B. Introduction to plant pests. Four main groups of pests include weeds, invertebrates, vertebrates, and disease agents. Most weeds produce a large number of seeds. Some weed seeds can remain dormant in the soil for 20 years before germinating. Weeds can be persistent and difficult to eradicate, because some have vegetative means of reproduction in addition to seeds.
Weeds compete with agricultural crops for water, nutrients, light and space.
Some weeds are toxic to livestock. A simple way to identify weeds is to compare them to colored photographs and drawings. To identify weeds yourself, become familiar with plant classification system and the weeds physical features, developmental stages, and life cycles. We will discuss weed control within the next few topics. Invertebrate pests include insects and their relatives, nematodes, snails and slugs.