Fall armyworm uses scent to select young plant

Discovery could revolutionize ecological management of Spodoptera frugiperda

05.06.2025 | 05:11 (UTC -3)
Cultivar Magazine
- Photo: Marina Pessoa
Spodoptera frugiperda - Photo: Marina Pessoa

Females of Spodoptera frugiperda prefer the corn in the early stages of development to lay their eggs. The choice does not happen by chance. A study conducted by Chinese researchers identified two volatile compounds released by young plants that guide this decision: p-xylene and (+)-camphor. These odors, more intense in newly sprouted corn, act as signals of ideal food for the next generation.

The research tested the pest's behavior in different phases of plant growth. Females showed a clear preference for plants in the seedling stage. The same pattern was repeated when it came to ovipositing.

On average, females laid more than twice as many eggs on young corn leaves compared to other stages.

Corn in the milk phase, on the other hand, was practically ignored. In this phase, there was no survival of the caterpillars, which died within five days after hatching.

This selectivity has a basis. The offspring born on young plants live longer, grow faster and reach greater weight.

They also reproduce better. On average, females raised on young corn laid almost twice as many eggs as those raised on older plants.

Furthermore, hatching rates exceeded 90%, while in the other groups they barely exceeded 70%.

The study used advanced electrophysiological techniques to identify the odors that trigger this reaction. Female antennae responded strongly to p-xylene and (+)-camphor. These compounds activated two different types of sensory neurons in the insects' antennae. The scientists then tested the effects in the laboratory and confirmed that the substances strongly attract females, especially at concentrations of 10% to 20%.

The result points to a promising path for ecological control of the pest. If traps are prepared with these compounds, it will be possible to attract females and interrupt the reproductive cycle.

Although traps with sexual pheromones to attract males already exist, they are limited. Females, by choosing where to lay their eggs, have a direct impact on the survival of the larvae. Therefore, food attractants — such as p-xylene and (+)-camphor — gain a tactical advantage.

According to the researchers, the application of the compounds can be combined with pheromones or even repellents, forming "push-pull" management strategies. These integrated approaches tend to be more effective, sustainable and economical for the producer.

More information at doi.org/10.3390/insects16060592

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