The California Department of Food and Agriculture grants the public opportunities to comment on proposed pest ratings.

The following categories of pest rating proposals are available for comment: Insects, Mites and Earthworms; Nematodes; Plant Pathogens; Snails and Slugs; Vertebrate Pests; and Weeds.

Insects and mites are related in that their skeletons are on the outside (Phyllum: Arthropoda), but differ in that adult insects have six legs and adult mites have eight. Both groups can be beneficial, neutral or destructive to their environment. Like nematodes, they can cause yearly losses in the billions of dollars for agricultural crops around the world.

Nematodes (also called ‘roundworms’) are relatively small, multicellular, worm-like animals. They are found in almost every environmental niche imaginable, living free in soil, marine and freshwater habitats while feeding on bacteria, fungi, and nematodes, or as parasites of humans, insects, fish, larger animals and plants.

Plant parasitic nematodes are abundant in many soils and may be feed on roots and other below ground plant tissue as external feeders while living outside a plant or penetrate and enter plant tissue to live and feed internally causing damage to plants. While most species of plant parasitic nematodes feed on below ground plant tissue, a relatively fewer number may inhabit and feed on above ground tissue. Billions of dollars in losses to agricultural crops due to damages caused by plant parasitic nematodes occur worldwide every year. California's agricultural industry could lose several hundred million dollars annually in crop losses if certain plant parasitic nematodes not known to occur or of limited occurrence in California would become widespread within the State.

Plant diseases can be caused by several pathogenic microorganisms including fungi, bacteria, viruses, viroids, phytoplasmas and plant parasitic nematodes. In California, several plant pathogens have evolved with native plants and consequently, caused little damage. However, many other pathogens are either not present or have only been newly discovered within the State. Without effective regulations in place, exotic pathogens may gain entry into California from other global regions through imported contaminated plant and soil commodities, and detrimentally impact the State’s agriculture and natural environments.

Snails and slugs are among the most bothersome pests in many gardens and landscapes. They feed on a variety of living plants and on decaying plant matter. They chew irregular holes with smooth edges in leaves and flowers and can clip succulent plant parts. They also can chew fruit and young plant bark.

The brown garden snail, Cornu aspersum (formerly Helix aspersa), is the most common snail causing problems in California gardens. It was introduced from France during the 1850s for use as food. Another troublesome snail is the white garden snail, Theba pisana.

Several species of slugs also cause damage including the gray garden slug (Deroceras reticulatum, formerly Agriolimax meticulatus), the banded slug (Lehmannia poirieri), the three-band garden slug (L. valentiana), the tawny slug (Limacus flavus), and the greenhouse slug (Milax gagates).

Source: UC IPM Online

Vertebrate pests are any species of mammal, bird, reptile, amphibian, or fish that causes damage to agricultural, natural, or industrial resources, or to any other resource, and to the public health or safety. Vertebrate pests cause millions of dollars in damage to agricultural crops, transportation infrastructure, water conveyance and restoration lands each year. Vertebrate pests threaten the public health and the environment as vectors of diseases that could be transmitted to humans, livestock and wildlife.

Weeds are simply an unwanted plant in the wrong place, at the right time. The weeds can directly and indirectly impact agricultural crops and are just as costly to the environment as any other unwanted species.