Voles are small rodents and common garden pests. Unlike moles, which primarily eat insects, voles are herbivores focused on plant material. Voles do eat tomatoes, targeting the fruit, stems, and especially the roots of the plants. They are a significant problem because they often work underground, making damage difficult to detect until it is too late.
The Vole Diet and Tomato Damage
Voles consume a wide variety of plants, making tomato plants a tempting food source. They often chew on fruit close to the ground, leaving small, ragged holes. The most destructive feeding occurs beneath the soil line where voles consume the plant’s root system. This root damage causes healthy tomato plants to suddenly wilt and collapse without obvious injury above the surface.
Voles may also girdle the lower stem just above or below the soil line by gnawing away the bark and cambium layer. This damage leaves characteristic irregular gnaw marks that are about 1/16 to 1/8 of an inch wide. A plant girdled all the way around is cut off from its root system and will rapidly die because it can no longer absorb water and nutrients.
Identifying Vole Presence in the Garden
Confirming a vole problem requires looking for specific signs rather than relying solely on plant damage. The most distinctive feature of vole activity is the presence of surface runways. These are narrow, clipped paths, typically one to two inches wide, through the grass or mulch that voles use repeatedly between their burrows and feeding areas.
The entrances to their underground burrows are small, numerous holes, usually about an inch in diameter, that are left open. They are not surrounded by a cone or fan-shaped mound of dirt, which differs from the tunnels of gophers or the mounds created by moles. Small, dark-colored droppings, about a quarter to three-quarters of an inch long, may also be found within these runways.
Protecting Tomato Plants from Voles
Protecting tomato plants relies heavily on exclusion and making the garden less appealing to the pests. Before planting, create a wire-mesh basket for the root ball of each plant using one-quarter-inch hardware cloth. This barrier should extend a few inches above the soil line and be buried at least six to ten inches deep to prevent voles from accessing the roots.
Cultural controls eliminate the cover voles need to avoid predators, as they dislike being exposed in open areas. Keep the grass surrounding your garden closely mowed and remove heavy layers of mulch, weeds, or plant debris that provide sheltered travel routes. Repellents, such as those containing castor oil, can deter burrowing, though they often require reapplication after rain. In cases of severe infestation, setting mouse snap traps baited with peanut butter along the identified runways can help reduce the population.