract: A series of field experiments were conducted during the 2018 and 2019 Kharif season at Arid Zone Research Institute, Bhakkar to find out the effect of different resistance and susceptible mungbean” genotypes to Megalurothrips distalis L. populationin relation to weather factors. During 2018, from the preliminary screening trial twenty-five mungbean genotypes were screened against M. distalis. Based on mean thrips population per flower, Sawat-1, Dera-M and NM-98 were found comparatively susceptible. Whereas, 13TM-04, NM-16 and AZRI-06 were found to be comparatively resistant. The genotypes NM-11, 12TM-03 and NM-06 showed intermediate response. During final screening trial in 2019, the resistance/susceptible response towards thrips in the selected genotypes found to be similar to that observed during the preliminary trial. During 2019, Dera-M showed maximum whereas, 13TM-04 showed minimum thrips population per flower. While the genotype 12TM-03 and NM-06 showed intermediate response aganist thrips followed by NM-11. Maximum HPSI, 15% was recorded in Dera –M while the minimum was recorded on 13TM-04 and NM-16 each with 8% based on cumulative data of both years. Due to susceptibility against thrips, Dera-M showed maximum flowers shedding per plant followed by Sawat-1 and NM-98 which ultimately resulted minimum total number of pods per plant. Moreover, maximum deformed pods, minimum seed per pod, minimum seed weight per plant, per ha were recorded in in both of these genotypes. While minimum flower shedding per plant and maximum hundred seed weight were recorded in AZRI-06, NM-16 and 13TM-04. Highest total pods per plant and minimum deformed pods per plant were recorded in 13TM-04 which was statistically similar to NM-16 followed by AZRI-06. Genotype 13TM-04 showed maximum number of seeds/pod with maximum seed weight per plant. Thrips population data in relation to various climate factors during the research years 2018 and 2019 showed that maximum population (5.32/flower) was observed, on the 04th July, at 35.50 °C average temperature, with 51.75% relative humidity % (RH) and with no rainfall. Maximum and average temperature showed highly significant correlation (r values 0.90 and 0.668 respectively) with thrips population. Whereas negative and significant correlation (r values 0.732 and 0.750)) with RH % and average rainfall. Whereas, non significant correlation was found with minimum temperature during both years and on cumulative basis. Among the four different tested entompathogenic fungi, Beauveria bassiana @ 7.5% concentration was found to be most effective compared to other tested EPF. While, Verticillium lecanii and Isaria fumosoroseus were found least effective against thrips. Efficacy of each tested EPF increased up to seven days but after fourteen days EPFs lost their efficacy. On cumulative basis B. bassiana @ 7.5% resulted in minimum number of thrips 1.76 per flower with maximum 59.42 percent reduction over control was found significantly effective than rest of the tested EPFs. Also, B. bassiana @ 7.5% treated plots significantly increased the yield 1018.9 kg ha-1 as compared to other tested EPFs. For the determination of the color preference of thrips five coloured sticky traps viz., yellow, blue, white, green and orange were evaluated on the mungbean variety NM- ix 2016. Among tested colored sticky traps blue followed by yellow color sticky trap attracted maximum number of thrips. Among various physio-morphological plant characters the moisture contents, number of fruiting branches and height had positive and significant correlation (r values 0.759, 0.897 and 0.883 respectively) while the dry matter, total pods number, pods length and per pod seed number exhibited negative and significant correlation ( r values 0.778, 0.936, 0.906 and 0.928 respectively with population of thrips. The moisture contributed maximum 57.6% in thrips population fluctuation followed by dry matter which showed 21.9% change in thrips population. Among various chemical plant characters, the effect of nitrogen, crude protein, reducing sugar, zinc and copper showed positive and significant correlation whereas those of non reducing sugar and boron have negative and significant correlation with thrips population on ‘mungbean’. However, phosphorous, potassium, ash, ether extract, total sugar, ferrous and manganese did not show a significant correlation with thrips population on ‘mungbean’. The nitrogen percentage in the mungbean flowers was the most significant factor contributing 59.9% increase in thrips population followed by reducing sugar (15.5%), non reducing sugar (9.9%) and protein (6.2). All other factors contributed between 0.1 to 1.4% when assessed individually, towards the thrips population fluctuation. Various control practices, viz., host plant resistance, imidacloprid seed-treatment+ use of blue sticky trap, neem seed kernel extract, entomopathogenic fungi B. bassiana and insecticides acephate and chlorfenapyr were applied separately as well as in their possible combinations, on a comparatively thrips resistant genotype of mungbean, 13TM 04 to control thrips population at three different locations of district Bhakkar during 2020. A combination of treatments, viz., imidacloprid seed treatment+ installation of blue sticky traps and chlorfenapyr spray was observed to be the most successful against thrips and showed maximum yield 1970.1 kg/ha of mungbean. While the outcome of imidacloprid seed-treatment+ blue sticky trap installation, alone, did not have distinctive impact on the thrips population as well as on the yield. The imidacloprid seeds treatment remained effective up to 38 days after sowing against the thrips. The application of chlorfenapyr and acephate when applied as aerial spray, alone and in combination with other control methods showed a significant decrease in the thrips population
Gov't Doc #: 25770
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

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