Development of sustainable plant protection strategies for control of fruit crop psyllids by innovative formulated semiochemicals combined with an entomopathogenic fungus

Psyllids are widespread worldwide and cause damage to various fruit crops as vector insects for phytoplasmoses. As the use of insecticides is increasingly limited, alternative agents and control strategies are coming into focus. Entomopathogenic fungi from the order Entomophthorales are known for their high host specificity and rapid speed-to-kill and are therefore considered a promising alternative to conventional synthetic insecticides. Despite their potential for pest control, no insecticide based on these fungi has been established to date. This can be attributed to difficult cultivability, and to low infection rates in field trials, due to insufficient humidity conditions and the lack of contact between target insect and entomopathogenic fungus (Hajek et al., 2012).
In addition to its advantage, the high host specificity in particular also poses a challenge, since a specific fungal isolate is not available for every insect. Recently, an entomophthorales fungus of the genus Pandora was isolated from a psyllid for the first time by Jensen et al. (2018). The BMEL-funded collaborative project PICTA-KILL aims to make this new Pandora species usable for biological psyllid control in Central European orchards and practically applicable through a suitable formulation.
In infection trials under laboratory conditions, the target insects Cacopsylla picta and C. pyri were successfully infected and killed by the encapsulated fungus. In addition, attractive semiochemicals were encapsulated to attract the respective leaf-sucking insects. The combination of both types of capsules will be used as an attract-and-kill strategy in the future. Initial tests in the field have already been promising.