Pro-insecticide with indoxacarb eliminates difficult-to-control caterpillars

By Leonardo Gottems, reporter for AgroPages

The Portuguese multinational Ascenza revealed to AgroPages about the launch in Brazil of a “pro-insecticide”, an agrochemical that is still inactive when sprayed, only coming into action when ingested by the caterpillar.

The insecticide, Indoxacarb 15 SC Guarda, is manufactured by the Indian company Gharda and will be distributed in Brazil by Ascenza. The product showed high efficacy against resistant insects and difficult-to-control species such as cotton’s false-measurer (Chrysodeixis includens).

According to Clérison Régis Perini, agronomist, doctor and entomology researcher at Proteplan Pesquisas e Assessoria Agrícola, after a caterpillar ingests the product, metabolic enzymes in the digestive tract transform the indoxacarb into highly active N-decarboxylated metabolites. This has a potent effect as an insecticide. “The resulting metabolites act as blockers of sodium channels in the nervous system of insects, which results in paralysis and death,” he explained.

Indoxacarb 15 SC Guarda also draws attention to its presentation in Concentrated Suspension, which has shown a significant difference in terms of the residual period in the control of caterpillars. “The indoxacarb molecule presents high photodegradation (1/2 life = 4.5 days at pH 5 and 25°C; FAO) and the product formulation becomes very important to increase the insecticide's effectiveness over time,” the researcher said.

The works published with indoxacarb are part of the master's and doctoral research by the Integrated Pest Management Laboratory (LabMIP) at the Federal University of Santa Maria, in southern Brazil. The experiments were carried out in the field under natural infestation of Helicoverpa armigera and C. includens during three seasons. According to the entomologist, indoxacarb showed satisfactory efficiency against both pest species and was among the three most effective insecticides to control caterpillars.

Caterpillars can damage leaves, flower buds, and apples in cotton farming. Among the defoliators, the false-measurer stands out due to its damage and the difficulty in controlling it with chemical insecticides. To evaluate the new product’s effect, a study was conducted in Mato Grosso by Proteplan, titled "Efficiency of the insecticide Indoxacarb 15 SC Gharda (indoxacarb 150 g/L) in the control of false meter (Chrysodeixis includens) in cotton cultivation." For managing this pest, indoxacarb achieved over 90% control, with two applications at an interval of seven days.

In addition, Dr. Perini emphasized that it was essential to continue monitoring pests in crops due to the reproductive characteristics of these species that provide high populations in the field. “Thus, the increase in these caterpillars occurs quickly, requiring intervention with insecticides to avoid damage to leaves and reproductive structures,” he added.

The new product that Ascenza brings to the market in partnership is an essential tool in the field after adopting Bt technology, already used in seeds most producers use. The sustainability of pest management in Bt crops can be achieved by integrating different control methods, whether these Bt plants, chemical and biological insecticides, or pheromones. "Thus, the application of indoxacarb associated with other methods will keep infestation levels low and reduce the chances of resistant insects, such as Spodoptera frugiperda, which are already populated with resistance genes to Bt toxins,” Perini said in conclusion.