The harmfulness of thrips (Thysanoptera: Terebrantia) to seed lucerne.
The damage caused to seed lucerne by Thysanoptera was studied in the field in southern Moravia, Czechoslovakia, on a cloned genotype originating from the cultivar Bobrava to reduce natural variability in seed yield and its effect on the evaluation of experimental replications and variants. The 3 species found damaging lucerne flowers were Odontothrips confusus, Thrips flavus and Frankliniella intonsa. Individuals of the predacious species Aeolothrips intermedius were also found in the flowers. When plants were kept more or less free from infestation by a chemical screen (0.2% Actellic [pirimiphos-methyl]), the number of pods forming per inflorescence averaged 8.1 in the treated variant and 4.1 in the untreated one, the number of inflorescences without pods averaged 1.27 and 8.5, respectively, and the seed yield per stem averaged 1.456 and 0.4275 g. The total seed yield from the treated plants was 242.8% higher than that from untreated ones.