Articles
SPECIFICITY OF B. THURINGIENSIS SUBSP. TENEBRIONIS EFFECT AND APPLICATION
Article number
462_159
Pages
1007 – 1014
Language
Abstract
In the course of 1993 and 1995, in the experiments on the potato biological preparation Ecotech on the basis of Bacillus thuringiensis subsp. tenebrionis in the Colorado Potato Beetle (CPB) (Leptinotarsa decemlineata Say), control in both generations was used.
Dosages of 2 l/ha, 2.2 l/ha and 2.5 l/ha were applied.
Efficient protection from the first generation of CPB was obtained with the first spraying in the beginning of the hatching of the larvae.
When the application started in the second generation of CPB, efficient potato protection was obtained when the number of older larvae was the lowest.
The efficiency of the preparation was not limited by high summer temperatures.
With high temperatures, when the increase of the overground part reached an end, two sprayings in the interval of 13 days protected the potato efficiently.
In the conditions of intensive growth of the overground part of the potato and abundant rainfall in the course of the first generation of CPB, the potato was successfully protected with three sprayings.
Exclusive larvicide effect made only the depositing of the egg masses and the appearance of newly hatched larvae possible.
Although the preparation had only a digestive effect, in the condition of an intensive growth of the potato and a permanent occurrence of new larvae, spraying every 8 days gave an effective protection of the potato.
In the estimation of the effect of the preparation on the basis of B. thuringiensis subsp. tenebrionis, a more suitable indicator was the percentage of damaged leaves.
The number of larvae was a less precise indicator, because among them there were those which did not feed because of their damaged intestines.
A suitable parameter for the determination of the right time interval for the following sprayings was the number of larvae fed by the potato leaf.
Dosages of 2 l/ha, 2.2 l/ha and 2.5 l/ha were applied.
Efficient protection from the first generation of CPB was obtained with the first spraying in the beginning of the hatching of the larvae.
When the application started in the second generation of CPB, efficient potato protection was obtained when the number of older larvae was the lowest.
The efficiency of the preparation was not limited by high summer temperatures.
With high temperatures, when the increase of the overground part reached an end, two sprayings in the interval of 13 days protected the potato efficiently.
In the conditions of intensive growth of the overground part of the potato and abundant rainfall in the course of the first generation of CPB, the potato was successfully protected with three sprayings.
Exclusive larvicide effect made only the depositing of the egg masses and the appearance of newly hatched larvae possible.
Although the preparation had only a digestive effect, in the condition of an intensive growth of the potato and a permanent occurrence of new larvae, spraying every 8 days gave an effective protection of the potato.
In the estimation of the effect of the preparation on the basis of B. thuringiensis subsp. tenebrionis, a more suitable indicator was the percentage of damaged leaves.
The number of larvae was a less precise indicator, because among them there were those which did not feed because of their damaged intestines.
A suitable parameter for the determination of the right time interval for the following sprayings was the number of larvae fed by the potato leaf.
Publication
Authors
I. Sivcev, A. Zabel, B. Manojlovic, M. Kostic
Keywords
Potato, Leptinotarsa decemlineata, Ecotech, efficacy
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