POSSIBILITY FOR BIOLOGICAL CONTROL OF THRIPS AND LEAF APHIDS ON TOBACCO

Abstract

The microbiological insecticides whit bacterial, fungal and viral origin are an alternative of chemicals. They are widely used in organic plant cultivation. The specific usage of tobacco and the increased restrictions on smoking discourage the testing and application of the bio-insecticides оn tobacco crop. The aim of field experiments was to assess the possibility of using bioinsecticides containing various natural substances and its effectiveness against thrips and leaf aphids on tobacco crop. For the thrips control have been tested effectiveness of Naturalis (a. i. Beauveria bassiana strain АТСС 74040 – 0.185 g/kg) at a dose of 150 ml/da; Neem Azal T/S (1% azadirachtin А + 0.5% azadirachtin B,W,G,D and 2.5% neem substance) at the dose of 0.3%; Savona (potassium salt of fatty acids) at the dose of 1l/0.5 da and Sineis 480 SK (spinosad 480 g/l) at the dose of 35 ml/da. The product Naturalis (a. i. Beauveria bassiana) have also been tested against tobacco leaf aphids at the dose of 150 ml/da. The best control and the longest suppression of the thrips` population are realized when Sineis 480 SK is applied. The product Naturalis has high effectiveness (over 85%) against thrips and leaf aphids and might be recommended for the joint control. Neem Azal T/S demonstrates intermediate effectiveness (over 65%) against the thrips. A relatively short action period of Neem Azal T/S and Naturalis may be overcomes by twice application in 7 days interval. The effectiveness of Savona against the thrips is unsatisfied (≈ 40%).