Biological control of the pear psylla

studies of its natural enemies and aspects of its chemical communication: Doctoral thesis abstract

Abstract

The pear psylla, Cacopsylla bidens, is one of the pests that has acquired a primary role in pear cultivation. Finding alternate control methods is required because the management of this hemipteran has relied on the usage of chemical control. To meet this demand, these project aims to improve the understanding of the biology, chemical communication and trophic webs of the predator guild to be able to design a biological control strategy. Molecular approaches were used to determine which of the predators present in the orchard was feeding on C. bidens. Likewise, it was sought to determine at what time of the season these natural enemies begin to act. The findings revealed that many predators from the orders Coleoptera and Neuroptera feed on the pest. Chrysoperla externa was the predator that most frequently fed on C. bidens. In turn, it was determined that these predators begin to act in a more relevant way only on the third generation of C. bidens. To anticipate the arrival of C. externa in the season, it was investigated whether the pear tree changed its volatile profile after being damaged by C. bidens. Likewise, the volatile released following Argyrotaenia sphaleropa damage were identified. The results showed that the pear tree modifies its volatile profile, and this alteration is specific to the herbivore. The predator C. externa was evaluated to determine whether this change could elicit a behavioral response, demonstrating that this predator benefits from the change by discriminating between undamaged plants and plants damaged by both herbivores by being more attracted to volatiles released when the plant is damaged by C. bidens. These finding provides critical information that may be used to move towards a more sustainable management of the pest.