Comparative efficacy of conventional vs new chemistry insecticides against mango thrips, scirtothrips dorsalis hood (Thripidae: Thysanoptera)

1 Introduction

Mangifera indica L. is a fruit crop of tropical and subtropical areas of the world an allopolyploid species from family Anacardiaceae (Yamanaka et al., 2019). Mango fruit is known as “King of fruits” globally (Usman et al., 2003). It is recorded that more than 75 % of this fruit is produced in Pakistan, China, India, Mexico, Thailand and Indonesia (Mitra, 2016), but our country Pakistan ranked 5th (Baloch and Bibi, 2012) among mango producing countries. Mango fruit is native to South East Asia and have many varieties with beautiful color, sweet aroma and delightful taste. Mango is also known for its balanced nutritive value as it contains 10–20 % sugar as well as good source of fiber and vitamins (Amin and Hanif, 2002). It is also suggested that by the consumption of every 100 g of mango fruit a man got more than 80 calories of energy (Rathore et al., 2007). Insect pests infesting to mango fruits were reported to be more than 300 species (Peña et al., 1998). Among these thrips is found to be an emerging threat to mango nursery which caused severe losses on leaves and young fruits. To overcome these losses the growers apply an insecticide which causes serious threats to atmosphere and have consequences like insecticide resistance and outbreak of secondary pests (Desneux et al., 2007). It is estimated that approximately 6000 species of thrips are documented which infesting many fruit crops as well as vegetables (Mirabbalou, 2013; Grimaldi et al., 2004) worldwide. Due to wide host range this pest mango is one of the consistent hosts of thrips (Aliakbarpour and Salmah, 2011) but Scirtothrips dorsalis Hood is key pest to many fruits as reported by Hood in 1919 (Patel et al., 1997). It is not only dangerous for leaves and fruits but also reported that this species is also responsible for the transmission of certain viruses in plants (Jones, 2005). Thrips causing substantial losses to the leaves by rubbing their mouthparts and produces whitish or silvery speaks on leaves as well as fruit causing economic damage. Primarily reduce the overall production by sucking the cell sap of the leaves and attacks the underside areas along the veins of the young leaves (Akram et al., 2002; Akram et al., 2003). Both larvae and adult preferred to attack on young leaves and inflorescence of the mango plant (Venette and Davis, 2004). So for the better production of mango nursery and to avoid such kind of economic damage to young fruit, it is obligatory to maintain its population under economic threshold level.

The prime objective of current research, reported herein to evaluate the comparative efficacies of selected chemicals against mango thrips, S. dorsalis on mango nursery for making superior management strategies and successful nursery production.

2 Materials and methods

A research trail was conducted at Mango Research Institute, Multan-Punjab Pakistan (30°09 N Latitude and 71°26 E Longitude with an elevation of 126 m above sea level) on tukhmi young nursery plants that were used for grafting of different mango varieties in the month of July 2018 and 2019. There were three replication under Randomized Complete Block Design (RCBD) with 13 insecticides viz., Stake 40WV (triazophos) @150 ml, Polo 500SC (diafenthiuron) (Syngenta Pakistan Limited) @50 ml, Actara 25WG (thiamethoxam) (Syngenta Pakistan Limited) @ 12 g, Chlorfenapyr 36SC (chlorfenapyr) (Jaffar Agro Services (Pvt.) ltd.) @100 ml, Maximal 60WG (nitenpyram + pymetrozine) @ 50 g, Crown 20SL (Pak China Chemicals (Pvt.) ltd.) @ 100 ml, Lescenta 80WG (fipronil + imidacloprid) (Bayer Crop Sciences) @ 30 g, Fyfanon 57EC (malathion) (Jaffar Agro Services (Pvt.) ltd) @ 100 ml, Talstar 10EC (bifenthrin) (FMC United Pvt. ltd.) @ 50 ml, Momentum 50WG (nitenpyram + chlorfenapyr) (Evyol Group) @ 150 g, Jozer 202SL (imidacloprid + acetamaprid) (Agrow Limited) @ 240 ml, Tresta 20SC (clothianidin) (FMC United Pvt. ltd.) @ 50 ml and Closer 240SC (sulfoxaflor) (Dow AgroSciences) @ 50 ml per 100 L of water. The nursery was regularly observed to measure the thrips abundance. When the thrips population reached at ETL the nursery was subjected to pesticides applications. Thrips population was recorded from thirty leaves selected at random from each treatment of hundred plants. The data was recorded before spray and then after 24 h, 72 h and 168 h post treatment. To determine quantity of water for each treatment, calibration was done by spraying water on untreated treatment. Spraying was done manually operated knapsack sprayer (Jecto ®). All the insecticides were sprayed early in the morning for better results. Before application of insecticides the spray machine was thoroughly washed and cleaned to avoid intermixing of insecticides. Percent mortality was calculated as mention below by using the formula: $$\%\text{M}=100\times \left({\text{N}}_{\text{bs}}-{\text{N}}_{\text{as}}\right)÷{\text{N}}_{\text{bs}}$$ where %M = Percent Mortality; N_bs = Insect abundance before spray and N_as = insect abundance after spray.

