Biological control of Tetranychus urticae varies with temperature.

The temperature increases the population of Tetranychus urticae in strawberry plants and alters the efficiency of predatory mites. A study conducted in a greenhouse indicates greater suppression of the pest with the combined release of Phytoseiulus persimilis e Amblyseius swirskii.

Researchers monitored the dynamics of Tetranychus urticae They evaluated biological control strategies in three temperature ranges: 25-27 ºC, 28-30 ºC, and 30-32 ºC. The average density of the two-spotted spider mite increased from 21,7 to 95,66 individuals per plant over the period. The temperature ranged from 23,83 ºC to 31,88 ºC. There was a strong positive correlation between temperature and population (r = 0,921).

Treatments included isolated release of Phytoseiulus persimilis e Amblyseius swirskii and combined release. Both predators reduced the population of Tetranychus urticae in relation to the witness. The most intense reduction occurred with combined use. The density of Tetranychus urticae It dropped from 43,49 to 0,63 individuals per plant at the end of the cycle.

Response and temperature

The response varied depending on the temperature. Amblyseius swirskii It showed greater efficiency above 28°C. The control of Tetranychus urticae It increased with the rise in temperature and reached 91,88% at 31,88 ºC. Phytoseiulus persimilis It showed peak efficiency near 28 ºC, at 86,67%. Above this point, performance dropped, falling to 47,24% at 31,88 ºC.

The combined release of Phytoseiulus persimilis e Amblyseius swirskii It outperformed isolated treatments across all temperature ranges. Efficiency reached 94,63% between 30-32 ºC. A gain occurred under conditions of 25-27 ºC, although without a statistically significant difference.

The data indicate a direct effect of temperature on the cycle of Tetranychus urticaeIncreased temperatures accelerate development and reproduction. Adjusting the biological control strategy according to the environment promotes greater stability in management.

The combined use of Phytoseiulus persimilis e Amblyseius swirskii It broadens the spectrum of action. Each species has a distinct temperature range of optimal performance. The combination reduces failures associated with climatic variations within the greenhouse.

More information at doi.org/10.3390/insects17040366