Document Type : Research Article
Authors
1
Department of Pesticides Research, Iranian Research Institute of Plant Protection, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
2
Department of Agricultural Entomology Research, Iranian Research Institute of Plant Protection, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
Abstract
Introduction[1]
Almost every year, various types of native and migratory locusts attack pastures and agricultural crops. Unfortunately, to control these locusts, EC formulations of various insecticides are used, which are sprayed with various hydraulic sprayers (the amount of solution used is 200 to 400 liters per hectare) instead of ULV sprayers (one liter per hectare), which increases the cost of spraying and creates major problems in areas with water restrictions. In some cases, technical pesticides are used with ULV sprayers to apply various insecticides. This issue, in addition to causing damage to the sprayers, can also be the source of various health problems, especially for users, as well as environmental problems. Therefore, this experiment was conducted with the aim of introducing the insecticide with a ULV formulation and also diversity the basket of pesticides for harmful locusts.
Materials and Methods
To conduct the experiment, lambda-cyhalothrin (Amigo ULV 4%) and deltamethrin (Delros ULV 1.25%) were used at two application rates of 300 and 500 ml/ha compared to malathion (EC 57%) at application rates of one liter/ha against Moroccan Locust Dociostaurus maroccanus (Orth. Acrididae). This experiment was conducted in two regions of Iran, Lowshan (Gilan province) and Abbar (Zanjan province). The experiments were conducted in a randomized complete block design with 5 treatments (plus control) in 4 replications. The area of each experimental plot was 1000 m2. A spinning disk sprayer was used for ULV formulation and hydraulic sprayer was used for spraying malathion. To determine the best time of spraying, areas susceptible to contamination were continuously monitored and spraying was initiated as soon as an appropriate density of locusts was encountered in the nymphal stages (The appropriate density for this group of locusts is 13 nymphs or adults inside the field or 25 outside the field). Spraying was performed on locust nymphs (3rd to 5th nymphal stages). Sampling of nymphs was done the day before and on the first and third day after treatment. The percentage of treatment efficiency was calculated using the Henderson-Tilton formula, and variance analysis was performed using SAS software, the means were compared using the Tukey test.
Results and Discussion
Results showed that mortality percentage in Loshan for lambda-cyhalothrin ULV 4% at 300 and 500 ml/ha, malathion EC 57% at 1 l/ha, deltamethrin ULV 1.25 at 300 and 500 ml/ha 3 days after treatment were 83.1 ± 7.3%, 90.9 ± 1.6%, 82.5 ± 5.8%, 82.4 ± 3.1 and 62.1 ± 4.3 respectively. Mortality percentage in Abbar for lambda-cyhalothrin ULV 4% at 300 and 500 ml/ha, malathion EC 57% at 1 l/ha, deltamethrin ULV 1.25 at 300 and 500 ml/ha 3 days after treatment were 87.8 ±5.2%, 94.5 ± 1.15%, 88.4 ± 3.8%, 53.6 ± 4.8 and 92.2 ± 4.6 respectively. Comparison of means showed that in both regions, both lambda-cyhalothrin ULV doses were in a same statistical group. Therefore, in order to reduce the application of insecticides, the lambda-cyhalothrin ULV 4% with application rates of 300 ml / ha is recommended for short horned grasshoppers control. While only an application rates of 500 ml per hectare of deltamethrin ULV insecticide has been able to control the pest to an acceptable level and is recommended. The results of this study match with the report of the FAO Pesticide Review Group, which shows that pyrethroid insecticides are the fastest-acting insecticides in controlling harmful locusts (Anonymous, 2014). In a conducted study about evaluation of the efficacy of insecticides in controlling the Moroccan locust, it was shown that the insecticide lambda- cyhalothrin with EC, SC and CS formulations, deltamethrin with EC formulation and fipronil with EC formulation had acceptable efficacy in control. In mentioned study, the ULV formulation was not used due to its advantages in locust-infested with restricted water for spraying (Sheikhi garjan et al., 2023). In a study conducted by (Martin et al. 1998) on the efficacy of deltamethrin (Decis 5F) in locust control, they showed that this insecticide controls the pest by over 90%. In a study conducted to compare the use of low-volume and ultra-low-volume ULV applications of a number of insecticides on locusts, it was shown that despite the same efficacy of the insecticides, the use of LV insecticides produces larger droplets and the volume of solution used is much larger compared to ULV, which creates problems in the application of pesticides in areas with limited water (Abdelatef, 2021). The authors' field studies show that in Iran, sometimes ULV sprayers are used for technical application of insecticides instead of ULV formulations of insecticides in locust control. This mistake is highly toxic to users (acute and chronic) and very destructive to the environment. Another problem in spraying for locust control is the use of hydraulic sprayers (solution consumption 200 to 400 liters per hectare) instead of ULV sprayers (one liter per hectare), which increases the cost of spraying and creates major problems in areas facing water restrictions. Therefore, the introduction of ULV formulations of insecticides for locust control is very useful. It should be noted that planning for the production and import of ULV sprayers by the government is very necessary for locust control, which is a common pest.
Conclusion
Due to the good efficacy of the lambda-cyhalothrin (Amigo ULV 4%), this insecticide can be used with application rate of 300 ml/ha for locust control. This study showed that the insecticide deltamethrin (Delros ULV 1.25%) at a rate of 300 ml/ha did not have acceptable efficacy in locust control, so it is recommended to use a rate of 500 ml/ha. It is emphasized that only ULV sprayers should be used for the application of these insecticides. In addition, these devices should not be used for technical application of pesticides under any circumstances.
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