The innovative oligonucleotide insecticide Hrit-11 shows high efficiency and selectivity on Macrosiphoniella sanborni Gillette
Macrosiphoniella sanborni Gillette is a widespread pest of Chrysanthemum morifolium Ramat., causing significant damage to the world floriculture. Along with its direct negative effect on the plant, chrysanthemum aphid is capable of spreading concomitant infections that adversely affect plants. To date, the use of chemical insecticides is a forced measure due to the lack of alternative competitive preparations that can effectively suppress the number of pests and at the same time not damage the ecosystem. Biological control methods, in turn, are ineffective and often time-consuming. An oligonucleotide insecticide (DNA insecticide) Hrit-11, based on the 5.8S rRNA gene sequence of the pest, can be a substance that combines the positive characteristics of chemical and biological methods of insect pest control. For Hrit-11 oligonucleotide the mortality rate of individuals of the wingless form was recorded at the level of 67.15 3.32 % with a single treatment with a solution at a concentration of 100 ng/µl and 97.38 2.49 % with double treatment with a solution of the same concentration with a daily interval. In addition, the influence of a random oligonucleotide Slog-11, as well as Hrit-11-3' and Hrit-11-5' with the replacement of one nitrogenous base at the 3'- and 5'-ends, respectively, was studied. Seedlings affected by aphids were monitored for seven days. The maximum daily efficiency was detected on the third day with any of the studied treatment options: the effect rapidly increased by the third day, and then gradually leveled off. The expression of the target 5.8S rRNA gene on the third day after treatment and the nuclease activity of the insect homogenate were evaluated. This study shows the promise of pest ribosomal genes as targets for the action of DNA insecticides, and also demonstrates the high specificity of such preparations