Document Type : Research Paper
Authors
1 Management General pests, Plant Protection Organization, Tehran, Iran.
2 Department of Plant Protection, Faculty of Agricultural, University of Tehran, Karaj, Iran.
3 Department of Plant Protection, Faculty of Agricultural, University of Tehran, Karaj, Iran
Abstract
Keywords
Extended Abstract
Introduction
The cereal ground beetle belongs to the Carabididae family that widely expanded from Europe to North Africa and Central Asia. Zabrus tenebrioides Goeze is the most important pest of wheat and barley in Golestan province, which causes great damage to the crop in fields without crop rotation despite chemical control by spraying in the tillering stage. The current research investigated the effect of fertilization or feeding, Planting Density, and seed treatment with imidacloprid insecticide on the number of damaged wheat, larvae, and grain yield in the fields to obtain the lowest number of damaged wheat by this pest and the highest grain yield in rain-fed wheat.
Materials and Methods
This research investigated the simultaneous effect of nutrition by fertilizing, planting density, and seed treatment by imidacloprid WS 70 on the infestation, the number of pest larvae, and the grain yield in rainfed wheat from 2020 to 2022. The research was conducted using a split split plot the main factor is fertilizing with two levels. The optimum level: 100 kg/ha is urea fertilizer, 75 kg/ha is phosphate fertilizer, and 25 kg/ha is potash fertilizer. The custom level: of 100 kg/ha is urea fertilizer. The sub factor is the planting density including 160, 180, and 210 kg/ hectare of seeds. Sub subfactor, imidacloprid including doses: 0, 1, 1.5, 2, and 2.5 g/100 kg seeds wheat.
Results and Discussion
The infestation was influenced by the effect of imidacloprid pesticide concentration and planting density and the number of larvae in m2 and grain yield was influenced by the effect of nutrition by fertilizing × planting density × imidacloprid doses. Results showed, the dependence between the number of larvae per m2 and the concentration of imidacloprid, so the highest number of larvae in the treatment without the use of insecticide was 1.74 larvae in m2, and the lowest number of larvae in the treatments with imidacloprid pesticide with concentrations 2 and 2.5g pesticide/100 kg seeds, observed, that 0.885 and 0.749 larvae in m2, respectively. Also, with optimal nutrition by fertilizing, the number of larvae was significantly reduced. The highest grain yield obtained separately in the treatments included, planting density of 160 and 180 kg seeds per hectare or the optimal nutrition by fertilizing or the concentration 2 and 2.5 g Imidacloprid/100 kg seeds. In the past, granulated and emulsifying solutions of insecticides were used for the chemical control of Z. tenebrioides after growing in the tillering stage. Nowadays neonicotinoid insecticides are used for seed treatment. According to the results of recent research, by increasing the concentration up to 2.5 gr imidacloprid /100 kg seeds, the infestation and the number of larvae pests in m2 have been significantly reduced. Meanwhile, treatments included: 2 and 2.5 gr pesticide/100 kg seeds have no significant difference at the 5% probability. The highest infestation was observed in the control treatment and the treatment with a concentration of 1 gr imidacloprid insecticide / 100 kg seeds.
Conclusion
According to the results of the recent study and considering the environmental hazards and the importance of grain yield in relationship with the farmer's income - compared to the infestation and the number of pest larvae -thus, two treatments with the highest grain yield which have no significant difference based on the PLSD test at the 5% probability suggested: the planting density by 160 kg seeds per hectare with a concentration 1.5 gr pesticides per 100 kg seeds or planting density by 210 kg seeds per hectare with a concentration 1gr imidacloprid per 100 kg seeds with optimal nutrition by fertilizing.
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