Study indicates acceleration in the life cycle of "Helicoverpa armigera"

Studies indicate that rising temperatures generally accelerate the life cycle and increase the reproductive capacity of Helicoverpa armigera. This makes its management increasingly challenging for farmers in different regions of the world.

Researchers evaluated how different climate scenarios — specifically varying temperature, photoperiod and humidity — affect the biological characteristics of the pest.

Through a meta-analysis, the study synthesized data from 26 studies to understand how rising temperatures influence the life cycle, development rate and reproductive capacity of H. armigera.

Temperature effects

The results showed that the rate of development of H. armigera is optimized at temperatures between 32 °C and 35 °C. They result in a shorter life cycle and a greater reproductive capacity of females.

When temperatures exceed 35 °C, however, there is a slowdown in development, increased mortality and a significant reduction in oviposition, suggesting that very high temperatures have an adverse effect on pest reproduction and growth.

For the eggs and larvae of the H. armigera, development time decreases with increasing temperature, being faster between 30 °C and 35 °C. Humidity and photoperiod also influence development conditions, with a relative humidity of 65% to 75% and balanced photoperiods (e.g.: 12:12 or 16:8) being ideal for the development of different larval stages.

Reproductive capacity

At moderate temperatures (25 °C to 27 °C), H. armigera showed an increase in reproductive capacity, with a greater number of eggs and oviposition period. This effect is less pronounced at temperatures above 32 °C, where the laying capacity of females decreases.

For the complete life cycle, a temperature close to 32 °C is ideal, with a humidity of 60% being favorable for the complete pest cycle.

Implications for agricultural management

The research highlights that the increase in global temperatures could, in the short term, favor the adaptation and proliferation of H. armigera, especially in regions where average annual temperatures remain within the favorable range for its development (20 °C to 35 °C).

On the other hand, the incidence of extreme temperatures could act as a limiting factor for the expansion of the pest in some regions.

These results reinforce the importance of monitoring climate change and considering variables such as temperature, humidity and photoperiod when formulating integrated pest management strategies.

A detailed understanding of the effects of temperature on H. armigera It allows producers to anticipate possible outbreaks and plan control methods that reduce dependence on insecticides, a practice that the pest has resisted due to its high adaptability.

More information can be found at doi.org/10.3390/insects15110888