3 Results

3.1

3.1 Percent mortality of S. dorsalis Hood during 2018

3.1.1

3.1.1 Percent mortality 24 h after spraying

The data on the effectiveness of insecticides for the control of S. dorsalis Hood after 24 h of the spray revealed a significant differences (p < 0.05, SE for comparison 3.06, DF 24, Critical Q value 5.17 and CV 13.209) between treatments. The maximum mortality was observed in those treatments where Chlorfenapyr, momentum and crown were applied with percent mortalities of 76.72 %, 72.65 % and 72.27 % recorded. Stake, Polo, Talstar and Closer proved very less effective with very low mortalities of 18.49 %, 29.75 %, 15.70 % and 29.49 % were recorded. Maximal, Lescenta, Jozer, Actara and Tresta showed relatively mortality less than 70 %. Very low mortality was observed with treatment of Fyfanon with mortality of 11.97 % (Fig. 1).

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Fig. 1

Showing the average percent mortality of S. dorsalis Hood.

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3.1.2

3.1.2 Percent mortality 72 h after spray

The data on the effectiveness of insecticides for the control of S. dorsalis Hood after 72 h of spray revealed significant differences (p < 0.05, SE for comparison 3.35, DF 24, Critical Q value 5.17 and CV 12.29) between treatments. The maximum mortalities were observed in treatments where Crown, Chlorfenapyr, Momentum, Jozer and Actara applied with mortalities of 79.93 %, 77.91 %, 74.83 %, 73.85 % and 71.74 % respectively. Stake, Maximal, Lescenta, Tresta and Closer showed mortalities of 26.14 %, 68.28 %, 49.79 %, 29.49 % and 24.38 % respectively. Very less mortality was recorded where Talstar and polo were applied with mortalities of 14.74 % and 18.62 % respectively.

3.1.3

3.1.3 Percent mortality 168 h after spray

The data on the effectiveness of the insecticides for the control of S. drsalis Hood after 168 h of spray revealed significant difference (p < 0.05, SE for comparison 3.12, DF 24, Critical Q value 5.17 and CV 11.44) between treatments. The maximum mortalities were observed in treatments where Jozer, Momentum and crown was applied with mortalities of 77.51 %, 76.32 % and 75.1 % recorded. Chlorfenapyr, Maximal and Actara showed mortality up to 68.31 %, 66.37 % and 64.89 % respectively. Very low mortality was observed as 10.38 % recorded.

4 Discussions

Thrips cause substantial loss as they feed on the leaves and inflorescence, which significantly harmful to the plant health at early stages (Pena et al., 2002). The cosmetic loss is definitely reduced its marketability both in nursery as well as in fruits (Nault et al., 2003). However insecticides proved the most suited management practice in nursery (Morse and Hoddle, 2006). So the use of suited insecticides will overcome the populations of this species. The most common use for controlling this pest is chemical control (Lewis, 1997). However different eradication campaign was studied earlier (MacLeod et al., 2004). In our experiment thirteen different insecticides were tested against S. dorsalis Hood under field conditions during 2018 and 2019. Among all chemicals few were proved very effective against this pest. Among these during the year 2018, Crown (Imidacloprid), Momentum (nitenpyrm + chlorfenapyr), chlorfenapyr and Jozer (imidacloprid + acetamaprid) showed maximum average percent mortality as 75.77 %, 74.60 %, 74.31 % and 71.67 % respectively. During 2019, Chlorfenapyr showed maximum average percent mortality up to 73.97 %. Chlorfenapyr was proved effective in reducing adult populations and Imidacloprid controlling larvae of thrips (Seal et al., 2006). Similarly Imidacloprid proved effective against adult of thrips population reducing 68.7 % population and 80.7 % larval population (Aliakbarpour et al., 2011). Among Neonicotinoids, Imidacloprid has very less toxic to humans (Tomizawa and Casida, 2005) and have highly effective against S. dorsalis Hood on different crops (Shibao et al., 2006).

5 Conclusion

It was concluded from this study that Chlorfenapyr is very effective in controlling S. dorsalis Hood on mango nursery plants followed by Crown and Jozer. If the nursery is infested with S. dorsalis Hood and is to be managed for further propagation and plantations, these insecticides can be recommended to control the pest populations for up to 168 h after application. While spraying at inflorescence against S. dorsalis Hood, application of insecticides should be done at evening time to avoid exposure of pollinators at morning hours.