The Spidex®-Spical® dual solution to spider mite control in glasshouse strawberry production

The two-spotted spider mite (TSSM), Tetranychus urticae, represents a significant threat to commercial strawberry crops grown in glasshouses. An in depth knowledge of this pest and the beneficial mites which are used for its control, is fundamental to the implementation of a successful, season-long strategy against this persistent and potentially crop destructive pest.

Stella Cubison, Koppert’s Technical Consultant in the South, has gained a wealth of knowledge and experience in the biological control of TSSM in glasshouses-grown strawberries. “It is essential that the grower keeps a watchful eye on the long-term weather forecast, and specifically notes when high temperatures are forecast. Temperature increases can cause an imbalance in the pest-predator ratio, leading to a population surge in the pest, and crop loss,” explained Stella.

At the beginning of the season, when the glasshouse environment is relatively cool, Neoseiulus californicus should be introduced in sachets, as Spical Plus® or Spical Ulti-Mite®, or applied as loose Spical® over the canopy surface. “Early release of this predator lays down the foundation to a successful TSSM control strategy. Its positioning reflects several key biological attributes including its ability to remain active at low temperatures, e.g. 12^oC, the ability to locate spider mites at low pest densities, and the potential to survive for an extended period of time in the absence of spider mite prey,” explained Stella. This biological control agent also has a higher temperature optimum and can tolerate lower humidities than the spider mite specialist Phytoseiulus persimilis. “Under prolonged spells of hot and dry summer conditions, the efficacy levels of P. persimilis decline, but fortunately this shortfall can be corrected with Spical,” commented Stella.

The development of the new product, Spidex Vital®, adds another dimension to spider mite control in glasshouse strawberry crops. Based on P. persimilis, this product offers additional benefits, such as increased energy levels, improved egg laying capacity, improved hot-spot control, and fully fecund females ready to lay eggs once released in the crop. In the temperature range 18-25^oC this species demonstrates its superiority as the highest performing spider mite predator, with the ability to reinstate its dominance over very high spider mite populations.

For more information on how to implement a successful biological control programme against spider mites and other pests in glasshouse strawberry, contact your regional Koppert consultant.