Host suitability of cash and catch crops for Pentastiridius leporinus (Hem., Cixiidae)
by Justus Detring
Date of Examination:2022-02-23
Date of issue:2025-08-18
Advisor:Prof. Dr. Michael Rostás
Referee:Prof. Dr. Michael Rostás
Referee:Prof. Dr. Mark Varrelmann
Persistent Address:
http://dx.doi.org/10.53846/goediss-11449
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Abstract
English
The “syndrome des basses richesses” (SBR) of sugar beet is an increasing economic threat to the sugar beet value chain in Europe. The causal agents for SBR are predominantly transmitted by P. leporinus. Insect vector control constitutes an important opportunity for SBR disease management. Recent field trials have shown that P. leporinus populations can be reduced by adapting sugar beet winter wheat crop rotations. Accordingly, differing per-formances of P. leporinus nymphs on different crop species were hypothesized. In this hy-pothesis, cultivating crops after sugar beet which show weak nymphal performances may disrupt the life cycle of P. leporinus in fields. A suitable in vitro method to investigate the host suitability of crops with similar plant development to field cultivation was missing. Therefore, a new in vitro method was designed to investigate the host suitability of crops during plant vegetation. In summary, three experiments were conducted to investigate the host suitability of wheat, maize, soybean, mustard and ramtilla for P. leporinus. The perfor-mance of 150 and accordingly 750 P. leporinus nymphs, evenly distributed on 30 repetitions per crop species were analyzed in two no choice experiments on crop seedlings and plants during vegetation. Additionally, the oviposition behavior of P. leporinus was investigated in a choice experiment. The differing nymphal performances of P. leporinus on different crop species could be confirmed. In fact, P. leporinus nymphs showed a low survival rate on soybean seedlings (6%) and no survival on soybean plants during vegetation. Additionally, P. leporinus nymphs did not survive on mustard seedlings and had a low mean survival rate on mustard plants during vegetation (25.4%). Nymphal performances on maize were con-tradictory in the performance experiments. The survival rate of P. leporinus nymphs on maize seedlings was 70%. In the performance experiment during maize vegetation, no nymphs survived. The performance experiment on crops during plant vegetation may have provided more reliable results because of the greater resemblance of plant development to field cultivation. This research is the first to show low survival rates of P. leporinus nymphs on soybean and mustard cultivars and successfully conducted a new in vitro method to in-vestigate host suitability of crops during plant vegetation for P. leporinus. The designed method allows a pre-screening which can tremendously increase the efficacy of extensive field experiments. Furthermore, host suitability of ramtilla is suggested. The mean survival rate of nymphs on ramtilla plants during vegetation (83.3%) and the oviposition initiation of adults in this treatment hypothesized ramtilla as a host plant for P. leporinus. This proposes to exclude ramtilla from catch crop mixtures in P. leporinus infested areas. Olfactory stimuli from sugar beet plants in the oviposition choice experiment may have prohibited differentia-tion of treatment and sugar beet plants during oviposition site selection of P. leporinus. This could mark a starting point for further research on P. leporinus oviposition behavior.
Keywords: Syndrome "Basses Richesses"; pest management; sugar beet; dead-end host; oviposition; plant herbivore interactions
