EFFECTIVITY OF THE BIOINSECTICIDE BOVETRÓPICO (Beauveria bassiana) FOR THE INSECT PEST WHITE FLY (Bemisia argentifolii) MANAGEMENT IN THE COTTON CROP.
The insect pests than affect the cotton crop in Colombia represents one of the most common problems than growers and techniques must face due to their great impact in the crop productivity. However, although there are many registered insect pests, only few cause severe crop losts in terms of the extent of the damage, the difficulty and cost of their management and control.
In order to evaluate the effect of the commercial product Bovetrópico (based on the fungus Beauveria bassiana) in the control of the white fly Bemisia argentifolii, experiments were carried out by comparing the commercial product Bovetrópico in different concentrations with other commercial bioproduct (Paecilotropico, based on the fungus Paecilomyces lilacinus) and the conventional chemical insecticides normally used in the sanitary management of the crop. Consequently, two trials were taken out in two different environments within the same productivity cycle due to the legal restrictions of the crop to be planted during the second semester of each year.
One trial was made by the preventive model, when the infestation level of adult and big nymph stages were below the economic damage level (EDL). Another, was carried out according to the integrated pest management concept (IPM), beginning with high adult insects pressure, which were considered of low susceptibility to the entomopathogens fungi.
It is necessary to establish that for the management of the white fly Bemisia argentifolii with the use of the entomopathogenic fungi Beauveria bassiana, the damage level of the crop must be lower than the established for the application of chemical synthetic insecticides of contact or systemic activity insecticides, because those have slower action than chemicals.
The evaluated variables were the infected leaves percentage and the infected disc percentage, which were correlated with the leaf adults mean and the nymphs mean per 2.5 cm diameter area, respectively, in order to establish the statistics differences by means of variance analysis (ANOVA) trials and relative efficiency estimations.
At the preventive model trial, the lowest concentration did not show efficiency in the white fly control, but the other treatments Bovetropico alone and Bovetropico mixed with other entomopathogens showed higher efficiency.
The insecticide activity focused on the reduction of the white fly adults per leaf and nymphs per disc levels caused by Bovetropico insecticide, without reach the economic damage level EDL.
To conclude the experiments have shown that the bioinsecticide Bovetropico alone and mixed with the bioinsecticide Paecilotropico has effective and economic control of adult and nymphal stages of the white fly (Bemisia argentifolii) in the cotton crop.