The screening of safe insecticides for the natural enemies of mustard aphid
i.e. ladybird beetle and syrphid larvae. The spraying of synthetic insecticides and bio-pesticides takes place in mustard crop and adverse effects of treatments on predators’ population causing mortality were recorded.
Effect of different synthetic insecticides and bio-pesticides on Coccinellids and Syrphid larvae population during first spray 2013-14 (Table 2 and 3)
The data recorded a day before insecticidal application revealed that the population of Coccinellids beetle ranged from 4.25 to 9.58 beetles/ 5 shoot and 1.8 to 4.1 syrphid larvae/ 5 shoot. 3
rd days after spraying maximum population noted in the treatment of
B. bassiana and
M. anisopliae 9.94 and 9.88 beetles/ 5 shoot and on synthetic insecticides imidacloprid found maximum population followed by thiamethoxam 7.23 and 5.19 beetles/ 5 shoot with 24.53 and 23.45 per cent reduction of
Coccinellids population minimum number of
Coccinellids beetle found on 3.06 beetles/5 shoots with highest per cent reduction among the chemical
i.e. 60.00 per cent. Maximum number of syrphid larvae population recorded on
M. anisopliae and
B. bassiana 3.7 and 3.9 larvae/5 shoot with increase 30.00 per cent population by
B. bassiana and on chemical thiamethoxam and imidacloprid found 2.2 and 1.5 larvae/5 shoot spinosad found hundred per cent mortality. No larvae found three day after spraying against spinosad. Five days after spraying increase population of beetles in
M.anisopliae and
B. bassiana 1.11 and 9.09 per cent. In chemical maximum percent reduction of beetles found 68.23 per cent of spinosad having most toxic to the predators.
Syrphid larval populations range from 0 to 4.3 maximum on
B. bassiana and
M. anisopliae 4.0 and 3.9 larvae/ 5 shoot with increase per cent 33.33 and 2.63. minimum reduction on chemical insecticides 54.05 and 83.33 of thiamethoxam and imidacloprid. Deltamethrin, spinosad and fipronil did not found single larvae. After seven days of application maximum population increases on
B. bassiana and
M. anisopliae 9.73 and 4.56 per cent both microbial insecticides helpful to increase population of beetles. Spinosad found most mortality of beetles 82.87 per cent which prove most harmful compare to other insecticides. Thiamethoxam found safe with less reduction population of beetles found 9.58 per cent.
Maximum population increase in
B. bassiana and
M. anisopliae up to 4.0 syrphid larvae/5 shoot with per cent 33.33 and 5.26 on chemical imidacloprid and thiamethoxam found 1.3 larvae/5 shoots with reducing 56.66 and 64.86% population.14 DAS 14.43 and 8.02 per cent increase population of
Coccinellids beetles in the
B. bassiana and
M. anisopoliae respectively. Spinosad caused 84.44 per cent mortality of beetles prove most toxic and fipronil and thiamethoxam followed least toxic to the beetle with 3.05 and 6.19 per cent reduction of beetle population over control. Mean syrphid population ranged in between 1.2 to 5.0 larvae/ 5 shoot having 4.8 and 4.2 larvae/ 5 shoots on
B. bassiana and
M. anisopliae with increase population 60.00 and 10.52 respectively. Maximum larvae found on chemical insecticides 2.5 larvae in imidacloprid and thiamethoxam having minimum reducing population 16.66 and 34.28%.
Effect of different synthetic insecticides and bio-pesticides on Coccinellids and syrphid larvae population during second spray 2013-14 (Table 2 and 3)
Natural enemies population counted third days after spraying in treatment spinosad caused 41.17 per cent mortality of
Coccinellids beetles followed by deltamethrin with 35.47 per cent loss of predators beetle caused most toxic chemical among the treatment. Thiamethoxam and imidacloprid found least mortality of beetles 17.77 and 23.79 per cent respectively.
B. bassiana and
M. anisopliae increase beetle population 3.64 and 2.91 per cent respectively. Deltamethrin, spinosad and fipronil did not record single larvae caused maximum mortality of syrphid larvae. Thiamethoxam and imidacloprid having 1.4 and 1.5 larvae/ 5 shoots with 40.00 to 72.00 per cent reduction of population
. B. bassiana and
M. anisopliae recorded maximum larvae 5.1 and 4.6 larvae/5 shoots with 30.00 and 9.52 per cent increases in population such as result found 5 DAS on both microbial insecticides. Thiamethoxam and imidacloprid having 72.00 and 88.00 per cent reduction of population.
