Development and harmfulness of Tychius quinquepunctatus L. (Coleoptera, Curculionidae) in pea crops in the southeast of the Central Chernozem Region

The biology, phenology, and harmfulness of the weevil Tychius quinquepunctatus L. in pea crops were studied for many years in the southeast of the Central Chernozem Region. The species showed a highly uneven distribution in Kamennaya Steppe, with preference for the early and short-stemmed pea varieties. A high pest density focus was found with heavy damage to the pea plants in the marginal field zone where 20–30% of the seeds were damaged; the yield loss may be as high as 6%. In later pea crops, T. quinquepunctatus appears at earlier phases of the plant development, oviposition and larval development proceed at higher rates, the damage to the crops increases, and the necessity of control measures against the weevil grows. Effective protection from T. quinquepunctatus in the crops with optimum sowing time may be achieved with a many-target insecticidal treatment at the budding phase.