Slugs as an example of a new and growing threat to crops in Poland.

Abstract

One of the most important group of agricultural pests that present an increasing threat to cultivated plants are the pulmonates (Gastropoda: Pulmonata), and in particular slugs. Since the mid 1990s an increase in the development of pest populations of some of slug species and increasing crop damage have been reported. Apart from the native species such as Deroceras reticulatum, invasive slug species are becoming of a great importance. This refers primarily to the slug species Arion lusitanicus, which was discovered in Poland in 1993 near Rzeszow, and currently is spread out in ten provinces. The greatest damage is caused by D. reticulatum in the case of agricultural crops, and A. lusitanicus in the case of horticultural crops. Irrespective of the species mentioned above, plants are often damaged by A. rufus, A. distinctus, A. subfuscus, D. laeve and Limax maximus. The greatest economic losses due to slug grazing are especially observed in winter rape, winter wheat and some vegetable crops. Locally, a high level of damage is also reported in the following crops: potato, beetroot, brassicas and root plants. In 1996–2010 the greatest threat to crops by slugs were in the southern and north-western parts of the country. The research results indicated that in the nearest years, the protection of small-area crops against the slug A. lusitanicus and winter rape and winter wheat against D. reticulatum may be regarded as a critical challenge.