After five days of application in the treatment spinosad against prove highest mortality of beetles 77.31 per cent reduction of population found it was not safe for beetles. least morality found in imidacloprid and thiamethoxam with 12.57 and 18.55 per cent reduction population of beetles
. M. anisopliae and
B. bassiana increase population of beetles 11.84 and 8.13 per cent both microbial insecticides does not caused any harmful effect on the
Coccinellids beetles. 7DAS the population of beetle gradually increase their population in
M. anisopliae and
B. bassiana having maximum population of beetle 12.77 and 12.42 beetle/ 5 shoots with increase in 20.01 and 16.07 per cent population. Spinosad have maximum mortality of beetle followed by deltamethrin imidacloprid and thiamethoxam found less mortality of beetles compare with other chemical that was safe up to 14 DAS with l.23 and 2.83 per cent of mortality that was not hundred per cent safe but safe to compare with other. Both microbs insecticides increase population of beetles 26.69 and 26.54 per cent by
M. anisopliae and
B. bassiana. 7
th and 14
th DAS maximum population recorded of syrphid larvae on
B. bassiana 5.6 and 5.8 larvae/ 5 shoots followed by
M. anisopliae 4.8 and 5.2 larvae/ 5 shoots with increase population 16.66 and 14.28, 20.83 and 23.80 per cent respectively. On chemical insecticides minimum larvae population recorded on 0.9 and 1.4 larvae/ 5 shoots of thiamethoxam followed by imidacloprid 1.3 and 1.8 larvae/ 5 shoots with reducing population 64.00 and 44.00, 76.92 and 28.00 per cent.
Effect of different synthetic insecticides and bio-pesticides on Coccinellids and Syrphid larvae population during first spray of 2014-15 (Table 4 and 5)
Population of natural enemies recorded a day before insecticides spraying revealed that the mean population of
Coccinellids beetles ranged from 6.78 to 12.35 beetles/ 5 shoots and 2.0 to 4.0 Syrphid larvae/5 shoots and did not differ significantly. 3
rd DAS the mean population of
Coccinellids beetles ranged from 5.57 to 12.34 beetles/ 5 shoots. Maximum population recorded on the 11.92 on
M. anisopliae with increase population 1.18 per cent. Maximum per cent reduction found in spinosad 37.34 with less number of 5.57 beetles/5 shoots. The population varied from 0.0 to 4.8 syrphid larvae/5 shoots maximum increase in population of larvae found in
B. bassiana 28.20 per cent with 4.8 larvae/ 5 shoots followed by
M. anisopliae increase 23.80 per cent population with 4.3 larvae/5 shoots. On the chemical per cent of reduction found in fipronil 91.66% followed by deltamethrin, thiamethoxam and imidacloprid having 66.67, 38.46 and 23.80 per cent respectively. In spinosad no larvae found maximum mortality occurred in this plot.
Simultaneously after five and seven days of application population varied from 3.46 to 12.82 and 2.03 to12.93 beetles/5 shoots respectively. Maximum per cent increase population found in
M. anisopliae 8.82 and 9.33 with 12.82 and 12.88 beetles/5 shoots followed by
B. bassiana 4.02 and .41 per cent having 12.14 and 12.27 beetles/shoots respectively. Fipronil found less percent of reduction 13.34 and 12.61 have more safe both dates compare to other insecticides. Maximum population reduction of larvae found on deltamethrin spinosad fipronil having 100 per cent mortality up to 7DAS. Maximum population increase 28.20 per cent in
B. bassiana after 5
th and 7
th days after spraying less reduction in population found in imidacloprid 52.38 and 38.09 per cent respectively. 14
th DAS the population intensity of beetles varied from 1.61 to 13.38 beetles /5 shoots.
