BASF analyzes the impact of climate change on pepper pests and diseases

Climate change and the breakdown of resistance by diseases such as powdery mildew or tomato wilt virus (TSWV) in pepper crops are reviving their incidence in the field and causing new pests to appear.

This was revealed last Thursday, May 11, in the presentation by Nunhems, BASF's horticultural seed business, on ″Challenges in pepper cultivation: emerging diseases and pests″, within the framework of the World Pepper Congress, which concluded that same day in Aguadulce (Almería).

During the presentation by Daniel Bellón, BASF Scientist Coordinator, he offered an overview of the evolution of powdery mildew and TSWV in different growing areas around the world, including Almería. He elaborated on the appearance of Thrips parvispinus in Spain as a consequence of climate change. ″It is a tropical insect that has been spread by globalization and has managed to adapt in less than two years,″ he said.

″Holding capacity″ as a tool

Bellón analyzed the evolution of the incidence of powdery mildew in pepper crops in the last five years. He concluded that climate change, combined with the lesser effectiveness of genetic resistance, has caused a "greater aggressiveness of the disease."

The proliferation of resistant varieties has generated resistance to the disease itself, decreasing the effectiveness in its control. So much so that, according to Bellón, it is directly impacting the evolution of organic crops. "These growers need resistant varieties, however, powdery mildew has evolved and has adapted to current resistance," he lamented.

The use of varieties with resistance, early detection and varieties with "holding capacity" (the plant’s ability to live with powdery mildew) are key elements to deal with the pathogen. "When selecting varieties, we consider not only resistance but also holding capacity," said Francisco Marín, Account Manager of BASF's horticultural seed business.

Similar is the case with tomato wilt virus (TSWV). The appearance of new isolates (populations of non-official breeds) "has broken the resistance," said Bellón, who analyzed its incidence in crops in Almería.

A tropical thrips

Thrips parvispinus has been seen in this campaign in Almería, although it was about two years ago when it arrived in Spain. It is a tropical insect native to Asia, with a presence in Thailand, Indonesia or India, where "it has caused great losses".

Bellón showed examples of its impact on crops in Florida, India, Murcia and Almería. And he explained how he had adapted in the province of Almería, but not in Murcia.

In this sense, he commented that, since it is a tropical insect, "it has found refuge in the greenhouses of Almería", where it has found the ideal temperature and humidity for its development. The same has not happened in Murcia, where the cold of January and February in outdoor crops prevent its spread.

"Varieties with an open plant help prevent Thrips parvispinus from establishing itself, being a natural resource for the fight," commented Francisco Marín. He added, "it is essential to take these factors into account when selecting varieties." The new range of Nunhems peppers has this characteristic, and this has been demonstrated throughout this campaign, where, for example, Arkos F1 and Bikos F1 have been less affected by Thrips.

The BASF Scientist Coordinator stressed throughout his speech the need to "constantly fight" against pests and diseases that evolve at the same time as climate change does. And he also pointed out the importance of advising and monitoring crops to achieve the best results, work that Nunhems carries out daily for the benefit of the entire sector.