Brazilian farmers report increased incidence of Spodoptera frugiperda caterpillar

The caterpillar, Spodoptera frugiperda, is present throughout Brazil, as the species has several alternative hosts, which maintains its population throughout the year and in different cultures.

Over time, it was possible to notice an increase in incidence of this pest, mainly in soybean and cotton crops.

The species prefers to attack the cartridge but can also be found attacking seedlings, with a habit similar to that of the caterpillar, feeding on ears and also piercing the base of the plant, After it reaches a certain growth point, it causes the symptom known as ″dead heart,″ which is typically from elasm. Control can be done through seed treatment in the early stages of the crop, as well as the application of systemic insecticides, which effectively controls the pest when water supply conditions are satisfactory. In conditions of water deficit, the previous treatments must be supplemented with sprays directed towards the area of the cartridge. It is recommended to use registered products for crops.

Lucia (Entomology Researcher at the MT Foundation), said, ″The scenario has worsened over the years, mainly because Bt proteins in soybeans do not have a control effect on Spodoptera frugiperda. Also, for the WS and Bt2 cotton cultivars, there is leakage, meaning that spraying is necessary, mainly from the reproductive period onwards.″ Due to this behavior, there is direct damage to soybean plants and a subsequent decrease in yield resulting from the loss of pods in stages R3 to R5. In addition, it has been observed that the most intense outbreaks of the pest in this crop are generally associated with drier periods or years and/or crops during periods of lower precipitation.

Regarding cotton, Lucia pointed out that damage to flowers and apples also affect production and are caused by loss of structure. In this case, the caterpillars attack plants from the flowering stage and, normally, have the habit of staying inside flowers and apples. Another important fact is that the soybean-corn system can cause more problems for the maintenance of the caterpillar population. According to Lucia, this is because corn is the main host for this species, and is at the mercy of the pest at all stages of development, due to the destruction of the cartridge, with the reduction of the photosynthetic area and attacks on the ears, compromising productivity.

A great tool for managing this species is by controlling the insect population through behavior. One of the research studies carried out is with sexual pheromone, with the objective of causing sexual confusion among males, which is possible with the application of a greater amount of synthetic pheromone in an affected area. ″This will prevent the males from locating the female, reducing mating and, consequently, a new generation,″ Lucia said.