M. anisopliae and
B. bassiana having maximum 13.38 and 13.19 beetles with increase their population 13.58 and 13.02 per cent. Maximum per cent reduction found in spinosad 81.88. fipronil and imidacloprid found less reduction 4.96 and 8.38 per cent. Population intensity of Syrphid larvae found 0 to 6.3 larvae/5 shoots having maximum in 5.3 and 5.0 in
M. anisopliae and
B. bassiana with increase in population up to 26.19 and 28.20 per cent respectively. Spinosad found 100 per cent mortality of larvae. Least population reduction recorded in imidacloprid 4.76 per cent
Effect of synthetic different insecticides and bio-pesticides on Coccinellids beetles and syrphid larvae population during second spray of 2014-15 (Table 4 and 5)
After third of spraying population intensity of beetles noted 1.22 to 13.53 beetles/ 5 shoots. Maximum population
M. anisopliae and
B. bassiana 13.92 and 13.30 beetle/ 5 shoots with increase population up to13.58 and 13.02 per cent respectively both microbial insecticides have significant to all treatment. Least reduction found in imidacloprid and thiamethoxam 8.71 and 12.00 per cent. Maximum reduction found in spinosad 23.36 per cent found no significant for
Coccinella beetles. No larvae of syrphid found in deltamethrin and spinosad on any dates of observation hence maximum mortality occurred both insecticides treated plots. Increase in population found only in
B. bassiana up to 14.00 per cent three days after spraying. 5
th and 7
th DAS maximum intensity of beetles found in
M. anisopoliae and
B. bassiana 14.47 and 13.87,14.88 and 14.31 beetles/ 5 shoots having 8.14 and 5.15,11.21 and 8.49 per cent population respectively. Maximum per cent mortality found in spinosad 62.73 and 89.44 per cent respectively. Least percent of reduction found in syrphid larvae treated thiamethoxam 47.36 and 42.10 in 5 and 7 days after spraying and increase population of larvae found in
B. bassiana 43.48 and 32.00 per cent. 14 DAS maximum population ob beetles found in
M. anisopliae and
B. bassiana 14.91 and 14.48 beetles/5 shoots with increase population 11.43 and 9.78 per cent and minimum reduction found in imidacloprid 0.77 per cent followed by thiamethoxam with 2.17 per cent and maximum mortality found in spinosad prove most toxic to the beetles
M. anisopliae and
B. bassiana found most effective for syrphid larvae population with increase 24.52 and 38.00 per cent having 6.6 and 6.9 larvae of syrphid fly/5 shoots. Least mortality found in imidacloprid and thiamethoxam 5.00 and 15.78 per cent. It is evident from the data that microbial and new insecticides were found safer than the conventional insecticides. The present findings are in conformity with
Awaneesh et al., (2014) reported that imidacloprid and thiamethoxam found safe for
Coccinella beetles by causing less mortality of beetles in treated chemicals.
Maula et al., (2010) reported that the lowest mortality of
Coccinella septempunctata due to dimethion treated plot.
Bana et al., (2014) recorded the minimum population (2.67 and 2.10/10 plants) was recorded in imidacloprid.
Amin et al., (2014) found that Imidacloprid showed 57.34% reduction in
C. septumpunctata population whereas dimethoate 52.77% reduction in larval population of syrphid flies after seven days of spray application. It is concluded that bifenthrin and imidacloprid can be used for the management of mustard insect pests because of their higher efficacy against aphids and leaf miners and less toxicity to beneficial insects.
Patel and Godhani (2017) revealed that there was no significant difference among the different treatments of synthetic insecticides, indicating no much hazardous effects of chemicals under investigation on activity of predators
i.e. coccinellids and syrphid fly and parasitoid
Diaeretiella rapae. It showed that imidacloprid and thiamethoxam chemicals proved to be safe or less toxic to predators as well as parasitoid in cauliflower ecosystem.
Jan et al., (2017) reported that cypermethrin caused toxicity to cabbage looper at lower, recommended and higher doses as compared to bifenthrin and control, nonetheless it also revealed more toxic to predator lady bird beetles as compared to bifenthrin and control.
Khedkar et al., (2012), flonicamid (0.015%), clothianidin (0.025%) and thiacloprid (0.024%) found comparatively less toxic to these predators in mustard ecosystem. More or less same trend was also observed for these chemicals under the present study in cauliflower ecosystem. For rest of chemicals, results could not be compared with earlier reports due to the scanty information this investigation also support to my work.