Resistance induction in some tomato cultivars against whiteflies bemisia tabaci (gennadius)‎ by applying of salicylic acid

Abstract EN

A field study was conducted to know the effect of salicylic acid spraying and different cultivars of tomato plants infested with the whitefly Bemisia tabaci Gennadius in one of the greenhouses at the research station of the College of Agriculture, University of Basra for the agricultural season 2019-2020.

And that by spraying three cultivars of tomato plants Wijdan, Randy and Newton with four concentrations of salicylic acid 0, 0.5, 0.75 and 1 mmol, and two sprays, The first spray was applied to the field experiment plants after 60 days of sowing the seeds on 24/11/2019, while the second spray was carried out 21 days after the first spray.

The studied cultivars differed in the characteristics of biochemical resistance and the percentages of containing the metabolic compounds, and through the study of the correlation it was possible to evaluate the occurrence of the induction in the resistance of the plant cultivar by the effect of spraying with salicylic acid by studying the relationship between increasing or decreasing the concentrations of salicylic acid and its relationship to reducing the population density of the insect.

A negative correlation was found between the content of the leaves of carbohydrates, proteins, and phenols and the intensity of the insect roles in the vegetative growth stage.

The tomato cultivars have a clear effect on the resistance of the whitefly during the vegetative growth period, where it was found that the two cultivars Wejdan (resistance to laying eggs) and Newton (resistance to nymphs), which contains the highest content of chlorophyll and phenol, They are the two cultivars that are resistance to laying eggs and the development of nymphs, which is represented by the low density of eggs laid on the leaves of those plants, the population density of nymphs, while the variety Randy, in which the content of carbohydrates and proteins increases, was found from the cultivars resistance to insects, which decreased the population density of the adult.

It is possible to conclude from this study the important role of salicylic acid in inducing resistance against whitefly infection during the vegetative growth period.

As spraying the tomato crop with a concentration of salicylic acid 0.75 mmol achieved the best increase in the chemical compounds in the treated plant in general, which have a role in inducing systemic resistance in the plant to prevent egg laying and reduce the population density of nymphs.

The tomato cultivars have a clear effect on the resistance of the whitefly during the vegetative growth period, where it was found that the two cultivars Wejdan (resistance to laying eggs) and Newton (resistance to nymphs), which contains the highest content of chlorophyll and phenol, They are the two cultivars that are resistance to laying eggs and the development of nymphs, which is represented by the low density of eggs laid on the leaves of those plants, the population density of nymphs, while the variety Randy, in which the content of carbohydrates and proteins increases, was found from the cultivars resistance to insects, which decreased the population density of the adult.

It is possible to conclude from this study the important role of salicylic acid in inducing resistance against whitefly infection during the vegetative growth period.

As spraying the tomato crop with a concentration of salicylic acid 0.75 mmol achieved the best increase in the chemical compounds in the treated plant in general, which have a role in inducing systemic resistance in the plant to prevent egg laying and reduce the population density of nymphs.